From mcd at goshenarc.org Mon Jan 1 00:10:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 19:10:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010015 SWOMCD SPC MCD 010014 MIZ000-OHZ000-INZ000-ILZ000-010215- MESOSCALE DISCUSSION 0001 NWS STORM PREDICTION CENTER NORMAN OK 0614 PM CST SUN DEC 31 2006 AREAS AFFECTED...NE IL...NRN IN...SRN LWR MI CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010014Z - 010215Z ONGOING CONVECTIVE CLUSTER...OCCURRING NEAR CYCLONIC VORTICITY CENTER ASSOCIATED WITH COLD CORE OF NORTHEASTWARD ACCELERATING UPPER LOW...HAS BEEN GENERATING STRONG GUSTY WINDS APPROACHING SEVERE LIMITS. PEAK GUSTS NEAR/IN EXCESS OF 40 KTS HAVE BEEN RECORDED AT BLOOMINGTON/CHAMPAIGN AND MATTOON...LIKELY IN RESPONSE TO EVAPORATIVE COOLING/DOWNWARD MOMENTUM TRANSFER IN STRONGER DOWNDRAFTS. THOUGH DAYTIME SURFACE HEATING HAS BEEN WEAK... LOWER/MID TROPOSPHERIC COOLING/DRYING AHEAD OF MAIN SURFACE FRONT HAS CONTRIBUTED TO VERY STEEP LOW-LEVEL LAPSE RATE ENVIRONMENT SUPPORTING THIS PROCESS...WHICH MAY NOT BE APPRECIABLY AFFECTED BY LOSS OF DAYTIME HEATING. THUS...RISK FOR STRONG GUSTY... POTENTIALLY DAMAGING WINDS MAY CONTINUE WITH CONVECTION AS IT SPREADS ACROSS LAFAYETTE IND AREA AND AREAS NEAR/SOUTH OF CHICAGO...THROUGH NORTHERN INDIANA INTO SOUTHERN LOWER MICHIGAN BY LATE EVENING. AS ACTIVITY APPROACHES THE DETROIT AREA TOWARD 04-06Z...MODEL GUIDANCE SUGGESTS STORMS MAY BEGIN TO DIMINISH ASSOCIATED WITH STABILIZATION AS LOW-LEVEL COOLING OVERTAKES COOLING ALOFT. ..KERR.. 01/01/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...IWX...GRR...IND...LOT...ILX... 41118844 41898801 42858666 42978527 42168426 40928502 39738605 39208713 39238780 40038772 40638817 WWWW From mcd at goshenarc.org Thu Jan 4 16:06:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 11:06:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 041610 SWOMCD SPC MCD 041609 LAZ000-041845- MESOSCALE DISCUSSION 0005 NWS STORM PREDICTION CENTER NORMAN OK 1009 AM CST THU JAN 04 2007 AREAS AFFECTED...PORTIONS SRN LA. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 041609Z - 041845Z AIR MASS FCST TO SLOWLY DESTABILIZE ALONG LA COAST NEXT SEVERAL HOURS...INCREASING POTENTIAL FOR SVR. DAMAGING GUSTS AND A FEW TORNADOES ARE POSSIBLE. LAND AREA AFFECTED INITIALLY WILL BE RATHER SMALL AND CONFINED TO IMMEDIATE COAST. HOWEVER...GRADUAL INLAND SHIFT OF POTENTIAL IS POSSIBLE WITH TIME AS MARINE/WARM FRONT NOW JUST OFFSHORE SHIFTS NWD. SFC MESOANALYSIS INDICATES WEAK FRONTAL-WAVE LOW OVER GULF S BPT AND E GLS...WITH WARM FRONT EWD OVER COASTAL WATERS TOWARD MOUTH OF MS RIVER. COLD FRONT EXTENDS SW OF LOW TO OFFSHORE BRO. BKN PREFRONTAL SQUALL LINE -- EVIDENT AT 1545Z FROM NEAR POE SSEWD ACROSS WARM FRONT...THEN SWWD OVER GULF -- WILL CONTINUE MOVING EWD ACROSS SRN LA. MAIN CONCERN ATTM IS EXTENT OF INLAND PENETRATION OF MARINE SECTOR BEFORE PASSAGE OF PREFRONTAL CONVECTIVE BAND. MORE PRECISE WARM FRONTAL LOCATION IS INDEFINITE...HOWEVER FCST SOUNDINGS INDICATE FRONTAL SLOPE IS VERY SHALLOW. TIME SERIES OF RUC SOUNDINGS INDICATE EFFECTIVE LIFTED PARCELS BECOMING SFC-BASED WITHIN 40-50 NM N OF MODELED WARM FROPA. NEARLY SATURATED LOW-MIDLEVEL AIR MASS AND WEAK LAPSE RATES WILL BE COUNTERBALANCED ALONG AND S OF WARM FRONT BY SFC DEW POINTS MID-UPPER 60S...AND ENOUGH SFC THETAE TO YIELD MLCAPES UP TO 500 J/KG AFTER 18Z. MODIFIED LCH RAOB...VWP DATA AND RUC SOUNDINGS INDICATE FAVORABLE VERTICAL SHEAR PROFILE FOR SUPERCELLS AND BOWS...WITH ROUGHLY 50 KT EFFECTIVE SHEAR AND 0-1 KM SRH POTENTIALLY 250-400 J/KG NEAR WARM FRONT WHERE SFC FLOW IS MOST STRONGLY BACKED. ..EDWARDS.. 01/04/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LIX...LCH... 29749307 29909227 30089082 29959012 29268964 29318993 29089022 29049041 29069068 29069096 29159090 29319134 29409119 29529147 29519155 29649165 29459176 29589206 29539229 29569269 WWWW From mcd at goshenarc.org Thu Jan 4 21:18:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 16:18:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 042123 SWOMCD SPC MCD 042122 ALZ000-MSZ000-LAZ000-042245- MESOSCALE DISCUSSION 0006 NWS STORM PREDICTION CENTER NORMAN OK 0322 PM CST THU JAN 04 2007 AREAS AFFECTED...SERN LA...PORTIONS SRN MS. CONCERNING...TORNADO WATCH 1... VALID 042122Z - 042245Z POTENTIAL CONTINUES FOR INTERMITTENT INTENSIFICATION OF LOW LEVEL MESOCYCLONES...AND ASSOCIATED RISK OF TORNADOES...FROM TSTMS EMBEDDED IN LARGE AREA OF CONVECTION AND PRECIP NOW SHIFTING EWD OVER WW AREA. ISOLATED DAMAGING GUSTS ALSO ARE POSSIBLE FROM WET DOWNBURSTS -- PARTICULARLY WITHIN SUPERCELLULAR REAR-FLANK DOWNDRAFTS OR SMALL BOW/LEWP FORMATIONS. SFC MESOANALYSIS SHOWS DIFFUSE WARM FRONT NOW INLAND BETWEEN ARA-BTR...SEWD ACROSS MSY AREA THEN OFFSHORE MS/AL COASTS. THIS FRONT -- WHICH WILL MAXIMIZE BOUNDARY LAYER VORTICITY...SHEAR AND LIFT -- SHOULD CONTINUE MOVING NEWD OVER REMAINDER SERN LA AND EXTREME SRN MS AHEAD OF MAIN PRECIP BAND. FRONT REMAINS SHALLOW AND SOME EFFECTIVE LIFTED PARCELS CAN BE SFC-BASED TO ITS N. MODIFIED 18Z SIL RAOB...VWP AND RUC SOUNDINGS INDICATE FAVORABLE SHEAR PROFILES...WITH 0-1 KM SRH 150-300 J/KG AND 0-6 KM SHEAR IN 40-50 KT RANGE. BOUNDARY LAYER THETAE OFFSETS WEAK DEEP-LAYER LAPSE RATES TO YIELD MRGL BUT STILL POTENTIALLY SUFFICIENT BUOYANCY...WHICH WILL CONTINUE TO DECREASE WITH NWD EXTENT. MLCAPES UP TO 500 J/KG WILL REMAIN POSSIBLE OVER WW AREA...ESPECIALLY E OF PRECIP SHIELD WHERE WEAK SFC HEATING AND WAA HAVE BOOSTED TEMPS TO NEAR 70 F. ..EDWARDS.. 01/04/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX...LCH... 29499179 29609201 30089183 30709138 31369043 31399000 31148952 30918900 30228837 30228893 29958881 29558899 29398929 29188899 28928941 29208948 29328981 29079018 29039039 29109052 29029085 29339134 29479122 29549149  From mcd at goshenarc.org Fri Jan 5 00:31:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 19:31:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050035 SWOMCD SPC MCD 050034 LAZ000-MSZ000-050200- MESOSCALE DISCUSSION 0007 NWS STORM PREDICTION CENTER NORMAN OK 0634 PM CST THU JAN 04 2007 AREAS AFFECTED...SE LA CONCERNING...TORNADO WATCH 1... VALID 050034Z - 050200Z THE THREAT FOR TORNADOES WILL CONTINUE ACROSS SOUTHEAST LA AS A LINE OF THUNDERSTORMS MOVES EWD ACROSS THE CNTRL PART OF TORNADO WATCH 1. ALTHOUGH TORNADOES WILL BE THE MOST LIKELY THREAT...ISOLATED WIND DAMAGE MAY ALSO OCCUR. AREAS IN SRN MS WILL CONTINUE TO BE MONITORED FOR NEW WW ISSUANCE LATER THIS EVENING. LATEST SFC ANALYSIS SHOWS A MESO-LOW CENTERED JUST NORTH OF BATON ROUGE LA. A COLD FRONT EXTENDS SWD FROM THE LOW WITH A WARM FRONT LOCATED NEWD ACROSS CNTRL MS. A LINE OF THUNDERSTORMS IS LOCATED FROM THE LOW EXTENDING SWD TO AREAS JUST OFF THE COAST FROM MORGAN CITY LA. AHEAD OF THE LINE...THE SFC DEWPOINT AT BATON ROUGE HAS RISEN A FEW DEGREES F OVER THE LAST FEW HOURS INTO THE UPPER 60S F. THIS INDICATES THAT LOW-LEVEL MOISTURE JUST AHEAD OF THE LINE MAY BE ENHANCING INSTABILITY SOMEWHAT. IN ADDITION...A 45 KT LOW-LEVEL JET IS SHOWN BY OBJECTIVE ANALYSIS IN SRN MS WHICH IS RESULTING IN STRONG LOW-LEVEL FLOW OVER SE LA. LOW-LEVEL WIND PROFILES ON WSR-88D VWPS IN THE NEW ORLEANS LA AREA CONTINUE TO SHOW ADEQUATE DIRECTIONAL SHEAR IN THE BOUNDARY LAYER AND 40 KT OF FLOW AT 1 KM. THIS AMOUNT OF SHEAR WILL BE FAVORABLE FOR TORNADOES WITH ROTATING STORMS IN THE LINE OVER THE NEXT FEW HOURS. THE STRONGEST THUNDERSTORMS MAY SHIFT INTO THE COASTAL AREAS WHERE INSTABILITY MAY BE LOCALLY ENHANCED. WIND DAMAGE WILL ALSO BE POSSIBLE WITH THE MORE ORGANIZED STORMS. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LIX...LCH... 28828988 28899100 29349148 30019135 30529121 30829083 30658976 30238937  From mcd at goshenarc.org Fri Jan 5 02:29:16 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 21:29:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050233 SWOMCD SPC MCD 050233 ALZ000-MSZ000-LAZ000-050400- MESOSCALE DISCUSSION 0008 NWS STORM PREDICTION CENTER NORMAN OK 0833 PM CST THU JAN 04 2007 AREAS AFFECTED...SE LA...SRN MS CONCERNING...TORNADO WATCH 1... VALID 050233Z - 050400Z THE TORNADO THREAT WILL CONTINUE FOR THE REMAINDER OF THE EVENING ACROSS SE LA AND SRN MS. A TORNADO WATCH WILL BE ISSUED SHORTLY TO REPLACE TORNADO WATCH 1. A LINE OF THUNDERSTORMS IS LOCATED FROM NEAR LAKE PONCHARTRAIN EXTENDING SWD TO THE LA COAST. ALTHOUGH THIS LINE HAS WEAKENED SOME OVER THE LAST HOUR...THE WIND SHEAR ENVIRONMENT SHOWN ON WSR-88D VWPS IN THE NEW ORLEANS AREA STILL APPEARS FAVORABLE FOR TORNADOES. AS THE LINE MOVES EWD LATE THIS EVENING...AN ISOLATED TORNADO THREAT WILL EXIST WITH ROTATING CELLS IN THE LINE. ALSO...A WIND DAMAGE THREAT MAY EXIST WITH THE MORE-ORGANIZED ROTATING STORMS. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX... 29578832 29068854 28808986 29309038 30409036 31109023 31528962 31278823  From mcd at goshenarc.org Fri Jan 5 04:52:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 23:52:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050456 SWOMCD SPC MCD 050456 ALZ000-MSZ000-LAZ000-050630- MESOSCALE DISCUSSION 0009 NWS STORM PREDICTION CENTER NORMAN OK 1056 PM CST THU JAN 04 2007 AREAS AFFECTED...SRN AND CNTRL MS...SE LA CONCERNING...TORNADO WATCH 2... VALID 050456Z - 050630Z THE TORNADO THREAT WILL CONTINUE ACROSS TORNADO WATCH 2 OVER THE NEXT SEVERAL HOURS. ALSO...THE TORNADO THREAT SHOULD EXPAND ENEWD CNTRL MS. A LINE OF THUNDERSTORMS IS INCREASING IN INTENSITY AND IS LOCATED ALONG THE INTERSTATE 55 CORRIDOR FROM NEAR LAKE PONTCHARTRAIN IN SE LA NWD INTO SWRN MS. LATEST SFC ANALYSIS SHOWS THAT DEWPOINTS AHEAD OF THE LINE HAVE RISEN OVER THE LAST HOUR WITH JACKSON MS AND MERIDIAN MS BOTH AT 66 F. THIS IS A RESULT OF SSELY FLOW NEAR THE SFC WHICH IS TRANSPORTING LOW-LEVEL MOISTURE NWD ACROSS SCNTRL MS. IN ADDITION...A 45 KT LOW-LEVEL JET IS LOCATED ACROSS SCNTRL MS WHICH IS CREATING VERY STRONG LOW-LEVEL SHEAR PROFILES. ALTHOUGH INSTABILITY IS RELATIVELY WEAK...THE SHEAR PROFILES COMBINED WITH LCL HEIGHTS BELOW 500 METERS WILL BE FAVORABLE FOR ROTATING STORMS AND TORNADOES AS THE CONVECTIVE LINE MOVES EWD TONIGHT. WIND DAMAGE WILL ALSO BE POSSIBLE WITH THE BETTER ORGANIZED STORMS EMBEDDED IN THE LINE. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...MOB...JAN...LIX... 28968894 29018994 29359021 30639032 32049026 32718992 32718857 32238833 30958825 29358838  From mcd at goshenarc.org Fri Jan 5 06:43:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 01:43:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050647 SWOMCD SPC MCD 050647 FLZ000-GAZ000-ALZ000-TNZ000-MSZ000-050715- MESOSCALE DISCUSSION 0010 NWS STORM PREDICTION CENTER NORMAN OK 1247 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN MS/MUCH OF AL/WRN FL PANHANDLE CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 050647Z - 050715Z NEW TORNADO WATCH WILL BE NEEDED SOON TO THE E AND NE OF WW 2. REGIONAL RADARS INDICATED WELL DEFINED SQUALL LINE EXTENDING FROM CENTRAL MS SSEWD INTO SERN MS...WITH THIS LINE MOVING TO THE ENE AT 40 KT. STRONG ASCENT/FORCING AHEAD OF UPPER TROUGH...NOW MOVING INTO LOWER MS VALLEY...WILL MAINTAIN THIS SQUALL LINE AS IT MOVES INTO DOWNSTREAM DESTABILIZING AIR MASS. SLY LOW LEVEL WINDS /40-50 KT LLJ/ WILL SUPPORT FURTHER MOISTURE INFLUX AND ALSO ENHANCE LOW LEVEL SHEAR FOR A CONTINUED POTENTIAL OF ROTATING STORMS. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...OHX...BMX...HUN...MOB...MEG...JAN... 29538767 30468767 31868809 32908834 34958880 35038797 34998659 34988559 32738495 30588489 29398488  From mcd at goshenarc.org Fri Jan 5 08:22:07 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 03:22:07 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050826 SWOMCD SPC MCD 050826 ALZ000-MSZ000-LAZ000-050930- MESOSCALE DISCUSSION 0011 NWS STORM PREDICTION CENTER NORMAN OK 0226 AM CST FRI JAN 05 2007 AREAS AFFECTED...FAR SERN LA/FAR SERN MS/SW-W CENTRAL AL CONCERNING...TORNADO WATCH 2... VALID 050826Z - 050930Z THREAT FOR TORNADOES AND DAMAGING WINDS WILL CONTINUE TO SPREAD FROM FAR ERN PARTS OF WW 2 INTO WW 3 THROUGH 09-0930Z. REGIONAL RADARS SHOWED WELL DEFINED SQUALL LINE EXTENDING FROM EAST CENTRAL MS /30 W CBM/ SSEWD ALONG SRN PART OF MS/AL BORDER TO 45 SE GPT. AIR MASS IMMEDIATELY DOWNSTREAM OF THIS SQUALL LINE CONTINUES TO DESTABILIZE BY WAA AND NWD MOISTURE ADVECTION...WHILE STRONG ASCENT AHEAD OF LOWER MS VALLEY TROUGH MAINTAINS INTENSITY OF SQUALL LINE. IN ADDITION TO DAMAGING WIND THREAT WITH THE SQUALL LINE... STRONG LOW LEVEL SHEAR /DIRECTIONAL AND SPEED SHEAR/...WITH 08Z MOB VAD INDICATING 0-1 KM SRH VALUES EXCEEDING 300 M2/S2...WILL MAINTAIN THREAT FOR ISOLATED TORNADOES EMBEDDED WITHIN THE LINE. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...MOB...JAN...LIX... 29499041 30578951 31138860 32168868 32938920 32918836 32228845 32278790 29808779 28668894 28648984 28769054  From mcd at goshenarc.org Fri Jan 5 09:09:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 04:09:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050913 SWOMCD SPC MCD 050913 FLZ000-GAZ000-ALZ000-MSZ000-051015- MESOSCALE DISCUSSION 0012 NWS STORM PREDICTION CENTER NORMAN OK 0313 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN MS/MUCH OF AL/WRN FL PANHANDLE CONCERNING...TORNADO WATCH 3... VALID 050913Z - 051015Z THREAT FOR TORNADOES AND DAMAGING WINDS TO PERSIST ACROSS PARTS OF NERN MS AND MUCH OF AL TO THE WRN FL PANHANDLE DURING THE EARLY MORNING HOURS. REGIONAL RADARS INDICATED A SQUALL LINE WITH EMBEDDED SUPERCELLS EXTENDING SWD THROUGH WRN AL FROM LAMAR COUNTY...WITH THE NRN PART OF THE LINE MOVING NEWD AT 40-45 KT. DISCRETE STORMS HAVE ALSO DEVELOPED EAST OF THE SQUALL LINE ACROSS CENTRAL AND SRN AL FROM BIBB TO DALLAS TO CONECUH COUNTIES...WITH THESE STORMS MOVING NWD AT 45-50 KT. EXTENSIVE AREA OF SURFACE PRESSURE FALLS FROM NERN MS TO CENTRAL AL/ WRN GA IS MAINTAINING SELY SURFACE WINDS ACROSS MUCH OF AL AND ENHANCING LOW LEVEL SHEAR FOR STORM ROTATION AND CONTINUED TORNADO POTENTIAL. IN ADDITION...RECENT DEVELOPMENT OF SURFACE PRESSURE RISE/FALL COUPLET EXTENDING RESPECTIVELY FROM SRN MS TO CENTRAL AL SUGGESTS THIS PORTION OF THE SQUALL LINE SHOULD MAINTAIN FASTER FORWARD SPEED AND ENHANCED DAMAGING WIND THREAT. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...MEG... 29878805 31618808 32648791 34118823 34328815 34378685 34518554 32238490 29958476 29238499  From mcd at goshenarc.org Fri Jan 5 11:42:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 06:42:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051147 SWOMCD SPC MCD 051146 GAZ000-FLZ000-ALZ000-051245- MESOSCALE DISCUSSION 0013 NWS STORM PREDICTION CENTER NORMAN OK 0546 AM CST FRI JAN 05 2007 AREAS AFFECTED...AL/WRN FL PANHANDLE/PARTS OF GA CONCERNING...TORNADO WATCH 3... VALID 051146Z - 051245Z THREAT FOR TORNADOES...MAINLY EMBEDDED WITHIN THE SQUALL LINE...AND THREAT FOR DAMAGING WINDS TO CONTINUE TO SPREAD EWD ACROSS AL AND THE WRN FL PANHANDLE. NEW WW MAY BE NEEDED BY 13-14Z TO THE EAST OF WW 3. AT 11Z...REGIONAL RADARS INDICATED A SQUALL LINE EXTENDING FROM NORTH CENTRAL AL /ERN CULLMAN AND BLOUNT COUNTIES/ SWD INTO SRN AL AND THE WRN FL PANHANDLE /ESCAMBIA AND SANTA ROSA COUNTIES/. CURRENT SPEED OF THIS LINE /EWD AT 25 KT/ SUGGESTS IT WILL MOVE THROUGH THE NERN AND EAST CENTRAL PARTS OF AL BY 14Z...AND REACH THE SERN PART OF AL AND CENTRAL FL PANHANDLE BY 15Z. LOW LEVEL WAA AND RICH MOISTURE /SURFACE DEWPOINTS IN THE LOW-MID 60S/ WILL CONTINUE TO SPREAD NWD THROUGH ERN AL AND GA IN ADVANCE OF THE SQUALL LINE THIS MORNING. LOW LCLS WITHIN THE MOIST AIR MASS AND SELY SURFACE WINDS...BENEATH DEEP SSWLY FLOW...ENHANCING LOW LEVEL SHEAR VALUES WILL MAINTAIN THREAT FOR TORNADOES...ESPECIALLY WITH EMBEDDED ROTATING STORMS ALONG THE SQUALL LINE. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GSP...JAX...FFC...TAE...BMX...HUN...MOB... 29658833 31238718 33158652 34528673 34598496 34558357 33198291 31508297 30418343 29088448  From mcd at goshenarc.org Fri Jan 5 14:59:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 09:59:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051502 SWOMCD SPC MCD 051502 GAZ000-FLZ000-ALZ000-051700- MESOSCALE DISCUSSION 0014 NWS STORM PREDICTION CENTER NORMAN OK 0902 AM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST AL....GA...FL PANHANDLE CONCERNING...TORNADO WATCH 4... VALID 051502Z - 051700Z STRONG TO SEVERE SQUALL LINE WITH EMBEDDED LEWPS/BOWS CONTINUES MOVING EWD/NEWD INTO NRN GA...SERN AL AND THE FL PANHANDLE THIS AM. CONVECTION IS BEING SUPPORTED BY POTENT UPPER SHORT WAVE TROUGH AND 70-75KT MID LEVEL JET STREAK ROTATING THROUGH THE BASE OF THE TROUGH ACROSS THE NCNTRL GULF COAST REGION ATTM. WARM/MOIST BOUNDARY LAYER WAS BEING TOPPED BY MID LEVEL DRY AIR INTRUSION FROM FL INLAND ACROSS SERN AL AND SWRN GA. RESULTING THERMODYNAMIC PROFILE EVIDENT ON TLH RAOB APPEARS VERY CONDUCIVE TO DAMAGING DOWNBURST WINDS ASSOCIATED WITH SMALL-SCALE BOWING SEGMENTS OF CONVECTION EXPECTED TO MOVE ACROSS PARTS OF WALTON AND HOLMES COUNTIES IN THE FL PANHANDLE...LEE...RUSSELL...AND BARBOUR COUNTIES IN SERN AL...AND COWETA COUNTY IN WEST-CNTRL GA...OVER THE NEXT HOUR OR SO. CELL MERGERS AND STORM SCALE INTERACTIONS WILL ALSO RESULT IN AN ENHANCED TORNADO THREAT WITH THIS ACTIVITY OVER THE NEXT TWO HOURS. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...FFC...TAE...BMX...MOB... 34058516 33918268 33138234 29628419 29828671 30038686 30698758 33458581 WWWW From mcd at goshenarc.org Fri Jan 5 17:03:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 12:03:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051707 SWOMCD SPC MCD 051706 SCZ000-GAZ000-051700- MESOSCALE DISCUSSION 0015 NWS STORM PREDICTION CENTER NORMAN OK 1106 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN GA...NWRN SC CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 051706Z - 051700Z STRONGLY FORCED LINE OF TSTMS SHOULD CONTINUE TO MOVE ENEWD AT UP TO 40KT AND INTO PARTS OF NERN GA/NWRN SC THROUGH THE LATE AFTERNOON. A NEW TORNADO WATCH COVERING PORTIONS OF THESE AREAS WILL LIKELY BE NEEDED SHORTLY. DESPITE GENERALLY WEAK INSTABILITY /MUCAPE AROUND 300-400 J PER KG/...STRONG FORCING AND POTENT WIND FIELDS ARE LIKELY TO RESULT IN A CONTINUING THREAT OF DAMAGING WINDS AND ISOLATED TORNADOES AS A STRONG MID LEVEL SHORT WAVE TROUGH EJECTS NEWD ACROSS THE SOUTHEAST U.S. THROUGH TONIGHT. LATEST RUC FORECASTS CONFIRM OBSERVATIONAL DATA THAT SURFACE AIR MASS ACROSS NWRN SC WILL LIKELY SUPPORT SURFACE-BASED CONVECTION WITH DEWPOINTS IN THE LOWER 60S F AND SURFACE TEMPERATURES INTO THE MID 60S. LATEST RUC SOUNDINGS DEPICT INCREASINGLY STRONG LOW LEVEL SHEAR WILL DEVELOP ACROSS THIS REGION OVER THE NEXT FEW HOURS AS STORMS SPREAD ENEWD. SMALL SCALE LEWP/BOW STRUCTURES ALREADY EVIDENT IN THE LINE SHOULD CONTINUE TO POSE A THREAT OF DAMAGING WINDS AND OCCASIONAL/BRIEF TORNADOES. A NEW WATCH WILL BE COORDINATED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 33988108 33938152 34168424 34588404 34808339 35108214 34988105 WWWW From mcd at goshenarc.org Fri Jan 5 17:27:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 12:27:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051731 SWOMCD SPC MCD 051731 GAZ000-SCZ000-FLZ000-ALZ000-051930- MESOSCALE DISCUSSION 0016 NWS STORM PREDICTION CENTER NORMAN OK 1131 AM CST FRI JAN 05 2007 AREAS AFFECTED...GA...EXTREME SERN AL AND THE CENTRAL FL PANHANDLE CONCERNING...TORNADO WATCH 4... VALID 051731Z - 051930Z TORNADO WATCH REMAINS IN EFFECT FOR PORTIONS OF GA...EXTREME SERN AL AND PORTIONS OF THE FL PANHANDLE UNTIL 21Z. AT 1715Z...A SQUALL LINE STRETCHED FROM 40 NE AHN T35 SW AHN TO 10 SE PFN AND WAS MOVING EWD AT 40 KT ON THE NORTH END AND 25-30 KT ON THE SOUTH END. THE SQUALL LINE WAS STRONGLY BOWED ACROSS NRN GA... WITH THE GREATEST POTENTIAL FOR WIND DAMAGE LOCATED ALONG THIS PORTION OF THE LINE. ALTHOUGH THE LINEAR NATURE OF THE STORMS SUGGEST MOSTLY A DAMAGING WINDS THREAT...THE STRONG LOW LEVEL SHEAR AND MLCAPES FROM 500 TO 1000 J/KG ARE SUPPORTIVE OF TORNADOES WITHIN THE LINE...AND ISOLATED STORMS THAT DEVELOP AHEAD OF THE LINE. THE THREAT FOR WIND DAMAGE AND TORNADOES MAY INCREASE ACROSS THE ERN PORTIONS OF THE WW THIS AFTERNOON AS TEMPERATURES AND DEWPOINTS CLIMB A FEW DEGREES HIGHER THAN CURRENT READINGS. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...FFC...TAE... 30028582 32328454 33388377 34138387 33778197 31138343 30008392 29318521  From mcd at goshenarc.org Fri Jan 5 18:12:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 13:12:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051816 SWOMCD SPC MCD 051816 WAZ000-060015- MESOSCALE DISCUSSION 0017 NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CST FRI JAN 05 2007 AREAS AFFECTED...OLYMPIC AND NRN CASCADE MTNS OF WA ABOVE 3000 FT CONCERNING...HEAVY SNOW VALID 051816Z - 060015Z HEAVY SNOW WITH HRLY RATES FROM 1-2 INCHES WILL DEVELOP THROUGH THE AFTERNOON OVER THE OLYMPIC AND NRN CASCADE MTNS OF WA. SNOW LEVELS WILL START OUT AROUND 1500 FT...BEFORE RISING TO AROUND 3500 FT BY 00Z. VERY STRONG WINDS /GUSTS FROM 35-45 MPH/ WILL SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES ABOVE 3500 FT. AS A WARM FRONT CONTINUES TO MOVE STEADILY EWD THROUGH THE AFTERNOON...SNOW LEVELS WILL GRADUALLY RISE THROUGH THE AFTERNOON. STRONG WAA IN ADVANCE OF THIS FRONT WILL SUPPORT CONTINUED SATURATION OF LOW LEVELS AND DEVELOPMENT OF HVY SNOW INTO THE OLYMPICS AND NRN CASCADE MTNS OVER THE NEXT SEVERAL HRS. AS A STRONG UPPER JET ASSOCIATED WITH THE MAIN UPPER TROUGH OFF THE BRITISH COLUMBIA COAST PROGRESSES TOWARD THE REGION LATER THIS AFTERNOON...STRONG UPPER DIVERGENCE COUPLED WITH LOW LEVEL WAA WILL SUPPORT AN INCREASING TREND IN THE SNOWFALL RATES. A WLY WIND SHIFT IN THE WAKE OF THE WARM FRONT WILL SUPPORTING INCREASING UPSLOPE FLOW...WITH SNOWFALL RATES POSSIBLY EXCEEDING 2 INCH/HR ABOVE 3500 FT. THE HEAVIEST SNOWFALL IS EXPECTED TO BEGIN OVER THE NRN CASCADE/OLYMPIC MTNS AFTER 21Z...BEFORE SLOWLY SPREADING SWD THIS EVENING. A STRONG PRESSURE GRADIENT /16 MB OVER WA/ WILL SUPPORT 20-30 MPH SUSTAINED WINDS WITH GUSTS OVER 40 MPH. THESE WINDS MAY SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. ..CROSBIE.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SEW...OTX...PDT... 47932331 48032387 47822410 47542392 47482380 47462365 47602332 47842314 48942176 48962214 48382204 47952188 47552183 47112187 46752158 46732132 47332104 48072112 48992129  From mcd at goshenarc.org Fri Jan 5 18:59:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 13:59:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051902 SWOMCD SPC MCD 051902 COR WAZ000-060015- MESOSCALE DISCUSSION 0017 NWS STORM PREDICTION CENTER NORMAN OK 0102 PM CST FRI JAN 05 2007 AREAS AFFECTED...OLYMPIC AND NRN CASCADE MTNS OF WA ABOVE 3000 FT CONCERNING...HEAVY SNOW VALID 051902Z - 060015Z CORRECTED FOR WEB GRAPHIC HEAVY SNOW WITH HRLY RATES FROM 1-2 INCHES WILL DEVELOP THROUGH THE AFTERNOON OVER THE OLYMPIC AND NRN CASCADE MTNS OF WA. SNOW LEVELS WILL START OUT AROUND 1500 FT...BEFORE RISING TO AROUND 3500 FT BY 00Z. VERY STRONG WINDS /GUSTS FROM 35-45 MPH/ WILL SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES ABOVE 3500 FT. AS A WARM FRONT CONTINUES TO MOVE STEADILY EWD THROUGH THE AFTERNOON...SNOW LEVELS WILL GRADUALLY RISE THROUGH THE AFTERNOON. STRONG WAA IN ADVANCE OF THIS FRONT WILL SUPPORT CONTINUED SATURATION OF LOW LEVELS AND DEVELOPMENT OF HVY SNOW INTO THE OLYMPICS AND NRN CASCADE MTNS OVER THE NEXT SEVERAL HRS. AS A STRONG UPPER JET ASSOCIATED WITH THE MAIN UPPER TROUGH OFF THE BRITISH COLUMBIA COAST PROGRESSES TOWARD THE REGION LATER THIS AFTERNOON...STRONG UPPER DIVERGENCE COUPLED WITH LOW LEVEL WAA WILL SUPPORT AN INCREASING TREND IN THE SNOWFALL RATES. A WLY WIND SHIFT IN THE WAKE OF THE WARM FRONT WILL SUPPORTING INCREASING UPSLOPE FLOW...WITH SNOWFALL RATES POSSIBLY EXCEEDING 2 INCH/HR ABOVE 3500 FT. THE HEAVIEST SNOWFALL IS EXPECTED TO BEGIN OVER THE NRN CASCADE/OLYMPIC MTNS AFTER 21Z...BEFORE SLOWLY SPREADING SWD THIS EVENING. A STRONG PRESSURE GRADIENT /16 MB OVER WA/ WILL SUPPORT 20-30 MPH SUSTAINED WINDS WITH GUSTS OVER 40 MPH. THESE WINDS MAY SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. ..CROSBIE.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW... 48942176 48962214 48382204 47952188 47552183 47112187 46752158 46732132 47332104 48072112 48992129  From mcd at goshenarc.org Fri Jan 5 19:12:53 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 14:12:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051917 SWOMCD SPC MCD 051916 SCZ000-GAZ000-FLZ000-052115- MESOSCALE DISCUSSION 0018 NWS STORM PREDICTION CENTER NORMAN OK 0116 PM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST GA...SRN SC...NRN FL CONCERNING...TORNADO WATCH 4... VALID 051916Z - 052115Z A NEW TORNADO WATCH...ENCOMPASSING PARTS OF SERN GA/NRN FL...AND PERHAPS SRN SC...MAY BE NEEDED IN ABOUT AN HOUR. WIDESPREAD DEEP CONVECTION PERSISTS FROM THE NERN GULF OF MEXICO INLAND ACROSS THE FL PANHANDLE AND SRN/CNTRL GA THIS AFTERNOON. THIS ACTIVITY WAS WITHIN A ZONE OF VERY STRONG DEEP-LAYER ASCENT AHEAD OF A VIGOROUS SHORT WAVE TROUGH EJECTING NEWD ACROSS MA/AL. NRN PART OF THE LARGER SCALE QLCS....FROM NERN GA INTO NWRN SC...HAS RACED NEWD AHEAD OF THE SRN AREA OF WIDESPREAD TSTM ACTIVITY OVER SWRN GA AND FL. THE STRONG CONVECTION ACROSS THESE AREAS HAS BECOME INCREASINGLY EMBEDDED WITHIN LARGER RAIN SHIELD AND HAS LOST SOME LINEARITY OVER THE PAST FEW HOURS. HOWEVER... ISOLATED CELLS ARE OCCASIONALLY DEVELOPING AHEAD OF THE MCS AND HAVE SHOWN A TENDENCY TO ROTATE. A COUPLE OF THE MORE INTENSE CELLS AHEAD OF THE MCS WERE NOTED IN HOUSTON COUNTY GA...AND SOUTH OF FRANKLIN COUNTY FL...IN THE GULF...OVER THE PAST HOUR. WHILE IT APPEARS THAT DEEP CONVECTION MAY HAVE TEMPORARILY OUTRUN STRONGER FORCING ASSOCIATED WITH THE EJECTING UPPER WAVE...THE STRONG DRY PUNCH NOTED ON WATER VAPOR WILL SOON BEGIN TO OVERRUN STRONGER DIURNAL DESTABILIZATION OCCURRING ACROSS NRN FL AND SRN GA. SHEAR ACROSS THESE AREAS IS EXPECTED TO REMAIN SUFFICIENTLY STRONG TO SUPPORT DAMAGING WINDS AND POSSIBLE TORNADOES INTO THE EVENING. THUS...EXPECT A NEW TORNADO WATCH MAY BE NEEDED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...TBW...JAX...FFC...TAE... 29658126 29438321 29488333 29798449 29548516 29618558 30088527 33098322 33278244 33108034  From mcd at goshenarc.org Fri Jan 5 19:27:18 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 14:27:18 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051931 SWOMCD SPC MCD 051930 COR SCZ000-GAZ000-FLZ000-052115- MESOSCALE DISCUSSION 0018 NWS STORM PREDICTION CENTER NORMAN OK 0130 PM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST GA...SRN SC...NRN FL CONCERNING...TORNADO WATCH 4... VALID 051930Z - 052115Z CORRECTED FOR STATE IDENTIFIER MA TO MS A NEW TORNADO WATCH...ENCOMPASSING PARTS OF SERN GA/NRN FL...AND PERHAPS SRN SC...MAY BE NEEDED IN ABOUT AN HOUR. WIDESPREAD DEEP CONVECTION PERSISTS FROM THE NERN GULF OF MEXICO INLAND ACROSS THE FL PANHANDLE AND SRN/CNTRL GA THIS AFTERNOON. THIS ACTIVITY WAS WITHIN A ZONE OF VERY STRONG DEEP-LAYER ASCENT AHEAD OF A VIGOROUS SHORT WAVE TROUGH EJECTING NEWD ACROSS MS/AL. NRN PART OF THE LARGER SCALE QLCS....FROM NERN GA INTO NWRN SC...HAS RACED NEWD AHEAD OF THE SRN AREA OF WIDESPREAD TSTM ACTIVITY OVER SWRN GA AND FL. THE STRONG CONVECTION ACROSS THESE AREAS HAS BECOME INCREASINGLY EMBEDDED WITHIN LARGER RAIN SHIELD AND HAS LOST SOME LINEARITY OVER THE PAST FEW HOURS. HOWEVER... ISOLATED CELLS ARE OCCASIONALLY DEVELOPING AHEAD OF THE MCS AND HAVE SHOWN A TENDENCY TO ROTATE. A COUPLE OF THE MORE INTENSE CELLS AHEAD OF THE MCS WERE NOTED IN HOUSTON COUNTY GA...AND SOUTH OF FRANKLIN COUNTY FL...IN THE GULF...OVER THE PAST HOUR. WHILE IT APPEARS THAT DEEP CONVECTION MAY HAVE TEMPORARILY OUTRUN STRONGER FORCING ASSOCIATED WITH THE EJECTING UPPER WAVE...THE STRONG DRY PUNCH NOTED ON WATER VAPOR WILL SOON BEGIN TO OVERRUN STRONGER DIURNAL DESTABILIZATION OCCURRING ACROSS NRN FL AND SRN GA. SHEAR ACROSS THESE AREAS IS EXPECTED TO REMAIN SUFFICIENTLY STRONG TO SUPPORT DAMAGING WINDS AND POSSIBLE TORNADOES INTO THE EVENING. THUS...EXPECT A NEW TORNADO WATCH MAY BE NEEDED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...TBW...JAX...FFC...TAE... 29658126 29438321 29488333 29798449 29548516 29618558 30088527 33098322 33278244 33108034  From mcd at goshenarc.org Fri Jan 5 20:00:36 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 15:00:36 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052004 SWOMCD SPC MCD 052004 SCZ000-NCZ000-GAZ000-052130- MESOSCALE DISCUSSION 0019 NWS STORM PREDICTION CENTER NORMAN OK 0204 PM CST FRI JAN 05 2007 AREAS AFFECTED...EXTREME NERN GA...SOUTH-CENTRAL NC AND NWRN AND SOUTH CENTRAL SC CONCERNING...TORNADO WATCH 5... VALID 052004Z - 052130Z DAMAGING WINDS AND ISOLATED TORNADOES ARE EXPECTED ACROSS WW INTO THE EVENING HOURS. AT 1950Z...SQUALL LINE EXTENDED FROM NEAR GSP TO 50 N AGS TO 50 SW AGS...MOVING ENEWD AT 35 TO 40 KT. A STATIONARY BOUNDARY EXTENDS FROM THE SQUALL...APPROXIMATELY FROM 50 NW OF CAE TO 40 NE OF CAE. SOUTH OF THE BOUNDARY TEMPERATURES ARE IN THE MID 70S WITH MID TO UPPER 60 DEWPOINTS...WHILE MID 60 TEMPERATURES AND DEWPOINTS IN THE LOWER 60S WERE LOCATED NORTH OF THIS BOUNDARY. GIVEN THE LINEAR NATURE OF THE STORMS...STRAIGHT LINE WIND DAMAGE IS MOST LIKELY WITH THIS LINE. HOWEVER...THE PRESENCE OF THE BOUNDARY...MLCAPES NEAR 1000 J/ AND STRONG LOW/MID LEVEL SHEAR...ISOLATED TORNADOES ARE ALSO POSSIBLE. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...GSP...FFC... 35108263 35408159 35478058 34358043 33298053 33028224 32928303 33928243 34358236  From mcd at goshenarc.org Fri Jan 5 21:17:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 16:17:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052120 SWOMCD SPC MCD 052120 NCZ000-SCZ000-052245- MESOSCALE DISCUSSION 0020 NWS STORM PREDICTION CENTER NORMAN OK 0320 PM CST FRI JAN 05 2007 AREAS AFFECTED...NC PIEDMONT/SANDHILLS AND PART OF NERN SC CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 052120Z - 052245Z NARROW ARC OF LOW-TOPPED STRONG/SEVERE CONVECTION CONTINUES MOVING ENEWD ACROSS UPSTATE SC AND WILL CONTINUE TO MOVE INTO SRN PIEDMONT AREA OF NC OVER THE NEXT HOUR. LATEST TRENDS SUGGEST THAT REFLECTIVITY WITHIN THE LINE HAS WEAKENED. HOWEVER...LARGE SCALE FORCING WILL CONTINUE TO SUPPORT STRONG ASCENT ACROSS NC THROUGH TONIGHT AND ANOTHER DOWNSTREAM WATCH MAY BE NEEDED. DESPITE INTENSITY TRENDS...FORCING ASSOCIATED WITH EXIT REGION OF 50-60KT MID LEVEL JET STREAK WILL CONTINUE TO SPREAD ATOP MOIST AND WEAKLY UNSTABLE AIR MASS ACROSS CNTRL NC AND NERN SC THROUGH THIS EVENING. CURRENT ACTIVITY MOVING INTO CLT AREA IN THE NEXT HALF HOUR WILL BE MONITORED CLOSELY FOR DAMAGING WINDS GIVEN AIR MASS AND LOW LEVEL SHEAR ACROSS THE AREA. GIVEN LATEST TRENDS AND TIME OF DAY...THE OVERALL SEVERE POTENTIAL MAY BE DIMINISHING. HOWEVER...IF ONGOING CONVECTION REMAINS STRONG TO NEAR SEVERE...A NEW WATCH MAY BE NEEDED DOWNSTREAM ACROSS PARTS OF CNTRL NC IN THE NEXT HOUR. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...RAH...ILM...RNK...CAE...GSP... 35548154 35628135 36278058 36437960 35867891 35057915 34407943 34407983 34667981 35448047  From mcd at goshenarc.org Fri Jan 5 21:23:15 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 16:23:15 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052127 SWOMCD SPC MCD 052126 SCZ000-GAZ000-052200- MESOSCALE DISCUSSION 0021 NWS STORM PREDICTION CENTER NORMAN OK 0326 PM CST FRI JAN 05 2007 AREAS AFFECTED...PORTIONS OF SC AND SERN GA CONCERNING...TORNADO WATCH VALID 052126Z - 052200Z A TORNADO WATCH IS BEING COORDINATED FOR PORTIONS OF SERN GA AND COASTAL PLAINS OF SC. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...ILM...CHS...CAE...JAX...FFC... 31868276 32778288 33278040 33387969 33117943 32248054 31418125 WWWW From mcd at goshenarc.org Fri Jan 5 23:31:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 18:31:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052335 SWOMCD SPC MCD 052335 SCZ000-GAZ000-FLZ000-060100- MESOSCALE DISCUSSION 0022 NWS STORM PREDICTION CENTER NORMAN OK 0535 PM CST FRI JAN 05 2007 AREAS AFFECTED...ERN SC...SE GA AND NRN FL CONCERNING...TORNADO WATCH 7... VALID 052335Z - 060100Z A SEVERE THREAT WILL EXIST ACROSS NRN FL...SE GA AND ERN SC OVER THE NEXT FEW HOURS. A FEW TORNADOES AND ISOLATED WIND DAMAGE WILL BE POSSIBLE WITH THE STRONGER THUNDERSTORMS EMBEDDED IN THE LARGE AREA OF RAIN. LATEST SFC ANALYSIS SHOWS A COLD FRONT AND PRE-FRONTAL TROUGH EXTENDING SWD FROM THE SRN APPALACHIAN MTNS TO THE WRN FL PANHANDLE. THE LARGE AREA OF RAIN IS LOCATED WELL AHEAD OF THESE SFC FEATURES AND IS ASSOCIATED WITH A BAROCLINIC LEAF AHEAD OF A NEGATIVELY TILTED UPPER-LEVEL TROUGH. AHEAD OF THE RAIN...SFC DEWPOINTS ARE IN THE MID TO UPPER 60S F AND THE WARM SECTOR IS CHARACTERIZED MOSTLY BY WEAK INSTABILITY. A CENTER OF STRONG VERTICAL SHEAR EXISTS NEAR THE COAST OF GA WHERE OBJECTIVE ANALYSIS SHOWS 0-6 KM SHEAR VALUES OF 65 KT. THIS IS DUE TO STRONG ONSHORE SSELY FLOW AT THE SFC COUPLED WITH A SSWLY MID-LEVEL JET AROUND 60 KT LOCATED IN SE GA. THIS SHEAR ENVIRONMENT WILL CONTINUE TO BE FAVORABLE FOR LOW-TOPPED SUPERCELLS EMBEDDED IN THE LARGE AREA OF RAIN. ISOLATED WIND DAMAGE MAY ALSO OCCUR WITH THE BETTER ORGANIZED THUNDERSTORMS THROUGH EARLY EVENING. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...ILM...CHS...CAE...TBW...JAX... 32108212 33008163 34148028 34427949 33717878 33007965 32058092 30898139 29408165 28968215 29138276 29838274 31158240 WWWW From mcd at goshenarc.org Sat Jan 6 00:41:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 19:41:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060045 SWOMCD SPC MCD 060045 WAZ000-ORZ000-060645- MESOSCALE DISCUSSION 0023 NWS STORM PREDICTION CENTER NORMAN OK 0645 PM CST FRI JAN 05 2007 AREAS AFFECTED...CASCADES OF WA/NRN ORE ABOVE 3500 FT CONCERNING...HEAVY SNOW VALID 060045Z - 060645Z HEAVY SNOW WITH RATES UP TO 2 INCH/HR WILL CONTINUE TO DEVELOP SWD THROUGH WA CASCADES INTO THE NRN ORE CASCADES THROUGH 06Z. SNOW LEVELS WILL CONTINUE TO SLOWLY RISE TO AROUND 3500 FT THROUGH THE EVENING. STRONG WINDS WILL LEAD TO NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. A VERY DYNAMIC SHORTWAVE TROUGH WILL CONTINUE TO APPROACH THE COAST OF SRN BRITISH COLUMBIA AND WA OVER THE NEXT 6 HOURS. AHEAD OF THIS SHORTWAVE...STRONG WARM ADVECTION /PER THE 00Z SLE SOUNDING/ COUPLED WITH STRONG SWLY /UPSLOPE/ LOW LEVEL FLOW AND UPPER LEVEL DIVERGENCE WILL SUPPORT A VERY STRONG VERTICAL MOTION PROFILE OVER WA AND NRN ORE CASCADES DURING THE NEXT 6+ HRS. BASED ON PRESENT SYSTEM MOTION...THE STRONGEST VERTICAL MOTION FIELDS WILL OCCUR OVER THE NRN WA CASCADES THROUGH 06Z...WHILE GRADUALLY DEVELOPING SWD INTO THE SRN WA/NRN ORE CASCADES BETWEEN 03-06Z AS THE UPPER DIVERGENCE MAXIMUM AND MID LEVEL COLD FRONT MOVE SEWD. GIVEN THE STRENGTH OF THE MESOSCALE FORCING...SNOWFALL RATES UP TO 2 INCH/HR WILL BE COMMONPLACE FOR MORE THAN A 6 HR PERIOD ESPECIALLY ACROSS THE WRN SLOPES. SNOWFALL LEVELS /PRESENTLY AROUND 2500 FT/ WILL CONTINUE TO RISE TO AROUND 3500 FT /PER THE UIL 00Z SOUNDING/ OVER THE NEXT FEW HRS UNDER THE PRESENCE OF CONTINUED STRONG WAA. A STRONG SFC PRESSURE/HEIGHT GRADIENT WILL SUPPORT SUSTAINED SSWLY WINDS FROM 20-30 MPH WITH GUSTS OVER 40 MPH...LEADING TO NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST TERRAIN. ..CROSBIE.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW...PQR... 48812098 48792167 48542189 47992186 46982174 46232200 45692206 45242216 44702242 44472205 44512171 45352150 46662104 47682095 48522088  From mcd at goshenarc.org Sat Jan 6 01:57:40 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 20:57:40 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060201 SWOMCD SPC MCD 060201 NCZ000-SCZ000-060330- MESOSCALE DISCUSSION 0024 NWS STORM PREDICTION CENTER NORMAN OK 0801 PM CST FRI JAN 05 2007 AREAS AFFECTED...ERN SC...CNTRL AND ERN NC CONCERNING...TORNADO WATCH 8... VALID 060201Z - 060330Z THE SEVERE THREAT ACROSS TORNADO WATCH 8 WILL INCREASE FROM WEST TO EAST LATE THIS EVENING. A FEW TORNADOES AND ISOLATED WIND DAMAGE WILL BE POSSIBLE WITH THE BETTER ORGANIZED STORMS. A LARGE AREA OF RAIN WITH EMBEDDED THUNDERSTORM ACTIVITY IS LOCATED NEAR GREENSBORO NC EXTENDING SWD ACROSS CNTRL SC. AHEAD OF THE AREA OF RAIN...A MOIST WARM SECTOR EXISTS AND THE AIRMASS HAS BEEN UNTOUCHED ACROSS MOST OF TORNADO WATCH 8 WITH SFC DEWPOINTS REMAINING IN THE MID TO UPPER 60S F. OBJECTIVE ANALYSIS SHOWS THAT MID-LEVEL LAPSE RATES HAVE STEEPENED SOME ACROSS THE SRN PART OF TORNADO WATCH 8 OVER THE LAST FEW HOURS AND THIS MAY BE RESPONSIBLE FOR THE INCREASE IN INSTABILITY SHOWN BY RUC ANALYSIS. IN ADDITION...MODERATE VERTICAL SHEAR EXISTS ACROSS THE WATCH AREA AND THIS SHOULD INCREASE WITH TIME AS A 60 KT MID-LEVEL JET DRIFTS ENEWD INTO THE AREA. FOR THIS REASON...THE SHEAR ENVIRONMENT WILL BECOME INCREASINGLY FAVORABLE FOR ROTATING THUNDERSTORMS OVER THE NEXT 1 TO 2 HOURS. LOW-TOPPED SUPERCELLS WILL BE CAPABLE OF ISOLATED TORNADOES AND WIND DAMAGE LATE THIS EVENING. ..BROYLES.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MHX...RAH...ILM... 33057876 33347975 34377980 34897967 35467952 35737869 35677728 35547632 35067605 34267670  From mcd at goshenarc.org Sat Jan 6 03:12:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 22:12:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060316 SWOMCD SPC MCD 060316 NCZ000-VAZ000-060445- MESOSCALE DISCUSSION 0025 NWS STORM PREDICTION CENTER NORMAN OK 0916 PM CST FRI JAN 05 2007 AREAS AFFECTED...NE NC...SE VA CONCERNING...TORNADO WATCH 8... VALID 060316Z - 060445Z AN AREA OF HEAVY RAIN OVER ERN SC AND CNTRL NC WILL MOVE ENEWD LATE THIS EVENING AFFECTING NE NC AND SE VA AFTER MIDNIGHT. THE REDEVELOPMENT OF THUNDERSTORM ACTIVITY REMAINS POSSIBLE AND A SEVERE THUNDERSTORM POTENTIAL WOULD EXIST AS STORMS ORGANIZE DURING THE OVERNIGHT PERIOD. TORNADO WATCH 8 MAY NEED TO BE REPLACED IF THIS SCENARIO DEVELOPS. A NEGATIVELY TILTED UPPER-LEVEL TROUGH OVER THE SRN APPALACHIAN MTNS WILL CONTINUE TO DRIFT NEWD TOWARD THE REGION TONIGHT. A BAND OF CONVECTION IS LOCATED ALONG THE LEADING EDGE OF LARGE-SCALE ASCENT ASSOCIATED WITH THE APPROACHING TROUGH. AHEAD OF THE CONVECTION...THE AIRMASS REMAINS UNDISTURBED WITH SFC DEWPOINTS IN THE MID TO UPPER 60S F AS FAR NORTH AS RICHMOND VA. IN ADDITION...MODERATE VERTICAL SHEAR PROFILES EXIST ACROSS THE REGION. AS THE UPPER-TROUGH APPROACHES...SHEAR PROFILES SHOULD GRADUALLY STRENGTHEN BECOMING INCREASINGLY FAVORABLE FOR LOW-TOPPED ROTATING STORMS. IF THIS WHERE TO HAPPEN...A THREAT FOR TORNADOES AND ISOLATED WIND DAMAGE WOULD BE POSSIBLE ACROSS THE REGION. ..BROYLES.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...RAH... 35257576 34957706 35487814 36127841 36947820 37457750 37507642 36627555  From mcd at goshenarc.org Sat Jan 6 08:07:34 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 03:07:34 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060811 SWOMCD SPC MCD 060811 VAZ000-NCZ000-060915- MESOSCALE DISCUSSION 0026 NWS STORM PREDICTION CENTER NORMAN OK 0211 AM CST SAT JAN 06 2007 AREAS AFFECTED...SERN VA/NERN NC CONCERNING...TORNADO WATCH 9... VALID 060811Z - 060915Z THREAT FOR ISOLATED TORNADOES AND DAMAGING WINDS TO CONTINUE ACROSS WW 9. ALTHOUGH THE AIR MASS ACROSS SERN VA/NERN NC REMAINS MARGINALLY UNSTABLE...RICH LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE MID- UPPER 60S/ ARE RESULTING IN LOW LCLS WITH THE LOW-TOPPED CONVECTION MOVING NEWD ACROSS THIS REGION. STRONG ASCENT AHEAD OF PROGRESSIVE SHORT WAVE TROUGH...NOW CENTERED FROM SWRN VA TO ERN SC...WILL PROMOTE ADDITIONAL CONVECTIVE DEVELOPMENT OVERNIGHT. DESPITE LACK OF LIGHTNING WITH MUCH OF THIS ACTIVITY...EFFECTIVE BULK SHEAR VALUES REMAIN SUPPORTIVE OF ORGANIZED STORMS. IN ADDITION...0-1 KM SRH VALUES NEAR 200 M2/S2 CONTINUE TO FAVOR STORM ROTATION...SUCH AS THE PERSISTENT ROTATION THAT HAS BEEN OBSERVED PER REGIONAL RADAR MOVING NEWD AND IS NOW LOCATED IN NERN HERTFORD COUNTY NC. ..PETERS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...LWX...RAH... 36147534 35987617 35797706 36297759 36507789 37047796 38027771 37987687 37637584 37227581 37047550 WWWW From mcd at goshenarc.org Sat Jan 6 10:16:18 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 05:16:18 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 061020 SWOMCD SPC MCD 061019 VAZ000-NCZ000-061115- MESOSCALE DISCUSSION 0027 NWS STORM PREDICTION CENTER NORMAN OK 0419 AM CST SAT JAN 06 2007 AREAS AFFECTED...SERN VA/NERN NC CONCERNING...TORNADO WATCH 9... VALID 061019Z - 061115Z SEVERE WEATHER THREAT WILL CONTINUE TO DIMINISH FROM W-E EARLY THIS MORNING ACROSS SERN VA AND NERN NC. REGIONAL RADARS INDICATED AN AREA OF LOW-TOPPED CONVECTION...SOME BECOMING DEEP ENOUGH FOR LIGHTNING PRODUCTION...EXTENDING FROM SERN VA TO NERN NC...AND MOVING EWD AT 30 KT. AT THIS SPEED...MOST OF THE CONVECTIVE ACTIVITY...AND ANY REMAINING SEVERE WEATHER THREAT... SHOULD BE LOCATED EAST OF THE COASTAL AREAS AFTER 11Z. THUS...WW 9 COULD BE CANCELLED PRIOR TO THE 12Z EXPIRATION TIME. ..PETERS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX... 36207541 36007644 36937645 37647626 37617582 37297575 37027550 WWWW From mcd at goshenarc.org Sat Jan 6 20:39:56 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 15:39:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 062043 SWOMCD SPC MCD 062043 MEZ000-NHZ000-062145- MESOSCALE DISCUSSION 0028 NWS STORM PREDICTION CENTER NORMAN OK 0243 PM CST SAT JAN 06 2007 AREAS AFFECTED...PORTIONS SRN/ERN NH...SRN/WRN MAINE. CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 062043Z - 062145Z SEVERAL SHORT LINES OF CONVECTION -- WITH ISOLATED EMBEDDED TSTMS -- MAY PRODUCE GUSTS NEAR SVR LIMITS WITH MINOR DAMAGE. SVR THREAT APPEARS TOO MRGL AND SHORT-LIVED FOR WW. SFC ANALYSIS SHOWS COLD FRONT MOVING EWD FROM VT INTO NH...EXPECTED TO MOVE EWD APPROXIMATELY 30 KT INTO WRN MAINE DURING NEXT 2 HOURS. SHORT/NARROW BANDS OF TSTMS -- INCLUDING ONE WHICH PRODUCED GUST TO 37 KT AROUND 19Z AT BTV -- WILL MOVE THROUGH RELATIVE MAX OF LOW LEVEL TEMPS AND MOISTURE. SFC THETAE AXIS IS EVIDENT ALONG A LINE FROM ORH...LEW...45 NNW AUG. MODIFIED RUC SOUNDINGS INDICATE BUOYANCY MAY EXTEND INTO LOWER LIMITS OF FAVORED THERMAL LAYERS FOR LIGHTNING PRODUCTION...AND A FEW CG STRIKES HAVE BEEN DETECTED OVER PORTIONS NRN VT/NH. POCKETS OF SBCAPES UP TO ABOUT 300 J/KG ARE EVIDENT INVOF THETAE AXIS AND WILL BE MAINTAINED UNTIL CONVECTION MOVES INTO CENTRAL/ERN MAINE...WHERE MARINE AIR WEAKENS SFC-BASED INSTABILITY. MOMENTUM ASSOCIATED WITH STRONG FLOW JUST ABOVE SFC -- E.G. 50-70 KT AT 2-3 KM AGL -- MAY BE TRANSPORTED TO SFC IN MOST VIGOROUS DOWNDRAFTS...ESPECIALLY ON W FACING SLOPES OF HIGHER ELEVATIONS. ..EDWARDS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GYX...BOX... 42927184 43857129 44817085 45167040 44356955 43866996 43657031 43257056 42927081  From mcd at goshenarc.org Sun Jan 7 11:35:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 06:35:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 071139 SWOMCD SPC MCD 071139 WAZ000-071545- MESOSCALE DISCUSSION 0029 NWS STORM PREDICTION CENTER NORMAN OK 0539 AM CST SUN JAN 07 2007 AREAS AFFECTED...OLYMPIC AND NRN/CENTRAL CASCADE MOUNTAINS ABOVE 3500-4000 FEET CONCERNING...HEAVY SNOW VALID 071139Z - 071545Z SNOWFALL IS EXPECTED TO INCREASE IN INTENSITY THIS MORNING...WITH HOURLY RATES UP TO 2 INCH/HOUR LIKELY...AND MAY LOCALLY REACH 3 INCH/HOUR. SNOW LEVELS WILL CONTINUE TO RISE TO AROUND 4000 FEET THROUGH 15Z. STRENGTHENING WLY WINDS SHOULD PRODUCE BLOWING SNOW AND NEAR BLIZZARD CONDITIONS AT TIMES. SNOW LEVELS WILL CONTINUE TO RISE DURING THE EARLY MORNING AS A WARM FRONT MOVES EWD ACROSS THE CASCADES...REACHING CENTRAL WA BY 18Z. PASSAGE OF THE WARM FRONT WILL ALSO RESULT IN STRENGTHENING DEEP LAYER WLY WINDS WITH 50-60 KT LIKELY IN THE LOW LEVELS. THIS UPSLOPE FLOW INTO THE MOUNTAINS COMBINED WITH LOW LEVEL WAA SPREADING EWD BENEATH INCREASING ASCENT WITHIN ENTRANCE REGION OF MID LEVEL JET WILL SUPPORT INCREASING SNOWFALL RATES. IN ADDITION...THE STRONGER FLOW WITH SURFACE WINDS AT 25-35 KT...WITH HIGHER SPEEDS AND GUSTS IN THE VICINITY OF THE CRESTS...WILL LIKELY PRODUCE AREAS OF BLOWING SNOW AND NEAR BLIZZARD CONDITIONS. ..PETERS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW... 48792181 48982111 48592060 47662078 47162150 47442169 47872161 48422171  From mcd at goshenarc.org Sun Jan 7 17:27:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 12:27:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 071731 SWOMCD SPC MCD 071731 GAZ000-ALZ000-FLZ000-MSZ000-072000- MESOSCALE DISCUSSION 0030 NWS STORM PREDICTION CENTER NORMAN OK 1131 AM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS AL...SERN MS...W-CENTRAL GA...WRN FL PANHANDLE. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 071731Z - 072000Z SLOWLY DEVELOPING SVR POTENTIAL EXISTS DURING NEXT 3-4 HOURS ACROSS DISCUSSION AREA...AS SFC GRADUALLY DESTABILIZES. LINEAR AND DISCRETE MODES ARE POSSIBLE...WITH VERTICAL SHEAR PROFILES FAVORABLE FOR SUPERCELLS AND SMALL BOWS. 17Z SFC MESOANALYSIS SHOWS COLD FRONT AND ASSOCIATED CONVECTIVE BAND NEAR LINE FROM BTR-35 NNW TCL...INTERSECTING WARM FRONT THAT EXTENDS ESEWD TO NEAR CSG AND VDI. WARM FRONT SHOULD CONTINUE TO LIFT/REFORM NEWD ACROSS CENTRAL/ERN AL AND WRN GA...CONSOLIDATING AGAINST SRN EDGE OF APPALACHIAN COLD-DAMMING REGIME OVER NERN AL AND N-CENTRAL/NWRN GA BY MID-AFTERNOON. WARM SECTOR LOW LEVEL SHEAR PROFILES WILL REMAIN FAVORABLE INVOF 45-55 KT SWLY LLJ...ANALYZED FROM MS COAST ACROSS NERN AL. HODOGRAPHS WILL BE FURTHER ENHANCED INVOF WARM FRONT WHERE SFC WINDS ARE RELATIVELY WEAK/BACKED. CONVECTION FORMING IN WARM SECTOR AND CROSSING THIS FRONT WILL ENCOUNTER RELATIVE MAXIMA IN SHEAR AND VORTICITY...WITH 0-1 KM SRH IN 250-350 J/KG RANGE. CLOUD BREAKS ARE EVIDENT IN VIS IMAGERY ATTM ACROSS PORTIONS SERN MS AND SRN AL...ALLOWING MORE INSOLATION AND DESTABILIZATION...AND SUPPORTING POTENTIAL TSTM DEVELOPMENT AHEAD OF COLD FRONT ALONG HORIZONTAL ROLLS AND CONFLUENCE LINES. OBSERVED AND RUC SOUNDINGS MODIFIED FOR LOW 70S SFC TEMPS AND 66-68 F DEW POINTS SHOW ALMOST NO CINH AND SBCAPES AROUND 500 J/KG. GRADUAL INCREASE IN BOUNDARY LAYER THETAE ALONG AND S OF WARM FRONT -- THROUGH BOTH ADVECTIVE AND DIABATIC PROCESSES...WILL BOOST THIS MARGINALLY BUOYANT LAYER INTO FAVORABLE THERMAL STRATA FOR LIGHTNING GENERATION. ..EDWARDS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...JAN...LIX... 34348684 34028612 33898565 33678427 32868440 32288467 31408551 30728702 30908944 32458879 34078742  From mcd at goshenarc.org Sun Jan 7 19:58:38 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 14:58:38 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072002 SWOMCD SPC MCD 072001 IDZ000-MTZ000-080130- MESOSCALE DISCUSSION 0031 NWS STORM PREDICTION CENTER NORMAN OK 0201 PM CST SUN JAN 07 2007 AREAS AFFECTED...THE BITTERROOT AND CLEARWATER MTNS OF NRN ID AND FAR WRN MT ABOVE 3500 FT CONCERNING...HEAVY SNOW VALID 072001Z - 080130Z HEAVY SNOW WITH HOURLY RATES IN EXCESS OF 1 INCH IS ANTICIPATED TO DEVELOP SWD OVER THE BITTERROOT AND CLEARWATER MTNS THROUGH 01Z. COMBINED WITH THE HVY SNOW...STRONG WINDS (GUSTING AT TIMES OVER 50 MPH) WILL LEAD TO NEAR BLIZZARD CONDITIONS IN THE HIGHER WEST FACING SLOPES INTO THE EARLY EVENING. A VERY STRONG MID/UPPER LEVEL JET MAX (100 KTS OBSERVED BY THE MISSOULA VWP AT 6KM) WILL CONTINUE TO PROGRESS SEWD. AS A RESULT...WSWLY LOW LEVEL FLOW WILL CONTINUE TO STRENGTHEN OVER ERN WA/NRN ID AND NERN ORE IN AGEOSTROPHIC RESPONSE TO THE RIGHT REAR QUAD OF THIS MID/UPPER LEVEL JET. IN ADDITION TO THE INCREASING WINDS...MODERATE MID LEVEL FRONTOGENESIS WILL AID IN INCREASING MID LEVEL VERTICAL MOTION. THIS WILL SUPPORT MID LEVEL SATURATION...WHICH HAS BEEN SLOW TO OCCUR THROUGH THE MORNING GIVEN THE STRONG DOWNSLOPE FLOW EAST OF THE CASCADES. THE COMBINATION OF STRONG MID LEVEL VERTICAL MOTION (COINCIDENT WITH A DEEP LAYER OF FAVORABLE TEMPERATURES FOR DENDRITIC SNOW GROWTH) AND STRONG (50-70 KTS) UPSLOPE FLOW WILL SUPPORT HVY SNOW DEVELOPMENT OVER THE WRN SLOPES OF THE BITTERROOT AND CLEARWATER MTNS THIS AFTERNOON. GIVEN THE DEGREE OF FORCING...AND MODEST PRECIPITABLE WATER VALUES (OVER 1/2 OF AN INCH PER GOES SOUNDER DATA) SNOWFALL RATES IN EXCESS OF 1 INCH/HR ARE EXPECTED FOR AT LEAST A 3-6 HR PERIOD INTO THE EARLY EVENING. ..CROSBIE.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...MSO...OTX... 47571520 47931582 47761630 47071634 46241556 45411582 45241572 45271535 45351488 45591461 46201432 46761443 WWWW From mcd at goshenarc.org Sun Jan 7 20:47:35 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 15:47:35 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072051 SWOMCD SPC MCD 072051 GAZ000-ALZ000-FLZ000-MSZ000-072215- MESOSCALE DISCUSSION 0032 NWS STORM PREDICTION CENTER NORMAN OK 0251 PM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS SERN MS...AL...WRN FL PANHANDLE...WRN/CENTRAL GA. CONCERNING...TORNADO WATCH 10... VALID 072051Z - 072215Z WW SHOULD CONTINUE ALONG/AHEAD OF MAIN CONVECTIVE LINE...BUT CAN BE CLEARED BEHIND IT DUE TO CAA AND RELATED STABILIZATION. ANOTHER WW MAY BE REQUIRED ACROSS PORTIONS GA. BAND OF STG-SVR TSTMS -- MAINLY ASSOCIATED WITH SFC COLD FRONT -- WILL CONTINUE TO MOVE E ACROSS WW AREA...PRECEDED BY SEVERAL SHORTER CONVECTIVE SEGMENTS WHICH ALSO MAY BECOME SVR. WARM FRONT HAS SHIFTED INTO NERN AL AND NWRN GA...AND SHOULD MOVE INTO PORTIONS ATL AREA BEFORE MAIN TSTM LINE ARRIVES. FAVORABLE DEEP-LAYER VERTICAL SHEAR SHOULD INCREASE WITH TIME ACROSS WRN/NRN GA AS MIDLEVEL HEIGHT GRADIENT TIGHTENS AHEAD OF CENTRAL CONUS TROUGH. WARM SECTOR WINDS WILL REMAIN FAVORABLE WITH 40-50 KT EFFECTIVE SHEAR AND 0-1 KM SRH 150-300 J/KG. 0-1 KM SRH SHOULD BE EVEN HIGHER IN IMMEDIATE VICINITY OF WARM FRONT -- 250-400 J/KG -- WHERE TORNADO POTENTIAL MAY BE RELATIVELY MAXIMIZED. RICH LOW LEVEL MOISTURE IS EXPECTED NEAR WARM FRONT AS WELL WITH SFC DEW POINTS NEAR 70 F JUST TO ITS S...ALTHOUGH MIXING HAS CREATED POCKET OF LOW-MID 60S DEW POINTS FARTHER S OVER SERN AL/SWRN GA/CENTRAL FL PANHANDLE. BUOYANCY WILL REMAIN MARGINAL EVEN IN AREAS OF MAXIMIZED MOISTURE...BECAUSE OF POOR LAPSE RATES ALOFT. HOWEVER...PRIND MUCAPES UP TO 500 J/KG WILL SUPPORT CONTINUED THREAT. ..EDWARDS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...LIX... 34518558 34208494 33938447 33448335 32768312 31928340 31668486 30378706 30458919 31998834 33468692  From mcd at goshenarc.org Sun Jan 7 23:30:36 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 18:30:36 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072334 SWOMCD SPC MCD 072334 GAZ000-SCZ000-080100- MESOSCALE DISCUSSION 0033 NWS STORM PREDICTION CENTER NORMAN OK 0534 PM CST SUN JAN 07 2007 AREAS AFFECTED...N CNTRL THROUGH NERN GA INTO WRN SC CONCERNING...TORNADO WATCH 11... VALID 072334Z - 080100Z THREAT FOR ISOLATED DAMAGING WIND AND PERHAPS AN ISOLATED TORNADO OR TWO WILL EXIST ACROSS NRN GA INCLUDING THE ATLANTA METRO AREA DURING THE NEXT HOUR OR SO. THREAT WILL BECOME MORE MARGINAL WITH ERN EXTENT INTO NERN GA AND WRN SC. PRE-FRONTAL LINE OF STORMS EXTENDS FROM EXTREME SWRN NC SWWD THROUGH N CNTRL GA NEAR ATLANTA AND FARTHER SW INTO SERN AL. PORTION OF THE LINE OVER N CNTRL GA IS MOVING EAST AT 35 KT. A WARM FRONT EXTENDS FROM SRN SC NWWD TO NEAR ATLANTA TO A WEAK SURFACE LOW OVER NWRN GA. DEWPOINTS GENERALLY IN THE LOW TO MID 60S EXIST NEAR AND S O OF THIS FRONT...AND LATEST OBJECTIVE ANALYSIS SHOW MLCAPE FROM 250 TO 500 J/KG. LATEST VWP DATA CONTINUE TO SHOW LARGE LOW LEVEL HODOGRAPHS AND STRONG DEEP LAYER. THREAT FOR BOW ECHOES AND SUPERCELLS WITH LOW LEVEL MESOCYCLONES WILL CONTINUE TO EXIST WITH THUNDERSTORMS WITHIN OR JUST E OF THE LINE. GREATEST SEVERE THREAT WILL PERSIST ALONG AND S OF THE WARM FRONT WHERE STORMS ARE MORE LIKELY TO BE SURFACE BASED. ACTIVITY WILL SHIFT EWD INTO NERN GA AND WRN SC LATER THIS EVENING. HOWEVER...SEVERE THREAT IN THIS REGION IS MORE MARGINAL AND CONDITIONAL UPON NWD BOUNDARY LAYER RECOVERY. ..DIAL.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 33638223 33538386 33728458 34248439 34438245  From mcd at goshenarc.org Mon Jan 8 00:54:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 19:54:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080057 SWOMCD SPC MCD 080057 VTZ000-NYZ000-080700- MESOSCALE DISCUSSION 0034 NWS STORM PREDICTION CENTER NORMAN OK 0657 PM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS OF NRN NY AND NRN/CENTRAL VT ABOVE 1000 FT CONCERNING...WINTER MIXED PRECIPITATION VALID 080057Z - 080700Z MODERATE SNOW WILL DEVELOP NWD ACROSS HIGHER ELEVATIONS OF THE AREA BETWEEN 04-06Z...BEFORE CHANGING OVER TO FREEZING RAIN AROUND OR SHORTLY AFTER 06Z. HRLY SNOWFALL RATES UP TO 1 INCH AND FREEZING RAIN RATES UP TO 0.10 INCH WILL BE POSSIBLE FOR A 2-3 HR PERIOD INTO THE EARLY MORNING HOURS. A DEEP LAYER OF STRONG VERTICAL MOTION ASSOCIATED WITH THE NOSE OF A STRONG /60 KT/ LOW LEVEL JET AND AHEAD OF A 150 KT UPPER LEVEL JET HAS SUPPORTED MODERATE TO HVY PRECIPITATION DEVELOPMENT OVER PORTIONS OF PA EARLY THIS EVENING. THIS FORCING WILL CONTINUE TO DEVELOP NNEWD IN ADVANCE OF THE UPPER AND LOW LEVEL JETS ACROSS NRN NEW ENGLAND DURING THE NEXT 3-6 HRS. INSPECTION OF 00Z ALBANY SOUNDING INDICATED A FAIRLY DEEP DRY LAYER BELOW 700 MB. HOWEVER...THE STRENGTH OF THE LOW LEVEL MOIST ADVECTION SHOULD SUPPORT SATURATION TO AT LEAST 850 MB WITHIN THE NEXT 3-4 HRS ACROSS NRN NY/NRN VT. OBS OVER NRN PA/SRN NY INDICATED LIGHT PRECIPITATION WAS FALLING FROM CIGS AROUND 6 KFT THAT DEVELOPED A MERE 1-2 HRS AFTER CIGS HAD BEEN ABOVE 10 KFT. HEAVIER PRECIPITATION WAS FALLING OVER CENTRAL/ERN PA WITH CIGS AROUND 5 KFT /850 MB/. GIVEN THE SPEED OF THE 850 MB FLOW AND STRENGTH OF THE WARM ADVECTION...AT LEAST MODERATE PRECIPITATION RATES ARE EXPECTED TO BEGIN OCCURRING BETWEEN 04-06Z OVER THE NRN NY AND NRN/CENTRAL VT. AN EXTRAPOLATION OF THE 00Z ALBANY/BUFFALO AND GREY MAINE SOUNDINGS ALONG WITH 00Z OBS INDICATE A WET BULB FREEZING LEVEL BETWEEN 1500-2000 FT OVER NRN NY AND NRN VT. THIS LEVEL IS LIKELY TO FALL SOMEWHAT TO BETWEEN 1000-1500 FT OVER THE NEXT FEW HOURS DUE TO RADIATIONAL COOLING. INITIAL PTYPE IS EXPECTED TO BE IN THE FORM OF SNOW GIVEN THE SUDDEN ONSET OF PRECIP AND ASSOCIATED WET-BULB COOLING AFFECTS. HOWEVER...GIVEN THE STRENGTH OF THE WARM ADVECTION...PTYPE IS EXPECTED TO CHANGE OVER TO FREEZING RAIN WITHIN 1-2 HRS OF SNOW DEVELOPMENT. ..CROSBIE.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...BTV...ALY...BUF... 43627334 43847286 44067239 44447233 44907252 44897300 44517313 44027319 43897348 44017366 44477382 44907382 44897462 44367514 43887527 43607497 43507440 43617378  From mcd at goshenarc.org Mon Jan 8 01:15:05 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 20:15:05 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080119 SWOMCD SPC MCD 080118 SCZ000-NCZ000-GAZ000-080245- MESOSCALE DISCUSSION 0035 NWS STORM PREDICTION CENTER NORMAN OK 0718 PM CST SUN JAN 07 2007 AREAS AFFECTED...NERN GA THROUGH NRN SC INTO A SMALL PART OF S CNTRL NC CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 080118Z - 080245Z THREAT FOR DAMAGING WIND AND ISOLATED TORNADOES IS EXPECTED TO PERSIST NEXT FEW HOURS AS STORMS ADVANCE EWD THROUGH THE REMAINDER OF NERN GA INTO SC. A STRONG SLY 50+ KT LOW LEVEL JET WILL INCREASE OVER THE CAROLINAS THIS EVENING WITHIN ZONE OF HEIGHT FALLS AND ASCENT DOWNSTREAM FROM EWD ADVANCING UPPER TROUGH. THIS SHOULD ALLOW WARM FRONT CURRENTLY FROM SERN SC SWWD INTO NERN GA TO LIFT A LITTLE FARTHER INLAND WITH RESULTING NWD DESTABILIZATION OF THE BOUNDARY LAYER. DEWPOINTS IN THE LOW TO MID 60S EXIST NEAR AND S OF THE WARM FRONT. HOWEVER...DUE TO WEAK MID LEVEL LAPSE RATES...INSTABILITY WILL REMAIN MARGINAL WITH MUCAPE GENERALLY BELOW 500 J/KG...AND THIS WILL CONTINUE TO SERVE AS A LIMITING FACTOR. NEVERTHELESS...LARGE 0-1 KM HODOGRAPHS ASSOCIATED WITH INTENSIFYING LOW LEVEL JET WILL MAINTAIN A THREAT FOR SUPERCELLS AND ISOLATED TORNADOES AS STORMS ADVANCE EWD. SEVERE THREAT WILL REMAIN GREATEST NEAR AND JUST S OF THE WARM FRONT WHERE STORMS ARE MORE LIKELY TO BE NEAR SURFACE BASED. ..DIAL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 34488025 33648302 33878362 34748237 35108060  From mcd at goshenarc.org Mon Jan 8 03:35:22 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 22:35:22 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080339 SWOMCD SPC MCD 080338 GAZ000-ALZ000-080445- MESOSCALE DISCUSSION 0036 NWS STORM PREDICTION CENTER NORMAN OK 0938 PM CST SUN JAN 07 2007 AREAS AFFECTED...EXTREME SERN AL THROUGH CNTRL AND SWRN GA CONCERNING...TORNADO WATCH 11... VALID 080338Z - 080445Z MARGINAL THREAT FOR ISOLATED DAMAGING AND A TORNADO OR TWO MAY PERSIST A LITTLE WHILE BEYOND 04Z...BUT THREAT IS EXPECTED TO GRADUALLY DIMINISH IN THIS REGION. WW 11 MAY BE LOCALLY EXTENDED IN TIME FOR A COUPLE HOURS IF DESIRED. OTHERWISE...TORNADO WATCH 11 WILL EXPIRE AT 04Z. PRE-FRONTAL SQUALL LINE EXTENDS FROM SWRN NC SWWD THROUGH CNTRL GA AND INTO EXTREME SERN AL AND THE FL PANHANDLE MOVING SLOWLY EAST. LOCAL RADAR DATA CONTINUE TO SHOW UPDRAFT ROTATION WITH A CELL OVER SWRN GA. PRE-FRONTAL WARM SECTOR IS CHARACTERIZED BY DEWPOINTS IN THE LOWER 60S AND WEAK MID LEVEL LAPSE RATES RESULTING IN MUCAPE BELOW 300 J/KG. TREND HAS BEEN FOR LIGHTNING TO DIMINISH DURING THE PAST COUPLE HOURS. FORECAST RUC SOUNDINGS SHOW WHAT LITTLE CAPE REMAINS IS GENERALLY IN LAYERS BELOW 500 MB WHERE TEMPERATURES ARE MOSTLY ABOVE -5C. THIS SUGGEST THE CONVECTION WILL REMAIN SHALLOW WITH LITTLE IF ANY ADDITIONAL LIGHTING EXPECTED IN THIS REGION AS THE LINE CONTINUES EAST. LOW LEVEL WIND FIELDS WILL GRADUALLY VEER AND WEAKEN SLIGHTLY AS THE STRONGER LOW LEVEL JET LIFTS NE OF THIS AREA INTO THE CAROLINAS. SOME THREAT FOR AN ISOLATED TORNADO OR DAMAGING WIND MAY PERSIST ANOTHER COUPLE OF HOURS OR SO IN THIS REGION...BUT OVERALL THREAT WILL REMAIN MARGINAL. ..DIAL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE... 31598526 33108399 33418299 32468295 31178494  From mcd at goshenarc.org Mon Jan 8 10:19:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 08 Jan 2007 05:19:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 081023 SWOMCD SPC MCD 081022 MEZ000-081615- MESOSCALE DISCUSSION 0037 NWS STORM PREDICTION CENTER NORMAN OK 0422 AM CST MON JAN 08 2007 AREAS AFFECTED...CNTRL AND NRN ME CONCERNING...HEAVY SNOW VALID 081022Z - 081615Z VERY STRONG WARM/MOIST ADVECTION WITHIN LOW LEVEL JET WILL MAINTAIN STRONG ISENTROPIC LIFT OVER ME THROUGH THE MORNING HOURS. SNOW IS CHANGING TO RAIN FROM SW-NE WITH RAIN/SNOW LINE EXTENDING ACROSS CNTRL ME BY 15Z. THIS LINE WILL CONTINUE TO SHIFT NWD WITH TIME. THUS...LONGEST DURATION OF HEAVY SNOW RATES WILL BE OVER FAR NRN ME...WHERE COMBINATION OF STRONG LIFT AND FAVORABLE THERMODYNAMICS WILL FAVOR SNOW RATES UP TO 1"/HR. SHORTER DURATION MDT/HVY SNOW WILL OCCUR ACROSS CNTRL ME FOR A FEW HOURS BEFORE CHANGING TO RAIN. ..JEWELL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CAR...GYX... 46026768 45116946 45047045 45347090 45537063 45927021 46537006 47456924 47336822 47106775  From mcd at goshenarc.org Mon Jan 8 11:29:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 08 Jan 2007 06:29:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 081133 SWOMCD SPC MCD 081133 VAZ000-NCZ000-081300- MESOSCALE DISCUSSION 0038 NWS STORM PREDICTION CENTER NORMAN OK 0533 AM CST MON JAN 08 2007 AREAS AFFECTED...FAR SERN VA/ERN NC INCLUDING THE OUTER BANKS CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 081133Z - 081300Z THREAT EXISTS FOR ISOLATED DAMAGING WINDS..AND PERHAPS A TORNADO ACROSS ERN NC INCLUDING THE OUTER BANKS NWD TO SERN VA UNTIL 14-15Z. GIVEN LOW POTENTIAL FOR SEVERE WEATHER AND SMALL AREAL COVERAGE OF THIS THREAT...A WW IS UNLIKELY. REGIONAL RADARS INDICATED A COUPLE OF LINES OF LOW TOPPED CONVECTION EXTENDING FROM SERN VA TO ERN NC AND SWD TO ABOUT 70 MILES E OF THE SC COAST. DESPITE THE LACK OF LIGHTNING...A VERY MOIST PRE-FRONTAL AIR MASS IS SUPPORTING MARGINAL INSTABILITY. STRONG WINDS EVIDENT PER AREA WSR-88D VADS WITH 40-50 KT SSWLY FLOW JUST OFF THE SURFACE SUGGEST THE POTENTIAL FOR STRONG WINDS TO REACH THE SURFACE PRODUCING AN ISOLATED DAMAGING WIND THREAT. IN ADDITION...09Z RUC FORECAST SOUNDINGS SUGGESTED EFFECTIVE INFLOW LAYER IS AT THE SURFACE ACROSS THE DISCUSSION AREA...WITH SRH VALUES FAVORABLE FOR STORM ROTATION. THUS...AN ISOLATED TORNADO THREAT SHOULD EXIST ACROSS ERN NC/SERN VA...PRIOR TO VEERING SURFACE AND LOW LEVEL WINDS WITH COLD FRONT PASSAGE AFTER 15Z. ..PETERS.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX... 34337723 35197699 36047682 37007623 37717570 37627521 36427535 35297518 34667587 34247639 34017731  From mcd at goshenarc.org Fri Jan 12 12:43:54 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 07:43:54 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121247 SWOMCD SPC MCD 121246 MOZ000-OKZ000-KSZ000-TXZ000-121645- MESOSCALE DISCUSSION 0041 NWS STORM PREDICTION CENTER NORMAN OK 0646 AM CST FRI JAN 12 2007 AREAS AFFECTED...SW OK...CNTRL OK..NE OK AND SE KS CONCERNING...FREEZING RAIN VALID 121246Z - 121645Z FREEZING RAIN WILL BECOME INCREASINGLY LIKELY THIS MORNING ON THE NORTH SIDE OF A COLD FRONT EXTENDING SW TO NE ACROSS THE REGION. THE AREAS MOST LIKELY TO BE AFFECTED BY FREEZING RAIN INCLUDE SW OK...CNTRL OK...NE OK AND SE KS. FREEZING RAIN ACCUMULATIONS SHOULD BE AROUND A TENTH OF AN INCH OR LESS THROUGH EARLY THIS AFTERNOON. LATEST SFC ANALYSIS SHOWS A COLD FRONT LOCATED FROM NEAR SPRINGFIELD MO EXTENDING SWWD TO SOUTH OF OKLAHOMA CITY OK TO NEAR LAWTON OK. SUBFREEZING TEMPERATURES CURRENTLY EXIST ABOUT 30 MILES TO THE NORTHWEST OF THE FRONT AND THIS COLD AIR WILL CONTINUE TO ADVECT SLOWLY SWD ACROSS THE REGION THIS MORNING. THIS WILL LIKELY KEEP TEMPS BELOW FREEZING ACROSS MOST OF THE MCD AREA THROUGH MIDDAY WITH A SUBSTANTIAL WARM LAYER JUST ABOVE THE SFC SHOWN ON THE 12Z SOUNDINGS FROM NORMAN AND AMARILLO. IN ADDITION...MODEL FORECASTS INCREASE LIFT ACROSS THE MCD AREA THIS MORNING. THE GREATEST LIFT SHOULD BE ASSOCIATED WITH THE LOW-LEVEL JET WHICH IS FORECAST TO REMAIN STRONG IN THE 35 TO 45 KT RANGE. IN ADDITION...A SUBTLE SHORTWAVE TROUGH MAY EXIST ACROSS NW TX AS EVIDENT ON WATER VAPOR IMAGERY. DIFFERENTIAL PVA WITH THIS APPROACHING WAVE WOULD LIKELY INCREASE THE CHANCE OF FREEZING RAIN FROM SOUTHWEST TO NORTHEAST LATER THIS MORNING. DUE TO SUBFREEZING TEMPERATURES AND WARM AIR JUST OFF THE GROUND EVIDENT ON THE 12Z SOUNDINGS...FREEZING RAIN SHOULD BE THE DOMINANT MODE OF PRECIPITATION. ..BROYLES.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...TSA...ICT...OUN... 36199541 35279730 34409931 34829989 35289990 35659963 37109684 37689539 37469474 36719456 WWWW From mcd at goshenarc.org Fri Jan 12 18:32:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 13:32:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121835 SWOMCD SPC MCD 121834 MOZ000-ILZ000-ARZ000-OKZ000-KSZ000-122330- MESOSCALE DISCUSSION 0042 NWS STORM PREDICTION CENTER NORMAN OK 1234 PM CST FRI JAN 12 2007 AREAS AFFECTED...MUCH OF CNTRL MO...FAR SERN KS...EXTREME NERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 121834Z - 122330Z FREEZING RAIN AND SLEET WILL INCREASE THIS AFTERNOON FROM SW TO NE. ICE ACCUMULATIONS OF .05 TO .10 IN/HR WILL BE LIKELY...WITH LOCAL RATES NEAR .15 IN/HR AT TIMES. A LARGE AREA OF MIXED PRECIPITATION ACROSS MUCH OF SWRN INTO N-CNTRL OK IS EXPECTED TO EXPAND NEWD INTO SERN KS/CNTRL MO DURING THE AFTERNOON. THE PRECIPITATION HAS BEEN ASSOCIATED WITH STRONG LOW-LEVEL FRONTOGENETICAL FORCING...AND WARM THETA-E ADVECTION ATOP AN INCREASINGLY COLD DOME NEAR THE SURFACE. IN ADDITION...A SUBTLE MID-LEVEL IMPULSE ENTERING WRN OK PER W/V SATELLITE IMAGERY...IS FORECAST TO LIFT NEWD...FURTHER ENHANCING LARGE-SCALE ASCENT DOWNSTREAM. AT 18Z...THE SURFACE FREEZING LINE WAS FROM AROUND GMJ TO JEF TO 50 N STL. CONTINUED LOW-LEVEL CAA BEHIND AN ARCTIC COLD FRONT SHOULD PUSH THE FREEZING LINE SEWD AT AROUND 10 KT THROUGH 00Z. 18Z SGF AND ILX OBSERVED SOUNDINGS INDICATE A RATHER LARGE WARM NOSE PRESENT WITH A SATURATED 850-900 MB LAYER AROUND 10 DEGREES C. THE LOW-LEVEL THERMAL STRUCTURE FROM BOTH THE 15Z RUC AND 12Z NAM MODEL FORECAST SOUNDINGS WERE IN EXCELLENT AGREEMENT WITH THE OBSERVED SGF SOUNDING. THEIR FORECAST SOUNDINGS INDICATE FREEZING RAIN WILL BE THE MAIN PRECIPITATION TYPE IN A 50-75 KM BAND CENTERED ROUGHLY ALONG THE 18Z SURFACE FREEZING LINE. FURTHER NW...FROM AROUND CNU TO SZL TO UIN...INITIAL LIGHT FREEZING RAIN/DRIZZLE SHOULD TRANSITION TO MAINLY SLEET. THIS SHOULD OCCUR AS THE DEPTH OF THE NEAR-SURFACE COLD AIR SLOWLY INCREASES BENEATH THE ELEVATED ABOVE FREEZING LAYER. ..GRAMS.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT... 37159586 37739574 38579481 39469341 39739218 39869124 39359038 38729055 37819194 37229279 36279444 36429510  From mcd at goshenarc.org Fri Jan 12 18:47:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 13:47:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121850 SWOMCD SPC MCD 121849 OKZ000-TXZ000-122345- MESOSCALE DISCUSSION 0043 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST FRI JAN 12 2007 AREAS AFFECTED...NWRN TX...OK CONCERNING...WINTER MIXED PRECIPITATION VALID 121849Z - 122345Z ICE PELLETS AND FREEZING RAIN...WITH ACCUMULATION RATES OF 0.05 TO 0.10 INCH PER HOUR...SHOULD PERSIST FROM SWRN THROUGH NCNTRL OK THROUGH THE AFTERNOON. A GRADUAL EWD SHIFT IN HEAVIER PRECIPITATION RATES MAY BEGIN TO OCCUR ACROSS WRN PARTS OF THE MCD AREA DURING THE AFTERNOON BASED ON SREF MEAN QPF AND LATEST RADAR TRENDS. RAIN IS LIKELY TO CHANGE TO FREEZING RAIN IN A NARROW BAND FROM NWRN TX INTO PARTS OF SRN AND ERN OK OVER THE NEXT 2-4 HOURS. PRECIPITATION SHIELD COMPOSED OF FREEZING RAIN AND ICE PELLETS HAS EXPANDED AND SPREAD NEWD ACROSS CNTRL AND NRN OK THROUGH EARLY AFTERNOON IN THE WAKE OF STRONG ARCTIC FROPA THIS MORNING. THE PRECIPITATION WAS INITIALLY INDUCED AS ISENTROPIC LIFT ACROSS THE FRONT DEVELOPED INTO A PLUME OF HIGHER THETA-E AIR EMANATING FROM SOUTH TX AND THE GULF. IT APPEARS THAT DEEPER ASCENT...AIDED BY A LOW AMPLITUDE SHORT WAVE TROUGH MOVING ENEWD FROM NM/WEST TX...HAS SUSTAINED THE MIXED PRECIPITATION ACROSS MUCH OF OK OVER THE PAST FEW HOURS. STRONGER LIFT ASSOCIATED THIS LEADING SHORT WAVE TROUGH WILL CONTINUE TO TRANSLATE EWD/NEWD ATOP THE LOWER LEVEL FRONTAL ZONE THIS AFTERNOON...AND A GRADUAL NEWD SHIFT IN THE HEAVIER PRECIPITATION AREA HAS RECENTLY BEEN NOTED ON COMPOSITE RADAR. MEANWHILE...A NEARLY STEADY-STATE WARM/MOIST CONVEYOR BELT HAS NOW BECOME ESTABLISHED FROM TX/RIO GRANDE VALLEY NEWD ATOP THE SURFACE-BASED COLD DOME. DEEP LAYER MOISTURE ACROSS THE REGION WAS ALSO BEING PROVIDED BY A TROPICAL CONNECTION EVIDENT IN SATELLITE IMAGERY. WITH THE FRONTAL ZONE NOW BECOMING INCREASINGLY ALIGNED WITH THE DEEP-LAYER SWLY FLOW ALOFT...AND LOW-AMPLITUDE PERTURBATIONS CONTINUING TO TRANSLATE NEWD ACROSS THE REGION...EXPECT MIXED WINTER PRECIPITATION TO CONTINUE TO DEVELOP AND SPREAD NEWD FROM THE RED RIVER TO CNTRL AND NERN OK THROUGH THE REST OF THE AFTERNOON. HIGHER PRECIPITATION RATES MAY OCCASIONALLY OCCUR ON THE MESOSCALE AS ENHANCED ASCENT WITH THE UPPER PERTURBATIONS COINCIDE WITH LIFT ACROSS THE LOW LEVEL FRONT. THIS APPEARS TO BE OCCURRING FROM NWRN TX INTO SWRN OK AT THIS TIME. A GRADUAL SWD/SEWD SHIFT TO THE SURFACE FREEZING LINE...AND CONTINUED STRONG INFLUX OF LOW LEVEL MOISTURE...WILL RESULT IN RAIN CHANGING TO FREEZING RAIN FROM NWRN TX INTO SCNTRL AND ERN OK THROUGH LATE THIS AFTERNOON. ..CARBIN.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...FWD...OUN...LUB... 35549864 36289790 36669710 36719590 36539537 36259485 35919478 35309521 34899559 34439606 34149662 33659735 33569834 33579930 33679987 34140011 34979929  From mcd at goshenarc.org Fri Jan 12 23:11:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 18:11:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 122314 SWOMCD SPC MCD 122314 TXZ000-130045- MESOSCALE DISCUSSION 0044 NWS STORM PREDICTION CENTER NORMAN OK 0514 PM CST FRI JAN 12 2007 AREAS AFFECTED...PART OF CNTRL/NCNTRL TX CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 122314Z - 130045Z THERE WAS A CONFIRMED SHORT-LIVED TORNADO AT 2235Z JUST SW OF TROY TX IN NRN BELL COUNTY. OTHER BRIEF ISOLD TORNADOES WILL BE POSSIBLE EARLY THIS EVENING ACROSS PORTIONS OF CNTRL/NCNTRL TX. A WW IS NOT ANTICIPATED GIVEN THE BRIEF THREAT. WARM ADVECTION SHOWERS AND ISOLD TSTMS CONTINUE TO DEVELOP AHEAD OF A SEWD MOVING ARCTIC FRONT ACROSS CNTRL TX. RUC SOUNDINGS SUGGEST THAT BUOYANCY IS LIMITED WITH MLCAPES OF A FEW HUNDRED J PER KG AND THE SHOWERS HAVE EXHIBITED WEAK REFLECTIVITY AND LITTLE C-G LIGHTNING. NONETHELESS...0-1KM SHEAR WAS IN EXCESS OF 230 M2/S2 AND SUPPORTS POSSIBLE BRIEF ROTATION DURING UPDRAFT INFANCY. THE REMAINDER OF THE PROFILE THROUGH ABOUT 3KM EXHIBITS WEAKER FLOW AND UPDRAFTS MAY STRUGGLE GIVEN WEAK BUOYANCY. THE TORNADO THREAT SHOULD WANE THIS EVENING AS THE BOUNDARY LAYER COOLS AND THE ARCTIC FRONT SLIPS SEWD TOWARD THE REGION EFFECTIVELY UNDERCUTTING THE SFC-BASED STORMS. ..RACY.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX...FWD...EWX...SJT... 31509830 32079726 32409663 31999606 31309588 30649644 30329724 30649854  From mcd at goshenarc.org Sat Jan 13 00:04:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 19:04:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 130007 SWOMCD SPC MCD 130006 OKZ000-130300- MESOSCALE DISCUSSION 0045 NWS STORM PREDICTION CENTER NORMAN OK 0606 PM CST FRI JAN 12 2007 AREAS AFFECTED...CNTRL/ERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 130006Z - 130300Z LARGE SHIELD OF PCPN CONTINUES ACROSS CNTRL/ERN PARTS OF OK EARLY THIS EVE. PRECIPITATION-TYPE HAS REMAINED THE MOST DIFFICULT CHALLENGE WITH THIS FIRST WAVE OF PCPN. 00Z OUN SOUNDING SHOWED A SUBSTANTIAL WARM NOSE /PLUS 10.5 DEG C JUST BELOW H85/...BUT COOLEST PART OF THE 1700 FT DEEP SFC-BASED COLD DOME WAS AROUND MINUS 5 DEG C. RESEARCH HAS SHOWN THAT SOME ICE NUCLEI CAN ACTIVATE AT TEMPERATURES AROUND MINUS 4-5 DEG C...THOUGH THE PROBABILITY AT THAT TEMPERATURE IS ONLY AROUND 20 PERCENT. PRESUMABLY...GIVEN THE PREDOMINANCE OF SLEET AND SNOW ACROSS CNTRL OK...THIS PROCESS DOMINATED TODAY. BACK EDGE OF THE PCPN SHIELD APPEARS TO BE ACCELERATING ENEWD ACROSS CNTRL OK ATTM...SIMILAR TO 18Z NAM AND 21Z SREF SOLUTIONS. THIS WOULD SUGGEST A DECREASING PCPN TREND ACROSS NERN OK BY 03Z. THE SAME MODELS...HOWEVER...INDICATE THAT THE HEAVIER RAINFALL IN THE DFW METROPLEX WILL TRANSLATE ENEWD ACROSS SCNTRL/SERN INTO ECNTRL OK 00-06Z. THUS...THERE MAY BE A CONTINUATION OF HOURLY RATES OF 0.10+ INCH FROM VCNTY KMLC NEWD TOWARD KFYV THROUGH 06Z. OTHERWISE...FARTHER N...THE DECREASE IN PCPN RATES WILL LIKELY BE REPLACED WITH FREEZING DRIZZLE AND OR SPORADIC SLEET SHOWERS. SFC FREEZING LINE WILL LIKELY REMAIN QUASI-STATIONARY OWING TO THE HIGHER ERN OK TERRAIN AND PRESENCE OF STRONGER PRESSURE RISES WELL NE OF THE REGION. THUS...PRECIPITATION TYPE WILL PROBABLY REMAIN STATUS-QUO THROUGH LATE EVENING. MORE SPECIFICALLY...A ZONE OF FREEZING RAIN WITH SIGNIFICANT ICING SHOULD EXIST FROM KMLC-KFYV WITH A TENDENCY FOR MORE SLEET MIXED IN N OF I-40 THROUGH LATE EVENING. ..RACY.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...OUN... 34739841 35799785 36569675 36809568 36429477 35919458 35019479 34429551 34179665 34299797 34469847  From mcd at goshenarc.org Sat Jan 13 00:30:40 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 19:30:40 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 130033 SWOMCD SPC MCD 130033 ILZ000-MOZ000-IAZ000-ARZ000-OKZ000-KSZ000-130530- MESOSCALE DISCUSSION 0046 NWS STORM PREDICTION CENTER NORMAN OK 0633 PM CST FRI JAN 12 2007 AREAS AFFECTED...CNTRL MO...CNTRL IL...FAR SERN KS...FAR NWRN AR...FAR NERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 130033Z - 130530Z A SIGNIFICANT ICE STORM WILL CONTINUE THROUGH MUCH OF THE EVENING HOURS NW OF A QUASI-STATIONARY ARCTIC FRONT. ICE ACCUMULATIONS OF .05 TO .10 IN/HR WILL REMAIN LIKELY. LOCALIZED RATES UP TO .25 IN/HR WILL ALSO OCCUR AT TIMES. A NEARLY STEADY-STATE MIXED PRECIPITATION EVENT IS EXPECTED TO OCCUR OVER THE NEXT SEVERAL HOURS ACROSS THE MCD AREA...AS A WARM/MOIST CONVEYOR BELT HAS BECOME WELL-ESTABLISHED FROM THE LOWER RIO GRANDE N/NEWD TOWARDS THE MID-MS RIVER VALLEY. LOW-LEVEL WARM THETA-E ADVECTION/ISENTROPIC LIFT ATOP A NEAR-SURFACE BASED COLD DOME WILL AID IN THE CONTINUED PRODUCTION OF MIXED PRECIPITATION. 18Z NAM/GFS AND 21Z RUC GUIDANCE ARE CONSISTENT WITH STRENGTHENING THE LLJ THIS EVENING FROM NERN TX INTO SRN MO AND SRN IL...WITH CORRESPONDING INCREASES IN QPF AS WELL. AT 00Z...THE SURFACE FREEZING LINE WAS LOCATED FROM AROUND FYV TO STL TO BMI. THIS BOUNDARY SHOULD PROGRESS VERY SLOWLY SWD IN THE OZARKS REGION...WITH MORE SUBSTANTIAL PROGRESS SEWD IN SRN IL WITH GREATER PRESSURE RISES. 00Z SGF AND ILX OBSERVED SOUNDINGS INDICATE FREEZING RAIN WILL REMAIN THE PREDOMINANT PTYPE CENTERED ALONG THE I-44 CORRIDOR ACROSS MO /INCLUDING THE STL METRO AREA/ NEWD INTO CNTRL IL. FURTHER NWWD...THE PTYPE WILL REMAIN MOSTLY SLEET FROM AROUND CNU NEWD TO SZL AND UIN. HERE...A LARGER NEAR-SURFACE COLD LAYER WILL REMAIN BENEATH A SMALLER ABOVE-FREEZING LAYER COMPARED TO LOCALES FURTHER SE. ..GRAMS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LOT...ILX...LSX...DVN...LZK...SGF...EAX...TSA...TOP...ICT... 37359570 38079547 38859468 39769337 40439202 41039013 41298912 41048824 40438813 39428871 38778950 38099064 37029257 35839394 36069497  From mcd at goshenarc.org Sat Jan 13 12:26:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 07:26:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131229 SWOMCD SPC MCD 131228 ARZ000-OKZ000-TXZ000-131630- MESOSCALE DISCUSSION 0048 NWS STORM PREDICTION CENTER NORMAN OK 0628 AM CST SAT JAN 13 2007 AREAS AFFECTED...NRN TX...SE OK AND NW AR CONCERNING...FREEZING RAIN VALID 131228Z - 131630Z SCATTERED SHOWERS OF FREEZING RAIN AND SLEET ARE CURRENTLY ONGOING FROM NORTH TX EXTENDING NEWD THROUGH SE OK INTO NW AR. THE COVERAGE OF FREEZING RAIN AND SLEET MAY INCREASE THIS MORNING WITH PRECIPITATION AMOUNTS THROUGH EARLY AFTERNOON GENERALLY RANGING FROM .2 TO .5 INCHES ACROSS THE MCD AREA. LATEST SFC ANALYSIS SHOWS A COLD FRONT LOCATED FROM LITTLE ROCK AR EXTENDING SWWD TO EAST TX AND WWD INTO THE TX HILL COUNTRY. THE FREEZING LINE IS LOCATED ABOUT 120 MILES NORTHWEST OF THE FRONT. SUBFREEZING TEMPS EXIST FROM JUST WEST AND NORTH OF THE DALLAS FORT WORTH METROPLEX NNEWD ACROSS MOST OF ERN OK TO NORTH OF FORT SMITH AR. THE FREEZING LINE SHOULD SLOWLY MOVE SWD THIS MORNING. AT THE SAME TIME...A SUBTROPICAL FEED OF LOW TO MID-LEVEL MOISTURE WILL REMAIN IN PLACE EXTENDING NEWD FROM WEST TX ACROSS NORTH TX INTO ERN OK. ALTHOUGH SUBTLE...THE LATEST WATER VAPOR IMAGERY SHOWS A LOW-AMPLITUDE SHORTWAVE ACROSS WEST TX WHICH SHOULD INCREASE LARGE-SCALE ASCENT ACROSS NORTH TX AND SRN OK OVER THE NEXT FEW HOURS AS THE FEATURE MOVES NEWD. IN ADDITION...A 40 TO 50 KT LOW-LEVEL JET IN EAST TX...SE OK AND WRN AR WILL RESULT IN STRONG ISENTROPIC LIFT NORTH OF THE BOUNDARY. THE INCREASING PVA ASSOCIATED WITH THE APPROACHING WAVE COUPLED WITH STRONG ASCENT DUE TO THE LOW-LEVEL JET SHOULD RESULT IN AN INCREASE IN PRECIPITATION COVERAGE THIS MORNING ALONG A CORRIDOR FROM FORT WORTH TX NEWD TO NEAR FORT SMITH AR. MODEL FORECASTS CONFIRM THIS WITH QPF AMOUNTS RANGING FROM .25 TO 1.00 INCHES ACROSS THE SERN HALF OF THE MCD AREA THROUGH MIDDAY. ALTHOUGH MODEL FORECASTS MAY BE A LITTLE HIGH IN THE QPF AMOUNTS...SUBFREEZING TEMPS ACROSS THE MCD AREA SHOULD RESULT IN SIGNIFICANT ICE ACCUMULATION THROUGH EARLY AFTERNOON. FORECAST SOUNDINGS AND 12Z OBSERVED SOUNDINGS FROM OUN AND FTW CONFIRM A WARM LAYER EXISTING 1500 TO 2000 FEET ABOVE THE GROUND WITH TEMPS AS WARM AS +10 TO +13 C. THIS SHOULD RESULT IN FREEZING RAIN AS THE DOMINANT MODE OF PRECIPITATION ALTHOUGH SLEET WILL ALSO BE POSSIBLE ESPECIALLY IN THE NWRN PART OF THE MCD AREA WHERE TEMPS IN THE WARM LAYER WILL BE A LITTLE COOLER. ..BROYLES.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SHV...TSA...FWD...OUN... 35969373 35389377 33969531 32919655 32689751 33169829 33829823 35389656 36499485 36159382  From mcd at goshenarc.org Sat Jan 13 13:45:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 08:45:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131348 SWOMCD SPC MCD 131347 MOZ000-OKZ000-KSZ000-131745- MESOSCALE DISCUSSION 0049 NWS STORM PREDICTION CENTER NORMAN OK 0747 AM CST SAT JAN 13 2007 AREAS AFFECTED...NRN OK...SERN KS AND WRN MO CONCERNING...WINTER MIXED PRECIPITATION VALID 131347Z - 131745Z A BAND OF HEAVY SLEET CURRENTLY OVER NW OK AND SRN KS WILL MOVE ENEWD THIS MORNING. AS A RESULT...SIGNIFICANT SLEET ACCUMULATION WILL BE LIKELY OVER NRN OK...SRN KS INTO WRN MO WITH .5 TO 1.5 INCHES OF SLEET ACCUMULATION POSSIBLE. LATEST WATER VAPOR AND RADAR IMAGERY SHOW A WELL-DEFINED AXIS OF ENHANCED LIFT EXTENDING SWD FROM SRN KS ACROSS WRN OK. THIS ENHANCEMENT IS LIKELY ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH EJECTING OUT OF NW TX ATTM. FORECAST SOUNDINGS ACROSS THE MCD AREA ALONG WITH THE 12Z SOUNDING FROM DDC AND AMA SHOW SLEET TEMPERATURE PROFILES WITH A WARM LAYER LOCATED NEAR 850 MB AND A VERY COLD LAYER IN THE LOWEST 2000 FEET ABOVE GROUND LEVEL. ALSO...THE 12Z SOUNDINGS SHOW SUFFICIENT MUCAPE FOR CONVECTIVE BURSTS. SFC TEMPS ACROSS THE MCD AREA RANGE FROM 18 TO 22 DEGREES F WHICH SHOULD BE COLD ENOUGH TO KEEP PRECIPITATION MODE IN THE FORM OF SLEET AND/OR SNOW. THE HEAVIEST SLEET ACCUMULATION SHOULD OCCUR NEAR THE OK-KS STATE-LINE WHERE IT APPEARS A BAND OF LOCALLY HEAVIER PRECIPITATION WILL TRACK THIS MORNING THROUGH EARLY AFTERNOON. ..BROYLES.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...DDC... 37149348 36339534 35789812 36779892 37779846 38619450  From mcd at goshenarc.org Sat Jan 13 16:23:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 11:23:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131625 SWOMCD SPC MCD 131625 TXZ000-131830- MESOSCALE DISCUSSION 0050 NWS STORM PREDICTION CENTER NORMAN OK 1025 AM CST SAT JAN 13 2007 AREAS AFFECTED...SOUTH-CENTRAL TX CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 131625Z - 131830Z STRONG TSTMS WITH HEAVY RAIN WILL CONTINUE TO SPREAD ACROSS PARTS OF TX HILL COUNTRY THROUGH NOON. RAINFALL RATES AROUND 1 INCH PER HOUR COMBINED WITH POTENTIAL FOR REPEAT/TRAINING CELLS WILL CONTINUE TO RESULT IN LOCALIZED FLOODING PROBLEMS. ADDITIONALLY... STRONGER CELLS IN THE WARM SECTOR AND/OR NEAR THE SURFACE FRONT COULD PRODUCE DAMAGING WINDS OR A TORNADO BEFORE CROSSING OVER THE BOUNDARY AND MOVING NORTH ATOP STABLE SURFACE-BASED AIR MASS. VERY SHARP SURFACE COLD FRONT ALONG A LINE FROM 10 SE CLL TO 40 SE AUS TO 45 N HDO CONTINUES TO MAKE VERY SLOW SWD PROGRESS ACROSS THE TX HILL COUNTRY LATE THIS MORNING. MOISTURE-LADEN LOW LEVEL JET EMANATING FROM THE LOWER RIO GRANDE VALLEY AND THE WRN GULF OF MEXICO HAS BEEN INTERSECTING THE SHARP FRONTAL SURFACE AND CONTRIBUTING TO AN ACTIVE ZONE HEAVY TSTMS FROM SAN ANTONIO AREA TO NORTH OF AUSTIN THIS MORNING. RECENT RADAR DATA INDICATES THAT A FEW DISCRETE CELLS HAVE EXHIBITED UPDRAFT ROTATION DURING AND AFTER THE TRANSITION ACROSS THE COLD FRONT WHERE LOW INTENSE LOW LEVEL SHEAR IS INDICATED IN OBJECTIVE ANALYSIS DATA AND PROFILER WINDS. IF PERSISTENT CELLS DEVELOPING IN THE WARM SECTOR CAN REMAIN DISCRETE...A BRIEF WIND GUST OR TORNADO CANNOT BE RULED OUT AS THIS ACTIVITY INTERACTS WITH THE FRONTAL ZONE. HOWEVER...LARGE SCALE UPPER SUPPORT FOR DEEPER VERTICAL MOTION ACROSS THE REGION DOES APPEAR LIMITED AT THIS TIME AND A WATCH IS NOT CURRENTLY EXPECTED. HEAVY RAIN AND LOCALIZED FLOODING POTENTIAL ARE LIKELY TO PERSIST ALONG AND NORTH OF THE FRONT INTO THE AFTERNOON. FOR THE TIME BEING...THE ZONE OF STRONGER STORMS APPEARS TO HAVE SHIFTED WEST OF I35 AND THIS SHOULD PROVIDE SOME RELIEF TO THE SAN MARCOS/AUSTIN AREAS AFTER VERY HEAVY RAIN THIS MORNING. HOWEVER... PW VALUES IN EXCESS OF 1.5 INCHES...AND POTENTIAL FOR REPEAT CONVECTION GENERATED NEAR SLOW-MOVING FRONT AND THEN MOVING NWD WITHIN MEAN DEEP-LAYER SSWLY FLOW...WILL CONTINUE TO RESULT IN COPIOUS RAINFALL AMOUNTS IN THE POST-FRONTAL REGION ALONG THE I35 CORRIDOR. ..CARBIN.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX...FWD...EWX... 30559834 31019804 31659757 31719668 31489648 30059697 29659727 29069769 28809819 28749864 29009887 29309896 29659890 30209859 WWWW From mcd at goshenarc.org Sat Jan 13 18:34:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 13:34:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131837 SWOMCD SPC MCD 131836 ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-TXZ000-132300- MESOSCALE DISCUSSION 0051 NWS STORM PREDICTION CENTER NORMAN OK 1236 PM CST SAT JAN 13 2007 AREAS AFFECTED...SERN KS...CNTRL/SRN MO...CNTRL/ERN OK...PORTIONS OF N-CNTRL TX CONCERNING...WINTER MIXED PRECIPITATION VALID 131836Z - 132300Z OCCASIONAL BURSTS OF FREEZING RAIN AND SLEET WILL CONTINUE THROUGH THE AFTERNOON HOURS...WITH ISOLATED TSTMS ACROSS ERN OK/PORTIONS OF N-CNTRL TX. ICE ACCUMULATION RATES SHOULD BRIEFLY REACH AROUND .05 TO .10 IN/HR...WITH LOCALIZED RATES EXCEEDING .10 IN/HR. INTERMITTENT FREEZING RAIN HAS BEEN ONGOING ON THE WRN PERIPHERY OF A WARM CONVEYOR BELT FROM THE LOWER RIO GRANDE VALLEY N/NEWD ACROSS THE MID-MS RIVER VALLEY. ALTHOUGH THE BULK OF PRECIPITATION HAS BEEN CONFINED BETWEEN THE SURFACE FREEZING LINE AND COLD FRONT...OCCASIONAL SHOWERS HAVE MOVED INTO THE BELOW FREEZING SECTOR AND PRODUCED LIGHT ICE ACCUMULATIONS THROUGH THE MORNING HOURS. 15Z RUC AND 12Z GFS/NAM GUIDANCE SUGGESTS VERY LITTLE EWD PROGRESS OF THIS WARM/MOIST OVERRUNNING AXIS THIS AFTERNOON. FURTHER W...A WEAK UPPER-LEVEL IMPULSE IN FAR WRN OK /PER WATER VAPOR IMAGERY/ HAS AIDED IN THE DEVELOPMENT OF NUMEROUS SLEET SHOWERS AND ISOLATED TSTMS ALONG THE I-35 CORRIDOR IN CNTRL OK. THIS IMPULSE WILL HELP STRENGTHEN THE UPPER-LEVEL JET THIS AFTERNOON ACROSS THE LOWER MO RIVER VALLEY...WITH SUBSTANTIAL RIGHT-ENTRANCE REGION DIVERGENCE TO ITS SOUTH. THUS...A RELATIVELY ELONGATED AXIS OF OCCASIONAL FREEZING RAIN WILL CONTINUE. THIS AXIS WILL REMAIN FROM THE WRN DFW METRO AREA NNEWD ALONG THE US-69 CORRIDOR IN OK...ARCING NEWD ALONG THE I-44 CORRIDOR IN MO. ..GRAMS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT...FWD...OUN... 36529414 35179529 32859692 32299736 32329760 32959774 33639806 33939800 34759768 35799726 36909668 37569612 38089507 38319390 38249252 38349019 38079028 37499115  From mcd at goshenarc.org Sat Jan 13 23:46:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 18:46:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 132350 SWOMCD SPC MCD 132349 MSZ000-ARZ000-LAZ000-TXZ000-140245- MESOSCALE DISCUSSION 0053 NWS STORM PREDICTION CENTER NORMAN OK 0549 PM CST SAT JAN 13 2007 AREAS AFFECTED...PORTIONS EXTREME E-CENTRAL/NE TX...NWRN LA...SRN/ERN AR. CONCERNING...HEAVY RAINFALL VALID 132349Z - 140245Z BAND OF TSTMS WITH HEAVY RAINFALL IS FCST TO MAINTAIN INTENSITY AS IT MOVES EWD ACROSS CORRIDOR NEAR LINE FROM GGG...SHV...ELD...PBF...50 SW MEM. RAIN RATES COMMONLY 1-1.25 INCH/HOUR ARE EXPECTED...LOCALLY/BRIEFLY TOPPING 2 INCHES/HOUR IN MOST INTENSE CORES. 23Z SFC MESOANALYSIS SHOWS FRONTAL-WAVE LOW BETWEEN SHV-GGG...WHICH SHOULD LIFT NEWD INTO SWRN AR DURING NEXT FEW HOURS. STRONGEST CONVERGENCE AND STORM-RELATIVE/SFC-BASED INFLOW LIKEWISE IS FCST TO SHIFT NEWD AHEAD OF LOW...WITH COLD FRONT UNDERCUTTING SFC-BASED BUOYANCY FOR DEVELOPMENT OCCURRING SW OF LOW. STILL...ACTIVITY MAY FORM ATOP SHALLOW FRONTAL LAYER IN ENVIRONMENT OF ELEVATED MOISTURE TRANSPORT AND WAA...AIDING PROPAGATIONAL MAINTENANCE OF SWRN PORTION OF PRECIP/TSTM BAND. GIVEN NEARLY PARALLEL ORIENTATION OF ACTIVITY RELATIVE TO AMBIENT MEAN FLOW...TRAINING OF CORES IS LIKELY TO FURTHER AUGMENT HEAVY RAIN HAZARD. ALTHOUGH 73 F DEW POINT AT SFC STATION IER IS BOGUS...GPS SENSOR DATA AND NEAR-TERM FCST SOUNDINGS AHEAD OF FRONT INDICATE FAVORABLY RICH MOISTURE WITH NARROW ZONE OF PW 1.4-1.7 INCH THROUGH NEARLY SATURATED DEEP-LAYER PROFILE...PORTENDING EFFICIENT PRECIP PROCESSES IN MOST INTENSE CONVECTION. HEAVIEST RAIN SHOULD REMAIN S OF FREEZING LINE ACROSS PORTIONS OZARKS. ADDITIONAL DETAILS ON FREEZING/FROZEN PRECIP POTENTIAL FARTHER N WILL BE DISCUSSED IN UPCOMING SPC WINTER WEATHER MESOSCALE DISCUSSIONS. WARM SECTOR VERTICAL SHEAR PROFILES ALSO ARE FAVORABLE FOR SOME SVR POTENTIAL WITH 0-1 KM SRH AROUND 200 J/KG...AND WEAK SBCAPES OF 200-300 J/KG. BRIEF TORNADO OR DAMAGING GUST CANNOT BE RULED OUT. HOWEVER...LACK OF MORE ROBUST BUOYANCY AND OF DISCRETE CONVECTIVE MODE SHOULD KEEP THIS THREAT MRGL AT MOST. ..EDWARDS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MEG...JAN...LZK...SHV... 32999409 33439346 34499237 34799096 34139083 33769120 32389241 31929448  From mcd at goshenarc.org Sun Jan 14 00:16:51 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 19:16:51 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140020 SWOMCD SPC MCD 140019 ILZ000-MOZ000-140415- MESOSCALE DISCUSSION 0054 NWS STORM PREDICTION CENTER NORMAN OK 0619 PM CST SAT JAN 13 2007 AREAS AFFECTED...SRN MO CONCERNING...FREEZING RAIN VALID 140019Z - 140415Z FREEZING RAIN WILL AFFECT PORTIONS OF SRN MO EARLY THIS EVENING...GENERALLY ALONG THE I-44 CORRIDOR FROM SGF TO THE SRN STL METRO AREA. PRECIPITATION RATES AROUND .05 IN/HR CAN BE EXPECTED...WITH LOCALIZED RATES IN EXCESS OF .10 IN/HR OVER THE NEXT FEW HOURS. THE OVERALL THREAT FOR ADDITIONAL FREEZING RAIN WILL GRADUALLY DIMINISH FROM WEST TO EAST...ESPECIALLY AFTER 03Z. THE SURFACE FREEZING LINE HAS REMAINED NEARLY STATIONARY OVER THE PAST SEVERAL HOURS ACROSS EXTREME NWRN AR...SRN MO AND WRN IL. AS OF 14/00Z...IT EXTENDED FROM AROUND 20 NW OF FYV TO 20 N UNO TO ALN. A LARGE AREA OF RAIN/FREEZING RAIN HAS BEEN STEADILY MOVING EWD ACROSS SWRN MO/FAR NWRN AR /PER REGIONAL RADAR IMAGERY/. THIS ACTIVITY IS EXPECTED TO CONTINUE THIS PROGRESSION AS IT BECOMES ABSORBED INTO THE WARM/MOIST CONVEYOR BELT REGION RUNNING FROM THE TX COASTAL BEND TOWARDS THE LOWER OH RIVER VALLEY. 13/21Z RUC AND 13/18Z NAM MODEL GUIDANCE INDICATE 700-500 MB MID-LEVEL DRYING WILL ENSUE BEHIND THIS LAST SUBSTANTIAL AREA OF PRECIPITATION...EVIDENCED BY THE 14/00Z OUN OBSERVED SOUNDING. IN ADDITION...AS THE UPPER MIDWEST/LOWER GREAT LAKES UPPER-LEVEL JET QUICKLY MOVES EWD THIS EVENING...FAVORABLE RIGHT-ENTRANCE DIVERGENCE PRESENTLY ACROSS THE MCD AREA WILL SHIFT EWD AS WELL. THUS...THE OVERALL THREAT FOR FREEZING RAIN WILL DIMINISH...ESPECIALLY AFTER 03Z. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF... 37289161 36999256 36869304 36789333 36779366 36969385 37349387 37699382 37869341 38149258 38469156 38689053 38299034 37809070  From mcd at goshenarc.org Sun Jan 14 02:10:54 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 21:10:54 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140214 SWOMCD SPC MCD 140213 LAZ000-TXZ000-140445- MESOSCALE DISCUSSION 0055 NWS STORM PREDICTION CENTER NORMAN OK 0813 PM CST SAT JAN 13 2007 AREAS AFFECTED...PORTIONS SE TX. CONCERNING...HEAVY RAINFALL VALID 140213Z - 140445Z POTENTIAL FOR HEAVY RAINFALL -- COMPOUNDED BY TRAINING OF HEAVIEST PRECIP CORES -- WILL SHIFT EWD ACROSS LFK-HOU CORRIDOR THROUGH 5Z...WITH LOCAL RAIN RATES BRIEFLY REACHING 2 INCHES/HOUR AND COMMONLY 1-1.5 INCH/HOUR IN TSTMS. SFC MESOANALYSIS AT 2Z SHOWS COLD FRONT BETWEEN ANGELINA-WRN HARRIS-NACOGDOCHES COUNTIES...MOVING SEWD APPROXIMATELY 15 KT. RICH MOISTURE IN GULF AIR MASS -- CHARACTERIZED BY 1.75-2 INCH PW...MID-UPPER 60S F SFC DEW POINTS... AND 14-15 DEG C ESTIMATED 850 MB DEW POINTS SHOULD PERSIST IN WARM SECTOR. MOST ACTIVITY WILL OCCUR JUST BEHIND BOUNDARY AS FRONTAL AND ISENTROPIC LIFT FORCED PARCELS TO LFC. WEAK MESOLOW --ANALYZED ALONG FRONT N HOU -- MAY LEAD TO ENHANCED LOW LEVEL CONVERGENCE TO ITS IMMEDIATE NE AS WELL. DEEP-LAYER MEAN FLOW WILL REMAIN ALIGNED NEARLY PARALLEL TO ZONE OF STRONGEST CONVECTIVE FORCING...AS LATTER MOVES SLOWLY EWD...RESULTING IN REPEAT PASSAGE OF HEAVY CORES OVER SOME LOCALES. MODIFIED PROFILER/VWP/RUC SOUNDING DATA INDICATE SUFFICIENT VERTICAL SHEAR TO SUPPORT SUPERCELL POTENTIAL...AND CONTINUED PRESENCE OF SFC-BASED EFFECTIVE LAYER IN WARM SECTOR SOUNDINGS INDICATES POTENTIAL FOR BRIEF TORNADO CANNOT BE RULED OUT. HOWEVER...LINEAR INCLINATION OF CONVECTIVE MODE...COMBINED WITH ANAFRONTAL REGIME KEEPING MOST ACTIVITY BEHIND COLD FRONT...WILL KEEP SVR POTENTIAL MRGL AT BEST. ..EDWARDS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LCH...SHV...HGX... 29449627 30319578 31659435 31529373 30739355 30359378 29119515 28939641  From mcd at goshenarc.org Sun Jan 14 06:18:21 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 01:18:21 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140621 SWOMCD SPC MCD 140621 OHZ000-MIZ000-INZ000-ILZ000-WIZ000-141145- MESOSCALE DISCUSSION 0056 NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CST SUN JAN 14 2007 AREAS AFFECTED...FAR SERN WI/NRN IL...NRN IN...SRN LOWER MI AND FAR NWRN OH CONCERNING...WINTER MIXED PRECIPITATION VALID 140621Z - 141145Z LIGHT FREEZING RAIN AND SLEET SHOWERS WILL CONTINUE TO DEVELOP NORTH OF THE SFC FREEZING LINE EXTENDING FROM NCENTRAL IL /PIA/ INTO NWRN OH /TOL/ OVER THE NEXT 6 HOURS. AVERAGE HRLY LIQUID EQUIVALENT ACCUMULATION RATES FROM 0.01 TO 0.05 INCH CAN BE EXPECTED. LATEST RADAR IMAGERY INDICATES THAT PRECIPITATION CONTINUES TO EXPAND OVER PORTIONS OF THE MID MS VALLEY AND WRN GREAT LAKES. THIS PRECIPITATION WAS DEVELOPING IN RESPONSE TO STRENGTHENING ISENTROPIC LIFT OVER THE SFC-850 MB FRONTAL BOUNDARY AND MID LEVEL VERTICAL MOTION BOTH ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH OVER MISSOURI. FORECAST AND OBSERVED SOUNDINGS INDICATE THAT PRECIP TYPE WILL RANGE FROM FREEZING RAIN OVER PORTIONS OF NERN IL/FAR NRN IND AND FAR SRN MI/NWRN OH WHERE THE COLD AIR WAS SHALLOWER. SLEET IS EXPECTED OVER FAR NERN IL AND PORTIONS OF SRN LOWER MI /GENERALLY NORTH OF I-94/ WHERE THE DEPTH OF THE SUB-FREEZING LAYER WAS GREATER. STEEP MID LEVEL LAPSE RATES WILL SUPPORT CONVECTIVE NATURE OF PRECIP WITH OCCASIONAL BURSTS OF ACCUMULATIONS RATES UP TO 0.10/HR. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT...ILX...MKX...DVN... 43188692 42298982 41048993 40418984 40478855 40998555 41258379 41558327 42718326 42978418  From mcd at goshenarc.org Sun Jan 14 07:12:31 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 02:12:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140715 SWOMCD SPC MCD 140715 OKZ000-TXZ000-141315- MESOSCALE DISCUSSION 0057 NWS STORM PREDICTION CENTER NORMAN OK 0115 AM CST SUN JAN 14 2007 AREAS AFFECTED...WCENTRAL/NWRN TX AND SWRN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 140715Z - 141315Z FREEZING DRIZZLE AND POSSIBLY VERY LIGHT FREEZING RAIN IS ANTICIPATED TO DEVELOP OVER THE AREA IN THE NEXT FEW HOURS. PRECIPITATION IS EXPECTED TO INCREASE IN INTENSITY AND MIX WITH OR CHANGEOVER TO SLEET TOWARDS 12Z. ANALYSES OF SFC WINDS/SLP OVER THE SRN PLAINS INDICATES A CONTINUED GRADUAL BACKING/FALLING OVER THE LAST FEW HRS IN RESPONSE TO APPROACHING SHORTWAVE TROUGH LOCATED NEAR THE AZ/NM BORDER. THE 850 MB FLOW ALSO HAS BEEN BACKING AND STRENGTHENING NOTED BY THE RECENT VWP DATA FROM MAF/SJT AND DYS. AS A RESULT...ISENTROPIC LIFT HAS BECOME MORE NORMAL TO THE FRONTAL ZONE ENHANCING LOW LEVEL VERTICAL MOTION. THIS WILL CONTINUE TO SUPPORT THE DEVELOPMENT OF A LARGE AREA OF FREEZING DRIZZLE AND POSSIBLY VERY LIGHT FREEZING RAIN ACROSS WCENTRAL/NWRN TX INTO SWRN OK OVER THE NEXT SEVERAL HOURS. MID LEVELS ARE BEGINNING TO MOISTEN AS NOTED BY THE 07Z OBS AT EL PASO AND CLOUD TOP COOLING ON IR SAT IMAGERY. THIS WAS OCCURRING WHERE A LARGE PLUME OF HIGH LEVEL PACIFIC MOIST PLUME HAS BEGUN TO INTERACT WITH THE SWRN SHORTWAVE TROUGH. THIS MID LEVEL MOISTURE AND ASSOCIATED LIFT SHOULD CONTINUE TO SPREAD NEWD AND BEGIN TO REACH THE MCD AREA AFTER 10Z. EVENTUALLY...THE COLUMN WILL SATURATE SUFFICIENTLY THAT SLEET AND/OR FREEZING RAIN DEVELOPMENT IS EXPECTED TOWARDS 12Z. THE PTYPE IS EXPECTED TO BE A MIX OF FREEZING RAIN AND SLEET WCENTRAL/NWRN TX. SLEET IS EXPECTED TO BE THE PRIMARY PTYPE OVER SWRN OK WHERE MIN TEMPERATURES IN THE LOWEST 2000 FT AGL ARE EXPECTED TO BE AROUND -10 DEG C. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF... 35229837 35329887 34660046 34180139 33450204 31920212 31480196 31120152 31080097 31240005 31629920 32759850 34319761 34919760  From mcd at goshenarc.org Sun Jan 14 12:37:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 07:37:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141240 SWOMCD SPC MCD 141239 OHZ000-MIZ000-INZ000-141845- MESOSCALE DISCUSSION 0058 NWS STORM PREDICTION CENTER NORMAN OK 0639 AM CST SUN JAN 14 2007 AREAS AFFECTED...SRN LOWER MI...NRN IN AND NWRN OH CONCERNING...WINTER MIXED PRECIPITATION VALID 141239Z - 141845Z A LARGE AREA OF FREEZING RAIN AND SLEET...WITH SLEET THE PREDOMINANT PTYPE IN SRN LOWER MI...WILL CONTINUE TO PROGRESS EWD ACROSS THE AREA THIS MORNING BEFORE ENDING BY 18Z. A REGION OF MODEST ISENTROPIC LIFT NORTH OF A STATIONARY FRONTAL BOUNDARY AND MID LEVEL LIFT AHEAD OF A SUBTLE SHORTWAVE TROUGH OVER THE MID MS VALLEY WAS SUPPORTING A LARGE OF MIXED PRECIP OVER NRN IN/NWRN OH AND SRN LOWER MI. THE 12Z ILX SOUNDING INDICATED STEEP MID LEVEL LAPSE RATES ALONG WITH SOME WEAK ELEVATED INSTABILITY WILL SUPPORT CONVECTIVE ACCUMULATION RATES UP TO 0.25 IN FOR BRIEF PERIODS. RECENT SFC OBS AND THE 12Z DTX SOUNDING INDICATED A SUFFICIENTLY SMALL ENOUGH ELEVATED WARM LAYER THAT SLEET WILL BE THE PRIMARY PTYPE NORTH OF I-94. GIVEN THE PROGRESSIVE NATURE OF THE FORCING...STEADY LIGHT TO MDT PRECIP SHOULD END ACROSS THE ENTIRE AREA BY AROUND 18Z. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT... 42568338 42738481 42618711 41838753 41378733 41188697 41168417 41428322  From mcd at goshenarc.org Sun Jan 14 12:48:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 07:48:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141252 SWOMCD SPC MCD 141251 TXZ000-OKZ000-KSZ000-141645- MESOSCALE DISCUSSION 0059 NWS STORM PREDICTION CENTER NORMAN OK 0651 AM CST SUN JAN 14 2007 AREAS AFFECTED...SRN KS...OK AND NE TX CONCERNING...WINTER MIXED PRECIPITATION VALID 141251Z - 141645Z MIXED PRECIPITATION WILL OCCUR ACROSS THE REGION THIS MORNING WITH SLEET AND LIGHT SNOW LIKELY FROM FAR SRN KS TO SCNTRL OK. FURTHER SOUTH IN SRN OK AND NE TX...FREEZING RAIN WILL BE THE DOMINANT MODE OF PRECIPITATION. QPF AMOUNTS SHOULD RANGE FROM .05 TO .15 THROUGH MIDDAY WITH LOCALLY HIGHER AMOUNTS POSSIBLE ESPECIALLY ALONG AND TO THE SOUTH OF THE RED RIVER. LATEST SFC ANALYSIS SHOWS A LARGE AREA OF ARCTIC HIGH PRESSURE EXTENDING SWD FROM THE NRN PLAINS INTO THE SRN PLAINS. NLY WINDS ASSOCIATED WITH THE HIGH WILL REINFORCE VERY COLD TEMPERATURES ACROSS THE REGION THIS MORNING. TEMPERATURES RANGE FROM 18 TO 20 DEGREES F IN FAR SRN KS TO AROUND 30 DEGREES F NEAR THE RED RIVER. 12Z MORNING SOUNDINGS FROM AMA AND OUN SHOW A WARM LAYER AROUND 2500-3000 FEET ABOVE GROUND LEVEL WITH TEMPS AS WARM AS +7.0 CELSIUS. THIS SHOULD BE FAVORABLE FOR SLEET WITH A MIXTURE OF LIGHT SNOW ACROSS NW OK AND SRN KS WHERE THE WARM LAYER IS NOT AS THICK. IN ADDITION...ELEVATED INSTABILITY EXISTS ACROSS THE MCD AREA WITH SOUNDINGS SHOWING MUCAPE VALUES BETWEEN 100 AND 300 J/KG. THIS SHOULD BE SUFFICIENT FOR CONVECTION AS THE STRONGER LARGE-SCALE ASCENT MOVES INTO THE PLAINS. AS A RESULT...THE COVERAGE OF MIXED PRECIPITATION SHOULD GRADUALLY INCREASE FROM WEST TO EAST ACROSS THE REGION THROUGH MIDDAY. FURTHER SOUTH...THE FWD 12Z SOUNDING SHOWS A SUBSTANTIAL WARM LAYER FROM JUST ABOVE THE GROUND TO ABOUT 800 MB WITH +12 CELSIUS NEAR 850 MB. IN ADDITION...ELEVATED MUCAPE VALUES EXCEED 500 J/KG WHICH SHOULD BE FAVORABLE FOR THUNDERSTORMS WITH SHORT BURSTS OF HEAVY FREEZING RAIN POSSIBLE. AS A RESULT...SIGNIFICANT ICE ACCUMULATION APPEARS LIKELY NEAR AND TO THE SOUTH OF THE RED RIVER AS THE STRONGER FORCING EJECTS NEWD ACROSS THE REGION LATE THIS MORNING. MOST AREAS IN NORTH TX AND FAR SRN OK SHOULD RECEIVE A TENTH OF AN INCH OF ICE WITH A QUARTER INCH OF ICE POSSIBLE WHERE CONVECTION DEVELOPS LATE THIS MORNING. ..BROYLES.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SHV...TSA...ICT...FWD...OUN...DDC... 32799776 33379837 34139869 35369933 36079997 36819984 37359913 37489746 37009652 35549548 33669511 32909611 32709713  From mcd at goshenarc.org Sun Jan 14 13:22:25 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 08:22:25 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141325 SWOMCD SPC MCD 141325 MAZ000-NHZ000-VTZ000-NYZ000-141730- MESOSCALE DISCUSSION 0060 NWS STORM PREDICTION CENTER NORMAN OK 0725 AM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS OF NY...MA AND FAR SRN VT/NH CONCERNING...WINTER MIXED PRECIPITATION VALID 141325Z - 141730Z EPISODES OF LIGHT FREEZING RAIN AND SLEET ARE EXPECTED TO OCCUR THIS MORNING ACROSS PORTIONS OF WRN NY EWD INTO FAR SRN VT/NH AND MA. HRLY ACCUMULATIONS RATES WILL GENERALLY AVERAGE LESS THAN 0.05 INCH. ISENTROPIC LIFT WAS INCREASING OVER THE ERN GREAT LAKES AND FAR WRN NY IN RESPONSE TO A STRENGTHENING AGEOSTROPHIC CIRCULATION IN THE RIGHT ENTRANCE REGION OF AN UPPER JET OVER SRN QUEBEC. SFC ANALYSIS SHOWED THE FREEZING LINE EXTENDING FROM NEAR JHW TO 40 N POU TO ORH. NWD MOVEMENT OF THIS LINE MAY OCCUR AS WAA INCREASES ...BUT GIVEN THE LACK OF SUBSTANTIAL PRESSURE FALLS OVER THE AREA...THE OVERALL MOVEMENT OF THE FREEZING ISOTHERM SHOULD BE MINIMAL THROUGH THE MORNING. THE 12Z ALB SOUNDING INDICATED THE DEPTH OF THE ABOVE FREEZING ELEVATED WARM LAYER IS SUFFICIENT TO SUPPORT FREEZING RAIN OVER SRN NEW ENGLAND AND PORTIONS OF SRN/ERN NY. STEEP MID LEVEL LAPSE RATES ON THE 12Z BUF SOUNDING WILL SUPPORT OCCASIONAL CONVECTIVE BURSTS OF PRECIP...WITH HRLY LIQUID ACCUMULATIONS RATES UP TO 0.10 IN. WITHIN THESE CONVECTIVE SHOWERS...SLEET MAY MIX WITH THE FREEZING RAIN. MORE STEADY FREEZING RAIN/SLEET IS EXPECTED TO DEVELOP OUT OF MI INTO SWRN/CENTRAL NY BETWEEN 15-17Z AHEAD OF THE SHORTWAVE TROUGH THAT WILL BE MOVING THROUGH THE CENTRAL LAKES AT THAT TIME. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...BOX...ALY...BGM...BUF... 43147566 43037805 42557872 42077794 42037424 42317219 42577164 42957168 43107374  From mcd at goshenarc.org Sun Jan 14 17:39:35 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 12:39:35 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141742 SWOMCD SPC MCD 141742 MNZ000-IAZ000-NEZ000-SDZ000-142345- MESOSCALE DISCUSSION 0061 NWS STORM PREDICTION CENTER NORMAN OK 1142 AM CST SUN JAN 14 2007 AREAS AFFECTED...NERN NEB...SERN SD...NWRN IA...SWRN MN CONCERNING...HEAVY SNOW VALID 141742Z - 142345Z MDT TO HVY SN ACROSS PORTIONS OF SERN/SCNTRL NEB WILL CONTINUE TO EXPAND ACROSS THE MO RIVER VALLEY THROUGH THIS AFTERNOON. SNOWFALL RATES WITHIN THE STRONGER BANDS WILL BE AROUND 1 INCH PER HOUR... WITH LIGHTER HOURLY AMOUNTS OCCURRING IN BETWEEN THE BANDS. THE ONGOING BANDING ACROSS NEB COINCIDES VERY WELL WITH A INTENSIFYING AXIS OF 700-500MB LAYER FRONTOGENESIS DEPICTED IN LATEST RUC AND NAM-WRF MODELS. THIS SW-NE ORIENTED AXIS OF MESOSCALE ASCENT WAS DEVELOPING AHEAD OF A SHORT WAVE TROUGH EJECTING NEWD FROM ERN CO AND LATEST GUIDANCE MAINTAINS STRONG ASCENT ACROSS THE REGION THROUGH ABOUT 15/00Z. WITH MID LEVEL LIFT OCCURRING IN A THERMODYNAMIC REGIME FAVORING EFFICIENT WATER VAPOR TO ICE TRANSPORT /-12C TO -17C/...AND A DEEP DENDRITE GROWTH LAYER...SNOWFALL RATES SHOULD EASILY REACH AN INCH PER HOUR AS LOW LEVEL SATURATION OCCURS FROM SW TO NE. SREF GUIDANCE DEPICTS THE HIGHEST PROBABILITY OF INCH PER HOUR SNOWFALL RATES DEVELOPING FROM CNTRL NEB INTO SERN SD BY LATE THIS AFTERNOON AND THROUGH EARLY EVENING. HOWEVER...LATEST RADAR TRENDS WOULD SUGGEST THAT PERHAPS A SECONDARY AXIS OF HVY SN MAY BE EVOLVING FARTHER SOUTH...ALONG A MCK-OFK-SUX LINE. GIVEN CLOSER PROXIMITY OF THIS BAND TO LOW LEVEL MOISTURE INFLOW...THE SREF GUIDANCE MAY BE DISPLACED SLIGHTLY NORTH OF GREATEST SNOWFALL RATE POTENTIAL THROUGH LATE THIS AFTERNOON. ..CARBIN.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...DMX...FSD...OAX...GID...LBF...GLD... 43029919 43769637 43579501 42089557 41449564 41049606 40619655 40449783 40419819 40589885 40279963 40260050 41260044 41890070 42320042 42729991  From mcd at goshenarc.org Sun Jan 14 17:48:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 12:48:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141751 SWOMCD SPC MCD 141750 MOZ000-IAZ000-OKZ000-KSZ000-NEZ000-142245- MESOSCALE DISCUSSION 0062 NWS STORM PREDICTION CENTER NORMAN OK 1150 AM CST SUN JAN 14 2007 AREAS AFFECTED...ERN KS...NRN/WRN/CNTRL MO...SRN IA...EXTREME SERN NEB CONCERNING...WINTER MIXED PRECIPITATION VALID 141750Z - 142245Z A MIX OF FREEZING RAIN...SLEET...AND SNOW WILL EXPAND E/NEWD THIS AFTERNOON. PRECIPITATION RATES OF .05 TO .15 IN/HR WILL BE COMMON...WITH LOCALLY HEAVIER RATES IN EXCESS OF .20 IN/HR IN CONVECTIVE CELLS. A SWATH OF MODERATE TO OCCASIONALLY HEAVY SLEET HAS BEEN ONGOING ACROSS MUCH OF CNTRL INTO ERN KS THIS MORNING...WITH MODERATE TO HEAVY SNOW RECENTLY DEVELOPING IN PORTIONS OF SRN NEB. RECENT SLEET ACCUMULATIONS OF AROUND 0.5 TO 1.5 INCHES HAVE BEEN REPORTED IN THE ICT AREA. BOTH THE 12Z GFS AND 15Z RUC HAVE GOOD QPF AGREEMENT WITH THE ONGOING PRECIPITATION EVOLUTION WHEN COMPARED TO REGIONAL RADAR IMAGERY...WHILE THE 12Z NAM HAS BEEN TOO SLOW/FARTHER WEST. BOTH LOW AND MID-LEVEL ISENTROPIC LIFT WILL CONTINUE DOWNSTREAM OF THIS PRECIPITATION REGION...AS A SHORTWAVE TROUGH EJECTS NEWD FROM CO. PRECIPITATION IS EXPECTED TO RAPIDLY EXPAND E/NEWD INTO MUCH OF MO AND FAR SRN IA THIS AFTERNOON. A MIX OF PRECIPITATION TYPES WILL OCCUR ACROSS THIS REGION WITH A TIGHT SW TO NE ORIENTED LOW-LEVEL THERMAL GRADIENT. AT 17Z...THE SURFACE FREEZING LINE WAS LOCATED FROM NEAR FYV TO 30 W STL TO BRL. THIS LINE SHOULD MAKE SLOW PROGRESS WWD THROUGH THE AFTERNOON....AS WEAK ELY WINDS CONTINUE TO THE N OF A DEVELOPING SURFACE LOW IN THE TEXARKANA REGION. JUST W OF THIS FREEZING LINE...OVER MUCH OF CNTRL MO...FREEZING RAIN WILL BE THE PRIMARY PTYPE AS EVIDENCED BY THE 12Z OBSERVED SGF SOUNDING. FURTHER NW...SLEET WILL BE THE PREDOMINANT PTYPE ACROSS SERN KS THROUGH THE KC METRO AREA. HERE...A SMALL WARM LAYER OF ABOVE FREEZING TEMPERATURES REMAINS BETWEEN 700-850 MB RELATIVE TO A MUCH COLDER SURFACE-BASED LAYER /PER 12Z TOP AND LAMONT OK SOUNDINGS/. ACROSS PORTIONS OF NERN KS/FAR NWRN MO INTO SRN IA...THE PRIMARY PTYPE WILL BECOME ALL SNOW...AS MORNING MODEL GUIDANCE IS INSISTENT ON COOLING THE 700-850 MB LAYER TO AOB FREEZING. AS THIS OCCURS...SNOW RATES SHOULD BRIEFLY REACH 1 IN/HR. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...DVN...SGF...DMX...EAX...TSA...OAX...TOP...ICT... 39429684 40359668 40979599 41359494 41139300 40799234 40159190 39629152 38899154 38169164 37609196 37229299 36639378 36519440 36699518 37099604 38289662  From mcd at goshenarc.org Sun Jan 14 18:47:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 13:47:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141850 SWOMCD SPC MCD 141849 OKZ000-TXZ000-142215- MESOSCALE DISCUSSION 0063 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST SUN JAN 14 2007 AREAS AFFECTED...ERN OK...PORTIONS OF N-CNTRL TX CONCERNING...WINTER MIXED PRECIPITATION VALID 141849Z - 142215Z NUMEROUS SHOWERS AND ISOLATED TSTMS OF SLEET AND FREEZING RAIN WILL MOVE EWD AFFECTING MUCH OF ERN OK THROUGH 22Z. PRECIPITATION ACCUMULATION RATES OF .10 TO .20 IN/HR WILL CONTINUE FOR THE NEXT FEW HOURS. SIGNIFICANT PRECIPITATION WILL DIMINISH LATER THIS AFTERNOON. A LARGE AREA OF SHOWERS WITH EMBEDDED TSTMS HAS MOVED RAPIDLY INTO ERN OK...WITH THE BACK EDGE OF PRECIPITATION FROM AROUND ALVA OK TO MWL. MUCH OF THE SIGNIFICANT PRECIPITATION HAS BEEN SLEET WITH AN OCCASIONAL MIX OF FREEZING RAIN IN CNTRL OK. RUC OBJECTIVE ANALYSIS INDICATES MUCAPES OF AOB 500 J/KG OVER CNTRL/ERN OK AND N-CNTRL TX WILL CONTINUE TO SUPPORT ELEVATED TSTM POTENTIAL. AT 18Z...THE SURFACE FREEZING LINE WAS LOCATED FROM AROUND 20 W OF FYV TO NEAR DFW. SIGNIFICANT ICE ACCUMULATIONS WILL LIKELY CONTINUE JUST W OF THIS LINE...ALONG THE US-69 CORRIDOR IN ERN OK. MORNING MODEL GUIDANCE ARE CONSISTENT IN DIMINISHING PRECIPITATION THROUGH THE AFTERNOON. THIS SHOULD OCCUR AS 850 TO 700 MB WINDS BECOME MORE WLY WITH CORRESPONDING DECREASES IN RH AND INTENSIFYING ISENTROPIC DOWNGLIDE. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...FWD...OUN... 32899698 32629747 33469731 33959720 34629704 35739672 36539622 36799596 36939537 36739500 36579477 36199502 34899566 34469603 33449669 WWWW From mcd at goshenarc.org Mon Jan 15 00:34:46 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 19:34:46 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150037 SWOMCD SPC MCD 150037 MOZ000-ARZ000-TXZ000-OKZ000-150600- MESOSCALE DISCUSSION 0064 NWS STORM PREDICTION CENTER NORMAN OK 0637 PM CST SUN JAN 14 2007 AREAS AFFECTED...SW MO/SE OK/NE AND CNTRL TX/NW AR CONCERNING...WINTER MIXED PRECIPITATION VALID 150037Z - 150600Z PERIODS OF SLEET AND FREEZING RAIN ARE EXPECTED ACROSS SOUTHWEST MISSOURI...SOUTHEAST OKLAHOMA...NORTHEAST AND CENTRAL TEXAS...AND NORTHWEST ARKANSAS THIS EVENING. ACCUMULATIONS ARE EXPECTED TO BE AROUND .05 INCHES TO .10 INCHES PER HOUR. PRECIPITATION RATES HAVE BEEN DIMINISHING THROUGHOUT THE AFTERNOON OVER THE REGION...HOWEVER...SOME AREAS OF FROZEN PRECIPITATION ARE STILL OCCURRING AND WILL CONTINUE FOR THE NEXT SEVERAL HOURS...ESPECIALLY OVER NORTH CENTRAL TEXAS INCLUDING THE DALLAS/FT. WORTH METROPLEX. LATEST RADAR IMAGERY CONTINUES TO SHOW DEVELOPING PRECIPITATION BANDS THROUGHOUT THE REGION...AND AS THESE MOVE NEAR AND AROUND THE 32 F ISOTHERM...A MIX OF LIQUID AND FROZEN PRECIP WILL OCCUR...WITH SOME LOCALIZED HEAVY AMOUNTS. ADDITIONALLY...THE FROZEN PRECIP WILL CONTINUE TO MOVE AND DEVELOP SOUTHEASTWARD WITH THE 32 F LINE. BOTH THE RUC AND NAM AGREE THAT THE AREAS OF HEAVY SLEET AND FREEZING RAIN WILL CONTINUE TO DIMINISH INTO THE EVENING. THE LATEST NAM SHOWS A NARROW WINDOW OF FOCUSED VERTICAL MOTION FOR THE NEXT SEVERAL HOURS...AND THEN DIMINISHES BY ROUGHLY 06Z AND MOVES EASTWARD. THUS...THE PERIOD OF SIGNIFICANT FROZEN PRECIPITATION WILL MAINLY OCCUR WITHIN THAT TIME FRAME. ..LEVIT.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SGF...SHV...TSA...FWD...OUN...EWX...SJT... 30929853 31079922 31349961 31899962 33099848 34199700 36159499 38009344 37839234 37049194 35959282 34869371 32659518 31589636 31119773  From mcd at goshenarc.org Mon Jan 15 01:05:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 20:05:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150108 SWOMCD SPC MCD 150107 MIZ000-OHZ000-INZ000-ILZ000-WIZ000-150600- MESOSCALE DISCUSSION 0065 NWS STORM PREDICTION CENTER NORMAN OK 0707 PM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS NRN IL...EXTREME SERN WI...SRN LM...EXTREME NRN INDIANA...EXTREME NWRN OH...SRN/CENTRAL LOWER MI. CONCERNING...WINTER MIXED PRECIPITATION VALID 150107Z - 150600Z NEWD MOVING AREA OF PRECIP NOW OVER CENTRAL PORTIONS INDIANA/IL WILL MOVE ATOP FREEZING SFC TEMPS IN MI/INDIANA AND ERN WI/IL BORDER REGIONS...AND PORTIONS N-CENTRAL/NERN IL...THROUGH 230Z. THIS ACTIVITY WILL BE PRIMARILY IN FORM OF LIGHT FREEZING RAIN WITH RATES GENERALLY AOB .10 INCH HOUR...BUT LOCALLY TO .25 INCH/HOUR. BETWEEN 3Z-6Z...FREEZING RAIN WITH RATES LOCALLY NEAR .25-.5 INCH/HOUR MAY MOVE NEWD ACROSS SRN LOWER MI. TRANSITION THROUGH MIXED PHASE WITH SLEET...THEN TO SLEET/SNOW MIX...IS POSSIBLE WITH NWD EXTENT ACROSS S-CENTRAL TO CENTRAL LOWER MI. ISOLATED SNOW RATES 1-2 INCH/HOUR MAY DEVELOP BY 6Z W-CENTRAL LOWER MI. LOW LEVEL WAA AND MOISTURE TRANSPORT WILL STRENGTHEN ACROSS THIS AREA FROM SW-NE AS MID-UPPER LEVEL PERTURBATION NOW OVER CENTRAL HIGH PLAINS CONTINUES TO EJECT NEWD. NRN PORTION OF MOST INTENSE ISENTROPIC ASCENT IN 291-297K LAYER WILL OVERLAP SFC FREEZING TEMPS ACROSS NERN IL...NRN INDIANA AND SRN LOWER MI BETWEEN 3Z AND 6Z...CONCURRENT WITH INCREASE IN 850 MB LLJ TO 40-50 KT JUST S OF AREA ACROSS CENTRAL/SRN INDIANA AND SRN IL. 850-750 MB LAYER FRONTOGENESIS REASONABLY IS PROGGED TO STRENGTHEN OVER THIS AREA THROUGH 6Z...AIDING LIFT. AT SFC...FREEZING LINE IS ANALYZED AT 0Z NEAR TOL...SBN...VPZ...NWD ACROSS RELATIVELY WARM LM WATERS...THEN SWWD AGAIN ACROSS NRN FRINGES CHI METRO...TO ABOUT 10 N PIA. PRIND CAA AND WEAK WET BULB EFFECTS WILL HELP TO DRIFT THIS LINE SWD OVER NRN INDIANA. HOWEVER FREEZING LINE MAY NOT CHANGE MUCH OVER IL DUE TO LACK OF SFC CAA...COMBINED WITH SENSIBLE WARMING FROM DESCENT OF RELATIVELY WARM PRECIP THROUGH SATURATED AIR. RUC FCST SOUNDINGS INDICATE THIS WILL LEAD TO SATURATED...ROUGHLY 7 KFT DEEP SUPERFREEZING LAYER ACROSS NRN INDIANA...ABOVE SHALLOW FREEZING LAYER NEAR SFC. SUPERFREEZING LAYER SHOULD TRANSITION TO 4-5 KFT DEPTH OVER SRN LOWER MI...ATOP DEEPER SUBFREEZING BOUNDARY LAYER MORE CONDUCIVE FOR SLEET. WITH NWWD EXTENT IN LOWER MI...THERMAL PROFILES ALOFT WILL SUPPORT SNOW. STEEP LAPSE RATES OF 6-7 DEG C/KM...IN PORTIONS OF MOST FAVORABLE THERMAL ZONES FOR DENDRITIC GROWTH...INDICATE SOME CONVECTIVE SNOW IS POSSIBLE WITH LOCALIZED HEAVY RATES. ..EDWARDS.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...APX...IWX...GRR...LOT...MKX...DVN... 41858983 43128761 44258652 44278507 42948295 42028310 41468363 41328525 41628648 42238670 42488728 42028825 41828888 41628964 41758988  From mcd at goshenarc.org Mon Jan 15 05:12:12 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 00:12:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150515 SWOMCD SPC MCD 150514 NYZ000-151115- MESOSCALE DISCUSSION 0066 NWS STORM PREDICTION CENTER NORMAN OK 1114 PM CST SUN JAN 14 2007 AREAS AFFECTED...SRN NY CONCERNING...FREEZING RAIN VALID 150514Z - 151115Z FREEZING RAIN WILL DEVELOP OVER SOUTHERN NEW YORK DURING THE NEXT SEVERAL HOURS. LOCALIZED AND HEAVIEST ACCUMULATION VALUES ARE EXPECTED TO BE AROUND ONE QUARTER INCH BY 12Z. NUMEROUS FREEZING RAIN REPORTS CONTINUE IN SOUTHERN MICHIGAN...AND THE AIR MASS OVER THE SOUTHERN NEW YORK AREA IS SIMILAR WITH TEMPERATURES EITHER AT FREEZING OR JUST BELOW. AS MOISTURE ADVECTS NORTHEASTWARD INTO NEW YORK...FREEZING RAIN WILL DEVELOP AND IS EXPECTED TO BE HEAVIEST FROM AROUND 09Z TO 12Z. OPERATIONAL MODELS AGREE THAT THE BROAD REGION OF UPWARD VERTICAL MOTION AHEAD OF THE LONGWAVE TROUGH CURRENTLY LOCATED OVER THE MIDWEST WILL CONTINUE TO MOVE TO THE EAST...PROVIDING A FAVORABLE ENVIRONMENT FOR PRECIPITATION IN THE REGION. THIS REGION OF LIFT WILL BE JUXTAPOSED WITH AN AIR MASS THAT IS CLOSE TO FREEZING...AIDING IN THE DEVELOPMENT OF SUPERCOOLED DROPLETS AS THE RAIN FALLS THROUGH THE SHALLOW COLD LAYER NEAR THE SURFACE. ADDITIONALLY...THE LATEST 21Z SREF RUN SHOWS A HIGH PROBABILITY FOR LOCALIZED FREEZING PRECIP RATES TO BE ABOVE .05 INCHES PER HOUR...ESPECIALLY DURING THE LATER HALF OF THE FORECAST PERIOD. FINALLY...SOME SLEET COULD BE MIXED IN WITH THE FREEZING RAIN...ALSO IN LOCALIZED AREAS...ESPECIALLY IN NORTHERN PORTIONS OF THE DISCUSSION AREA WHERE TEMPERATURES WILL BE A FEW DEGREES COOLER THAN 32 F. ..LEVIT.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...ALY...BGM...BUF... 43257890 43267785 43317673 43347621 43287571 43207511 42977455 42637385 42157366 42057393 41947432 41927482 42037550 42037694 42007770 42027840 42027882 42037922 42137951 42577899 42967890  From mcd at goshenarc.org Mon Jan 15 05:31:39 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 00:31:39 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150534 SWOMCD SPC MCD 150534 MIZ000-OHZ000-INZ000-ILZ000-WIZ000-151030- MESOSCALE DISCUSSION 0067 NWS STORM PREDICTION CENTER NORMAN OK 1134 PM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS CENTRAL/SRN LOWER MI...EXTREME SERN WI...EXTREME NWRN OH...EXTREME NRN INDIANA...SRN LM...AND NRN IL. CONCERNING...WINTER MIXED PRECIPITATION VALID 150534Z - 151030Z MAJOR SFC ICING EVENT POSSIBLE THROUGH 12Z ACROSS PORTIONS S-CENTRAL/SERN LOWER MI...EXTREME NRN INDIANA AND NWRN OH...WITH FREEZING RAIN CONTINUING THROUGH MUCH OF DISCUSSION PERIOD. RATES LOCALLY EXCEEDING .25 INCH/HOUR ARE POSSIBLE BRIEFLY...WITH .10-.25 INCH RATES COMMON. TRANSITION TO LIGHTER FREEZING RAIN RATES IS EXPECTED WITH WWD EXTENT ACROSS EXTREME SWRN LOWER MI...SRN LM INTO NRN IL...WHERE PRECIP SHOULD WEAKEN FROM SW-NE DURING NEXT 4-6 HOURS. MEANWHILE MIXED-PHASE TRANSITION IS EXPECTED FROM FREEZING RAIN TO SLEET TO SNOW -- FROM S-N ACROSS S-CENTRAL AND ERN LOWER MI. 5Z SFC MESOANALYSIS SHOWED FREEZING LINE NEAR NRN SHORE LE...THEN INVOF MI/OH AND MI/INDIANA BORDERS...ARCHING NWD OVER SRN LM...THEN WINDING ERRATICALLY SWWD ACROSS NRN IL. MODIFIED RAOBS AND RUC SOUNDINGS INDICATE 5-8 KFT DEEP SUPERFREEZING AIR MASS ABOVE SHALLOW NEAR-SFC FREEZING LAYER FROM MI/INDIANA AND MI/OH BORDER REGIONS NWD OVER S-CENTRAL/SWRN LOWER MI. THIS PROFILE GRADUALLY WILL COOL WITH TIME...AS APPARENT TOP-DOWN PRECIP COOLING OCCURS IN WARM LAYER THROUGH MELTING AND RELATED LATENT HEAT ABSORPTION PROCESSES. THIS WILL MAINTAIN FREEZING RAIN FOR SEVERAL MORE HOURS OVER SERN LOWER MI BUT AID IN TRANSITION TO MORE FROZEN PRECIP FARTHER W AND NW. MEANWHILE...WITH BOUNDARY LAYER NEARLY SATURATED...WET BULB COOLING EFFECTS NEAR SFC SHOULD BE MINIMAL...AND FREEZING LINE SHOULD MOVE LITTLE OVER MOST OF AREA THROUGH REMAINDER OVERNIGHT HOURS. STRONGEST ISENTROPIC ASCENT IN 288-294 K LAYER...AND GREATEST FRONTOGENETIC FORCING IN 800-850 MB PRESSURE LAYER...ARE FCST TO MOVE NEWD ACROSS REGION THROUGH 9Z...THEN DIMINISH THEREAFTER AS BULK OF STRONGEST FORCING SHIFTS EWD OVER SRN ONT AND INTO UPSTATE NY. REF SPC MESOSCALE DISCUSSION 676 FOR MORE DETAILS ON DOWNSTREAM FREEZING RAIN POTENTIAL. ..EDWARDS.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT...MKX...DVN... 42948787 43538557 43598409 43868251 43168234 41858309 41558342 41548499 41678653 42238670 42488728 42028825 41388844 41528968 41758988  From mcd at goshenarc.org Mon Jan 15 12:48:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 07:48:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 151250 SWOMCD SPC MCD 151250 MEZ000-NHZ000-MAZ000-VTZ000-NYZ000-151645- MESOSCALE DISCUSSION 0068 NWS STORM PREDICTION CENTER NORMAN OK 0650 AM CST MON JAN 15 2007 AREAS AFFECTED...NY...NH...VT...MA CONCERNING...FREEZING RAIN VALID 151250Z - 151645Z FREEZING RAIN MIXED WITH SLEET WILL CONTINUE THROUGH LATE MORNING IN A WIDESPREAD AREA FROM BUFFALO NY EXTENDING EWD TO ALBANY NY AND TO JUST NORTH OF BOSTON MA. ADDITIONAL ICE ACCUMULATION SHOULD OCCUR WITH UP TO A HALF INCH OF FREEZING RAIN MIXED WITH SLEET POSSIBLE IN SOME AREAS. LATEST SFC ANALYSIS SHOWS A QUASI-STATIONARY FRONT LOCATED FROM NRN OH EXTENDING EWD INTO FAR NRN PA AND ACROSS TO SRN NEW ENGLAND. ATTM...THE FREEZING LINE IS LOCATED WITHIN 50 MILES NORTH OF THE BOUNDARY IN FAR SRN NY AND MA. 12Z SOUNDINGS FROM ALBANY NY AND BUFFALO NY SHOW A THICK WARM LAYER STARTING FROM 1500 TO 2500 FEET ABOVE GROUND LEVEL EXTENDING NEARLY TO THE 700 MB LEVEL IN BOTH SOUNDINGS. THE WARMEST AIR IS LOCATED NEAR 850 MB WITH TEMPS IN THE 4 TO 6 CELSIUS RANGE. FORECAST SOUNDINGS KEEP THE WARM LAYER INTACT THROUGH MIDDAY SUGGESTING A STRONG POTENTIAL FOR FREEZING RAIN AND TO A LESSER EXTENT SLEET. WIDESPREAD FREEZING RAIN SHOULD CONTINUE DUE TO STRONG ASCENT ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY MOVING EWD ACROSS THE REGION. PRECIPITATION MAY ALSO BECOME ENHANCED BY LATE MORNING DUE TO INCREASING LOW-LEVEL WARM ADVECTION NORTH OF THE FRONTAL BOUNDARY. THE SLEET POTENTIAL SHOULD BE GREATEST ACROSS THE NRN PART OF THE MCD AREA. FREEZING RAIN MAY DIMINISH BY LATE MORNING ACROSS THE FAR WRN PART OF THE MCD AREA AS THE SHORTWAVE TROUGH MOVES EWD. IN ADDITION...THE FREEZING LINE SHOULD MOVE SLOWLY NWD ALLOWING FOR SOME AREAS IN THE SRN PART OF THE MCD AREA TO CHANGEOVER TO RAIN. ..BROYLES.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF... 43547093 42677160 42367268 41937446 42097547 42067736 42167805 42377891 43027929 43777866 43927667 43977227 43687087 WWWW From mcd at goshenarc.org Tue Jan 16 05:44:12 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 16 Jan 2007 00:44:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 160546 SWOMCD SPC MCD 160546 TXZ000-161015- MESOSCALE DISCUSSION 0071 NWS STORM PREDICTION CENTER NORMAN OK 1146 PM CST MON JAN 15 2007 AREAS AFFECTED...SOUTH CENTRAL TX/TX HILL COUNTRY INTO SOUTHEAST TX CONCERNING...WINTER MIXED PRECIPITATION VALID 160546Z - 161015Z FREEZING RAIN/PERHAPS SOME SLEET IS LIKELY TO PERSIST OVERNIGHT ACROSS MUCH OF SOUTH CENTRAL TX/THE TX HILL COUNTRY INTO SOUTHEAST TX...INCLUDING A CORRIDOR FROM SAN ANTONIO/AUSTIN TO COLLEGE STATION AND LUFKIN. LIQUID EQUIVALENTS UP TO 0.05-0.10 IN/HR WILL CONTRIBUTE TO ADDITIONAL ICE GLAZE AND HAZARDOUS TRAVEL CONDITIONS. AS COLD ARCTIC AIR BECOMES PROGRESSIVELY ENTRENCHED ACROSS SOUTH TX...SURFACE WET BULB ZERO C LINE AT 05Z IS ANALYZED FROM NEAR THE UVALDE-HONDO-SAN ANTONIO CORRIDOR...TO NEAR VICTORIA AND THE NORTHWEST HOUSTON METRO WITH EASTERN EXTENT. COINCIDENT WITH DEEP PACIFIC MOISTURE PLUME AND ALIGNED WITH LOW TO MID LEVEL BAROCLINIC ZONE/FRONTOGENETICAL FORCING...VOLUMETRIC RADAR DATA AND SURFACE OBSERVATIONS HAVE SHOWN A PERSISTENT BELT OF PRECIPITATION STREAMING NORTHEASTWARD THIS EVENING OUT OF MEXICO INTO SOUTH CENTRAL/SOUTHEAST TX. ALTHOUGH SOMEWHAT LIMITED BY DRY AIR IN THE LOW LEVELS PER SURFACE OBSERVATIONS AND RECENT ACARS DATA FROM NEAR SAN ANTONIO...LIGHT FREEZING RAIN/ICE GLAZE HAS BEEN COMMON THIS EVENING ACROSS SOUTH CENTRAL/SOUTHEAST TX. PER MODEL SOUNDINGS AND THE AFOREMENTIONED ACARS DATA...FREEZING RAIN SHOULD REMAIN PREDOMINANT OVERNIGHT VIA A WARM/MELTING LAYER /5-7 DEG C/ ABOVE A SHALLOW SUB-FREEZING LAYER IN THE LOWEST 1 KM. LIQUID EQUIVALENTS AROUND 0.05 IN/HR HAVE BECOME MORE COMMON OVER THE PAST HOUR OR TWO PER RECENT OBSERVATIONS AROUND SAN ANTONIO /KSAT AND KSSF/...SUGGESTING THAT THE DRY LOW LEVELS HAVE BECOME SATURATED SIMILAR TO FORECAST TRENDS REFLECTED IN 00Z NAM SOUNDINGS. 00Z NAM/WRM-NMM 4KM GUIDANCE SUGGESTS THIS GENERAL SOUTHWEST-NORTHEAST BAND OF AT LEAST LIGHT MIXED PRECIPITATION SHOULD PERSIST THROUGH THE OVERNIGHT...WITH SOME INCREASE/NORTHWARD SPREAD SUGGESTED OVERNIGHT ACROSS THE HILL COUNTRY...INCLUDING THE JUNCTION/KERRVILLE TX VICINITIES. PREDOMINANT FREEZING RAIN WITH LIQUID EQUIVALENTS UP TO 0.10 IN/HR WILL CONTRIBUTE TO FURTHER ICE GLAZE OVERNIGHT. ..GUYER.. 01/16/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SHV...HGX...FWD...EWX...SJT... 29100042 29690085 30430016 30579750 31609481 30559490 28979807 28849902  From mcd at goshenarc.org Fri Jan 19 06:55:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 01:55:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190658 SWOMCD SPC MCD 190658 MEZ000-191300- MESOSCALE DISCUSSION 0080 NWS STORM PREDICTION CENTER NORMAN OK 1258 AM CST FRI JAN 19 2007 AREAS AFFECTED...PORTIONS OF SRN AND ERN ME CONCERNING...HEAVY SNOW VALID 190658Z - 191300Z ...SNOW WILL CONTINUE TO SPREAD ACROSS MUCH OF SRN AND CNTRL ME EARLY THIS MORNING... LATEST SFC ANALYSIS SHOWS WEAK SFC LOW JUST NORTH OF CAPE COD. SFC PRESSURE FALLS OF 1-2 MB/HR ARE OBSERVED FROM PORTIONS OF MA ACROSS NRN NEW ENGLAND...SUGGESTING THAT INTENSIFYING SFC LOW WILL LIFT NWD TOWARD GULF OF ME BY 12Z FRIDAY. RADAR LOOPS INDICATE PRECIPITATION HAS ALREADY SPREAD AS FAR NORTH AS BANGOR WITH RAIN OR FREEZING RAIN OBSERVED CLOSE TO THE COAST. LARGE SCALE ASCENT ASSOCIATED WITH ERN NY SHORTWAVE IS APPARENT ON SATELLITE LOOPS...AND THIS WILL LIKELY INTERACT WITH BAROCLINIC ZONE ALONG THE COAST. LOW LEVEL FRONTOGENESIS IS FORECAST TO INCREASE OVERNIGHT...AND THIS WILL SUPPORT THE DEVELOPMENT OF A MORE SUBSTANTIAL SNOW BAND BY 12Z...WITH HEAVIEST SNOW RATES EXPECTED AFTER 09Z. FORECAST SOUNDINGS SUGGEST PROFILES FROM AUGUSTA TO BANGOR ARE OR WILL BECOME SATURATED THROUGH A DEEP LAYER WITH DENDRITIC GROWTH ZONES FAVORABLE FOR MODERATE TO HEAVY SNOW PRODUCTION. ..TAYLOR.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CAR...GYX... 45286784 43966978 43837074 44377095 45246986 45746891 45966837 45876783  From mcd at goshenarc.org Fri Jan 19 08:19:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 03:19:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190821 SWOMCD SPC MCD 190821 TXZ000-NMZ000-191215- MESOSCALE DISCUSSION 0081 NWS STORM PREDICTION CENTER NORMAN OK 0221 AM CST FRI JAN 19 2007 AREAS AFFECTED...EXTREME SOUTHEAST NM...PARTS OF WEST TX CONCERNING...FREEZING RAIN VALID 190821Z - 191215Z THE POTENTIAL FOR MORE WIDESPREAD FREEZING RAIN APPEARS TO BE ON THE INCREASE EARLY TODAY ACROSS PARTS OF WEST TX AND SOUTHEAST NM. THE GREATEST CHANCE FOR GLAZE AMOUNTS IN EXCESS OF 0.10 INCH PER 3H SHOULD EVOLVE GENERALLY NORTH OF I20/I10 AND WEST OF MAF THROUGH DAYBREAK. LATEST SATELLITE IMAGERY DEPICTS EXTENSIVE TROPICAL CONNECTION AND EVOLVING BAROCLINIC LEAF CLOUD PATTERN ACROSS NRN MEXICO...NM... AND WEST TX. BENEATH THE MID/UPPER LEVEL MOISTURE PLUME AND INCREASING MID LEVEL DYNAMICS WELL AHEAD OF BAJA CLOSED LOW...LOW LEVEL AIR MASS ACROSS THE PECOS VALLEY AND POINTS WEST WAS COOL/COLD AND RELATIVELY DRY. AN EXPANDING AREA OF PRECIPITATION ACROSS THE RIO GRANDE AND PECOS VALLEYS TO SERN NM HAS CONTRIBUTED TO DIABATIC COOLING IN THE BOUNDARY LAYER AND SURFACE WET BULB FREEZING LINE CURRENTLY EXTENDS FROM BIG SPRING WWD ACROSS THE PECOS VALLEY TO WEST OF GDP. THE SURFACE FREEZING LINE LAGS THE WET BULB FREEZING LINE TO THE NORTH BUT HAS BEEN SETTLING SWD EARLY TODAY AS PRECIPITATION RATES INCREASE. LATEST MODEL GUIDANCE IS SUGGESTING THAT A BAND OF FREEZING RAIN COULD BECOME ESTABLISHED ACROSS THE REGION OVER THE NEXT FEW HOURS. PERSISTENT ISENTROPIC LIFT ATOP THE SURFACE-BASED COLD DOME COULD RESULT IN FREEZING RAIN RATES UP TO A FEW HUNDREDTHS PER HOUR THROUGH 12Z. ..CARBIN.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SJT...MAF...EPZ... 31930556 31510537 31120471 31410354 31530174 31770092 32240071 32640101 32760189 32530393 32270551  From mcd at goshenarc.org Fri Jan 19 12:22:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 07:22:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191225 SWOMCD SPC MCD 191225 TXZ000-NMZ000-191830- MESOSCALE DISCUSSION 0082 NWS STORM PREDICTION CENTER NORMAN OK 0625 AM CST FRI JAN 19 2007 AREAS AFFECTED...SOUTHEAST NM...WEST TX CONCERNING...WINTER MIXED PRECIPITATION VALID 191225Z - 191830Z AREAS OF ICE PELLETS...FREEZING RAIN...AND LIGHT SNOW ARE EXPECTED TO PLAGUE PARTS OF SOUTHEAST NM AND WEST TX THROUGH THE MORNING. WHILE OVERALL ACCUMULATIONS WILL REMAIN LIGHT...GENERALLY LESS THAN 0.05 INCH LIQUID EQUIVALENT PER HOUR...ROAD SURFACES BETWEEN MAF AND LBB MAY BECOME SLICK. HIGHER ELEVATIONS ACROSS FAR WEST TX AND SERN NM COULD EXPERIENCE A MIX OF ICE PELLETS AND SNOW... PERHAPS CHANGING TO ALL SNOW AT SOME LOCATIONS DURING THE MORNING. WARM/MOIST CONVEYOR BELT HAS DEVELOPED ATOP COLD SURFACE-BASED AIR MASS FROM THE RIO GRANDE VALLEY TO THE TX SOUTH PLAINS THIS MORNING. LARGE SCALE JET COUPLING BETWEEN MID LEVEL CONFLUENCE ZONE ACROSS THE PLAINS AND UPPER LOW OVER BAJA WILL MAINTAIN STRONG LOW THROUGH MID LEVEL ISENTROPIC ASCENT OVER THESE AREAS THROUGH THE MORNING. LATEST 4KM WRF-NMM AND WRF-NSSL SUPPORT MAXIMUM HOURLY PRECIPITATION RATES BETWEEN 0.03 AND 0.05 INCH ACROSS THE AREA OF CONCERN THROUGH 18Z. RECENT RADAR AND OBSERVATIONAL TRENDS WOULD SUGGEST A RELATIVELY NARROW RIBBON OF FREEZING RAIN SHOULD DEVELOP CLOSEST TO THE SURFACE WET-BULB FREEZING LINE. THIS LINE CURRENTLY PARALLELS I20 FROM THE MAF AREA TO NORTH OF PECOS. FARTHER NORTH...RADAR REFLECTIVITY AND MODEL SOUNDING PROFILES INDICATE ICE PELLETS AND/OR FREEZING RAIN WILL BE POSSIBLE. FORECAST PROFILES ALSO INDICATE THAT WEAK ELEVATED WARM LAYER DIMINISHES IN STRENGTH NORTH OF A GDP-CNM-LBB LINE AS STRONGER ASCENT DEVELOPS ACROSS THESE AREAS THROUGH THE MORNING. THUS...A TRANSITION TO LIGHT SNOW...OR A MIX OF SNOW AND ICE PELLETS WOULD BE THE MOST LIKELY PRECIPITATION TYPES IN THE NRN/NWRN PORTIONS OF THE MESOSCALE DISCUSSION AREA. ..CARBIN.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SJT...LUB...MAF...ABQ...EPZ... 32410073 32130138 31730213 31690356 31390400 30990429 31030485 31490551 31720554 32490531 33080498 33480434 33700331 33830223 33920144 33860029 33380022 32740047  From mcd at goshenarc.org Fri Jan 19 19:01:09 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 14:01:09 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191903 SWOMCD SPC MCD 191903 TXZ000-NMZ000-200000- MESOSCALE DISCUSSION 0083 NWS STORM PREDICTION CENTER NORMAN OK 0103 PM CST FRI JAN 19 2007 AREAS AFFECTED...CAPROCK/SOUTH PLAINS OF WEST TX AND EASTERN NM CONCERNING...WINTER MIXED PRECIPITATION VALID 191903Z - 200000Z A MIX OF SLEET AND SOME FREEZING RAIN IS EXPECTED TO DEVELOP NORTHWARD AND INCREASE ACROSS THE WEST TX PLAINS/CAPROCK VICINITY THROUGH THE AFTERNOON...INCLUDING THE LUBBOCK AND PLAINVIEW AREAS...WITH SNOW BECOMING MORE PREDOMINANT BY LATE AFTERNOON. MAINLY SNOW WILL BECOME INCREASINGLY HEAVY ACROSS EAST CENTRAL NM...WHERE SNOW RATES COULD REACH 1 IN/HR AFTER 21Z. WATER VAPOR IMAGERY AND UPPER AIR DIAGNOSTICS FEATURE A CLOSED UPPER LOW CENTERED NEAR NORTHERN BAJA MEXICO...WITH A DEEP PACIFIC MOISTURE PLUME EXTENDING ACROSS NORTHERN MEXICO INTO NM AND THE ADJACENT SOUTHERN PLAINS. OBSERVATIONAL TRENDS AND LATEST NAM/RUC AND 4KM WRF NMM/NSSL GUIDANCE SUPPORTS A NORTHWARD EXPANSION/INCREASE OF WINTER MIXED PRECIPITATION ACROSS NORTHWEST TX THIS AFTERNOON. WHILE LOW LEVEL DRY AIR WILL INITIALLY DETER HEAVY PRECIPITATION DEVELOPMENT WITH NORTH EXTENT ACROSS THE TX PANHANDLE...AND LOW LEVEL TEMPERATURE PROFILES HAVE GENERALLY BEEN MARGINAL AROUND FREEZING ACROSS WEST TX...HIGHER PRECIPITATION RATES/EVAPORATIVE COOLING HAVE BEEN SUFFICIENT TO BRING TEMPERATURES DOWN TO BELOW 32F AMIDST MIXED PRECIPITATION. A MIX OF SLEET/LIGHT FREEZING RAIN HAS BEEN COMMON OVER THE PAST FEW HOURS IN OBSERVATIONS AT LUBBOCK TX/CLOVIS NM. WITH LARGE SCALE FORCING FOR ASCENT INCREASING THIS AFTERNOON...A SPECIAL 15Z OBSERVED RAOB FROM REESE CENTER /JUST WEST OF LUBBOCK/ SUPPORTS A MAINTENANCE OF MAINLY SLEET/SOME FREEZING RAIN THROUGH AT LEAST EARLY AFTERNOON PER THE PARTIAL MELTING LAYER OBSERVED BETWEEN 750-825 MB. OF NOTE...BASED ON THE OBSERVED REESE SOUNDING DATA...IT APPEARS THE 12Z NAM/GFS POINT SOUNDINGS MAY BE EXHIBITING A FEW DEGREE COOL BIAS WITHIN THE ELEVATED WARM LAYER. RUC/NAM FORECAST SOUNDINGS ULTIMATELY SUPPORT SNOW BECOMING MORE PREDOMINANT ACROSS NORTHWEST TX BY LATE AFTERNOON. ACROSS EAST CENTRAL NM...VERTICAL PROFILES APPEAR MORE FAVORABLE FOR SNOW AS THE PREDOMINANT PRECIPITATION TYPE...ESPECIALLY FROM CLOVIS WESTWARD. OBSERVATIONAL TRENDS/NUMERICAL GUIDANCE SUGGEST SNOW RATES COULD REACH 1 IN/HR AFTER 21Z ACROSS EAST CENTRAL NM...INCLUDING THE CLOVIS/FORT SUMNER AREAS TO NEAR/JUST SOUTH OF I-40. ..GUYER.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LUB...AMA...MAF...ABQ...EPZ... 34680528 35030440 34970273 34840162 34420065 34300057 33140077 32770107 31920210 31860270 32000368 31990515 33420579  From mcd at goshenarc.org Sat Jan 20 01:52:53 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 20:52:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200155 SWOMCD SPC MCD 200154 OKZ000-TXZ000-200600- MESOSCALE DISCUSSION 0084 NWS STORM PREDICTION CENTER NORMAN OK 0754 PM CST FRI JAN 19 2007 AREAS AFFECTED...NORTHWEST TX/SOUTHWEST OK CONCERNING...WINTER MIXED PRECIPITATION VALID 200154Z - 200600Z A MIX OF FREEZING RAIN/SLEET IN ADDITION TO SOME SNOW WILL LIKELY PERSIST THROUGH MUCH OF THE EVENING FROM THE TX SOUTH PLAINS/CAPROCK VICINITY INTO PORTIONS OF NORTH CENTRAL TX AND SOUTHWEST/FAR SOUTH CENTRAL OK. A LIGHT ICE GLAZE IS POSSIBLE. IN ASSOCIATION WITH INCREASING PRECIPITATION RATES ACROSS MUCH OF NORTHWEST TX INTO FAR SOUTHWEST/SOUTH CENTRAL OK...WITH TEMPERATURES BORDERLINE AROUND FREEZING...SURFACE OBSERVATIONS CONTINUE TO GENERALLY REFLECT A MIX OF FREEZING RAIN/SOME SLEET ACROSS THIS CORRIDOR. THE 00Z AMARILLO RAOB FEATURES A 100 MB DEEP ELEVATED ABOVE-FREEZING LAYER CENTERED AROUND 750 MB...CONSISTENT WITH THE MIX OF SLEET/FREEZING RAIN AND SOME SNOW THAT HAS BEEN PREVALENT ACROSS NORTHWEST TX. FARTHER EAST...THE 00Z NORMAN OBSERVED RAOB FEATURES ABOVE FREEZING WARM LAYER /NEARLY 2 C/ CENTERED AROUND 770 MB...WITH AN ABUNDANCE OF DRY AIR IN THE LOW LEVELS BELOW 800 MB. BASED ON THESE OBSERVED SOUNDINGS...IT APPEARS 18Z NAM/18Z GFS POINT SOUNDINGS CONTINUE TO FEATURE A SLIGHT COOL BIAS /1-2 DEG C/ WITHIN THE CRITICAL ELEVATED WARM LAYER. WITH LITTLE THERMAL ADVECTION/FLUCTUATION...THIS SUGGESTS THE ONSET OF PREDOMINANT SNOW WILL REMAIN DELAYED AS THE ELEVATED WARM LAYER STRUGGLES TO COOL BELOW FREEZING...WITH A CONTINUANCE OF A FREEZING RAIN/SLEET MIX FROM THE CAPROCK/TX SOUTH PLAINS INTO SOUTHWEST OK THIS EVENING. THIS SCENARIO MAY SUPPORT LIGHT ICE ACCUMULATIONS. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OUN...LUB...AMA...MAF... 35420028 35389904 34769773 34049789 34199943 33580040 32550119 32670256 33960262 35150154  From mcd at goshenarc.org Sat Jan 20 06:21:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 01:21:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200624 SWOMCD SPC MCD 200623 TXZ000-201030- MESOSCALE DISCUSSION 0085 NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CST SAT JAN 20 2007 AREAS AFFECTED...S PLAINS/CAPROCK OF NWRN TX CONCERNING...FREEZING RAIN VALID 200623Z - 201030Z LIGHT FREEZING RAIN OCCASIONALLY MIXED WITH SLEET WILL PERSIST THROUGH THE OVERNIGHT HOURS. 3-HR PRECIP ACCUMULATIONS FROM .05 TO .10 IN WILL BE LIKELY. SURFACE TEMPERATURES ACROSS THE S PLAINS/CAPROCK REGION HAVE LEVELED OFF FROM 30 TO 32 DEGREES. AT 06Z...THE SURFACE FREEZING LINE WAS LOCATED FROM MAF TO 20 W ABI TO 40 SE CDS. 06Z MAF AND 03Z REESE TX OBSERVED SOUNDINGS WERE INDICATIVE OF FREEZING RAIN WITH OCCASIONAL SLEET ACROSS THE S PLAINS/CAPROCK REGION. NAMELY...A 100 MB DEEP ABOVE FREEZING WARM NOSE BETWEEN 725 TO 825 MB IN THE 06Z MAF SOUNDING TO A LESS THAN 50 MB ABOVE FREEZING LAYER IN THE 03Z REESE SOUNDING. BOTH 00Z NAM AND 03Z RUC POINT FORECAST SOUNDINGS CONTINUE THE TREND OF A SLIGHT COOL BIAS /AROUND 1 DEG C/ WITH THE ELEVATED WARM LAYER. THE THERMODYNAMIC PROFILE FROM THE SURFACE TO 700 MB IS EXPECTED TO CHANGE LITTLE THROUGH 12Z...WITH OCCASIONAL PHASE CHANGES LIKELY A RESULT OF SUBTLE VARIATIONS IN UPWARD VERTICAL MOTION. EVENING SATELLITE IMAGERY HAS DEPICTED A WELL-DEFINED MID/UPPER-LEVEL SUB-TROPICAL MOISTURE PLUME FROM THE SRN TIP OF BAJA CA NEWD ACROSS THE SRN HIGH PLAINS. THIS PLUME WAS LOCATED DOWNSTREAM OF A QUASI-STATIONARY UPPER LOW IN FAR NWRN SONORA. ALTHOUGH THIS LOW WILL BEGIN TO ACCELERATE EWD BY 12Z...THE MOISTURE PLUME SHOULD ONLY SHIFT SLOWLY EWD. IN ADDITION...LOW-LEVEL WAA /AS INFERRED FROM VEERING IN 06Z MAF SOUNDING/ IN WARM/MOIST CONVEYOR BELT REGION IS EXPECTED TO REMAIN NEARLY STATIONARY OVERNIGHT. THUS...LIGHT PRECIPITATION FOR THE NEXT SEVERAL HOURS WILL CONTINUE. ..GRAMS.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OUN...SJT...LUB...MAF... 33770170 34449996 34139979 33150010 32440036 32140076 31550131 31960209 32520269 33030255  From mcd at goshenarc.org Sat Jan 20 18:12:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 13:12:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201817 SWOMCD SPC MCD 201816 KSZ000-OKZ000-TXZ000-202215- MESOSCALE DISCUSSION 0087 NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CST SAT JAN 20 2007 AREAS AFFECTED...TX PANHANDLE/NORTHWEST OK INTO MUCH OF CENTRAL/EASTERN KS CONCERNING...HEAVY SNOW VALID 201816Z - 202215Z MODERATE/PERHAPS LOCALLY HEAVY SNOW WILL DEVELOP NORTHWARD AND BECOME MORE PREVALENT FROM NORTHWEST OK INTO MUCH OF CENTRAL AND EASTERN KS THROUGH THE AFTERNOON...INCLUDING THE WOODWARD OK AREA TO THE WICHITA/SALINA KS VICINITIES AND KS TURNPIKE. SNOW RATES UP TO 1 IN/HR ARE POSSIBLE. WITH UPPER LOW CONTINUING TO ADVANCE EASTWARD ACROSS NM...LARGELY COINCIDENT WITH THE EXIT REGION OF THE ASSOCIATED MID/UPPER LEVEL JET...MODERATE/LOCALLY HEAVY SNOW HAS BEEN PREVALENT FROM THE TX PANHANDLE/NORTHWEST OK INTO SOUTH CENTRAL KS THROUGH MIDDAY. IN FACT...1 IN/HR SNOW RATES HAVE BEEN RECENTLY REPORTED AT AMARILLO TX...WITH HEAVY SNOW ALSO REPORTED AT BORGER TX. WHILE SNOW SHOULD NOT BE PARTICULARLY FOCUSED ON THE MESOSCALE ACROSS NORTHWEST OK INTO CENTRAL/EASTERN KS THIS AFTERNOON...WEAKENING STATIC STABILITY /LARGELY COINCIDENT WITH NORTHEAST-ADVANCING DRY SLOT CURRENTLY ACROSS EASTERN NM INTO FAR WEST TX/ MAY TEND TO SOMEWHAT ENHANCE SNOW RATES IN A SCENARIO OTHERWISE CHARACTERIZED BY AMPLE FORCING FOR ASCENT/UVVS COINCIDENT WITH A FAVORABLE DENDRITIC GROWTH LAYER. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...EAX...TOP...ICT...OUN...GID...DDC...AMA... 38899554 38479494 38069471 37519485 37369544 37049662 36929720 36589819 36399869 36059957 35600078 36320111 36990083 37710011 39319825 WWWW From mcd at goshenarc.org Sat Jan 20 19:09:42 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 14:09:42 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201914 SWOMCD SPC MCD 201914 MOZ000-ARZ000-OKZ000-KSZ000-202345- MESOSCALE DISCUSSION 0088 NWS STORM PREDICTION CENTER NORMAN OK 0114 PM CST SAT JAN 20 2007 AREAS AFFECTED...CENTRAL/NORTHEAST OK INTO FAR SOUTHEAST KS/FAR NORTHERN AR/SOUTHWEST MO CONCERNING...WINTER MIXED PRECIPITATION VALID 201914Z - 202345Z A MIX OF FREEZING RAIN/SLEET APPEARS LIKELY TO PERSIST MUCH OF THE AFTERNOON FROM THE OKC METRO AREA TO AREAS ALONG/NORTH OF THE I-44 TURNPIKE IN NORTHEAST OK...AND INTO EXTREME SOUTHEAST KS...WITH SOME LIGHT ICE ACCUMULATIONS POSSIBLE. MIXED PRECIPITATION WILL ALSO STEADILY INCREASE THIS AFTERNOON ALONG I-44 IN SOUTHWEST MO...INCLUDING THE JOPLIN/SPRINGFIELD VICINITIES. SPECIAL 18Z NORMAN OK OBSERVED RAOB AND RECENT ACARS SOUNDING DATA NEAR THE OKLAHOMA CITY AIRPORT SUGGEST THE VERTICAL THERMAL PROFILE HAS FLUCTUATED VERY LITTLE FROM THIS MORNING /REFERENCE 12Z NORMAN RAOB/ ACROSS CENTRAL OK. WITH SURFACE TEMPERATURES GENERALLY HOLDING NEAR 32F...AT LEAST A PARTIAL MELTING LAYER /NEARLY 2 DEG C PER THE 18Z RAOB/ AROUND 800 MB WILL REMAIN CONDUCIVE FOR A CONTINUANCE OF FREEZING RAIN AND SLEET THIS AFTERNOON ACROSS PORTIONS OF CENTRAL/NORTHEAST OK. FARTHER EAST...WET BULB PROFILES FROM THE 18Z OBSERVED RAOB FROM SPRINGFIELD MO SEEMS TO PRIMARILY SUPPORT SLEET WITH PRECIPITATION ONSET ACROSS SOUTHWEST MO. THE 18Z SPRINGFIELD SOUNDING ALSO REFLECTS A TOP-DOWN SATURATION BETWEEN 600-800 MB SINCE 12Z. WITH FURTHER SATURATION AND PRECIPITATION RATES EXPECTED TO INCREASE THROUGH MID/LATE AFTERNOON FROM NORTHWEST AR INTO SOUTHWEST MO...A MIX OF SLEET AND SOME SNOW/PERHAPS FREEZING RAIN APPEARS LIKELY. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SGF...TSA...ICT...OUN... 37369249 37109183 36879170 36609168 36199220 35989313 36249418 36299577 36149639 35549709 35329756 35529799 36319764 37409540 37569405  From mcd at goshenarc.org Sun Jan 21 06:21:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 01:21:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210626 SWOMCD SPC MCD 210625 KYZ000-INZ000-211130- MESOSCALE DISCUSSION 0089 NWS STORM PREDICTION CENTER NORMAN OK 1225 AM CST SUN JAN 21 2007 AREAS AFFECTED...PORTIONS OF CNTRL KY...EXTREME SRN IND CONCERNING...WINTER MIXED PRECIPITATION VALID 210625Z - 211130Z AN ASSORTMENT OF PTYPES SHOULD OCCUR THROUGH 12Z AS A LARGE PRECIPITATION AREA ALONG THE MID-MS RIVER VALLEY EXPANDS EWD. ALTHOUGH SNOW AND RAIN MAY OCCUR AT TIMES...FREEZING RAIN AND SLEET WILL LIKELY BECOME THE PRIMARY PTYPES. ICE ACCUMULATIONS IN EXCESS OF .05 IN/HR WILL BE POSSIBLE...ESPECIALLY TOWARDS 12Z. AT 06Z...THE SURFACE WET BULB FREEZING LINE WAS LOCATED FROM AROUND 40 NE PAH TO 25 NE BWG TO 25 W CSV. THIS LINE HAS REMAINED NEARLY STATIONARY OVER THE PAST FEW HOURS AND SHOULD REMAIN AS SUCH FOR THE NEXT SEVERAL HOURS. RECENT SURFACE OBSERVATIONS INDICATE LIGHT RAIN/SNOW HAS REACHED WRN KY AND FAR SRN IND. IT WILL CONTINUE A GRADUAL PROGRESSION EWD AS TOP-DOWN SATURATION OCCURS GIVEN THE DRY LOW-LEVELS /AS EVIDENCED BY 00Z BNA SOUNDING/. MORE SUBSTANTIAL PRECIPITATION SHOULD OCCUR TOWARDS 12Z AS A 50-60 KT LLJ FROM THE LOWER MS VALLEY FOCUSES STRONG WARM/MOIST ADVECTION INTO THE REGION. BOTH 03Z RUC AND 00Z NAM MODEL GUIDANCE INDICATE SLOW WARMING OF THE 700 TO 850 MB LAYER EVEN AS SATURATION/UPWARD VERTICAL MOTION OCCURS. POINT FORECAST SOUNDINGS SHOW AN ABOVE FREEZING WARM NOSE DEVELOPING...WHICH WOULD SUPPORT FREEZING RAIN AND/OR SLEET. THIS IS ALSO SUPPORTED IN THE 20/21Z SREF GUIDANCE WHICH INDICATE THESE AS THE MOST LIKELY PTYPES. IF THIS INDEED OCCURS...PRECIPITATION RATES WOULD CERTAINLY SUPPORT ICE ACCUMULATIONS IN EXCESS OF .05 IN/HR. ..GRAMS.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...JKL...LMK...PAH... 38498642 38518571 38388506 37948419 37378431 37028498 37348561 37828638 38148684 38378719  From mcd at goshenarc.org Sun Jan 21 08:48:17 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 03:48:17 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210853 SWOMCD SPC MCD 210852 INZ000-KYZ000-ILZ000-211215- MESOSCALE DISCUSSION 0090 NWS STORM PREDICTION CENTER NORMAN OK 0252 AM CST SUN JAN 21 2007 AREAS AFFECTED...ERN IL...CNTRL IND CONCERNING...HEAVY SNOW VALID 210852Z - 211215Z A BURST OF HEAVY SNOWFALL WITH RATES OF UP TO AN INCH AN HOUR APPEARS LIKELY EARLY THIS MORNING FROM EAST-CNTRL IL ACROSS CNTRL AND SCNTRL SECTIONS OF INDIANA. INTENSE ISENTROPIC LIFT AND RESULTANT ADIABATIC COOLING WILL CONTINUE TO COUNTER LOW LEVEL WARMING ON THE NOSE OF THE 850MB JET TRANSITIONING OVER THE LOWER OH VALLEY EARLY TODAY. GIVEN UPSTREAM PW VALUES AROUND AN 1 INCH...AND 30-40KT LOW LEVEL JET... STRONG MOISTURE TRANSPORT WILL SUPPORT HIGH PRECIPITATION RATES OVER THE NEXT FEW HOURS. ADDITIONALLY...MELTING-INDUCED THERMALLY INDIRECT CIRCULATIONS DEVELOPING ACROSS THE RAIN/SNOW LINE COULD FURTHER BOOST SNOWFALL ON THE COLD SIDE OF THE PRECIPITATION TRANSITION ZONE. DEEP ISOTHERMAL NEAR/BELOW 0C PROFILES WILL ALSO FAVOR SNOWFLAKE GROWTH THROUGH ACCRETION AND RIMING. LATEST MODEL GUIDANCE APPEARS TO SUGGEST AN AXIS OF 3-4 INCH SNOWFALL ALONG THE I70 CORRIDOR...FROM NEAR MATTOON IL TO INDIANAPOLIS THROUGH 12Z. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...ILN...LMK...IND...ILX... 38818818 39348874 40098880 40238806 40358669 40038548 39668499 39098502 38678543 38708664  From mcd at goshenarc.org Sun Jan 21 09:25:38 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 04:25:38 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210930 SWOMCD SPC MCD 210929 WIZ000-ILZ000-IAZ000-MNZ000-211530- MESOSCALE DISCUSSION 0091 NWS STORM PREDICTION CENTER NORMAN OK 0329 AM CST SUN JAN 21 2007 AREAS AFFECTED...NERN IA TO EXTREME SERN MN/SWRN WI/NWRN IL CONCERNING...HEAVY SNOW VALID 210929Z - 211530Z MDT TO HVY SNOW SHOULD DEVELOP NEWD FROM THE MO RIVER VALLEY AND ACROSS PARTS OF THE UPPER MS VALLEY THROUGH THE MORNING. SNOWFALL RATES UP TO AN INCH PER HOUR APPEAR POSSIBLE. STRONG DYNAMIC FORCING FOR ASCENT WITHIN COMMA-HEAD OF DEEP LAYER CYCLONE WILL CONTINUE TO TRANSITION NEWD FROM THE MID MO RIVER VALLEY THIS MORNING. PRONOUNCED ASCENT OCCURRING WITHIN LEFT EXIT REGION OF 100KT MID LEVEL JET WAS CURRENTLY SUPPORTING A BROAD AREA OF MDT TO HVY SNOW ACROSS PARTS OF ERN NEB AND WRN IA. MEANWHILE...MID LEVEL DRY INTRUSION..CLEARLY EVIDENT IN SATELLITE IMAGERY...WAS PROBABLY LIMITING SNOWFALL RATES ACROSS PARTS OF CNTRL AND ERN IA ATTM. EXPECT HEAVIER SNOW TO REDEVELOP TO THE NORTHEAST THROUGH THE MORNING AS THE MID LEVEL LOW BEGINS OPEN UP AND TRACK NEWD OVER IA. A ZONE OF MODEST MID/UPPER LEVEL FRONTOGENESIS/LIFT OCCURRING IN A THERMODYNAMIC REGIME FAVORABLE FOR BOTH VAPOR TO ICE TRANSPORT AND DENDRITE GROWTH SHOULD EVOLVE ALONG THE MID LEVEL LOW TRACK. THIS PROCESS IS EXPECTED TO CONTRIBUTE TO AN AXIS OF ENHANCED SNOWFALL FROM NCNTRL IA TO SWRN WI THROUGH ABOUT 15Z. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...MKX...DVN...ARX...MPX...DMX... 42149008 41999347 41839391 42679482 43429402 43659212 43569108 43068978 WWWW From mcd at goshenarc.org Sun Jan 21 12:22:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 07:22:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 211227 SWOMCD SPC MCD 211227 WVZ000-VAZ000-OHZ000-KYZ000-INZ000-211730- MESOSCALE DISCUSSION 0092 NWS STORM PREDICTION CENTER NORMAN OK 0627 AM CST SUN JAN 21 2007 AREAS AFFECTED...SRN OH...NERN KY...AND PARTS OF WV CONCERNING...WINTER MIXED PRECIPITATION VALID 211227Z - 211730Z A RANGE OF WINTER PRECIPITATION TYPES WILL SPREAD ACROSS PARTS OF THE CUMBERLAND PLATEAU AND UPPER OH VALLEY THROUGH EARLY AFTERNOON. NRN PORTIONS OF THE DISCUSSION AREA...FROM SWRN OH ACROSS MUCH OF CNTRL WV WILL EXPERIENCE SNOW...POSSIBLY CHANGING TO FREEZING RAIN IN SOME AREAS BY LATER THIS MORNING. SRN PARTS OF THE AREA...ALONG THE OH RIVER...NERN KY...AND SRN WV WILL EXPERIENCE A PERIOD OF FREEZING RAIN...PERHAPS MIXED WITH ICE PELLETS AT TIMES. STRONG WARM/MOIST CONVEYOR BELT CONTINUES TO IMPINGE UPON ENTRENCHED SURFACE-BASED COLD DOME FROM THE UPPER OH VALLEY TO THE WRN SLOPES OF THE APPALACHIANS THIS MORNING. GRADUAL SATURATION OF DRY LOW LEVEL AIR MASS...AND RESULTANT EVAPORATIVE COOLING FROM SWRN OH INTO WV...WILL SUPPORT SNOW ACROSS THESE AREAS THROUGH THE MORNING. LATEST MODEL GUIDANCE SUGGESTS MAXIMUM SNOWFALL RATES OF AROUND 0.5 TO 1 INCH PER HOUR COULD OCCUR NORTH OF A CVG-CRW-BKW LINE THROUGH ABOUT 18Z. INCREASINGLY STRONG LOW LEVEL JET DEVELOPING NEWD FROM THE TN AND LOWER OH VALLEYS WILL ADVECT A WARMER LAYER OF AIR NEWD ATOP THE SURFACE-BASED SUB-FREEZING AIRMASS FROM NERN KY INTO SRN WV. PRECIPITATION IN THESE AREAS IS LIKELY TO FALL IN THE FORM OF FREEZING RAIN...PERHAPS MIXED WITH SLEET AT TIMES. UPSTREAM HOURLY PRECIPITATION AMOUNTS WOULD SUPPORT GLAZE ACCUMULATIONS OF AS MUCH AS 0.10 INCH PER HOUR IN SOME AREAS OVER THE NEXT FEW HOURS. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...RNK...RLX...JKL...ILN...LMK... 37538236 37838282 37968359 38028463 38478520 39668440 39808281 39418165 39208102 38638029 38258006 37628048 37118079 37038129 37198191 WWWW From mcd at goshenarc.org Sun Jan 21 16:45:50 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 11:45:50 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 211650 SWOMCD SPC MCD 211650 VAZ000-WVZ000-NCZ000-212115- MESOSCALE DISCUSSION 0093 NWS STORM PREDICTION CENTER NORMAN OK 1050 AM CST SUN JAN 21 2007 AREAS AFFECTED...EASTERN WV/WESTERN VA AND NORTHERN PART OF WESTERN NC CONCERNING...WINTER MIXED PRECIPITATION VALID 211650Z - 212115Z A MIX OF FREEZING RAIN AND SOME SLEET IS EXPECTED TO BECOME PREDOMINANT THROUGH THE AFTERNOON ACROSS EASTERN WV/NORTHWEST NC INTO MUCH OF WESTERN VA...INCLUDING THE I-81 CORRIDOR AND THE BLACKSBURG/ROANOKE/LYNCHBURG AREAS...AS WELL AS I-64 FROM SOUTHEAST WV THROUGH THE STAUNTON/WAYNESBORO VA AREAS. ICE ACCUMULATIONS ARE LIKELY VIA LIQUID EQUIVALENTS OF 0.05-0.10 IN/HR. WHILE THE 12Z OBSERVED RAOB FROM ROANOKE VA EXHIBITED AN ENTIRELY SUB-FREEZING RELATIVE WARM LAYER ALOFT /700-850 MB 1-2 DEG C BELOW ZERO/...A PRONOUNCED WARM ADVECTION REGIME IS QUICKLY MODIFYING THE ELEVATED THERMODYNAMIC PROFILE. OVER THE PAST COUPLE OF HOURS...OBSERVATIONS OF FREEZING RAIN HAVE BECOME MORE COMMON FROM SOUTHERN WV TO THE ROANOKE VA VICINITY...WITH LIGHT FREEZING RAIN JUST REPORTED /16Z/ AS FAR EAST AS THE LYNCHBURG VA AREA. WITH A SUB-FREEZING BOUNDARY LAYER LOCKED IN PLACE IN THE LOWEST 1 KM ALONG/EAST OF THE APPALACHIANS /REFERENCE 12Z ROANOKE RAOB/...AND PARTIAL/FULL MELTING ALOFT BECOMING MORE LIKELY...FREEZING RAIN/SLEET SHOULD BECOME PREDOMINANT FROM EASTERN WV/NORTHWEST NC INTO MUCH OF WESTERN VA THROUGH THE AFTERNOON. THIS IS ALSO SUPPORTED BY 09Z SREF PROBABILISTIC PRECIP-TYPE GUIDANCE. REGARDING THE ELEVATED WARM LAYER...COMPARISONS BETWEEN REGIONAL OBSERVED 12Z RAOBS AND 12Z NAM/12Z GFS GUIDANCE SUGGESTS THE SHORT TERM MODEL DEPICTIONS MAY BE SLIGHTLY TOO COOL...PERHAPS SUGGESTIVE OF A RELATIVELY QUICKER CHANGE-OVER TO FREEZING RAIN THROUGH EARLY/MID AFTERNOON VIA THE WARMER TEMPERATURES ALOFT. ..GUYER.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...AKQ...LWX...RNK...RLX... 38677952 38427856 37777820 37307828 36747898 36288009 36378131 37668135 38488027  From mcd at goshenarc.org Sun Jan 21 23:04:16 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 18:04:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 212309 SWOMCD SPC MCD 212308 VAZ000-MDZ000-220345- MESOSCALE DISCUSSION 0094 NWS STORM PREDICTION CENTER NORMAN OK 0508 PM CST SUN JAN 21 2007 AREAS AFFECTED...MUCH OF VA AND FAR SOUTHERN MD CONCERNING...WINTER MIXED PRECIPITATION VALID 212308Z - 220345Z FREEZING RAIN WILL CONTINUE TO REMAIN DOMINANT/SHIFT EAST-NORTHEAST THIS EVENING ACROSS CENTRAL VA...ESPECIALLY ALONG/SOUTHWEST OF I-64...FROM LYNCHBURG/DANVILLE TO THE CHARLOTTESVILLE/RICHMOND AREAS. ICE ACCUMULATIONS WILL BE POSSIBLE INTO THE VA PIEDMONT VIA LIQUID EQUIVALENTS UP TO 0.05 IN/HR. FARTHER NORTH...MAINLY SNOW WILL LIKELY YIELD TO A MIX OF SLEET/FREEZING RAIN EARLY THIS EVENING WITH NORTH EXTENT ALONG I-95 THROUGH THE FREDERICKSBURG VICINITY AND PERHAPS PORTIONS OF THE DC METRO. WITH A COLD/SUB-FREEZING WEDGE REMAINING IN PLACE VIA EXITING HIGH PRESSURE...STRONG WARM ADVECTION REGIME INTO THE MID ATLANTIC STATES AND ASSOCIATED ELEVATED WARM/MELTING LAYER HAS PROVED FAVORABLE FOR FREEZING RAIN MUCH OF THE AFTERNOON ACROSS SOUTHWEST INTO CENTRAL VA. WELL REPRESENTATIVE OF THIS SCENARIO...THE WET BULB PROFILE FROM THE EARLIER 18Z OBSERVED SOUNDING FROM GREENSBORO SC FEATURED A 4.0 DEG C WARM NOSE AROUND 800 MB...FAVORABLE FOR MELTING AND RESULTANT FREEZING RAIN. FARTHER NORTH...OBSERVATIONAL TRENDS IN ACCORDANCE WITH RECENT ACARS DATA /NEAR CHARLOTTESVILLE AND THE DC AREA/ AND LATEST SREF PROBABILISTIC GUIDANCE SUGGEST BOUTS OF INITIAL SNOW WILL CHANGE OVER TO SOME SLEET AND FREEZING RAIN EARLY THIS EVENING ALONG I-95 NORTH OF RICHMOND...INCLUDING THE FREDERICKSBURG AREA AND PERHAPS PORTIONS OF THE DC METRO. ..GUYER.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...AKQ...LWX...RNK... 38637751 38627699 38077653 37707668 37087750 36617888 36698010 37318007 38237855  From mcd at goshenarc.org Mon Jan 1 00:10:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 19:10:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010015 SWOMCD SPC MCD 010014 MIZ000-OHZ000-INZ000-ILZ000-010215- MESOSCALE DISCUSSION 0001 NWS STORM PREDICTION CENTER NORMAN OK 0614 PM CST SUN DEC 31 2006 AREAS AFFECTED...NE IL...NRN IN...SRN LWR MI CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010014Z - 010215Z ONGOING CONVECTIVE CLUSTER...OCCURRING NEAR CYCLONIC VORTICITY CENTER ASSOCIATED WITH COLD CORE OF NORTHEASTWARD ACCELERATING UPPER LOW...HAS BEEN GENERATING STRONG GUSTY WINDS APPROACHING SEVERE LIMITS. PEAK GUSTS NEAR/IN EXCESS OF 40 KTS HAVE BEEN RECORDED AT BLOOMINGTON/CHAMPAIGN AND MATTOON...LIKELY IN RESPONSE TO EVAPORATIVE COOLING/DOWNWARD MOMENTUM TRANSFER IN STRONGER DOWNDRAFTS. THOUGH DAYTIME SURFACE HEATING HAS BEEN WEAK... LOWER/MID TROPOSPHERIC COOLING/DRYING AHEAD OF MAIN SURFACE FRONT HAS CONTRIBUTED TO VERY STEEP LOW-LEVEL LAPSE RATE ENVIRONMENT SUPPORTING THIS PROCESS...WHICH MAY NOT BE APPRECIABLY AFFECTED BY LOSS OF DAYTIME HEATING. THUS...RISK FOR STRONG GUSTY... POTENTIALLY DAMAGING WINDS MAY CONTINUE WITH CONVECTION AS IT SPREADS ACROSS LAFAYETTE IND AREA AND AREAS NEAR/SOUTH OF CHICAGO...THROUGH NORTHERN INDIANA INTO SOUTHERN LOWER MICHIGAN BY LATE EVENING. AS ACTIVITY APPROACHES THE DETROIT AREA TOWARD 04-06Z...MODEL GUIDANCE SUGGESTS STORMS MAY BEGIN TO DIMINISH ASSOCIATED WITH STABILIZATION AS LOW-LEVEL COOLING OVERTAKES COOLING ALOFT. ..KERR.. 01/01/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...IWX...GRR...IND...LOT...ILX... 41118844 41898801 42858666 42978527 42168426 40928502 39738605 39208713 39238780 40038772 40638817 WWWW From mcd at goshenarc.org Thu Jan 4 16:06:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 11:06:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 041610 SWOMCD SPC MCD 041609 LAZ000-041845- MESOSCALE DISCUSSION 0005 NWS STORM PREDICTION CENTER NORMAN OK 1009 AM CST THU JAN 04 2007 AREAS AFFECTED...PORTIONS SRN LA. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 041609Z - 041845Z AIR MASS FCST TO SLOWLY DESTABILIZE ALONG LA COAST NEXT SEVERAL HOURS...INCREASING POTENTIAL FOR SVR. DAMAGING GUSTS AND A FEW TORNADOES ARE POSSIBLE. LAND AREA AFFECTED INITIALLY WILL BE RATHER SMALL AND CONFINED TO IMMEDIATE COAST. HOWEVER...GRADUAL INLAND SHIFT OF POTENTIAL IS POSSIBLE WITH TIME AS MARINE/WARM FRONT NOW JUST OFFSHORE SHIFTS NWD. SFC MESOANALYSIS INDICATES WEAK FRONTAL-WAVE LOW OVER GULF S BPT AND E GLS...WITH WARM FRONT EWD OVER COASTAL WATERS TOWARD MOUTH OF MS RIVER. COLD FRONT EXTENDS SW OF LOW TO OFFSHORE BRO. BKN PREFRONTAL SQUALL LINE -- EVIDENT AT 1545Z FROM NEAR POE SSEWD ACROSS WARM FRONT...THEN SWWD OVER GULF -- WILL CONTINUE MOVING EWD ACROSS SRN LA. MAIN CONCERN ATTM IS EXTENT OF INLAND PENETRATION OF MARINE SECTOR BEFORE PASSAGE OF PREFRONTAL CONVECTIVE BAND. MORE PRECISE WARM FRONTAL LOCATION IS INDEFINITE...HOWEVER FCST SOUNDINGS INDICATE FRONTAL SLOPE IS VERY SHALLOW. TIME SERIES OF RUC SOUNDINGS INDICATE EFFECTIVE LIFTED PARCELS BECOMING SFC-BASED WITHIN 40-50 NM N OF MODELED WARM FROPA. NEARLY SATURATED LOW-MIDLEVEL AIR MASS AND WEAK LAPSE RATES WILL BE COUNTERBALANCED ALONG AND S OF WARM FRONT BY SFC DEW POINTS MID-UPPER 60S...AND ENOUGH SFC THETAE TO YIELD MLCAPES UP TO 500 J/KG AFTER 18Z. MODIFIED LCH RAOB...VWP DATA AND RUC SOUNDINGS INDICATE FAVORABLE VERTICAL SHEAR PROFILE FOR SUPERCELLS AND BOWS...WITH ROUGHLY 50 KT EFFECTIVE SHEAR AND 0-1 KM SRH POTENTIALLY 250-400 J/KG NEAR WARM FRONT WHERE SFC FLOW IS MOST STRONGLY BACKED. ..EDWARDS.. 01/04/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LIX...LCH... 29749307 29909227 30089082 29959012 29268964 29318993 29089022 29049041 29069068 29069096 29159090 29319134 29409119 29529147 29519155 29649165 29459176 29589206 29539229 29569269 WWWW From mcd at goshenarc.org Thu Jan 4 21:18:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 16:18:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 042123 SWOMCD SPC MCD 042122 ALZ000-MSZ000-LAZ000-042245- MESOSCALE DISCUSSION 0006 NWS STORM PREDICTION CENTER NORMAN OK 0322 PM CST THU JAN 04 2007 AREAS AFFECTED...SERN LA...PORTIONS SRN MS. CONCERNING...TORNADO WATCH 1... VALID 042122Z - 042245Z POTENTIAL CONTINUES FOR INTERMITTENT INTENSIFICATION OF LOW LEVEL MESOCYCLONES...AND ASSOCIATED RISK OF TORNADOES...FROM TSTMS EMBEDDED IN LARGE AREA OF CONVECTION AND PRECIP NOW SHIFTING EWD OVER WW AREA. ISOLATED DAMAGING GUSTS ALSO ARE POSSIBLE FROM WET DOWNBURSTS -- PARTICULARLY WITHIN SUPERCELLULAR REAR-FLANK DOWNDRAFTS OR SMALL BOW/LEWP FORMATIONS. SFC MESOANALYSIS SHOWS DIFFUSE WARM FRONT NOW INLAND BETWEEN ARA-BTR...SEWD ACROSS MSY AREA THEN OFFSHORE MS/AL COASTS. THIS FRONT -- WHICH WILL MAXIMIZE BOUNDARY LAYER VORTICITY...SHEAR AND LIFT -- SHOULD CONTINUE MOVING NEWD OVER REMAINDER SERN LA AND EXTREME SRN MS AHEAD OF MAIN PRECIP BAND. FRONT REMAINS SHALLOW AND SOME EFFECTIVE LIFTED PARCELS CAN BE SFC-BASED TO ITS N. MODIFIED 18Z SIL RAOB...VWP AND RUC SOUNDINGS INDICATE FAVORABLE SHEAR PROFILES...WITH 0-1 KM SRH 150-300 J/KG AND 0-6 KM SHEAR IN 40-50 KT RANGE. BOUNDARY LAYER THETAE OFFSETS WEAK DEEP-LAYER LAPSE RATES TO YIELD MRGL BUT STILL POTENTIALLY SUFFICIENT BUOYANCY...WHICH WILL CONTINUE TO DECREASE WITH NWD EXTENT. MLCAPES UP TO 500 J/KG WILL REMAIN POSSIBLE OVER WW AREA...ESPECIALLY E OF PRECIP SHIELD WHERE WEAK SFC HEATING AND WAA HAVE BOOSTED TEMPS TO NEAR 70 F. ..EDWARDS.. 01/04/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX...LCH... 29499179 29609201 30089183 30709138 31369043 31399000 31148952 30918900 30228837 30228893 29958881 29558899 29398929 29188899 28928941 29208948 29328981 29079018 29039039 29109052 29029085 29339134 29479122 29549149  From mcd at goshenarc.org Fri Jan 5 00:31:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 19:31:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050035 SWOMCD SPC MCD 050034 LAZ000-MSZ000-050200- MESOSCALE DISCUSSION 0007 NWS STORM PREDICTION CENTER NORMAN OK 0634 PM CST THU JAN 04 2007 AREAS AFFECTED...SE LA CONCERNING...TORNADO WATCH 1... VALID 050034Z - 050200Z THE THREAT FOR TORNADOES WILL CONTINUE ACROSS SOUTHEAST LA AS A LINE OF THUNDERSTORMS MOVES EWD ACROSS THE CNTRL PART OF TORNADO WATCH 1. ALTHOUGH TORNADOES WILL BE THE MOST LIKELY THREAT...ISOLATED WIND DAMAGE MAY ALSO OCCUR. AREAS IN SRN MS WILL CONTINUE TO BE MONITORED FOR NEW WW ISSUANCE LATER THIS EVENING. LATEST SFC ANALYSIS SHOWS A MESO-LOW CENTERED JUST NORTH OF BATON ROUGE LA. A COLD FRONT EXTENDS SWD FROM THE LOW WITH A WARM FRONT LOCATED NEWD ACROSS CNTRL MS. A LINE OF THUNDERSTORMS IS LOCATED FROM THE LOW EXTENDING SWD TO AREAS JUST OFF THE COAST FROM MORGAN CITY LA. AHEAD OF THE LINE...THE SFC DEWPOINT AT BATON ROUGE HAS RISEN A FEW DEGREES F OVER THE LAST FEW HOURS INTO THE UPPER 60S F. THIS INDICATES THAT LOW-LEVEL MOISTURE JUST AHEAD OF THE LINE MAY BE ENHANCING INSTABILITY SOMEWHAT. IN ADDITION...A 45 KT LOW-LEVEL JET IS SHOWN BY OBJECTIVE ANALYSIS IN SRN MS WHICH IS RESULTING IN STRONG LOW-LEVEL FLOW OVER SE LA. LOW-LEVEL WIND PROFILES ON WSR-88D VWPS IN THE NEW ORLEANS LA AREA CONTINUE TO SHOW ADEQUATE DIRECTIONAL SHEAR IN THE BOUNDARY LAYER AND 40 KT OF FLOW AT 1 KM. THIS AMOUNT OF SHEAR WILL BE FAVORABLE FOR TORNADOES WITH ROTATING STORMS IN THE LINE OVER THE NEXT FEW HOURS. THE STRONGEST THUNDERSTORMS MAY SHIFT INTO THE COASTAL AREAS WHERE INSTABILITY MAY BE LOCALLY ENHANCED. WIND DAMAGE WILL ALSO BE POSSIBLE WITH THE MORE ORGANIZED STORMS. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LIX...LCH... 28828988 28899100 29349148 30019135 30529121 30829083 30658976 30238937  From mcd at goshenarc.org Fri Jan 5 02:29:16 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 21:29:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050233 SWOMCD SPC MCD 050233 ALZ000-MSZ000-LAZ000-050400- MESOSCALE DISCUSSION 0008 NWS STORM PREDICTION CENTER NORMAN OK 0833 PM CST THU JAN 04 2007 AREAS AFFECTED...SE LA...SRN MS CONCERNING...TORNADO WATCH 1... VALID 050233Z - 050400Z THE TORNADO THREAT WILL CONTINUE FOR THE REMAINDER OF THE EVENING ACROSS SE LA AND SRN MS. A TORNADO WATCH WILL BE ISSUED SHORTLY TO REPLACE TORNADO WATCH 1. A LINE OF THUNDERSTORMS IS LOCATED FROM NEAR LAKE PONCHARTRAIN EXTENDING SWD TO THE LA COAST. ALTHOUGH THIS LINE HAS WEAKENED SOME OVER THE LAST HOUR...THE WIND SHEAR ENVIRONMENT SHOWN ON WSR-88D VWPS IN THE NEW ORLEANS AREA STILL APPEARS FAVORABLE FOR TORNADOES. AS THE LINE MOVES EWD LATE THIS EVENING...AN ISOLATED TORNADO THREAT WILL EXIST WITH ROTATING CELLS IN THE LINE. ALSO...A WIND DAMAGE THREAT MAY EXIST WITH THE MORE-ORGANIZED ROTATING STORMS. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX... 29578832 29068854 28808986 29309038 30409036 31109023 31528962 31278823  From mcd at goshenarc.org Fri Jan 5 04:52:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 04 Jan 2007 23:52:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050456 SWOMCD SPC MCD 050456 ALZ000-MSZ000-LAZ000-050630- MESOSCALE DISCUSSION 0009 NWS STORM PREDICTION CENTER NORMAN OK 1056 PM CST THU JAN 04 2007 AREAS AFFECTED...SRN AND CNTRL MS...SE LA CONCERNING...TORNADO WATCH 2... VALID 050456Z - 050630Z THE TORNADO THREAT WILL CONTINUE ACROSS TORNADO WATCH 2 OVER THE NEXT SEVERAL HOURS. ALSO...THE TORNADO THREAT SHOULD EXPAND ENEWD CNTRL MS. A LINE OF THUNDERSTORMS IS INCREASING IN INTENSITY AND IS LOCATED ALONG THE INTERSTATE 55 CORRIDOR FROM NEAR LAKE PONTCHARTRAIN IN SE LA NWD INTO SWRN MS. LATEST SFC ANALYSIS SHOWS THAT DEWPOINTS AHEAD OF THE LINE HAVE RISEN OVER THE LAST HOUR WITH JACKSON MS AND MERIDIAN MS BOTH AT 66 F. THIS IS A RESULT OF SSELY FLOW NEAR THE SFC WHICH IS TRANSPORTING LOW-LEVEL MOISTURE NWD ACROSS SCNTRL MS. IN ADDITION...A 45 KT LOW-LEVEL JET IS LOCATED ACROSS SCNTRL MS WHICH IS CREATING VERY STRONG LOW-LEVEL SHEAR PROFILES. ALTHOUGH INSTABILITY IS RELATIVELY WEAK...THE SHEAR PROFILES COMBINED WITH LCL HEIGHTS BELOW 500 METERS WILL BE FAVORABLE FOR ROTATING STORMS AND TORNADOES AS THE CONVECTIVE LINE MOVES EWD TONIGHT. WIND DAMAGE WILL ALSO BE POSSIBLE WITH THE BETTER ORGANIZED STORMS EMBEDDED IN THE LINE. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...MOB...JAN...LIX... 28968894 29018994 29359021 30639032 32049026 32718992 32718857 32238833 30958825 29358838  From mcd at goshenarc.org Fri Jan 5 06:43:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 01:43:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050647 SWOMCD SPC MCD 050647 FLZ000-GAZ000-ALZ000-TNZ000-MSZ000-050715- MESOSCALE DISCUSSION 0010 NWS STORM PREDICTION CENTER NORMAN OK 1247 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN MS/MUCH OF AL/WRN FL PANHANDLE CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 050647Z - 050715Z NEW TORNADO WATCH WILL BE NEEDED SOON TO THE E AND NE OF WW 2. REGIONAL RADARS INDICATED WELL DEFINED SQUALL LINE EXTENDING FROM CENTRAL MS SSEWD INTO SERN MS...WITH THIS LINE MOVING TO THE ENE AT 40 KT. STRONG ASCENT/FORCING AHEAD OF UPPER TROUGH...NOW MOVING INTO LOWER MS VALLEY...WILL MAINTAIN THIS SQUALL LINE AS IT MOVES INTO DOWNSTREAM DESTABILIZING AIR MASS. SLY LOW LEVEL WINDS /40-50 KT LLJ/ WILL SUPPORT FURTHER MOISTURE INFLUX AND ALSO ENHANCE LOW LEVEL SHEAR FOR A CONTINUED POTENTIAL OF ROTATING STORMS. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...OHX...BMX...HUN...MOB...MEG...JAN... 29538767 30468767 31868809 32908834 34958880 35038797 34998659 34988559 32738495 30588489 29398488  From mcd at goshenarc.org Fri Jan 5 08:22:07 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 03:22:07 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050826 SWOMCD SPC MCD 050826 ALZ000-MSZ000-LAZ000-050930- MESOSCALE DISCUSSION 0011 NWS STORM PREDICTION CENTER NORMAN OK 0226 AM CST FRI JAN 05 2007 AREAS AFFECTED...FAR SERN LA/FAR SERN MS/SW-W CENTRAL AL CONCERNING...TORNADO WATCH 2... VALID 050826Z - 050930Z THREAT FOR TORNADOES AND DAMAGING WINDS WILL CONTINUE TO SPREAD FROM FAR ERN PARTS OF WW 2 INTO WW 3 THROUGH 09-0930Z. REGIONAL RADARS SHOWED WELL DEFINED SQUALL LINE EXTENDING FROM EAST CENTRAL MS /30 W CBM/ SSEWD ALONG SRN PART OF MS/AL BORDER TO 45 SE GPT. AIR MASS IMMEDIATELY DOWNSTREAM OF THIS SQUALL LINE CONTINUES TO DESTABILIZE BY WAA AND NWD MOISTURE ADVECTION...WHILE STRONG ASCENT AHEAD OF LOWER MS VALLEY TROUGH MAINTAINS INTENSITY OF SQUALL LINE. IN ADDITION TO DAMAGING WIND THREAT WITH THE SQUALL LINE... STRONG LOW LEVEL SHEAR /DIRECTIONAL AND SPEED SHEAR/...WITH 08Z MOB VAD INDICATING 0-1 KM SRH VALUES EXCEEDING 300 M2/S2...WILL MAINTAIN THREAT FOR ISOLATED TORNADOES EMBEDDED WITHIN THE LINE. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...MOB...JAN...LIX... 29499041 30578951 31138860 32168868 32938920 32918836 32228845 32278790 29808779 28668894 28648984 28769054  From mcd at goshenarc.org Fri Jan 5 09:09:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 04:09:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050913 SWOMCD SPC MCD 050913 FLZ000-GAZ000-ALZ000-MSZ000-051015- MESOSCALE DISCUSSION 0012 NWS STORM PREDICTION CENTER NORMAN OK 0313 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN MS/MUCH OF AL/WRN FL PANHANDLE CONCERNING...TORNADO WATCH 3... VALID 050913Z - 051015Z THREAT FOR TORNADOES AND DAMAGING WINDS TO PERSIST ACROSS PARTS OF NERN MS AND MUCH OF AL TO THE WRN FL PANHANDLE DURING THE EARLY MORNING HOURS. REGIONAL RADARS INDICATED A SQUALL LINE WITH EMBEDDED SUPERCELLS EXTENDING SWD THROUGH WRN AL FROM LAMAR COUNTY...WITH THE NRN PART OF THE LINE MOVING NEWD AT 40-45 KT. DISCRETE STORMS HAVE ALSO DEVELOPED EAST OF THE SQUALL LINE ACROSS CENTRAL AND SRN AL FROM BIBB TO DALLAS TO CONECUH COUNTIES...WITH THESE STORMS MOVING NWD AT 45-50 KT. EXTENSIVE AREA OF SURFACE PRESSURE FALLS FROM NERN MS TO CENTRAL AL/ WRN GA IS MAINTAINING SELY SURFACE WINDS ACROSS MUCH OF AL AND ENHANCING LOW LEVEL SHEAR FOR STORM ROTATION AND CONTINUED TORNADO POTENTIAL. IN ADDITION...RECENT DEVELOPMENT OF SURFACE PRESSURE RISE/FALL COUPLET EXTENDING RESPECTIVELY FROM SRN MS TO CENTRAL AL SUGGESTS THIS PORTION OF THE SQUALL LINE SHOULD MAINTAIN FASTER FORWARD SPEED AND ENHANCED DAMAGING WIND THREAT. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...MEG... 29878805 31618808 32648791 34118823 34328815 34378685 34518554 32238490 29958476 29238499  From mcd at goshenarc.org Fri Jan 5 11:42:59 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 06:42:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051147 SWOMCD SPC MCD 051146 GAZ000-FLZ000-ALZ000-051245- MESOSCALE DISCUSSION 0013 NWS STORM PREDICTION CENTER NORMAN OK 0546 AM CST FRI JAN 05 2007 AREAS AFFECTED...AL/WRN FL PANHANDLE/PARTS OF GA CONCERNING...TORNADO WATCH 3... VALID 051146Z - 051245Z THREAT FOR TORNADOES...MAINLY EMBEDDED WITHIN THE SQUALL LINE...AND THREAT FOR DAMAGING WINDS TO CONTINUE TO SPREAD EWD ACROSS AL AND THE WRN FL PANHANDLE. NEW WW MAY BE NEEDED BY 13-14Z TO THE EAST OF WW 3. AT 11Z...REGIONAL RADARS INDICATED A SQUALL LINE EXTENDING FROM NORTH CENTRAL AL /ERN CULLMAN AND BLOUNT COUNTIES/ SWD INTO SRN AL AND THE WRN FL PANHANDLE /ESCAMBIA AND SANTA ROSA COUNTIES/. CURRENT SPEED OF THIS LINE /EWD AT 25 KT/ SUGGESTS IT WILL MOVE THROUGH THE NERN AND EAST CENTRAL PARTS OF AL BY 14Z...AND REACH THE SERN PART OF AL AND CENTRAL FL PANHANDLE BY 15Z. LOW LEVEL WAA AND RICH MOISTURE /SURFACE DEWPOINTS IN THE LOW-MID 60S/ WILL CONTINUE TO SPREAD NWD THROUGH ERN AL AND GA IN ADVANCE OF THE SQUALL LINE THIS MORNING. LOW LCLS WITHIN THE MOIST AIR MASS AND SELY SURFACE WINDS...BENEATH DEEP SSWLY FLOW...ENHANCING LOW LEVEL SHEAR VALUES WILL MAINTAIN THREAT FOR TORNADOES...ESPECIALLY WITH EMBEDDED ROTATING STORMS ALONG THE SQUALL LINE. ..PETERS.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GSP...JAX...FFC...TAE...BMX...HUN...MOB... 29658833 31238718 33158652 34528673 34598496 34558357 33198291 31508297 30418343 29088448  From mcd at goshenarc.org Fri Jan 5 14:59:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 09:59:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051502 SWOMCD SPC MCD 051502 GAZ000-FLZ000-ALZ000-051700- MESOSCALE DISCUSSION 0014 NWS STORM PREDICTION CENTER NORMAN OK 0902 AM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST AL....GA...FL PANHANDLE CONCERNING...TORNADO WATCH 4... VALID 051502Z - 051700Z STRONG TO SEVERE SQUALL LINE WITH EMBEDDED LEWPS/BOWS CONTINUES MOVING EWD/NEWD INTO NRN GA...SERN AL AND THE FL PANHANDLE THIS AM. CONVECTION IS BEING SUPPORTED BY POTENT UPPER SHORT WAVE TROUGH AND 70-75KT MID LEVEL JET STREAK ROTATING THROUGH THE BASE OF THE TROUGH ACROSS THE NCNTRL GULF COAST REGION ATTM. WARM/MOIST BOUNDARY LAYER WAS BEING TOPPED BY MID LEVEL DRY AIR INTRUSION FROM FL INLAND ACROSS SERN AL AND SWRN GA. RESULTING THERMODYNAMIC PROFILE EVIDENT ON TLH RAOB APPEARS VERY CONDUCIVE TO DAMAGING DOWNBURST WINDS ASSOCIATED WITH SMALL-SCALE BOWING SEGMENTS OF CONVECTION EXPECTED TO MOVE ACROSS PARTS OF WALTON AND HOLMES COUNTIES IN THE FL PANHANDLE...LEE...RUSSELL...AND BARBOUR COUNTIES IN SERN AL...AND COWETA COUNTY IN WEST-CNTRL GA...OVER THE NEXT HOUR OR SO. CELL MERGERS AND STORM SCALE INTERACTIONS WILL ALSO RESULT IN AN ENHANCED TORNADO THREAT WITH THIS ACTIVITY OVER THE NEXT TWO HOURS. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...FFC...TAE...BMX...MOB... 34058516 33918268 33138234 29628419 29828671 30038686 30698758 33458581 WWWW From mcd at goshenarc.org Fri Jan 5 17:03:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 12:03:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051707 SWOMCD SPC MCD 051706 SCZ000-GAZ000-051700- MESOSCALE DISCUSSION 0015 NWS STORM PREDICTION CENTER NORMAN OK 1106 AM CST FRI JAN 05 2007 AREAS AFFECTED...NERN GA...NWRN SC CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 051706Z - 051700Z STRONGLY FORCED LINE OF TSTMS SHOULD CONTINUE TO MOVE ENEWD AT UP TO 40KT AND INTO PARTS OF NERN GA/NWRN SC THROUGH THE LATE AFTERNOON. A NEW TORNADO WATCH COVERING PORTIONS OF THESE AREAS WILL LIKELY BE NEEDED SHORTLY. DESPITE GENERALLY WEAK INSTABILITY /MUCAPE AROUND 300-400 J PER KG/...STRONG FORCING AND POTENT WIND FIELDS ARE LIKELY TO RESULT IN A CONTINUING THREAT OF DAMAGING WINDS AND ISOLATED TORNADOES AS A STRONG MID LEVEL SHORT WAVE TROUGH EJECTS NEWD ACROSS THE SOUTHEAST U.S. THROUGH TONIGHT. LATEST RUC FORECASTS CONFIRM OBSERVATIONAL DATA THAT SURFACE AIR MASS ACROSS NWRN SC WILL LIKELY SUPPORT SURFACE-BASED CONVECTION WITH DEWPOINTS IN THE LOWER 60S F AND SURFACE TEMPERATURES INTO THE MID 60S. LATEST RUC SOUNDINGS DEPICT INCREASINGLY STRONG LOW LEVEL SHEAR WILL DEVELOP ACROSS THIS REGION OVER THE NEXT FEW HOURS AS STORMS SPREAD ENEWD. SMALL SCALE LEWP/BOW STRUCTURES ALREADY EVIDENT IN THE LINE SHOULD CONTINUE TO POSE A THREAT OF DAMAGING WINDS AND OCCASIONAL/BRIEF TORNADOES. A NEW WATCH WILL BE COORDINATED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 33988108 33938152 34168424 34588404 34808339 35108214 34988105 WWWW From mcd at goshenarc.org Fri Jan 5 17:27:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 12:27:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051731 SWOMCD SPC MCD 051731 GAZ000-SCZ000-FLZ000-ALZ000-051930- MESOSCALE DISCUSSION 0016 NWS STORM PREDICTION CENTER NORMAN OK 1131 AM CST FRI JAN 05 2007 AREAS AFFECTED...GA...EXTREME SERN AL AND THE CENTRAL FL PANHANDLE CONCERNING...TORNADO WATCH 4... VALID 051731Z - 051930Z TORNADO WATCH REMAINS IN EFFECT FOR PORTIONS OF GA...EXTREME SERN AL AND PORTIONS OF THE FL PANHANDLE UNTIL 21Z. AT 1715Z...A SQUALL LINE STRETCHED FROM 40 NE AHN T35 SW AHN TO 10 SE PFN AND WAS MOVING EWD AT 40 KT ON THE NORTH END AND 25-30 KT ON THE SOUTH END. THE SQUALL LINE WAS STRONGLY BOWED ACROSS NRN GA... WITH THE GREATEST POTENTIAL FOR WIND DAMAGE LOCATED ALONG THIS PORTION OF THE LINE. ALTHOUGH THE LINEAR NATURE OF THE STORMS SUGGEST MOSTLY A DAMAGING WINDS THREAT...THE STRONG LOW LEVEL SHEAR AND MLCAPES FROM 500 TO 1000 J/KG ARE SUPPORTIVE OF TORNADOES WITHIN THE LINE...AND ISOLATED STORMS THAT DEVELOP AHEAD OF THE LINE. THE THREAT FOR WIND DAMAGE AND TORNADOES MAY INCREASE ACROSS THE ERN PORTIONS OF THE WW THIS AFTERNOON AS TEMPERATURES AND DEWPOINTS CLIMB A FEW DEGREES HIGHER THAN CURRENT READINGS. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...FFC...TAE... 30028582 32328454 33388377 34138387 33778197 31138343 30008392 29318521  From mcd at goshenarc.org Fri Jan 5 18:12:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 13:12:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051816 SWOMCD SPC MCD 051816 WAZ000-060015- MESOSCALE DISCUSSION 0017 NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CST FRI JAN 05 2007 AREAS AFFECTED...OLYMPIC AND NRN CASCADE MTNS OF WA ABOVE 3000 FT CONCERNING...HEAVY SNOW VALID 051816Z - 060015Z HEAVY SNOW WITH HRLY RATES FROM 1-2 INCHES WILL DEVELOP THROUGH THE AFTERNOON OVER THE OLYMPIC AND NRN CASCADE MTNS OF WA. SNOW LEVELS WILL START OUT AROUND 1500 FT...BEFORE RISING TO AROUND 3500 FT BY 00Z. VERY STRONG WINDS /GUSTS FROM 35-45 MPH/ WILL SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES ABOVE 3500 FT. AS A WARM FRONT CONTINUES TO MOVE STEADILY EWD THROUGH THE AFTERNOON...SNOW LEVELS WILL GRADUALLY RISE THROUGH THE AFTERNOON. STRONG WAA IN ADVANCE OF THIS FRONT WILL SUPPORT CONTINUED SATURATION OF LOW LEVELS AND DEVELOPMENT OF HVY SNOW INTO THE OLYMPICS AND NRN CASCADE MTNS OVER THE NEXT SEVERAL HRS. AS A STRONG UPPER JET ASSOCIATED WITH THE MAIN UPPER TROUGH OFF THE BRITISH COLUMBIA COAST PROGRESSES TOWARD THE REGION LATER THIS AFTERNOON...STRONG UPPER DIVERGENCE COUPLED WITH LOW LEVEL WAA WILL SUPPORT AN INCREASING TREND IN THE SNOWFALL RATES. A WLY WIND SHIFT IN THE WAKE OF THE WARM FRONT WILL SUPPORTING INCREASING UPSLOPE FLOW...WITH SNOWFALL RATES POSSIBLY EXCEEDING 2 INCH/HR ABOVE 3500 FT. THE HEAVIEST SNOWFALL IS EXPECTED TO BEGIN OVER THE NRN CASCADE/OLYMPIC MTNS AFTER 21Z...BEFORE SLOWLY SPREADING SWD THIS EVENING. A STRONG PRESSURE GRADIENT /16 MB OVER WA/ WILL SUPPORT 20-30 MPH SUSTAINED WINDS WITH GUSTS OVER 40 MPH. THESE WINDS MAY SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. ..CROSBIE.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SEW...OTX...PDT... 47932331 48032387 47822410 47542392 47482380 47462365 47602332 47842314 48942176 48962214 48382204 47952188 47552183 47112187 46752158 46732132 47332104 48072112 48992129  From mcd at goshenarc.org Fri Jan 5 18:59:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 13:59:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051902 SWOMCD SPC MCD 051902 COR WAZ000-060015- MESOSCALE DISCUSSION 0017 NWS STORM PREDICTION CENTER NORMAN OK 0102 PM CST FRI JAN 05 2007 AREAS AFFECTED...OLYMPIC AND NRN CASCADE MTNS OF WA ABOVE 3000 FT CONCERNING...HEAVY SNOW VALID 051902Z - 060015Z CORRECTED FOR WEB GRAPHIC HEAVY SNOW WITH HRLY RATES FROM 1-2 INCHES WILL DEVELOP THROUGH THE AFTERNOON OVER THE OLYMPIC AND NRN CASCADE MTNS OF WA. SNOW LEVELS WILL START OUT AROUND 1500 FT...BEFORE RISING TO AROUND 3500 FT BY 00Z. VERY STRONG WINDS /GUSTS FROM 35-45 MPH/ WILL SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES ABOVE 3500 FT. AS A WARM FRONT CONTINUES TO MOVE STEADILY EWD THROUGH THE AFTERNOON...SNOW LEVELS WILL GRADUALLY RISE THROUGH THE AFTERNOON. STRONG WAA IN ADVANCE OF THIS FRONT WILL SUPPORT CONTINUED SATURATION OF LOW LEVELS AND DEVELOPMENT OF HVY SNOW INTO THE OLYMPICS AND NRN CASCADE MTNS OVER THE NEXT SEVERAL HRS. AS A STRONG UPPER JET ASSOCIATED WITH THE MAIN UPPER TROUGH OFF THE BRITISH COLUMBIA COAST PROGRESSES TOWARD THE REGION LATER THIS AFTERNOON...STRONG UPPER DIVERGENCE COUPLED WITH LOW LEVEL WAA WILL SUPPORT AN INCREASING TREND IN THE SNOWFALL RATES. A WLY WIND SHIFT IN THE WAKE OF THE WARM FRONT WILL SUPPORTING INCREASING UPSLOPE FLOW...WITH SNOWFALL RATES POSSIBLY EXCEEDING 2 INCH/HR ABOVE 3500 FT. THE HEAVIEST SNOWFALL IS EXPECTED TO BEGIN OVER THE NRN CASCADE/OLYMPIC MTNS AFTER 21Z...BEFORE SLOWLY SPREADING SWD THIS EVENING. A STRONG PRESSURE GRADIENT /16 MB OVER WA/ WILL SUPPORT 20-30 MPH SUSTAINED WINDS WITH GUSTS OVER 40 MPH. THESE WINDS MAY SUPPORT NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. ..CROSBIE.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW... 48942176 48962214 48382204 47952188 47552183 47112187 46752158 46732132 47332104 48072112 48992129  From mcd at goshenarc.org Fri Jan 5 19:12:53 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 14:12:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051917 SWOMCD SPC MCD 051916 SCZ000-GAZ000-FLZ000-052115- MESOSCALE DISCUSSION 0018 NWS STORM PREDICTION CENTER NORMAN OK 0116 PM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST GA...SRN SC...NRN FL CONCERNING...TORNADO WATCH 4... VALID 051916Z - 052115Z A NEW TORNADO WATCH...ENCOMPASSING PARTS OF SERN GA/NRN FL...AND PERHAPS SRN SC...MAY BE NEEDED IN ABOUT AN HOUR. WIDESPREAD DEEP CONVECTION PERSISTS FROM THE NERN GULF OF MEXICO INLAND ACROSS THE FL PANHANDLE AND SRN/CNTRL GA THIS AFTERNOON. THIS ACTIVITY WAS WITHIN A ZONE OF VERY STRONG DEEP-LAYER ASCENT AHEAD OF A VIGOROUS SHORT WAVE TROUGH EJECTING NEWD ACROSS MA/AL. NRN PART OF THE LARGER SCALE QLCS....FROM NERN GA INTO NWRN SC...HAS RACED NEWD AHEAD OF THE SRN AREA OF WIDESPREAD TSTM ACTIVITY OVER SWRN GA AND FL. THE STRONG CONVECTION ACROSS THESE AREAS HAS BECOME INCREASINGLY EMBEDDED WITHIN LARGER RAIN SHIELD AND HAS LOST SOME LINEARITY OVER THE PAST FEW HOURS. HOWEVER... ISOLATED CELLS ARE OCCASIONALLY DEVELOPING AHEAD OF THE MCS AND HAVE SHOWN A TENDENCY TO ROTATE. A COUPLE OF THE MORE INTENSE CELLS AHEAD OF THE MCS WERE NOTED IN HOUSTON COUNTY GA...AND SOUTH OF FRANKLIN COUNTY FL...IN THE GULF...OVER THE PAST HOUR. WHILE IT APPEARS THAT DEEP CONVECTION MAY HAVE TEMPORARILY OUTRUN STRONGER FORCING ASSOCIATED WITH THE EJECTING UPPER WAVE...THE STRONG DRY PUNCH NOTED ON WATER VAPOR WILL SOON BEGIN TO OVERRUN STRONGER DIURNAL DESTABILIZATION OCCURRING ACROSS NRN FL AND SRN GA. SHEAR ACROSS THESE AREAS IS EXPECTED TO REMAIN SUFFICIENTLY STRONG TO SUPPORT DAMAGING WINDS AND POSSIBLE TORNADOES INTO THE EVENING. THUS...EXPECT A NEW TORNADO WATCH MAY BE NEEDED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...TBW...JAX...FFC...TAE... 29658126 29438321 29488333 29798449 29548516 29618558 30088527 33098322 33278244 33108034  From mcd at goshenarc.org Fri Jan 5 19:27:18 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 14:27:18 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051931 SWOMCD SPC MCD 051930 COR SCZ000-GAZ000-FLZ000-052115- MESOSCALE DISCUSSION 0018 NWS STORM PREDICTION CENTER NORMAN OK 0130 PM CST FRI JAN 05 2007 AREAS AFFECTED...SOUTHEAST GA...SRN SC...NRN FL CONCERNING...TORNADO WATCH 4... VALID 051930Z - 052115Z CORRECTED FOR STATE IDENTIFIER MA TO MS A NEW TORNADO WATCH...ENCOMPASSING PARTS OF SERN GA/NRN FL...AND PERHAPS SRN SC...MAY BE NEEDED IN ABOUT AN HOUR. WIDESPREAD DEEP CONVECTION PERSISTS FROM THE NERN GULF OF MEXICO INLAND ACROSS THE FL PANHANDLE AND SRN/CNTRL GA THIS AFTERNOON. THIS ACTIVITY WAS WITHIN A ZONE OF VERY STRONG DEEP-LAYER ASCENT AHEAD OF A VIGOROUS SHORT WAVE TROUGH EJECTING NEWD ACROSS MS/AL. NRN PART OF THE LARGER SCALE QLCS....FROM NERN GA INTO NWRN SC...HAS RACED NEWD AHEAD OF THE SRN AREA OF WIDESPREAD TSTM ACTIVITY OVER SWRN GA AND FL. THE STRONG CONVECTION ACROSS THESE AREAS HAS BECOME INCREASINGLY EMBEDDED WITHIN LARGER RAIN SHIELD AND HAS LOST SOME LINEARITY OVER THE PAST FEW HOURS. HOWEVER... ISOLATED CELLS ARE OCCASIONALLY DEVELOPING AHEAD OF THE MCS AND HAVE SHOWN A TENDENCY TO ROTATE. A COUPLE OF THE MORE INTENSE CELLS AHEAD OF THE MCS WERE NOTED IN HOUSTON COUNTY GA...AND SOUTH OF FRANKLIN COUNTY FL...IN THE GULF...OVER THE PAST HOUR. WHILE IT APPEARS THAT DEEP CONVECTION MAY HAVE TEMPORARILY OUTRUN STRONGER FORCING ASSOCIATED WITH THE EJECTING UPPER WAVE...THE STRONG DRY PUNCH NOTED ON WATER VAPOR WILL SOON BEGIN TO OVERRUN STRONGER DIURNAL DESTABILIZATION OCCURRING ACROSS NRN FL AND SRN GA. SHEAR ACROSS THESE AREAS IS EXPECTED TO REMAIN SUFFICIENTLY STRONG TO SUPPORT DAMAGING WINDS AND POSSIBLE TORNADOES INTO THE EVENING. THUS...EXPECT A NEW TORNADO WATCH MAY BE NEEDED SHORTLY. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...TBW...JAX...FFC...TAE... 29658126 29438321 29488333 29798449 29548516 29618558 30088527 33098322 33278244 33108034  From mcd at goshenarc.org Fri Jan 5 20:00:36 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 15:00:36 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052004 SWOMCD SPC MCD 052004 SCZ000-NCZ000-GAZ000-052130- MESOSCALE DISCUSSION 0019 NWS STORM PREDICTION CENTER NORMAN OK 0204 PM CST FRI JAN 05 2007 AREAS AFFECTED...EXTREME NERN GA...SOUTH-CENTRAL NC AND NWRN AND SOUTH CENTRAL SC CONCERNING...TORNADO WATCH 5... VALID 052004Z - 052130Z DAMAGING WINDS AND ISOLATED TORNADOES ARE EXPECTED ACROSS WW INTO THE EVENING HOURS. AT 1950Z...SQUALL LINE EXTENDED FROM NEAR GSP TO 50 N AGS TO 50 SW AGS...MOVING ENEWD AT 35 TO 40 KT. A STATIONARY BOUNDARY EXTENDS FROM THE SQUALL...APPROXIMATELY FROM 50 NW OF CAE TO 40 NE OF CAE. SOUTH OF THE BOUNDARY TEMPERATURES ARE IN THE MID 70S WITH MID TO UPPER 60 DEWPOINTS...WHILE MID 60 TEMPERATURES AND DEWPOINTS IN THE LOWER 60S WERE LOCATED NORTH OF THIS BOUNDARY. GIVEN THE LINEAR NATURE OF THE STORMS...STRAIGHT LINE WIND DAMAGE IS MOST LIKELY WITH THIS LINE. HOWEVER...THE PRESENCE OF THE BOUNDARY...MLCAPES NEAR 1000 J/ AND STRONG LOW/MID LEVEL SHEAR...ISOLATED TORNADOES ARE ALSO POSSIBLE. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...CAE...GSP...FFC... 35108263 35408159 35478058 34358043 33298053 33028224 32928303 33928243 34358236  From mcd at goshenarc.org Fri Jan 5 21:17:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 16:17:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052120 SWOMCD SPC MCD 052120 NCZ000-SCZ000-052245- MESOSCALE DISCUSSION 0020 NWS STORM PREDICTION CENTER NORMAN OK 0320 PM CST FRI JAN 05 2007 AREAS AFFECTED...NC PIEDMONT/SANDHILLS AND PART OF NERN SC CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 052120Z - 052245Z NARROW ARC OF LOW-TOPPED STRONG/SEVERE CONVECTION CONTINUES MOVING ENEWD ACROSS UPSTATE SC AND WILL CONTINUE TO MOVE INTO SRN PIEDMONT AREA OF NC OVER THE NEXT HOUR. LATEST TRENDS SUGGEST THAT REFLECTIVITY WITHIN THE LINE HAS WEAKENED. HOWEVER...LARGE SCALE FORCING WILL CONTINUE TO SUPPORT STRONG ASCENT ACROSS NC THROUGH TONIGHT AND ANOTHER DOWNSTREAM WATCH MAY BE NEEDED. DESPITE INTENSITY TRENDS...FORCING ASSOCIATED WITH EXIT REGION OF 50-60KT MID LEVEL JET STREAK WILL CONTINUE TO SPREAD ATOP MOIST AND WEAKLY UNSTABLE AIR MASS ACROSS CNTRL NC AND NERN SC THROUGH THIS EVENING. CURRENT ACTIVITY MOVING INTO CLT AREA IN THE NEXT HALF HOUR WILL BE MONITORED CLOSELY FOR DAMAGING WINDS GIVEN AIR MASS AND LOW LEVEL SHEAR ACROSS THE AREA. GIVEN LATEST TRENDS AND TIME OF DAY...THE OVERALL SEVERE POTENTIAL MAY BE DIMINISHING. HOWEVER...IF ONGOING CONVECTION REMAINS STRONG TO NEAR SEVERE...A NEW WATCH MAY BE NEEDED DOWNSTREAM ACROSS PARTS OF CNTRL NC IN THE NEXT HOUR. ..CARBIN.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...RAH...ILM...RNK...CAE...GSP... 35548154 35628135 36278058 36437960 35867891 35057915 34407943 34407983 34667981 35448047  From mcd at goshenarc.org Fri Jan 5 21:23:15 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 16:23:15 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052127 SWOMCD SPC MCD 052126 SCZ000-GAZ000-052200- MESOSCALE DISCUSSION 0021 NWS STORM PREDICTION CENTER NORMAN OK 0326 PM CST FRI JAN 05 2007 AREAS AFFECTED...PORTIONS OF SC AND SERN GA CONCERNING...TORNADO WATCH VALID 052126Z - 052200Z A TORNADO WATCH IS BEING COORDINATED FOR PORTIONS OF SERN GA AND COASTAL PLAINS OF SC. ..IMY.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...ILM...CHS...CAE...JAX...FFC... 31868276 32778288 33278040 33387969 33117943 32248054 31418125 WWWW From mcd at goshenarc.org Fri Jan 5 23:31:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 18:31:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 052335 SWOMCD SPC MCD 052335 SCZ000-GAZ000-FLZ000-060100- MESOSCALE DISCUSSION 0022 NWS STORM PREDICTION CENTER NORMAN OK 0535 PM CST FRI JAN 05 2007 AREAS AFFECTED...ERN SC...SE GA AND NRN FL CONCERNING...TORNADO WATCH 7... VALID 052335Z - 060100Z A SEVERE THREAT WILL EXIST ACROSS NRN FL...SE GA AND ERN SC OVER THE NEXT FEW HOURS. A FEW TORNADOES AND ISOLATED WIND DAMAGE WILL BE POSSIBLE WITH THE STRONGER THUNDERSTORMS EMBEDDED IN THE LARGE AREA OF RAIN. LATEST SFC ANALYSIS SHOWS A COLD FRONT AND PRE-FRONTAL TROUGH EXTENDING SWD FROM THE SRN APPALACHIAN MTNS TO THE WRN FL PANHANDLE. THE LARGE AREA OF RAIN IS LOCATED WELL AHEAD OF THESE SFC FEATURES AND IS ASSOCIATED WITH A BAROCLINIC LEAF AHEAD OF A NEGATIVELY TILTED UPPER-LEVEL TROUGH. AHEAD OF THE RAIN...SFC DEWPOINTS ARE IN THE MID TO UPPER 60S F AND THE WARM SECTOR IS CHARACTERIZED MOSTLY BY WEAK INSTABILITY. A CENTER OF STRONG VERTICAL SHEAR EXISTS NEAR THE COAST OF GA WHERE OBJECTIVE ANALYSIS SHOWS 0-6 KM SHEAR VALUES OF 65 KT. THIS IS DUE TO STRONG ONSHORE SSELY FLOW AT THE SFC COUPLED WITH A SSWLY MID-LEVEL JET AROUND 60 KT LOCATED IN SE GA. THIS SHEAR ENVIRONMENT WILL CONTINUE TO BE FAVORABLE FOR LOW-TOPPED SUPERCELLS EMBEDDED IN THE LARGE AREA OF RAIN. ISOLATED WIND DAMAGE MAY ALSO OCCUR WITH THE BETTER ORGANIZED THUNDERSTORMS THROUGH EARLY EVENING. ..BROYLES.. 01/05/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...ILM...CHS...CAE...TBW...JAX... 32108212 33008163 34148028 34427949 33717878 33007965 32058092 30898139 29408165 28968215 29138276 29838274 31158240 WWWW From mcd at goshenarc.org Sat Jan 6 00:41:47 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 19:41:47 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060045 SWOMCD SPC MCD 060045 WAZ000-ORZ000-060645- MESOSCALE DISCUSSION 0023 NWS STORM PREDICTION CENTER NORMAN OK 0645 PM CST FRI JAN 05 2007 AREAS AFFECTED...CASCADES OF WA/NRN ORE ABOVE 3500 FT CONCERNING...HEAVY SNOW VALID 060045Z - 060645Z HEAVY SNOW WITH RATES UP TO 2 INCH/HR WILL CONTINUE TO DEVELOP SWD THROUGH WA CASCADES INTO THE NRN ORE CASCADES THROUGH 06Z. SNOW LEVELS WILL CONTINUE TO SLOWLY RISE TO AROUND 3500 FT THROUGH THE EVENING. STRONG WINDS WILL LEAD TO NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST ELEVATIONS. A VERY DYNAMIC SHORTWAVE TROUGH WILL CONTINUE TO APPROACH THE COAST OF SRN BRITISH COLUMBIA AND WA OVER THE NEXT 6 HOURS. AHEAD OF THIS SHORTWAVE...STRONG WARM ADVECTION /PER THE 00Z SLE SOUNDING/ COUPLED WITH STRONG SWLY /UPSLOPE/ LOW LEVEL FLOW AND UPPER LEVEL DIVERGENCE WILL SUPPORT A VERY STRONG VERTICAL MOTION PROFILE OVER WA AND NRN ORE CASCADES DURING THE NEXT 6+ HRS. BASED ON PRESENT SYSTEM MOTION...THE STRONGEST VERTICAL MOTION FIELDS WILL OCCUR OVER THE NRN WA CASCADES THROUGH 06Z...WHILE GRADUALLY DEVELOPING SWD INTO THE SRN WA/NRN ORE CASCADES BETWEEN 03-06Z AS THE UPPER DIVERGENCE MAXIMUM AND MID LEVEL COLD FRONT MOVE SEWD. GIVEN THE STRENGTH OF THE MESOSCALE FORCING...SNOWFALL RATES UP TO 2 INCH/HR WILL BE COMMONPLACE FOR MORE THAN A 6 HR PERIOD ESPECIALLY ACROSS THE WRN SLOPES. SNOWFALL LEVELS /PRESENTLY AROUND 2500 FT/ WILL CONTINUE TO RISE TO AROUND 3500 FT /PER THE UIL 00Z SOUNDING/ OVER THE NEXT FEW HRS UNDER THE PRESENCE OF CONTINUED STRONG WAA. A STRONG SFC PRESSURE/HEIGHT GRADIENT WILL SUPPORT SUSTAINED SSWLY WINDS FROM 20-30 MPH WITH GUSTS OVER 40 MPH...LEADING TO NEAR BLIZZARD CONDITIONS AT TIMES IN THE HIGHEST TERRAIN. ..CROSBIE.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW...PQR... 48812098 48792167 48542189 47992186 46982174 46232200 45692206 45242216 44702242 44472205 44512171 45352150 46662104 47682095 48522088  From mcd at goshenarc.org Sat Jan 6 01:57:40 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 20:57:40 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060201 SWOMCD SPC MCD 060201 NCZ000-SCZ000-060330- MESOSCALE DISCUSSION 0024 NWS STORM PREDICTION CENTER NORMAN OK 0801 PM CST FRI JAN 05 2007 AREAS AFFECTED...ERN SC...CNTRL AND ERN NC CONCERNING...TORNADO WATCH 8... VALID 060201Z - 060330Z THE SEVERE THREAT ACROSS TORNADO WATCH 8 WILL INCREASE FROM WEST TO EAST LATE THIS EVENING. A FEW TORNADOES AND ISOLATED WIND DAMAGE WILL BE POSSIBLE WITH THE BETTER ORGANIZED STORMS. A LARGE AREA OF RAIN WITH EMBEDDED THUNDERSTORM ACTIVITY IS LOCATED NEAR GREENSBORO NC EXTENDING SWD ACROSS CNTRL SC. AHEAD OF THE AREA OF RAIN...A MOIST WARM SECTOR EXISTS AND THE AIRMASS HAS BEEN UNTOUCHED ACROSS MOST OF TORNADO WATCH 8 WITH SFC DEWPOINTS REMAINING IN THE MID TO UPPER 60S F. OBJECTIVE ANALYSIS SHOWS THAT MID-LEVEL LAPSE RATES HAVE STEEPENED SOME ACROSS THE SRN PART OF TORNADO WATCH 8 OVER THE LAST FEW HOURS AND THIS MAY BE RESPONSIBLE FOR THE INCREASE IN INSTABILITY SHOWN BY RUC ANALYSIS. IN ADDITION...MODERATE VERTICAL SHEAR EXISTS ACROSS THE WATCH AREA AND THIS SHOULD INCREASE WITH TIME AS A 60 KT MID-LEVEL JET DRIFTS ENEWD INTO THE AREA. FOR THIS REASON...THE SHEAR ENVIRONMENT WILL BECOME INCREASINGLY FAVORABLE FOR ROTATING THUNDERSTORMS OVER THE NEXT 1 TO 2 HOURS. LOW-TOPPED SUPERCELLS WILL BE CAPABLE OF ISOLATED TORNADOES AND WIND DAMAGE LATE THIS EVENING. ..BROYLES.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MHX...RAH...ILM... 33057876 33347975 34377980 34897967 35467952 35737869 35677728 35547632 35067605 34267670  From mcd at goshenarc.org Sat Jan 6 03:12:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 05 Jan 2007 22:12:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060316 SWOMCD SPC MCD 060316 NCZ000-VAZ000-060445- MESOSCALE DISCUSSION 0025 NWS STORM PREDICTION CENTER NORMAN OK 0916 PM CST FRI JAN 05 2007 AREAS AFFECTED...NE NC...SE VA CONCERNING...TORNADO WATCH 8... VALID 060316Z - 060445Z AN AREA OF HEAVY RAIN OVER ERN SC AND CNTRL NC WILL MOVE ENEWD LATE THIS EVENING AFFECTING NE NC AND SE VA AFTER MIDNIGHT. THE REDEVELOPMENT OF THUNDERSTORM ACTIVITY REMAINS POSSIBLE AND A SEVERE THUNDERSTORM POTENTIAL WOULD EXIST AS STORMS ORGANIZE DURING THE OVERNIGHT PERIOD. TORNADO WATCH 8 MAY NEED TO BE REPLACED IF THIS SCENARIO DEVELOPS. A NEGATIVELY TILTED UPPER-LEVEL TROUGH OVER THE SRN APPALACHIAN MTNS WILL CONTINUE TO DRIFT NEWD TOWARD THE REGION TONIGHT. A BAND OF CONVECTION IS LOCATED ALONG THE LEADING EDGE OF LARGE-SCALE ASCENT ASSOCIATED WITH THE APPROACHING TROUGH. AHEAD OF THE CONVECTION...THE AIRMASS REMAINS UNDISTURBED WITH SFC DEWPOINTS IN THE MID TO UPPER 60S F AS FAR NORTH AS RICHMOND VA. IN ADDITION...MODERATE VERTICAL SHEAR PROFILES EXIST ACROSS THE REGION. AS THE UPPER-TROUGH APPROACHES...SHEAR PROFILES SHOULD GRADUALLY STRENGTHEN BECOMING INCREASINGLY FAVORABLE FOR LOW-TOPPED ROTATING STORMS. IF THIS WHERE TO HAPPEN...A THREAT FOR TORNADOES AND ISOLATED WIND DAMAGE WOULD BE POSSIBLE ACROSS THE REGION. ..BROYLES.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...RAH... 35257576 34957706 35487814 36127841 36947820 37457750 37507642 36627555  From mcd at goshenarc.org Sat Jan 6 08:07:34 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 03:07:34 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 060811 SWOMCD SPC MCD 060811 VAZ000-NCZ000-060915- MESOSCALE DISCUSSION 0026 NWS STORM PREDICTION CENTER NORMAN OK 0211 AM CST SAT JAN 06 2007 AREAS AFFECTED...SERN VA/NERN NC CONCERNING...TORNADO WATCH 9... VALID 060811Z - 060915Z THREAT FOR ISOLATED TORNADOES AND DAMAGING WINDS TO CONTINUE ACROSS WW 9. ALTHOUGH THE AIR MASS ACROSS SERN VA/NERN NC REMAINS MARGINALLY UNSTABLE...RICH LOW LEVEL MOISTURE /SURFACE DEWPOINTS IN THE MID- UPPER 60S/ ARE RESULTING IN LOW LCLS WITH THE LOW-TOPPED CONVECTION MOVING NEWD ACROSS THIS REGION. STRONG ASCENT AHEAD OF PROGRESSIVE SHORT WAVE TROUGH...NOW CENTERED FROM SWRN VA TO ERN SC...WILL PROMOTE ADDITIONAL CONVECTIVE DEVELOPMENT OVERNIGHT. DESPITE LACK OF LIGHTNING WITH MUCH OF THIS ACTIVITY...EFFECTIVE BULK SHEAR VALUES REMAIN SUPPORTIVE OF ORGANIZED STORMS. IN ADDITION...0-1 KM SRH VALUES NEAR 200 M2/S2 CONTINUE TO FAVOR STORM ROTATION...SUCH AS THE PERSISTENT ROTATION THAT HAS BEEN OBSERVED PER REGIONAL RADAR MOVING NEWD AND IS NOW LOCATED IN NERN HERTFORD COUNTY NC. ..PETERS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...LWX...RAH... 36147534 35987617 35797706 36297759 36507789 37047796 38027771 37987687 37637584 37227581 37047550 WWWW From mcd at goshenarc.org Sat Jan 6 10:16:18 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 05:16:18 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 061020 SWOMCD SPC MCD 061019 VAZ000-NCZ000-061115- MESOSCALE DISCUSSION 0027 NWS STORM PREDICTION CENTER NORMAN OK 0419 AM CST SAT JAN 06 2007 AREAS AFFECTED...SERN VA/NERN NC CONCERNING...TORNADO WATCH 9... VALID 061019Z - 061115Z SEVERE WEATHER THREAT WILL CONTINUE TO DIMINISH FROM W-E EARLY THIS MORNING ACROSS SERN VA AND NERN NC. REGIONAL RADARS INDICATED AN AREA OF LOW-TOPPED CONVECTION...SOME BECOMING DEEP ENOUGH FOR LIGHTNING PRODUCTION...EXTENDING FROM SERN VA TO NERN NC...AND MOVING EWD AT 30 KT. AT THIS SPEED...MOST OF THE CONVECTIVE ACTIVITY...AND ANY REMAINING SEVERE WEATHER THREAT... SHOULD BE LOCATED EAST OF THE COASTAL AREAS AFTER 11Z. THUS...WW 9 COULD BE CANCELLED PRIOR TO THE 12Z EXPIRATION TIME. ..PETERS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX... 36207541 36007644 36937645 37647626 37617582 37297575 37027550 WWWW From mcd at goshenarc.org Sat Jan 6 20:39:56 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 06 Jan 2007 15:39:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 062043 SWOMCD SPC MCD 062043 MEZ000-NHZ000-062145- MESOSCALE DISCUSSION 0028 NWS STORM PREDICTION CENTER NORMAN OK 0243 PM CST SAT JAN 06 2007 AREAS AFFECTED...PORTIONS SRN/ERN NH...SRN/WRN MAINE. CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 062043Z - 062145Z SEVERAL SHORT LINES OF CONVECTION -- WITH ISOLATED EMBEDDED TSTMS -- MAY PRODUCE GUSTS NEAR SVR LIMITS WITH MINOR DAMAGE. SVR THREAT APPEARS TOO MRGL AND SHORT-LIVED FOR WW. SFC ANALYSIS SHOWS COLD FRONT MOVING EWD FROM VT INTO NH...EXPECTED TO MOVE EWD APPROXIMATELY 30 KT INTO WRN MAINE DURING NEXT 2 HOURS. SHORT/NARROW BANDS OF TSTMS -- INCLUDING ONE WHICH PRODUCED GUST TO 37 KT AROUND 19Z AT BTV -- WILL MOVE THROUGH RELATIVE MAX OF LOW LEVEL TEMPS AND MOISTURE. SFC THETAE AXIS IS EVIDENT ALONG A LINE FROM ORH...LEW...45 NNW AUG. MODIFIED RUC SOUNDINGS INDICATE BUOYANCY MAY EXTEND INTO LOWER LIMITS OF FAVORED THERMAL LAYERS FOR LIGHTNING PRODUCTION...AND A FEW CG STRIKES HAVE BEEN DETECTED OVER PORTIONS NRN VT/NH. POCKETS OF SBCAPES UP TO ABOUT 300 J/KG ARE EVIDENT INVOF THETAE AXIS AND WILL BE MAINTAINED UNTIL CONVECTION MOVES INTO CENTRAL/ERN MAINE...WHERE MARINE AIR WEAKENS SFC-BASED INSTABILITY. MOMENTUM ASSOCIATED WITH STRONG FLOW JUST ABOVE SFC -- E.G. 50-70 KT AT 2-3 KM AGL -- MAY BE TRANSPORTED TO SFC IN MOST VIGOROUS DOWNDRAFTS...ESPECIALLY ON W FACING SLOPES OF HIGHER ELEVATIONS. ..EDWARDS.. 01/06/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GYX...BOX... 42927184 43857129 44817085 45167040 44356955 43866996 43657031 43257056 42927081  From mcd at goshenarc.org Sun Jan 7 11:35:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 06:35:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 071139 SWOMCD SPC MCD 071139 WAZ000-071545- MESOSCALE DISCUSSION 0029 NWS STORM PREDICTION CENTER NORMAN OK 0539 AM CST SUN JAN 07 2007 AREAS AFFECTED...OLYMPIC AND NRN/CENTRAL CASCADE MOUNTAINS ABOVE 3500-4000 FEET CONCERNING...HEAVY SNOW VALID 071139Z - 071545Z SNOWFALL IS EXPECTED TO INCREASE IN INTENSITY THIS MORNING...WITH HOURLY RATES UP TO 2 INCH/HOUR LIKELY...AND MAY LOCALLY REACH 3 INCH/HOUR. SNOW LEVELS WILL CONTINUE TO RISE TO AROUND 4000 FEET THROUGH 15Z. STRENGTHENING WLY WINDS SHOULD PRODUCE BLOWING SNOW AND NEAR BLIZZARD CONDITIONS AT TIMES. SNOW LEVELS WILL CONTINUE TO RISE DURING THE EARLY MORNING AS A WARM FRONT MOVES EWD ACROSS THE CASCADES...REACHING CENTRAL WA BY 18Z. PASSAGE OF THE WARM FRONT WILL ALSO RESULT IN STRENGTHENING DEEP LAYER WLY WINDS WITH 50-60 KT LIKELY IN THE LOW LEVELS. THIS UPSLOPE FLOW INTO THE MOUNTAINS COMBINED WITH LOW LEVEL WAA SPREADING EWD BENEATH INCREASING ASCENT WITHIN ENTRANCE REGION OF MID LEVEL JET WILL SUPPORT INCREASING SNOWFALL RATES. IN ADDITION...THE STRONGER FLOW WITH SURFACE WINDS AT 25-35 KT...WITH HIGHER SPEEDS AND GUSTS IN THE VICINITY OF THE CRESTS...WILL LIKELY PRODUCE AREAS OF BLOWING SNOW AND NEAR BLIZZARD CONDITIONS. ..PETERS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OTX...PDT...SEW... 48792181 48982111 48592060 47662078 47162150 47442169 47872161 48422171  From mcd at goshenarc.org Sun Jan 7 17:27:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 12:27:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 071731 SWOMCD SPC MCD 071731 GAZ000-ALZ000-FLZ000-MSZ000-072000- MESOSCALE DISCUSSION 0030 NWS STORM PREDICTION CENTER NORMAN OK 1131 AM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS AL...SERN MS...W-CENTRAL GA...WRN FL PANHANDLE. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 071731Z - 072000Z SLOWLY DEVELOPING SVR POTENTIAL EXISTS DURING NEXT 3-4 HOURS ACROSS DISCUSSION AREA...AS SFC GRADUALLY DESTABILIZES. LINEAR AND DISCRETE MODES ARE POSSIBLE...WITH VERTICAL SHEAR PROFILES FAVORABLE FOR SUPERCELLS AND SMALL BOWS. 17Z SFC MESOANALYSIS SHOWS COLD FRONT AND ASSOCIATED CONVECTIVE BAND NEAR LINE FROM BTR-35 NNW TCL...INTERSECTING WARM FRONT THAT EXTENDS ESEWD TO NEAR CSG AND VDI. WARM FRONT SHOULD CONTINUE TO LIFT/REFORM NEWD ACROSS CENTRAL/ERN AL AND WRN GA...CONSOLIDATING AGAINST SRN EDGE OF APPALACHIAN COLD-DAMMING REGIME OVER NERN AL AND N-CENTRAL/NWRN GA BY MID-AFTERNOON. WARM SECTOR LOW LEVEL SHEAR PROFILES WILL REMAIN FAVORABLE INVOF 45-55 KT SWLY LLJ...ANALYZED FROM MS COAST ACROSS NERN AL. HODOGRAPHS WILL BE FURTHER ENHANCED INVOF WARM FRONT WHERE SFC WINDS ARE RELATIVELY WEAK/BACKED. CONVECTION FORMING IN WARM SECTOR AND CROSSING THIS FRONT WILL ENCOUNTER RELATIVE MAXIMA IN SHEAR AND VORTICITY...WITH 0-1 KM SRH IN 250-350 J/KG RANGE. CLOUD BREAKS ARE EVIDENT IN VIS IMAGERY ATTM ACROSS PORTIONS SERN MS AND SRN AL...ALLOWING MORE INSOLATION AND DESTABILIZATION...AND SUPPORTING POTENTIAL TSTM DEVELOPMENT AHEAD OF COLD FRONT ALONG HORIZONTAL ROLLS AND CONFLUENCE LINES. OBSERVED AND RUC SOUNDINGS MODIFIED FOR LOW 70S SFC TEMPS AND 66-68 F DEW POINTS SHOW ALMOST NO CINH AND SBCAPES AROUND 500 J/KG. GRADUAL INCREASE IN BOUNDARY LAYER THETAE ALONG AND S OF WARM FRONT -- THROUGH BOTH ADVECTIVE AND DIABATIC PROCESSES...WILL BOOST THIS MARGINALLY BUOYANT LAYER INTO FAVORABLE THERMAL STRATA FOR LIGHTNING GENERATION. ..EDWARDS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...JAN...LIX... 34348684 34028612 33898565 33678427 32868440 32288467 31408551 30728702 30908944 32458879 34078742  From mcd at goshenarc.org Sun Jan 7 19:58:38 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 14:58:38 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072002 SWOMCD SPC MCD 072001 IDZ000-MTZ000-080130- MESOSCALE DISCUSSION 0031 NWS STORM PREDICTION CENTER NORMAN OK 0201 PM CST SUN JAN 07 2007 AREAS AFFECTED...THE BITTERROOT AND CLEARWATER MTNS OF NRN ID AND FAR WRN MT ABOVE 3500 FT CONCERNING...HEAVY SNOW VALID 072001Z - 080130Z HEAVY SNOW WITH HOURLY RATES IN EXCESS OF 1 INCH IS ANTICIPATED TO DEVELOP SWD OVER THE BITTERROOT AND CLEARWATER MTNS THROUGH 01Z. COMBINED WITH THE HVY SNOW...STRONG WINDS (GUSTING AT TIMES OVER 50 MPH) WILL LEAD TO NEAR BLIZZARD CONDITIONS IN THE HIGHER WEST FACING SLOPES INTO THE EARLY EVENING. A VERY STRONG MID/UPPER LEVEL JET MAX (100 KTS OBSERVED BY THE MISSOULA VWP AT 6KM) WILL CONTINUE TO PROGRESS SEWD. AS A RESULT...WSWLY LOW LEVEL FLOW WILL CONTINUE TO STRENGTHEN OVER ERN WA/NRN ID AND NERN ORE IN AGEOSTROPHIC RESPONSE TO THE RIGHT REAR QUAD OF THIS MID/UPPER LEVEL JET. IN ADDITION TO THE INCREASING WINDS...MODERATE MID LEVEL FRONTOGENESIS WILL AID IN INCREASING MID LEVEL VERTICAL MOTION. THIS WILL SUPPORT MID LEVEL SATURATION...WHICH HAS BEEN SLOW TO OCCUR THROUGH THE MORNING GIVEN THE STRONG DOWNSLOPE FLOW EAST OF THE CASCADES. THE COMBINATION OF STRONG MID LEVEL VERTICAL MOTION (COINCIDENT WITH A DEEP LAYER OF FAVORABLE TEMPERATURES FOR DENDRITIC SNOW GROWTH) AND STRONG (50-70 KTS) UPSLOPE FLOW WILL SUPPORT HVY SNOW DEVELOPMENT OVER THE WRN SLOPES OF THE BITTERROOT AND CLEARWATER MTNS THIS AFTERNOON. GIVEN THE DEGREE OF FORCING...AND MODEST PRECIPITABLE WATER VALUES (OVER 1/2 OF AN INCH PER GOES SOUNDER DATA) SNOWFALL RATES IN EXCESS OF 1 INCH/HR ARE EXPECTED FOR AT LEAST A 3-6 HR PERIOD INTO THE EARLY EVENING. ..CROSBIE.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...MSO...OTX... 47571520 47931582 47761630 47071634 46241556 45411582 45241572 45271535 45351488 45591461 46201432 46761443 WWWW From mcd at goshenarc.org Sun Jan 7 20:47:35 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 15:47:35 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072051 SWOMCD SPC MCD 072051 GAZ000-ALZ000-FLZ000-MSZ000-072215- MESOSCALE DISCUSSION 0032 NWS STORM PREDICTION CENTER NORMAN OK 0251 PM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS SERN MS...AL...WRN FL PANHANDLE...WRN/CENTRAL GA. CONCERNING...TORNADO WATCH 10... VALID 072051Z - 072215Z WW SHOULD CONTINUE ALONG/AHEAD OF MAIN CONVECTIVE LINE...BUT CAN BE CLEARED BEHIND IT DUE TO CAA AND RELATED STABILIZATION. ANOTHER WW MAY BE REQUIRED ACROSS PORTIONS GA. BAND OF STG-SVR TSTMS -- MAINLY ASSOCIATED WITH SFC COLD FRONT -- WILL CONTINUE TO MOVE E ACROSS WW AREA...PRECEDED BY SEVERAL SHORTER CONVECTIVE SEGMENTS WHICH ALSO MAY BECOME SVR. WARM FRONT HAS SHIFTED INTO NERN AL AND NWRN GA...AND SHOULD MOVE INTO PORTIONS ATL AREA BEFORE MAIN TSTM LINE ARRIVES. FAVORABLE DEEP-LAYER VERTICAL SHEAR SHOULD INCREASE WITH TIME ACROSS WRN/NRN GA AS MIDLEVEL HEIGHT GRADIENT TIGHTENS AHEAD OF CENTRAL CONUS TROUGH. WARM SECTOR WINDS WILL REMAIN FAVORABLE WITH 40-50 KT EFFECTIVE SHEAR AND 0-1 KM SRH 150-300 J/KG. 0-1 KM SRH SHOULD BE EVEN HIGHER IN IMMEDIATE VICINITY OF WARM FRONT -- 250-400 J/KG -- WHERE TORNADO POTENTIAL MAY BE RELATIVELY MAXIMIZED. RICH LOW LEVEL MOISTURE IS EXPECTED NEAR WARM FRONT AS WELL WITH SFC DEW POINTS NEAR 70 F JUST TO ITS S...ALTHOUGH MIXING HAS CREATED POCKET OF LOW-MID 60S DEW POINTS FARTHER S OVER SERN AL/SWRN GA/CENTRAL FL PANHANDLE. BUOYANCY WILL REMAIN MARGINAL EVEN IN AREAS OF MAXIMIZED MOISTURE...BECAUSE OF POOR LAPSE RATES ALOFT. HOWEVER...PRIND MUCAPES UP TO 500 J/KG WILL SUPPORT CONTINUED THREAT. ..EDWARDS.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...HUN...MOB...LIX... 34518558 34208494 33938447 33448335 32768312 31928340 31668486 30378706 30458919 31998834 33468692  From mcd at goshenarc.org Sun Jan 7 23:30:36 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 18:30:36 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 072334 SWOMCD SPC MCD 072334 GAZ000-SCZ000-080100- MESOSCALE DISCUSSION 0033 NWS STORM PREDICTION CENTER NORMAN OK 0534 PM CST SUN JAN 07 2007 AREAS AFFECTED...N CNTRL THROUGH NERN GA INTO WRN SC CONCERNING...TORNADO WATCH 11... VALID 072334Z - 080100Z THREAT FOR ISOLATED DAMAGING WIND AND PERHAPS AN ISOLATED TORNADO OR TWO WILL EXIST ACROSS NRN GA INCLUDING THE ATLANTA METRO AREA DURING THE NEXT HOUR OR SO. THREAT WILL BECOME MORE MARGINAL WITH ERN EXTENT INTO NERN GA AND WRN SC. PRE-FRONTAL LINE OF STORMS EXTENDS FROM EXTREME SWRN NC SWWD THROUGH N CNTRL GA NEAR ATLANTA AND FARTHER SW INTO SERN AL. PORTION OF THE LINE OVER N CNTRL GA IS MOVING EAST AT 35 KT. A WARM FRONT EXTENDS FROM SRN SC NWWD TO NEAR ATLANTA TO A WEAK SURFACE LOW OVER NWRN GA. DEWPOINTS GENERALLY IN THE LOW TO MID 60S EXIST NEAR AND S O OF THIS FRONT...AND LATEST OBJECTIVE ANALYSIS SHOW MLCAPE FROM 250 TO 500 J/KG. LATEST VWP DATA CONTINUE TO SHOW LARGE LOW LEVEL HODOGRAPHS AND STRONG DEEP LAYER. THREAT FOR BOW ECHOES AND SUPERCELLS WITH LOW LEVEL MESOCYCLONES WILL CONTINUE TO EXIST WITH THUNDERSTORMS WITHIN OR JUST E OF THE LINE. GREATEST SEVERE THREAT WILL PERSIST ALONG AND S OF THE WARM FRONT WHERE STORMS ARE MORE LIKELY TO BE SURFACE BASED. ACTIVITY WILL SHIFT EWD INTO NERN GA AND WRN SC LATER THIS EVENING. HOWEVER...SEVERE THREAT IN THIS REGION IS MORE MARGINAL AND CONDITIONAL UPON NWD BOUNDARY LAYER RECOVERY. ..DIAL.. 01/07/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 33638223 33538386 33728458 34248439 34438245  From mcd at goshenarc.org Mon Jan 8 00:54:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 19:54:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080057 SWOMCD SPC MCD 080057 VTZ000-NYZ000-080700- MESOSCALE DISCUSSION 0034 NWS STORM PREDICTION CENTER NORMAN OK 0657 PM CST SUN JAN 07 2007 AREAS AFFECTED...PORTIONS OF NRN NY AND NRN/CENTRAL VT ABOVE 1000 FT CONCERNING...WINTER MIXED PRECIPITATION VALID 080057Z - 080700Z MODERATE SNOW WILL DEVELOP NWD ACROSS HIGHER ELEVATIONS OF THE AREA BETWEEN 04-06Z...BEFORE CHANGING OVER TO FREEZING RAIN AROUND OR SHORTLY AFTER 06Z. HRLY SNOWFALL RATES UP TO 1 INCH AND FREEZING RAIN RATES UP TO 0.10 INCH WILL BE POSSIBLE FOR A 2-3 HR PERIOD INTO THE EARLY MORNING HOURS. A DEEP LAYER OF STRONG VERTICAL MOTION ASSOCIATED WITH THE NOSE OF A STRONG /60 KT/ LOW LEVEL JET AND AHEAD OF A 150 KT UPPER LEVEL JET HAS SUPPORTED MODERATE TO HVY PRECIPITATION DEVELOPMENT OVER PORTIONS OF PA EARLY THIS EVENING. THIS FORCING WILL CONTINUE TO DEVELOP NNEWD IN ADVANCE OF THE UPPER AND LOW LEVEL JETS ACROSS NRN NEW ENGLAND DURING THE NEXT 3-6 HRS. INSPECTION OF 00Z ALBANY SOUNDING INDICATED A FAIRLY DEEP DRY LAYER BELOW 700 MB. HOWEVER...THE STRENGTH OF THE LOW LEVEL MOIST ADVECTION SHOULD SUPPORT SATURATION TO AT LEAST 850 MB WITHIN THE NEXT 3-4 HRS ACROSS NRN NY/NRN VT. OBS OVER NRN PA/SRN NY INDICATED LIGHT PRECIPITATION WAS FALLING FROM CIGS AROUND 6 KFT THAT DEVELOPED A MERE 1-2 HRS AFTER CIGS HAD BEEN ABOVE 10 KFT. HEAVIER PRECIPITATION WAS FALLING OVER CENTRAL/ERN PA WITH CIGS AROUND 5 KFT /850 MB/. GIVEN THE SPEED OF THE 850 MB FLOW AND STRENGTH OF THE WARM ADVECTION...AT LEAST MODERATE PRECIPITATION RATES ARE EXPECTED TO BEGIN OCCURRING BETWEEN 04-06Z OVER THE NRN NY AND NRN/CENTRAL VT. AN EXTRAPOLATION OF THE 00Z ALBANY/BUFFALO AND GREY MAINE SOUNDINGS ALONG WITH 00Z OBS INDICATE A WET BULB FREEZING LEVEL BETWEEN 1500-2000 FT OVER NRN NY AND NRN VT. THIS LEVEL IS LIKELY TO FALL SOMEWHAT TO BETWEEN 1000-1500 FT OVER THE NEXT FEW HOURS DUE TO RADIATIONAL COOLING. INITIAL PTYPE IS EXPECTED TO BE IN THE FORM OF SNOW GIVEN THE SUDDEN ONSET OF PRECIP AND ASSOCIATED WET-BULB COOLING AFFECTS. HOWEVER...GIVEN THE STRENGTH OF THE WARM ADVECTION...PTYPE IS EXPECTED TO CHANGE OVER TO FREEZING RAIN WITHIN 1-2 HRS OF SNOW DEVELOPMENT. ..CROSBIE.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...BTV...ALY...BUF... 43627334 43847286 44067239 44447233 44907252 44897300 44517313 44027319 43897348 44017366 44477382 44907382 44897462 44367514 43887527 43607497 43507440 43617378  From mcd at goshenarc.org Mon Jan 8 01:15:05 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 20:15:05 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080119 SWOMCD SPC MCD 080118 SCZ000-NCZ000-GAZ000-080245- MESOSCALE DISCUSSION 0035 NWS STORM PREDICTION CENTER NORMAN OK 0718 PM CST SUN JAN 07 2007 AREAS AFFECTED...NERN GA THROUGH NRN SC INTO A SMALL PART OF S CNTRL NC CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 080118Z - 080245Z THREAT FOR DAMAGING WIND AND ISOLATED TORNADOES IS EXPECTED TO PERSIST NEXT FEW HOURS AS STORMS ADVANCE EWD THROUGH THE REMAINDER OF NERN GA INTO SC. A STRONG SLY 50+ KT LOW LEVEL JET WILL INCREASE OVER THE CAROLINAS THIS EVENING WITHIN ZONE OF HEIGHT FALLS AND ASCENT DOWNSTREAM FROM EWD ADVANCING UPPER TROUGH. THIS SHOULD ALLOW WARM FRONT CURRENTLY FROM SERN SC SWWD INTO NERN GA TO LIFT A LITTLE FARTHER INLAND WITH RESULTING NWD DESTABILIZATION OF THE BOUNDARY LAYER. DEWPOINTS IN THE LOW TO MID 60S EXIST NEAR AND S OF THE WARM FRONT. HOWEVER...DUE TO WEAK MID LEVEL LAPSE RATES...INSTABILITY WILL REMAIN MARGINAL WITH MUCAPE GENERALLY BELOW 500 J/KG...AND THIS WILL CONTINUE TO SERVE AS A LIMITING FACTOR. NEVERTHELESS...LARGE 0-1 KM HODOGRAPHS ASSOCIATED WITH INTENSIFYING LOW LEVEL JET WILL MAINTAIN A THREAT FOR SUPERCELLS AND ISOLATED TORNADOES AS STORMS ADVANCE EWD. SEVERE THREAT WILL REMAIN GREATEST NEAR AND JUST S OF THE WARM FRONT WHERE STORMS ARE MORE LIKELY TO BE NEAR SURFACE BASED. ..DIAL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAE...GSP...FFC... 34488025 33648302 33878362 34748237 35108060  From mcd at goshenarc.org Mon Jan 8 03:35:22 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 07 Jan 2007 22:35:22 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 080339 SWOMCD SPC MCD 080338 GAZ000-ALZ000-080445- MESOSCALE DISCUSSION 0036 NWS STORM PREDICTION CENTER NORMAN OK 0938 PM CST SUN JAN 07 2007 AREAS AFFECTED...EXTREME SERN AL THROUGH CNTRL AND SWRN GA CONCERNING...TORNADO WATCH 11... VALID 080338Z - 080445Z MARGINAL THREAT FOR ISOLATED DAMAGING AND A TORNADO OR TWO MAY PERSIST A LITTLE WHILE BEYOND 04Z...BUT THREAT IS EXPECTED TO GRADUALLY DIMINISH IN THIS REGION. WW 11 MAY BE LOCALLY EXTENDED IN TIME FOR A COUPLE HOURS IF DESIRED. OTHERWISE...TORNADO WATCH 11 WILL EXPIRE AT 04Z. PRE-FRONTAL SQUALL LINE EXTENDS FROM SWRN NC SWWD THROUGH CNTRL GA AND INTO EXTREME SERN AL AND THE FL PANHANDLE MOVING SLOWLY EAST. LOCAL RADAR DATA CONTINUE TO SHOW UPDRAFT ROTATION WITH A CELL OVER SWRN GA. PRE-FRONTAL WARM SECTOR IS CHARACTERIZED BY DEWPOINTS IN THE LOWER 60S AND WEAK MID LEVEL LAPSE RATES RESULTING IN MUCAPE BELOW 300 J/KG. TREND HAS BEEN FOR LIGHTNING TO DIMINISH DURING THE PAST COUPLE HOURS. FORECAST RUC SOUNDINGS SHOW WHAT LITTLE CAPE REMAINS IS GENERALLY IN LAYERS BELOW 500 MB WHERE TEMPERATURES ARE MOSTLY ABOVE -5C. THIS SUGGEST THE CONVECTION WILL REMAIN SHALLOW WITH LITTLE IF ANY ADDITIONAL LIGHTING EXPECTED IN THIS REGION AS THE LINE CONTINUES EAST. LOW LEVEL WIND FIELDS WILL GRADUALLY VEER AND WEAKEN SLIGHTLY AS THE STRONGER LOW LEVEL JET LIFTS NE OF THIS AREA INTO THE CAROLINAS. SOME THREAT FOR AN ISOLATED TORNADO OR DAMAGING WIND MAY PERSIST ANOTHER COUPLE OF HOURS OR SO IN THIS REGION...BUT OVERALL THREAT WILL REMAIN MARGINAL. ..DIAL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE... 31598526 33108399 33418299 32468295 31178494  From mcd at goshenarc.org Mon Jan 8 10:19:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 08 Jan 2007 05:19:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 081023 SWOMCD SPC MCD 081022 MEZ000-081615- MESOSCALE DISCUSSION 0037 NWS STORM PREDICTION CENTER NORMAN OK 0422 AM CST MON JAN 08 2007 AREAS AFFECTED...CNTRL AND NRN ME CONCERNING...HEAVY SNOW VALID 081022Z - 081615Z VERY STRONG WARM/MOIST ADVECTION WITHIN LOW LEVEL JET WILL MAINTAIN STRONG ISENTROPIC LIFT OVER ME THROUGH THE MORNING HOURS. SNOW IS CHANGING TO RAIN FROM SW-NE WITH RAIN/SNOW LINE EXTENDING ACROSS CNTRL ME BY 15Z. THIS LINE WILL CONTINUE TO SHIFT NWD WITH TIME. THUS...LONGEST DURATION OF HEAVY SNOW RATES WILL BE OVER FAR NRN ME...WHERE COMBINATION OF STRONG LIFT AND FAVORABLE THERMODYNAMICS WILL FAVOR SNOW RATES UP TO 1"/HR. SHORTER DURATION MDT/HVY SNOW WILL OCCUR ACROSS CNTRL ME FOR A FEW HOURS BEFORE CHANGING TO RAIN. ..JEWELL.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CAR...GYX... 46026768 45116946 45047045 45347090 45537063 45927021 46537006 47456924 47336822 47106775  From mcd at goshenarc.org Mon Jan 8 11:29:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 08 Jan 2007 06:29:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 081133 SWOMCD SPC MCD 081133 VAZ000-NCZ000-081300- MESOSCALE DISCUSSION 0038 NWS STORM PREDICTION CENTER NORMAN OK 0533 AM CST MON JAN 08 2007 AREAS AFFECTED...FAR SERN VA/ERN NC INCLUDING THE OUTER BANKS CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 081133Z - 081300Z THREAT EXISTS FOR ISOLATED DAMAGING WINDS..AND PERHAPS A TORNADO ACROSS ERN NC INCLUDING THE OUTER BANKS NWD TO SERN VA UNTIL 14-15Z. GIVEN LOW POTENTIAL FOR SEVERE WEATHER AND SMALL AREAL COVERAGE OF THIS THREAT...A WW IS UNLIKELY. REGIONAL RADARS INDICATED A COUPLE OF LINES OF LOW TOPPED CONVECTION EXTENDING FROM SERN VA TO ERN NC AND SWD TO ABOUT 70 MILES E OF THE SC COAST. DESPITE THE LACK OF LIGHTNING...A VERY MOIST PRE-FRONTAL AIR MASS IS SUPPORTING MARGINAL INSTABILITY. STRONG WINDS EVIDENT PER AREA WSR-88D VADS WITH 40-50 KT SSWLY FLOW JUST OFF THE SURFACE SUGGEST THE POTENTIAL FOR STRONG WINDS TO REACH THE SURFACE PRODUCING AN ISOLATED DAMAGING WIND THREAT. IN ADDITION...09Z RUC FORECAST SOUNDINGS SUGGESTED EFFECTIVE INFLOW LAYER IS AT THE SURFACE ACROSS THE DISCUSSION AREA...WITH SRH VALUES FAVORABLE FOR STORM ROTATION. THUS...AN ISOLATED TORNADO THREAT SHOULD EXIST ACROSS ERN NC/SERN VA...PRIOR TO VEERING SURFACE AND LOW LEVEL WINDS WITH COLD FRONT PASSAGE AFTER 15Z. ..PETERS.. 01/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX... 34337723 35197699 36047682 37007623 37717570 37627521 36427535 35297518 34667587 34247639 34017731  From mcd at goshenarc.org Fri Jan 12 12:43:54 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 07:43:54 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121247 SWOMCD SPC MCD 121246 MOZ000-OKZ000-KSZ000-TXZ000-121645- MESOSCALE DISCUSSION 0041 NWS STORM PREDICTION CENTER NORMAN OK 0646 AM CST FRI JAN 12 2007 AREAS AFFECTED...SW OK...CNTRL OK..NE OK AND SE KS CONCERNING...FREEZING RAIN VALID 121246Z - 121645Z FREEZING RAIN WILL BECOME INCREASINGLY LIKELY THIS MORNING ON THE NORTH SIDE OF A COLD FRONT EXTENDING SW TO NE ACROSS THE REGION. THE AREAS MOST LIKELY TO BE AFFECTED BY FREEZING RAIN INCLUDE SW OK...CNTRL OK...NE OK AND SE KS. FREEZING RAIN ACCUMULATIONS SHOULD BE AROUND A TENTH OF AN INCH OR LESS THROUGH EARLY THIS AFTERNOON. LATEST SFC ANALYSIS SHOWS A COLD FRONT LOCATED FROM NEAR SPRINGFIELD MO EXTENDING SWWD TO SOUTH OF OKLAHOMA CITY OK TO NEAR LAWTON OK. SUBFREEZING TEMPERATURES CURRENTLY EXIST ABOUT 30 MILES TO THE NORTHWEST OF THE FRONT AND THIS COLD AIR WILL CONTINUE TO ADVECT SLOWLY SWD ACROSS THE REGION THIS MORNING. THIS WILL LIKELY KEEP TEMPS BELOW FREEZING ACROSS MOST OF THE MCD AREA THROUGH MIDDAY WITH A SUBSTANTIAL WARM LAYER JUST ABOVE THE SFC SHOWN ON THE 12Z SOUNDINGS FROM NORMAN AND AMARILLO. IN ADDITION...MODEL FORECASTS INCREASE LIFT ACROSS THE MCD AREA THIS MORNING. THE GREATEST LIFT SHOULD BE ASSOCIATED WITH THE LOW-LEVEL JET WHICH IS FORECAST TO REMAIN STRONG IN THE 35 TO 45 KT RANGE. IN ADDITION...A SUBTLE SHORTWAVE TROUGH MAY EXIST ACROSS NW TX AS EVIDENT ON WATER VAPOR IMAGERY. DIFFERENTIAL PVA WITH THIS APPROACHING WAVE WOULD LIKELY INCREASE THE CHANCE OF FREEZING RAIN FROM SOUTHWEST TO NORTHEAST LATER THIS MORNING. DUE TO SUBFREEZING TEMPERATURES AND WARM AIR JUST OFF THE GROUND EVIDENT ON THE 12Z SOUNDINGS...FREEZING RAIN SHOULD BE THE DOMINANT MODE OF PRECIPITATION. ..BROYLES.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...TSA...ICT...OUN... 36199541 35279730 34409931 34829989 35289990 35659963 37109684 37689539 37469474 36719456 WWWW From mcd at goshenarc.org Fri Jan 12 18:32:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 13:32:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121835 SWOMCD SPC MCD 121834 MOZ000-ILZ000-ARZ000-OKZ000-KSZ000-122330- MESOSCALE DISCUSSION 0042 NWS STORM PREDICTION CENTER NORMAN OK 1234 PM CST FRI JAN 12 2007 AREAS AFFECTED...MUCH OF CNTRL MO...FAR SERN KS...EXTREME NERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 121834Z - 122330Z FREEZING RAIN AND SLEET WILL INCREASE THIS AFTERNOON FROM SW TO NE. ICE ACCUMULATIONS OF .05 TO .10 IN/HR WILL BE LIKELY...WITH LOCAL RATES NEAR .15 IN/HR AT TIMES. A LARGE AREA OF MIXED PRECIPITATION ACROSS MUCH OF SWRN INTO N-CNTRL OK IS EXPECTED TO EXPAND NEWD INTO SERN KS/CNTRL MO DURING THE AFTERNOON. THE PRECIPITATION HAS BEEN ASSOCIATED WITH STRONG LOW-LEVEL FRONTOGENETICAL FORCING...AND WARM THETA-E ADVECTION ATOP AN INCREASINGLY COLD DOME NEAR THE SURFACE. IN ADDITION...A SUBTLE MID-LEVEL IMPULSE ENTERING WRN OK PER W/V SATELLITE IMAGERY...IS FORECAST TO LIFT NEWD...FURTHER ENHANCING LARGE-SCALE ASCENT DOWNSTREAM. AT 18Z...THE SURFACE FREEZING LINE WAS FROM AROUND GMJ TO JEF TO 50 N STL. CONTINUED LOW-LEVEL CAA BEHIND AN ARCTIC COLD FRONT SHOULD PUSH THE FREEZING LINE SEWD AT AROUND 10 KT THROUGH 00Z. 18Z SGF AND ILX OBSERVED SOUNDINGS INDICATE A RATHER LARGE WARM NOSE PRESENT WITH A SATURATED 850-900 MB LAYER AROUND 10 DEGREES C. THE LOW-LEVEL THERMAL STRUCTURE FROM BOTH THE 15Z RUC AND 12Z NAM MODEL FORECAST SOUNDINGS WERE IN EXCELLENT AGREEMENT WITH THE OBSERVED SGF SOUNDING. THEIR FORECAST SOUNDINGS INDICATE FREEZING RAIN WILL BE THE MAIN PRECIPITATION TYPE IN A 50-75 KM BAND CENTERED ROUGHLY ALONG THE 18Z SURFACE FREEZING LINE. FURTHER NW...FROM AROUND CNU TO SZL TO UIN...INITIAL LIGHT FREEZING RAIN/DRIZZLE SHOULD TRANSITION TO MAINLY SLEET. THIS SHOULD OCCUR AS THE DEPTH OF THE NEAR-SURFACE COLD AIR SLOWLY INCREASES BENEATH THE ELEVATED ABOVE FREEZING LAYER. ..GRAMS.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT... 37159586 37739574 38579481 39469341 39739218 39869124 39359038 38729055 37819194 37229279 36279444 36429510  From mcd at goshenarc.org Fri Jan 12 18:47:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 13:47:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 121850 SWOMCD SPC MCD 121849 OKZ000-TXZ000-122345- MESOSCALE DISCUSSION 0043 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST FRI JAN 12 2007 AREAS AFFECTED...NWRN TX...OK CONCERNING...WINTER MIXED PRECIPITATION VALID 121849Z - 122345Z ICE PELLETS AND FREEZING RAIN...WITH ACCUMULATION RATES OF 0.05 TO 0.10 INCH PER HOUR...SHOULD PERSIST FROM SWRN THROUGH NCNTRL OK THROUGH THE AFTERNOON. A GRADUAL EWD SHIFT IN HEAVIER PRECIPITATION RATES MAY BEGIN TO OCCUR ACROSS WRN PARTS OF THE MCD AREA DURING THE AFTERNOON BASED ON SREF MEAN QPF AND LATEST RADAR TRENDS. RAIN IS LIKELY TO CHANGE TO FREEZING RAIN IN A NARROW BAND FROM NWRN TX INTO PARTS OF SRN AND ERN OK OVER THE NEXT 2-4 HOURS. PRECIPITATION SHIELD COMPOSED OF FREEZING RAIN AND ICE PELLETS HAS EXPANDED AND SPREAD NEWD ACROSS CNTRL AND NRN OK THROUGH EARLY AFTERNOON IN THE WAKE OF STRONG ARCTIC FROPA THIS MORNING. THE PRECIPITATION WAS INITIALLY INDUCED AS ISENTROPIC LIFT ACROSS THE FRONT DEVELOPED INTO A PLUME OF HIGHER THETA-E AIR EMANATING FROM SOUTH TX AND THE GULF. IT APPEARS THAT DEEPER ASCENT...AIDED BY A LOW AMPLITUDE SHORT WAVE TROUGH MOVING ENEWD FROM NM/WEST TX...HAS SUSTAINED THE MIXED PRECIPITATION ACROSS MUCH OF OK OVER THE PAST FEW HOURS. STRONGER LIFT ASSOCIATED THIS LEADING SHORT WAVE TROUGH WILL CONTINUE TO TRANSLATE EWD/NEWD ATOP THE LOWER LEVEL FRONTAL ZONE THIS AFTERNOON...AND A GRADUAL NEWD SHIFT IN THE HEAVIER PRECIPITATION AREA HAS RECENTLY BEEN NOTED ON COMPOSITE RADAR. MEANWHILE...A NEARLY STEADY-STATE WARM/MOIST CONVEYOR BELT HAS NOW BECOME ESTABLISHED FROM TX/RIO GRANDE VALLEY NEWD ATOP THE SURFACE-BASED COLD DOME. DEEP LAYER MOISTURE ACROSS THE REGION WAS ALSO BEING PROVIDED BY A TROPICAL CONNECTION EVIDENT IN SATELLITE IMAGERY. WITH THE FRONTAL ZONE NOW BECOMING INCREASINGLY ALIGNED WITH THE DEEP-LAYER SWLY FLOW ALOFT...AND LOW-AMPLITUDE PERTURBATIONS CONTINUING TO TRANSLATE NEWD ACROSS THE REGION...EXPECT MIXED WINTER PRECIPITATION TO CONTINUE TO DEVELOP AND SPREAD NEWD FROM THE RED RIVER TO CNTRL AND NERN OK THROUGH THE REST OF THE AFTERNOON. HIGHER PRECIPITATION RATES MAY OCCASIONALLY OCCUR ON THE MESOSCALE AS ENHANCED ASCENT WITH THE UPPER PERTURBATIONS COINCIDE WITH LIFT ACROSS THE LOW LEVEL FRONT. THIS APPEARS TO BE OCCURRING FROM NWRN TX INTO SWRN OK AT THIS TIME. A GRADUAL SWD/SEWD SHIFT TO THE SURFACE FREEZING LINE...AND CONTINUED STRONG INFLUX OF LOW LEVEL MOISTURE...WILL RESULT IN RAIN CHANGING TO FREEZING RAIN FROM NWRN TX INTO SCNTRL AND ERN OK THROUGH LATE THIS AFTERNOON. ..CARBIN.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...FWD...OUN...LUB... 35549864 36289790 36669710 36719590 36539537 36259485 35919478 35309521 34899559 34439606 34149662 33659735 33569834 33579930 33679987 34140011 34979929  From mcd at goshenarc.org Fri Jan 12 23:11:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 18:11:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 122314 SWOMCD SPC MCD 122314 TXZ000-130045- MESOSCALE DISCUSSION 0044 NWS STORM PREDICTION CENTER NORMAN OK 0514 PM CST FRI JAN 12 2007 AREAS AFFECTED...PART OF CNTRL/NCNTRL TX CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 122314Z - 130045Z THERE WAS A CONFIRMED SHORT-LIVED TORNADO AT 2235Z JUST SW OF TROY TX IN NRN BELL COUNTY. OTHER BRIEF ISOLD TORNADOES WILL BE POSSIBLE EARLY THIS EVENING ACROSS PORTIONS OF CNTRL/NCNTRL TX. A WW IS NOT ANTICIPATED GIVEN THE BRIEF THREAT. WARM ADVECTION SHOWERS AND ISOLD TSTMS CONTINUE TO DEVELOP AHEAD OF A SEWD MOVING ARCTIC FRONT ACROSS CNTRL TX. RUC SOUNDINGS SUGGEST THAT BUOYANCY IS LIMITED WITH MLCAPES OF A FEW HUNDRED J PER KG AND THE SHOWERS HAVE EXHIBITED WEAK REFLECTIVITY AND LITTLE C-G LIGHTNING. NONETHELESS...0-1KM SHEAR WAS IN EXCESS OF 230 M2/S2 AND SUPPORTS POSSIBLE BRIEF ROTATION DURING UPDRAFT INFANCY. THE REMAINDER OF THE PROFILE THROUGH ABOUT 3KM EXHIBITS WEAKER FLOW AND UPDRAFTS MAY STRUGGLE GIVEN WEAK BUOYANCY. THE TORNADO THREAT SHOULD WANE THIS EVENING AS THE BOUNDARY LAYER COOLS AND THE ARCTIC FRONT SLIPS SEWD TOWARD THE REGION EFFECTIVELY UNDERCUTTING THE SFC-BASED STORMS. ..RACY.. 01/12/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX...FWD...EWX...SJT... 31509830 32079726 32409663 31999606 31309588 30649644 30329724 30649854  From mcd at goshenarc.org Sat Jan 13 00:04:04 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 19:04:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 130007 SWOMCD SPC MCD 130006 OKZ000-130300- MESOSCALE DISCUSSION 0045 NWS STORM PREDICTION CENTER NORMAN OK 0606 PM CST FRI JAN 12 2007 AREAS AFFECTED...CNTRL/ERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 130006Z - 130300Z LARGE SHIELD OF PCPN CONTINUES ACROSS CNTRL/ERN PARTS OF OK EARLY THIS EVE. PRECIPITATION-TYPE HAS REMAINED THE MOST DIFFICULT CHALLENGE WITH THIS FIRST WAVE OF PCPN. 00Z OUN SOUNDING SHOWED A SUBSTANTIAL WARM NOSE /PLUS 10.5 DEG C JUST BELOW H85/...BUT COOLEST PART OF THE 1700 FT DEEP SFC-BASED COLD DOME WAS AROUND MINUS 5 DEG C. RESEARCH HAS SHOWN THAT SOME ICE NUCLEI CAN ACTIVATE AT TEMPERATURES AROUND MINUS 4-5 DEG C...THOUGH THE PROBABILITY AT THAT TEMPERATURE IS ONLY AROUND 20 PERCENT. PRESUMABLY...GIVEN THE PREDOMINANCE OF SLEET AND SNOW ACROSS CNTRL OK...THIS PROCESS DOMINATED TODAY. BACK EDGE OF THE PCPN SHIELD APPEARS TO BE ACCELERATING ENEWD ACROSS CNTRL OK ATTM...SIMILAR TO 18Z NAM AND 21Z SREF SOLUTIONS. THIS WOULD SUGGEST A DECREASING PCPN TREND ACROSS NERN OK BY 03Z. THE SAME MODELS...HOWEVER...INDICATE THAT THE HEAVIER RAINFALL IN THE DFW METROPLEX WILL TRANSLATE ENEWD ACROSS SCNTRL/SERN INTO ECNTRL OK 00-06Z. THUS...THERE MAY BE A CONTINUATION OF HOURLY RATES OF 0.10+ INCH FROM VCNTY KMLC NEWD TOWARD KFYV THROUGH 06Z. OTHERWISE...FARTHER N...THE DECREASE IN PCPN RATES WILL LIKELY BE REPLACED WITH FREEZING DRIZZLE AND OR SPORADIC SLEET SHOWERS. SFC FREEZING LINE WILL LIKELY REMAIN QUASI-STATIONARY OWING TO THE HIGHER ERN OK TERRAIN AND PRESENCE OF STRONGER PRESSURE RISES WELL NE OF THE REGION. THUS...PRECIPITATION TYPE WILL PROBABLY REMAIN STATUS-QUO THROUGH LATE EVENING. MORE SPECIFICALLY...A ZONE OF FREEZING RAIN WITH SIGNIFICANT ICING SHOULD EXIST FROM KMLC-KFYV WITH A TENDENCY FOR MORE SLEET MIXED IN N OF I-40 THROUGH LATE EVENING. ..RACY.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...OUN... 34739841 35799785 36569675 36809568 36429477 35919458 35019479 34429551 34179665 34299797 34469847  From mcd at goshenarc.org Sat Jan 13 00:30:40 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 12 Jan 2007 19:30:40 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 130033 SWOMCD SPC MCD 130033 ILZ000-MOZ000-IAZ000-ARZ000-OKZ000-KSZ000-130530- MESOSCALE DISCUSSION 0046 NWS STORM PREDICTION CENTER NORMAN OK 0633 PM CST FRI JAN 12 2007 AREAS AFFECTED...CNTRL MO...CNTRL IL...FAR SERN KS...FAR NWRN AR...FAR NERN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 130033Z - 130530Z A SIGNIFICANT ICE STORM WILL CONTINUE THROUGH MUCH OF THE EVENING HOURS NW OF A QUASI-STATIONARY ARCTIC FRONT. ICE ACCUMULATIONS OF .05 TO .10 IN/HR WILL REMAIN LIKELY. LOCALIZED RATES UP TO .25 IN/HR WILL ALSO OCCUR AT TIMES. A NEARLY STEADY-STATE MIXED PRECIPITATION EVENT IS EXPECTED TO OCCUR OVER THE NEXT SEVERAL HOURS ACROSS THE MCD AREA...AS A WARM/MOIST CONVEYOR BELT HAS BECOME WELL-ESTABLISHED FROM THE LOWER RIO GRANDE N/NEWD TOWARDS THE MID-MS RIVER VALLEY. LOW-LEVEL WARM THETA-E ADVECTION/ISENTROPIC LIFT ATOP A NEAR-SURFACE BASED COLD DOME WILL AID IN THE CONTINUED PRODUCTION OF MIXED PRECIPITATION. 18Z NAM/GFS AND 21Z RUC GUIDANCE ARE CONSISTENT WITH STRENGTHENING THE LLJ THIS EVENING FROM NERN TX INTO SRN MO AND SRN IL...WITH CORRESPONDING INCREASES IN QPF AS WELL. AT 00Z...THE SURFACE FREEZING LINE WAS LOCATED FROM AROUND FYV TO STL TO BMI. THIS BOUNDARY SHOULD PROGRESS VERY SLOWLY SWD IN THE OZARKS REGION...WITH MORE SUBSTANTIAL PROGRESS SEWD IN SRN IL WITH GREATER PRESSURE RISES. 00Z SGF AND ILX OBSERVED SOUNDINGS INDICATE FREEZING RAIN WILL REMAIN THE PREDOMINANT PTYPE CENTERED ALONG THE I-44 CORRIDOR ACROSS MO /INCLUDING THE STL METRO AREA/ NEWD INTO CNTRL IL. FURTHER NWWD...THE PTYPE WILL REMAIN MOSTLY SLEET FROM AROUND CNU NEWD TO SZL AND UIN. HERE...A LARGER NEAR-SURFACE COLD LAYER WILL REMAIN BENEATH A SMALLER ABOVE-FREEZING LAYER COMPARED TO LOCALES FURTHER SE. ..GRAMS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LOT...ILX...LSX...DVN...LZK...SGF...EAX...TSA...TOP...ICT... 37359570 38079547 38859468 39769337 40439202 41039013 41298912 41048824 40438813 39428871 38778950 38099064 37029257 35839394 36069497  From mcd at goshenarc.org Sat Jan 13 12:26:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 07:26:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131229 SWOMCD SPC MCD 131228 ARZ000-OKZ000-TXZ000-131630- MESOSCALE DISCUSSION 0048 NWS STORM PREDICTION CENTER NORMAN OK 0628 AM CST SAT JAN 13 2007 AREAS AFFECTED...NRN TX...SE OK AND NW AR CONCERNING...FREEZING RAIN VALID 131228Z - 131630Z SCATTERED SHOWERS OF FREEZING RAIN AND SLEET ARE CURRENTLY ONGOING FROM NORTH TX EXTENDING NEWD THROUGH SE OK INTO NW AR. THE COVERAGE OF FREEZING RAIN AND SLEET MAY INCREASE THIS MORNING WITH PRECIPITATION AMOUNTS THROUGH EARLY AFTERNOON GENERALLY RANGING FROM .2 TO .5 INCHES ACROSS THE MCD AREA. LATEST SFC ANALYSIS SHOWS A COLD FRONT LOCATED FROM LITTLE ROCK AR EXTENDING SWWD TO EAST TX AND WWD INTO THE TX HILL COUNTRY. THE FREEZING LINE IS LOCATED ABOUT 120 MILES NORTHWEST OF THE FRONT. SUBFREEZING TEMPS EXIST FROM JUST WEST AND NORTH OF THE DALLAS FORT WORTH METROPLEX NNEWD ACROSS MOST OF ERN OK TO NORTH OF FORT SMITH AR. THE FREEZING LINE SHOULD SLOWLY MOVE SWD THIS MORNING. AT THE SAME TIME...A SUBTROPICAL FEED OF LOW TO MID-LEVEL MOISTURE WILL REMAIN IN PLACE EXTENDING NEWD FROM WEST TX ACROSS NORTH TX INTO ERN OK. ALTHOUGH SUBTLE...THE LATEST WATER VAPOR IMAGERY SHOWS A LOW-AMPLITUDE SHORTWAVE ACROSS WEST TX WHICH SHOULD INCREASE LARGE-SCALE ASCENT ACROSS NORTH TX AND SRN OK OVER THE NEXT FEW HOURS AS THE FEATURE MOVES NEWD. IN ADDITION...A 40 TO 50 KT LOW-LEVEL JET IN EAST TX...SE OK AND WRN AR WILL RESULT IN STRONG ISENTROPIC LIFT NORTH OF THE BOUNDARY. THE INCREASING PVA ASSOCIATED WITH THE APPROACHING WAVE COUPLED WITH STRONG ASCENT DUE TO THE LOW-LEVEL JET SHOULD RESULT IN AN INCREASE IN PRECIPITATION COVERAGE THIS MORNING ALONG A CORRIDOR FROM FORT WORTH TX NEWD TO NEAR FORT SMITH AR. MODEL FORECASTS CONFIRM THIS WITH QPF AMOUNTS RANGING FROM .25 TO 1.00 INCHES ACROSS THE SERN HALF OF THE MCD AREA THROUGH MIDDAY. ALTHOUGH MODEL FORECASTS MAY BE A LITTLE HIGH IN THE QPF AMOUNTS...SUBFREEZING TEMPS ACROSS THE MCD AREA SHOULD RESULT IN SIGNIFICANT ICE ACCUMULATION THROUGH EARLY AFTERNOON. FORECAST SOUNDINGS AND 12Z OBSERVED SOUNDINGS FROM OUN AND FTW CONFIRM A WARM LAYER EXISTING 1500 TO 2000 FEET ABOVE THE GROUND WITH TEMPS AS WARM AS +10 TO +13 C. THIS SHOULD RESULT IN FREEZING RAIN AS THE DOMINANT MODE OF PRECIPITATION ALTHOUGH SLEET WILL ALSO BE POSSIBLE ESPECIALLY IN THE NWRN PART OF THE MCD AREA WHERE TEMPS IN THE WARM LAYER WILL BE A LITTLE COOLER. ..BROYLES.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SHV...TSA...FWD...OUN... 35969373 35389377 33969531 32919655 32689751 33169829 33829823 35389656 36499485 36159382  From mcd at goshenarc.org Sat Jan 13 13:45:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 08:45:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131348 SWOMCD SPC MCD 131347 MOZ000-OKZ000-KSZ000-131745- MESOSCALE DISCUSSION 0049 NWS STORM PREDICTION CENTER NORMAN OK 0747 AM CST SAT JAN 13 2007 AREAS AFFECTED...NRN OK...SERN KS AND WRN MO CONCERNING...WINTER MIXED PRECIPITATION VALID 131347Z - 131745Z A BAND OF HEAVY SLEET CURRENTLY OVER NW OK AND SRN KS WILL MOVE ENEWD THIS MORNING. AS A RESULT...SIGNIFICANT SLEET ACCUMULATION WILL BE LIKELY OVER NRN OK...SRN KS INTO WRN MO WITH .5 TO 1.5 INCHES OF SLEET ACCUMULATION POSSIBLE. LATEST WATER VAPOR AND RADAR IMAGERY SHOW A WELL-DEFINED AXIS OF ENHANCED LIFT EXTENDING SWD FROM SRN KS ACROSS WRN OK. THIS ENHANCEMENT IS LIKELY ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH EJECTING OUT OF NW TX ATTM. FORECAST SOUNDINGS ACROSS THE MCD AREA ALONG WITH THE 12Z SOUNDING FROM DDC AND AMA SHOW SLEET TEMPERATURE PROFILES WITH A WARM LAYER LOCATED NEAR 850 MB AND A VERY COLD LAYER IN THE LOWEST 2000 FEET ABOVE GROUND LEVEL. ALSO...THE 12Z SOUNDINGS SHOW SUFFICIENT MUCAPE FOR CONVECTIVE BURSTS. SFC TEMPS ACROSS THE MCD AREA RANGE FROM 18 TO 22 DEGREES F WHICH SHOULD BE COLD ENOUGH TO KEEP PRECIPITATION MODE IN THE FORM OF SLEET AND/OR SNOW. THE HEAVIEST SLEET ACCUMULATION SHOULD OCCUR NEAR THE OK-KS STATE-LINE WHERE IT APPEARS A BAND OF LOCALLY HEAVIER PRECIPITATION WILL TRACK THIS MORNING THROUGH EARLY AFTERNOON. ..BROYLES.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...DDC... 37149348 36339534 35789812 36779892 37779846 38619450  From mcd at goshenarc.org Sat Jan 13 16:23:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 11:23:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131625 SWOMCD SPC MCD 131625 TXZ000-131830- MESOSCALE DISCUSSION 0050 NWS STORM PREDICTION CENTER NORMAN OK 1025 AM CST SAT JAN 13 2007 AREAS AFFECTED...SOUTH-CENTRAL TX CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 131625Z - 131830Z STRONG TSTMS WITH HEAVY RAIN WILL CONTINUE TO SPREAD ACROSS PARTS OF TX HILL COUNTRY THROUGH NOON. RAINFALL RATES AROUND 1 INCH PER HOUR COMBINED WITH POTENTIAL FOR REPEAT/TRAINING CELLS WILL CONTINUE TO RESULT IN LOCALIZED FLOODING PROBLEMS. ADDITIONALLY... STRONGER CELLS IN THE WARM SECTOR AND/OR NEAR THE SURFACE FRONT COULD PRODUCE DAMAGING WINDS OR A TORNADO BEFORE CROSSING OVER THE BOUNDARY AND MOVING NORTH ATOP STABLE SURFACE-BASED AIR MASS. VERY SHARP SURFACE COLD FRONT ALONG A LINE FROM 10 SE CLL TO 40 SE AUS TO 45 N HDO CONTINUES TO MAKE VERY SLOW SWD PROGRESS ACROSS THE TX HILL COUNTRY LATE THIS MORNING. MOISTURE-LADEN LOW LEVEL JET EMANATING FROM THE LOWER RIO GRANDE VALLEY AND THE WRN GULF OF MEXICO HAS BEEN INTERSECTING THE SHARP FRONTAL SURFACE AND CONTRIBUTING TO AN ACTIVE ZONE HEAVY TSTMS FROM SAN ANTONIO AREA TO NORTH OF AUSTIN THIS MORNING. RECENT RADAR DATA INDICATES THAT A FEW DISCRETE CELLS HAVE EXHIBITED UPDRAFT ROTATION DURING AND AFTER THE TRANSITION ACROSS THE COLD FRONT WHERE LOW INTENSE LOW LEVEL SHEAR IS INDICATED IN OBJECTIVE ANALYSIS DATA AND PROFILER WINDS. IF PERSISTENT CELLS DEVELOPING IN THE WARM SECTOR CAN REMAIN DISCRETE...A BRIEF WIND GUST OR TORNADO CANNOT BE RULED OUT AS THIS ACTIVITY INTERACTS WITH THE FRONTAL ZONE. HOWEVER...LARGE SCALE UPPER SUPPORT FOR DEEPER VERTICAL MOTION ACROSS THE REGION DOES APPEAR LIMITED AT THIS TIME AND A WATCH IS NOT CURRENTLY EXPECTED. HEAVY RAIN AND LOCALIZED FLOODING POTENTIAL ARE LIKELY TO PERSIST ALONG AND NORTH OF THE FRONT INTO THE AFTERNOON. FOR THE TIME BEING...THE ZONE OF STRONGER STORMS APPEARS TO HAVE SHIFTED WEST OF I35 AND THIS SHOULD PROVIDE SOME RELIEF TO THE SAN MARCOS/AUSTIN AREAS AFTER VERY HEAVY RAIN THIS MORNING. HOWEVER... PW VALUES IN EXCESS OF 1.5 INCHES...AND POTENTIAL FOR REPEAT CONVECTION GENERATED NEAR SLOW-MOVING FRONT AND THEN MOVING NWD WITHIN MEAN DEEP-LAYER SSWLY FLOW...WILL CONTINUE TO RESULT IN COPIOUS RAINFALL AMOUNTS IN THE POST-FRONTAL REGION ALONG THE I35 CORRIDOR. ..CARBIN.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX...FWD...EWX... 30559834 31019804 31659757 31719668 31489648 30059697 29659727 29069769 28809819 28749864 29009887 29309896 29659890 30209859 WWWW From mcd at goshenarc.org Sat Jan 13 18:34:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 13:34:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 131837 SWOMCD SPC MCD 131836 ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-TXZ000-132300- MESOSCALE DISCUSSION 0051 NWS STORM PREDICTION CENTER NORMAN OK 1236 PM CST SAT JAN 13 2007 AREAS AFFECTED...SERN KS...CNTRL/SRN MO...CNTRL/ERN OK...PORTIONS OF N-CNTRL TX CONCERNING...WINTER MIXED PRECIPITATION VALID 131836Z - 132300Z OCCASIONAL BURSTS OF FREEZING RAIN AND SLEET WILL CONTINUE THROUGH THE AFTERNOON HOURS...WITH ISOLATED TSTMS ACROSS ERN OK/PORTIONS OF N-CNTRL TX. ICE ACCUMULATION RATES SHOULD BRIEFLY REACH AROUND .05 TO .10 IN/HR...WITH LOCALIZED RATES EXCEEDING .10 IN/HR. INTERMITTENT FREEZING RAIN HAS BEEN ONGOING ON THE WRN PERIPHERY OF A WARM CONVEYOR BELT FROM THE LOWER RIO GRANDE VALLEY N/NEWD ACROSS THE MID-MS RIVER VALLEY. ALTHOUGH THE BULK OF PRECIPITATION HAS BEEN CONFINED BETWEEN THE SURFACE FREEZING LINE AND COLD FRONT...OCCASIONAL SHOWERS HAVE MOVED INTO THE BELOW FREEZING SECTOR AND PRODUCED LIGHT ICE ACCUMULATIONS THROUGH THE MORNING HOURS. 15Z RUC AND 12Z GFS/NAM GUIDANCE SUGGESTS VERY LITTLE EWD PROGRESS OF THIS WARM/MOIST OVERRUNNING AXIS THIS AFTERNOON. FURTHER W...A WEAK UPPER-LEVEL IMPULSE IN FAR WRN OK /PER WATER VAPOR IMAGERY/ HAS AIDED IN THE DEVELOPMENT OF NUMEROUS SLEET SHOWERS AND ISOLATED TSTMS ALONG THE I-35 CORRIDOR IN CNTRL OK. THIS IMPULSE WILL HELP STRENGTHEN THE UPPER-LEVEL JET THIS AFTERNOON ACROSS THE LOWER MO RIVER VALLEY...WITH SUBSTANTIAL RIGHT-ENTRANCE REGION DIVERGENCE TO ITS SOUTH. THUS...A RELATIVELY ELONGATED AXIS OF OCCASIONAL FREEZING RAIN WILL CONTINUE. THIS AXIS WILL REMAIN FROM THE WRN DFW METRO AREA NNEWD ALONG THE US-69 CORRIDOR IN OK...ARCING NEWD ALONG THE I-44 CORRIDOR IN MO. ..GRAMS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT...FWD...OUN... 36529414 35179529 32859692 32299736 32329760 32959774 33639806 33939800 34759768 35799726 36909668 37569612 38089507 38319390 38249252 38349019 38079028 37499115  From mcd at goshenarc.org Sat Jan 13 23:46:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 18:46:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 132350 SWOMCD SPC MCD 132349 MSZ000-ARZ000-LAZ000-TXZ000-140245- MESOSCALE DISCUSSION 0053 NWS STORM PREDICTION CENTER NORMAN OK 0549 PM CST SAT JAN 13 2007 AREAS AFFECTED...PORTIONS EXTREME E-CENTRAL/NE TX...NWRN LA...SRN/ERN AR. CONCERNING...HEAVY RAINFALL VALID 132349Z - 140245Z BAND OF TSTMS WITH HEAVY RAINFALL IS FCST TO MAINTAIN INTENSITY AS IT MOVES EWD ACROSS CORRIDOR NEAR LINE FROM GGG...SHV...ELD...PBF...50 SW MEM. RAIN RATES COMMONLY 1-1.25 INCH/HOUR ARE EXPECTED...LOCALLY/BRIEFLY TOPPING 2 INCHES/HOUR IN MOST INTENSE CORES. 23Z SFC MESOANALYSIS SHOWS FRONTAL-WAVE LOW BETWEEN SHV-GGG...WHICH SHOULD LIFT NEWD INTO SWRN AR DURING NEXT FEW HOURS. STRONGEST CONVERGENCE AND STORM-RELATIVE/SFC-BASED INFLOW LIKEWISE IS FCST TO SHIFT NEWD AHEAD OF LOW...WITH COLD FRONT UNDERCUTTING SFC-BASED BUOYANCY FOR DEVELOPMENT OCCURRING SW OF LOW. STILL...ACTIVITY MAY FORM ATOP SHALLOW FRONTAL LAYER IN ENVIRONMENT OF ELEVATED MOISTURE TRANSPORT AND WAA...AIDING PROPAGATIONAL MAINTENANCE OF SWRN PORTION OF PRECIP/TSTM BAND. GIVEN NEARLY PARALLEL ORIENTATION OF ACTIVITY RELATIVE TO AMBIENT MEAN FLOW...TRAINING OF CORES IS LIKELY TO FURTHER AUGMENT HEAVY RAIN HAZARD. ALTHOUGH 73 F DEW POINT AT SFC STATION IER IS BOGUS...GPS SENSOR DATA AND NEAR-TERM FCST SOUNDINGS AHEAD OF FRONT INDICATE FAVORABLY RICH MOISTURE WITH NARROW ZONE OF PW 1.4-1.7 INCH THROUGH NEARLY SATURATED DEEP-LAYER PROFILE...PORTENDING EFFICIENT PRECIP PROCESSES IN MOST INTENSE CONVECTION. HEAVIEST RAIN SHOULD REMAIN S OF FREEZING LINE ACROSS PORTIONS OZARKS. ADDITIONAL DETAILS ON FREEZING/FROZEN PRECIP POTENTIAL FARTHER N WILL BE DISCUSSED IN UPCOMING SPC WINTER WEATHER MESOSCALE DISCUSSIONS. WARM SECTOR VERTICAL SHEAR PROFILES ALSO ARE FAVORABLE FOR SOME SVR POTENTIAL WITH 0-1 KM SRH AROUND 200 J/KG...AND WEAK SBCAPES OF 200-300 J/KG. BRIEF TORNADO OR DAMAGING GUST CANNOT BE RULED OUT. HOWEVER...LACK OF MORE ROBUST BUOYANCY AND OF DISCRETE CONVECTIVE MODE SHOULD KEEP THIS THREAT MRGL AT MOST. ..EDWARDS.. 01/13/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MEG...JAN...LZK...SHV... 32999409 33439346 34499237 34799096 34139083 33769120 32389241 31929448  From mcd at goshenarc.org Sun Jan 14 00:16:51 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 19:16:51 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140020 SWOMCD SPC MCD 140019 ILZ000-MOZ000-140415- MESOSCALE DISCUSSION 0054 NWS STORM PREDICTION CENTER NORMAN OK 0619 PM CST SAT JAN 13 2007 AREAS AFFECTED...SRN MO CONCERNING...FREEZING RAIN VALID 140019Z - 140415Z FREEZING RAIN WILL AFFECT PORTIONS OF SRN MO EARLY THIS EVENING...GENERALLY ALONG THE I-44 CORRIDOR FROM SGF TO THE SRN STL METRO AREA. PRECIPITATION RATES AROUND .05 IN/HR CAN BE EXPECTED...WITH LOCALIZED RATES IN EXCESS OF .10 IN/HR OVER THE NEXT FEW HOURS. THE OVERALL THREAT FOR ADDITIONAL FREEZING RAIN WILL GRADUALLY DIMINISH FROM WEST TO EAST...ESPECIALLY AFTER 03Z. THE SURFACE FREEZING LINE HAS REMAINED NEARLY STATIONARY OVER THE PAST SEVERAL HOURS ACROSS EXTREME NWRN AR...SRN MO AND WRN IL. AS OF 14/00Z...IT EXTENDED FROM AROUND 20 NW OF FYV TO 20 N UNO TO ALN. A LARGE AREA OF RAIN/FREEZING RAIN HAS BEEN STEADILY MOVING EWD ACROSS SWRN MO/FAR NWRN AR /PER REGIONAL RADAR IMAGERY/. THIS ACTIVITY IS EXPECTED TO CONTINUE THIS PROGRESSION AS IT BECOMES ABSORBED INTO THE WARM/MOIST CONVEYOR BELT REGION RUNNING FROM THE TX COASTAL BEND TOWARDS THE LOWER OH RIVER VALLEY. 13/21Z RUC AND 13/18Z NAM MODEL GUIDANCE INDICATE 700-500 MB MID-LEVEL DRYING WILL ENSUE BEHIND THIS LAST SUBSTANTIAL AREA OF PRECIPITATION...EVIDENCED BY THE 14/00Z OUN OBSERVED SOUNDING. IN ADDITION...AS THE UPPER MIDWEST/LOWER GREAT LAKES UPPER-LEVEL JET QUICKLY MOVES EWD THIS EVENING...FAVORABLE RIGHT-ENTRANCE DIVERGENCE PRESENTLY ACROSS THE MCD AREA WILL SHIFT EWD AS WELL. THUS...THE OVERALL THREAT FOR FREEZING RAIN WILL DIMINISH...ESPECIALLY AFTER 03Z. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...SGF... 37289161 36999256 36869304 36789333 36779366 36969385 37349387 37699382 37869341 38149258 38469156 38689053 38299034 37809070  From mcd at goshenarc.org Sun Jan 14 02:10:54 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 13 Jan 2007 21:10:54 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140214 SWOMCD SPC MCD 140213 LAZ000-TXZ000-140445- MESOSCALE DISCUSSION 0055 NWS STORM PREDICTION CENTER NORMAN OK 0813 PM CST SAT JAN 13 2007 AREAS AFFECTED...PORTIONS SE TX. CONCERNING...HEAVY RAINFALL VALID 140213Z - 140445Z POTENTIAL FOR HEAVY RAINFALL -- COMPOUNDED BY TRAINING OF HEAVIEST PRECIP CORES -- WILL SHIFT EWD ACROSS LFK-HOU CORRIDOR THROUGH 5Z...WITH LOCAL RAIN RATES BRIEFLY REACHING 2 INCHES/HOUR AND COMMONLY 1-1.5 INCH/HOUR IN TSTMS. SFC MESOANALYSIS AT 2Z SHOWS COLD FRONT BETWEEN ANGELINA-WRN HARRIS-NACOGDOCHES COUNTIES...MOVING SEWD APPROXIMATELY 15 KT. RICH MOISTURE IN GULF AIR MASS -- CHARACTERIZED BY 1.75-2 INCH PW...MID-UPPER 60S F SFC DEW POINTS... AND 14-15 DEG C ESTIMATED 850 MB DEW POINTS SHOULD PERSIST IN WARM SECTOR. MOST ACTIVITY WILL OCCUR JUST BEHIND BOUNDARY AS FRONTAL AND ISENTROPIC LIFT FORCED PARCELS TO LFC. WEAK MESOLOW --ANALYZED ALONG FRONT N HOU -- MAY LEAD TO ENHANCED LOW LEVEL CONVERGENCE TO ITS IMMEDIATE NE AS WELL. DEEP-LAYER MEAN FLOW WILL REMAIN ALIGNED NEARLY PARALLEL TO ZONE OF STRONGEST CONVECTIVE FORCING...AS LATTER MOVES SLOWLY EWD...RESULTING IN REPEAT PASSAGE OF HEAVY CORES OVER SOME LOCALES. MODIFIED PROFILER/VWP/RUC SOUNDING DATA INDICATE SUFFICIENT VERTICAL SHEAR TO SUPPORT SUPERCELL POTENTIAL...AND CONTINUED PRESENCE OF SFC-BASED EFFECTIVE LAYER IN WARM SECTOR SOUNDINGS INDICATES POTENTIAL FOR BRIEF TORNADO CANNOT BE RULED OUT. HOWEVER...LINEAR INCLINATION OF CONVECTIVE MODE...COMBINED WITH ANAFRONTAL REGIME KEEPING MOST ACTIVITY BEHIND COLD FRONT...WILL KEEP SVR POTENTIAL MRGL AT BEST. ..EDWARDS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LCH...SHV...HGX... 29449627 30319578 31659435 31529373 30739355 30359378 29119515 28939641  From mcd at goshenarc.org Sun Jan 14 06:18:21 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 01:18:21 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140621 SWOMCD SPC MCD 140621 OHZ000-MIZ000-INZ000-ILZ000-WIZ000-141145- MESOSCALE DISCUSSION 0056 NWS STORM PREDICTION CENTER NORMAN OK 1221 AM CST SUN JAN 14 2007 AREAS AFFECTED...FAR SERN WI/NRN IL...NRN IN...SRN LOWER MI AND FAR NWRN OH CONCERNING...WINTER MIXED PRECIPITATION VALID 140621Z - 141145Z LIGHT FREEZING RAIN AND SLEET SHOWERS WILL CONTINUE TO DEVELOP NORTH OF THE SFC FREEZING LINE EXTENDING FROM NCENTRAL IL /PIA/ INTO NWRN OH /TOL/ OVER THE NEXT 6 HOURS. AVERAGE HRLY LIQUID EQUIVALENT ACCUMULATION RATES FROM 0.01 TO 0.05 INCH CAN BE EXPECTED. LATEST RADAR IMAGERY INDICATES THAT PRECIPITATION CONTINUES TO EXPAND OVER PORTIONS OF THE MID MS VALLEY AND WRN GREAT LAKES. THIS PRECIPITATION WAS DEVELOPING IN RESPONSE TO STRENGTHENING ISENTROPIC LIFT OVER THE SFC-850 MB FRONTAL BOUNDARY AND MID LEVEL VERTICAL MOTION BOTH ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH OVER MISSOURI. FORECAST AND OBSERVED SOUNDINGS INDICATE THAT PRECIP TYPE WILL RANGE FROM FREEZING RAIN OVER PORTIONS OF NERN IL/FAR NRN IND AND FAR SRN MI/NWRN OH WHERE THE COLD AIR WAS SHALLOWER. SLEET IS EXPECTED OVER FAR NERN IL AND PORTIONS OF SRN LOWER MI /GENERALLY NORTH OF I-94/ WHERE THE DEPTH OF THE SUB-FREEZING LAYER WAS GREATER. STEEP MID LEVEL LAPSE RATES WILL SUPPORT CONVECTIVE NATURE OF PRECIP WITH OCCASIONAL BURSTS OF ACCUMULATIONS RATES UP TO 0.10/HR. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT...ILX...MKX...DVN... 43188692 42298982 41048993 40418984 40478855 40998555 41258379 41558327 42718326 42978418  From mcd at goshenarc.org Sun Jan 14 07:12:31 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 02:12:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 140715 SWOMCD SPC MCD 140715 OKZ000-TXZ000-141315- MESOSCALE DISCUSSION 0057 NWS STORM PREDICTION CENTER NORMAN OK 0115 AM CST SUN JAN 14 2007 AREAS AFFECTED...WCENTRAL/NWRN TX AND SWRN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 140715Z - 141315Z FREEZING DRIZZLE AND POSSIBLY VERY LIGHT FREEZING RAIN IS ANTICIPATED TO DEVELOP OVER THE AREA IN THE NEXT FEW HOURS. PRECIPITATION IS EXPECTED TO INCREASE IN INTENSITY AND MIX WITH OR CHANGEOVER TO SLEET TOWARDS 12Z. ANALYSES OF SFC WINDS/SLP OVER THE SRN PLAINS INDICATES A CONTINUED GRADUAL BACKING/FALLING OVER THE LAST FEW HRS IN RESPONSE TO APPROACHING SHORTWAVE TROUGH LOCATED NEAR THE AZ/NM BORDER. THE 850 MB FLOW ALSO HAS BEEN BACKING AND STRENGTHENING NOTED BY THE RECENT VWP DATA FROM MAF/SJT AND DYS. AS A RESULT...ISENTROPIC LIFT HAS BECOME MORE NORMAL TO THE FRONTAL ZONE ENHANCING LOW LEVEL VERTICAL MOTION. THIS WILL CONTINUE TO SUPPORT THE DEVELOPMENT OF A LARGE AREA OF FREEZING DRIZZLE AND POSSIBLY VERY LIGHT FREEZING RAIN ACROSS WCENTRAL/NWRN TX INTO SWRN OK OVER THE NEXT SEVERAL HOURS. MID LEVELS ARE BEGINNING TO MOISTEN AS NOTED BY THE 07Z OBS AT EL PASO AND CLOUD TOP COOLING ON IR SAT IMAGERY. THIS WAS OCCURRING WHERE A LARGE PLUME OF HIGH LEVEL PACIFIC MOIST PLUME HAS BEGUN TO INTERACT WITH THE SWRN SHORTWAVE TROUGH. THIS MID LEVEL MOISTURE AND ASSOCIATED LIFT SHOULD CONTINUE TO SPREAD NEWD AND BEGIN TO REACH THE MCD AREA AFTER 10Z. EVENTUALLY...THE COLUMN WILL SATURATE SUFFICIENTLY THAT SLEET AND/OR FREEZING RAIN DEVELOPMENT IS EXPECTED TOWARDS 12Z. THE PTYPE IS EXPECTED TO BE A MIX OF FREEZING RAIN AND SLEET WCENTRAL/NWRN TX. SLEET IS EXPECTED TO BE THE PRIMARY PTYPE OVER SWRN OK WHERE MIN TEMPERATURES IN THE LOWEST 2000 FT AGL ARE EXPECTED TO BE AROUND -10 DEG C. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF... 35229837 35329887 34660046 34180139 33450204 31920212 31480196 31120152 31080097 31240005 31629920 32759850 34319761 34919760  From mcd at goshenarc.org Sun Jan 14 12:37:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 07:37:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141240 SWOMCD SPC MCD 141239 OHZ000-MIZ000-INZ000-141845- MESOSCALE DISCUSSION 0058 NWS STORM PREDICTION CENTER NORMAN OK 0639 AM CST SUN JAN 14 2007 AREAS AFFECTED...SRN LOWER MI...NRN IN AND NWRN OH CONCERNING...WINTER MIXED PRECIPITATION VALID 141239Z - 141845Z A LARGE AREA OF FREEZING RAIN AND SLEET...WITH SLEET THE PREDOMINANT PTYPE IN SRN LOWER MI...WILL CONTINUE TO PROGRESS EWD ACROSS THE AREA THIS MORNING BEFORE ENDING BY 18Z. A REGION OF MODEST ISENTROPIC LIFT NORTH OF A STATIONARY FRONTAL BOUNDARY AND MID LEVEL LIFT AHEAD OF A SUBTLE SHORTWAVE TROUGH OVER THE MID MS VALLEY WAS SUPPORTING A LARGE OF MIXED PRECIP OVER NRN IN/NWRN OH AND SRN LOWER MI. THE 12Z ILX SOUNDING INDICATED STEEP MID LEVEL LAPSE RATES ALONG WITH SOME WEAK ELEVATED INSTABILITY WILL SUPPORT CONVECTIVE ACCUMULATION RATES UP TO 0.25 IN FOR BRIEF PERIODS. RECENT SFC OBS AND THE 12Z DTX SOUNDING INDICATED A SUFFICIENTLY SMALL ENOUGH ELEVATED WARM LAYER THAT SLEET WILL BE THE PRIMARY PTYPE NORTH OF I-94. GIVEN THE PROGRESSIVE NATURE OF THE FORCING...STEADY LIGHT TO MDT PRECIP SHOULD END ACROSS THE ENTIRE AREA BY AROUND 18Z. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT... 42568338 42738481 42618711 41838753 41378733 41188697 41168417 41428322  From mcd at goshenarc.org Sun Jan 14 12:48:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 07:48:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141252 SWOMCD SPC MCD 141251 TXZ000-OKZ000-KSZ000-141645- MESOSCALE DISCUSSION 0059 NWS STORM PREDICTION CENTER NORMAN OK 0651 AM CST SUN JAN 14 2007 AREAS AFFECTED...SRN KS...OK AND NE TX CONCERNING...WINTER MIXED PRECIPITATION VALID 141251Z - 141645Z MIXED PRECIPITATION WILL OCCUR ACROSS THE REGION THIS MORNING WITH SLEET AND LIGHT SNOW LIKELY FROM FAR SRN KS TO SCNTRL OK. FURTHER SOUTH IN SRN OK AND NE TX...FREEZING RAIN WILL BE THE DOMINANT MODE OF PRECIPITATION. QPF AMOUNTS SHOULD RANGE FROM .05 TO .15 THROUGH MIDDAY WITH LOCALLY HIGHER AMOUNTS POSSIBLE ESPECIALLY ALONG AND TO THE SOUTH OF THE RED RIVER. LATEST SFC ANALYSIS SHOWS A LARGE AREA OF ARCTIC HIGH PRESSURE EXTENDING SWD FROM THE NRN PLAINS INTO THE SRN PLAINS. NLY WINDS ASSOCIATED WITH THE HIGH WILL REINFORCE VERY COLD TEMPERATURES ACROSS THE REGION THIS MORNING. TEMPERATURES RANGE FROM 18 TO 20 DEGREES F IN FAR SRN KS TO AROUND 30 DEGREES F NEAR THE RED RIVER. 12Z MORNING SOUNDINGS FROM AMA AND OUN SHOW A WARM LAYER AROUND 2500-3000 FEET ABOVE GROUND LEVEL WITH TEMPS AS WARM AS +7.0 CELSIUS. THIS SHOULD BE FAVORABLE FOR SLEET WITH A MIXTURE OF LIGHT SNOW ACROSS NW OK AND SRN KS WHERE THE WARM LAYER IS NOT AS THICK. IN ADDITION...ELEVATED INSTABILITY EXISTS ACROSS THE MCD AREA WITH SOUNDINGS SHOWING MUCAPE VALUES BETWEEN 100 AND 300 J/KG. THIS SHOULD BE SUFFICIENT FOR CONVECTION AS THE STRONGER LARGE-SCALE ASCENT MOVES INTO THE PLAINS. AS A RESULT...THE COVERAGE OF MIXED PRECIPITATION SHOULD GRADUALLY INCREASE FROM WEST TO EAST ACROSS THE REGION THROUGH MIDDAY. FURTHER SOUTH...THE FWD 12Z SOUNDING SHOWS A SUBSTANTIAL WARM LAYER FROM JUST ABOVE THE GROUND TO ABOUT 800 MB WITH +12 CELSIUS NEAR 850 MB. IN ADDITION...ELEVATED MUCAPE VALUES EXCEED 500 J/KG WHICH SHOULD BE FAVORABLE FOR THUNDERSTORMS WITH SHORT BURSTS OF HEAVY FREEZING RAIN POSSIBLE. AS A RESULT...SIGNIFICANT ICE ACCUMULATION APPEARS LIKELY NEAR AND TO THE SOUTH OF THE RED RIVER AS THE STRONGER FORCING EJECTS NEWD ACROSS THE REGION LATE THIS MORNING. MOST AREAS IN NORTH TX AND FAR SRN OK SHOULD RECEIVE A TENTH OF AN INCH OF ICE WITH A QUARTER INCH OF ICE POSSIBLE WHERE CONVECTION DEVELOPS LATE THIS MORNING. ..BROYLES.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SHV...TSA...ICT...FWD...OUN...DDC... 32799776 33379837 34139869 35369933 36079997 36819984 37359913 37489746 37009652 35549548 33669511 32909611 32709713  From mcd at goshenarc.org Sun Jan 14 13:22:25 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 08:22:25 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141325 SWOMCD SPC MCD 141325 MAZ000-NHZ000-VTZ000-NYZ000-141730- MESOSCALE DISCUSSION 0060 NWS STORM PREDICTION CENTER NORMAN OK 0725 AM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS OF NY...MA AND FAR SRN VT/NH CONCERNING...WINTER MIXED PRECIPITATION VALID 141325Z - 141730Z EPISODES OF LIGHT FREEZING RAIN AND SLEET ARE EXPECTED TO OCCUR THIS MORNING ACROSS PORTIONS OF WRN NY EWD INTO FAR SRN VT/NH AND MA. HRLY ACCUMULATIONS RATES WILL GENERALLY AVERAGE LESS THAN 0.05 INCH. ISENTROPIC LIFT WAS INCREASING OVER THE ERN GREAT LAKES AND FAR WRN NY IN RESPONSE TO A STRENGTHENING AGEOSTROPHIC CIRCULATION IN THE RIGHT ENTRANCE REGION OF AN UPPER JET OVER SRN QUEBEC. SFC ANALYSIS SHOWED THE FREEZING LINE EXTENDING FROM NEAR JHW TO 40 N POU TO ORH. NWD MOVEMENT OF THIS LINE MAY OCCUR AS WAA INCREASES ...BUT GIVEN THE LACK OF SUBSTANTIAL PRESSURE FALLS OVER THE AREA...THE OVERALL MOVEMENT OF THE FREEZING ISOTHERM SHOULD BE MINIMAL THROUGH THE MORNING. THE 12Z ALB SOUNDING INDICATED THE DEPTH OF THE ABOVE FREEZING ELEVATED WARM LAYER IS SUFFICIENT TO SUPPORT FREEZING RAIN OVER SRN NEW ENGLAND AND PORTIONS OF SRN/ERN NY. STEEP MID LEVEL LAPSE RATES ON THE 12Z BUF SOUNDING WILL SUPPORT OCCASIONAL CONVECTIVE BURSTS OF PRECIP...WITH HRLY LIQUID ACCUMULATIONS RATES UP TO 0.10 IN. WITHIN THESE CONVECTIVE SHOWERS...SLEET MAY MIX WITH THE FREEZING RAIN. MORE STEADY FREEZING RAIN/SLEET IS EXPECTED TO DEVELOP OUT OF MI INTO SWRN/CENTRAL NY BETWEEN 15-17Z AHEAD OF THE SHORTWAVE TROUGH THAT WILL BE MOVING THROUGH THE CENTRAL LAKES AT THAT TIME. ..CROSBIE.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...BOX...ALY...BGM...BUF... 43147566 43037805 42557872 42077794 42037424 42317219 42577164 42957168 43107374  From mcd at goshenarc.org Sun Jan 14 17:39:35 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 12:39:35 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141742 SWOMCD SPC MCD 141742 MNZ000-IAZ000-NEZ000-SDZ000-142345- MESOSCALE DISCUSSION 0061 NWS STORM PREDICTION CENTER NORMAN OK 1142 AM CST SUN JAN 14 2007 AREAS AFFECTED...NERN NEB...SERN SD...NWRN IA...SWRN MN CONCERNING...HEAVY SNOW VALID 141742Z - 142345Z MDT TO HVY SN ACROSS PORTIONS OF SERN/SCNTRL NEB WILL CONTINUE TO EXPAND ACROSS THE MO RIVER VALLEY THROUGH THIS AFTERNOON. SNOWFALL RATES WITHIN THE STRONGER BANDS WILL BE AROUND 1 INCH PER HOUR... WITH LIGHTER HOURLY AMOUNTS OCCURRING IN BETWEEN THE BANDS. THE ONGOING BANDING ACROSS NEB COINCIDES VERY WELL WITH A INTENSIFYING AXIS OF 700-500MB LAYER FRONTOGENESIS DEPICTED IN LATEST RUC AND NAM-WRF MODELS. THIS SW-NE ORIENTED AXIS OF MESOSCALE ASCENT WAS DEVELOPING AHEAD OF A SHORT WAVE TROUGH EJECTING NEWD FROM ERN CO AND LATEST GUIDANCE MAINTAINS STRONG ASCENT ACROSS THE REGION THROUGH ABOUT 15/00Z. WITH MID LEVEL LIFT OCCURRING IN A THERMODYNAMIC REGIME FAVORING EFFICIENT WATER VAPOR TO ICE TRANSPORT /-12C TO -17C/...AND A DEEP DENDRITE GROWTH LAYER...SNOWFALL RATES SHOULD EASILY REACH AN INCH PER HOUR AS LOW LEVEL SATURATION OCCURS FROM SW TO NE. SREF GUIDANCE DEPICTS THE HIGHEST PROBABILITY OF INCH PER HOUR SNOWFALL RATES DEVELOPING FROM CNTRL NEB INTO SERN SD BY LATE THIS AFTERNOON AND THROUGH EARLY EVENING. HOWEVER...LATEST RADAR TRENDS WOULD SUGGEST THAT PERHAPS A SECONDARY AXIS OF HVY SN MAY BE EVOLVING FARTHER SOUTH...ALONG A MCK-OFK-SUX LINE. GIVEN CLOSER PROXIMITY OF THIS BAND TO LOW LEVEL MOISTURE INFLOW...THE SREF GUIDANCE MAY BE DISPLACED SLIGHTLY NORTH OF GREATEST SNOWFALL RATE POTENTIAL THROUGH LATE THIS AFTERNOON. ..CARBIN.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...DMX...FSD...OAX...GID...LBF...GLD... 43029919 43769637 43579501 42089557 41449564 41049606 40619655 40449783 40419819 40589885 40279963 40260050 41260044 41890070 42320042 42729991  From mcd at goshenarc.org Sun Jan 14 17:48:10 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 12:48:10 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141751 SWOMCD SPC MCD 141750 MOZ000-IAZ000-OKZ000-KSZ000-NEZ000-142245- MESOSCALE DISCUSSION 0062 NWS STORM PREDICTION CENTER NORMAN OK 1150 AM CST SUN JAN 14 2007 AREAS AFFECTED...ERN KS...NRN/WRN/CNTRL MO...SRN IA...EXTREME SERN NEB CONCERNING...WINTER MIXED PRECIPITATION VALID 141750Z - 142245Z A MIX OF FREEZING RAIN...SLEET...AND SNOW WILL EXPAND E/NEWD THIS AFTERNOON. PRECIPITATION RATES OF .05 TO .15 IN/HR WILL BE COMMON...WITH LOCALLY HEAVIER RATES IN EXCESS OF .20 IN/HR IN CONVECTIVE CELLS. A SWATH OF MODERATE TO OCCASIONALLY HEAVY SLEET HAS BEEN ONGOING ACROSS MUCH OF CNTRL INTO ERN KS THIS MORNING...WITH MODERATE TO HEAVY SNOW RECENTLY DEVELOPING IN PORTIONS OF SRN NEB. RECENT SLEET ACCUMULATIONS OF AROUND 0.5 TO 1.5 INCHES HAVE BEEN REPORTED IN THE ICT AREA. BOTH THE 12Z GFS AND 15Z RUC HAVE GOOD QPF AGREEMENT WITH THE ONGOING PRECIPITATION EVOLUTION WHEN COMPARED TO REGIONAL RADAR IMAGERY...WHILE THE 12Z NAM HAS BEEN TOO SLOW/FARTHER WEST. BOTH LOW AND MID-LEVEL ISENTROPIC LIFT WILL CONTINUE DOWNSTREAM OF THIS PRECIPITATION REGION...AS A SHORTWAVE TROUGH EJECTS NEWD FROM CO. PRECIPITATION IS EXPECTED TO RAPIDLY EXPAND E/NEWD INTO MUCH OF MO AND FAR SRN IA THIS AFTERNOON. A MIX OF PRECIPITATION TYPES WILL OCCUR ACROSS THIS REGION WITH A TIGHT SW TO NE ORIENTED LOW-LEVEL THERMAL GRADIENT. AT 17Z...THE SURFACE FREEZING LINE WAS LOCATED FROM NEAR FYV TO 30 W STL TO BRL. THIS LINE SHOULD MAKE SLOW PROGRESS WWD THROUGH THE AFTERNOON....AS WEAK ELY WINDS CONTINUE TO THE N OF A DEVELOPING SURFACE LOW IN THE TEXARKANA REGION. JUST W OF THIS FREEZING LINE...OVER MUCH OF CNTRL MO...FREEZING RAIN WILL BE THE PRIMARY PTYPE AS EVIDENCED BY THE 12Z OBSERVED SGF SOUNDING. FURTHER NW...SLEET WILL BE THE PREDOMINANT PTYPE ACROSS SERN KS THROUGH THE KC METRO AREA. HERE...A SMALL WARM LAYER OF ABOVE FREEZING TEMPERATURES REMAINS BETWEEN 700-850 MB RELATIVE TO A MUCH COLDER SURFACE-BASED LAYER /PER 12Z TOP AND LAMONT OK SOUNDINGS/. ACROSS PORTIONS OF NERN KS/FAR NWRN MO INTO SRN IA...THE PRIMARY PTYPE WILL BECOME ALL SNOW...AS MORNING MODEL GUIDANCE IS INSISTENT ON COOLING THE 700-850 MB LAYER TO AOB FREEZING. AS THIS OCCURS...SNOW RATES SHOULD BRIEFLY REACH 1 IN/HR. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LSX...DVN...SGF...DMX...EAX...TSA...OAX...TOP...ICT... 39429684 40359668 40979599 41359494 41139300 40799234 40159190 39629152 38899154 38169164 37609196 37229299 36639378 36519440 36699518 37099604 38289662  From mcd at goshenarc.org Sun Jan 14 18:47:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 13:47:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 141850 SWOMCD SPC MCD 141849 OKZ000-TXZ000-142215- MESOSCALE DISCUSSION 0063 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST SUN JAN 14 2007 AREAS AFFECTED...ERN OK...PORTIONS OF N-CNTRL TX CONCERNING...WINTER MIXED PRECIPITATION VALID 141849Z - 142215Z NUMEROUS SHOWERS AND ISOLATED TSTMS OF SLEET AND FREEZING RAIN WILL MOVE EWD AFFECTING MUCH OF ERN OK THROUGH 22Z. PRECIPITATION ACCUMULATION RATES OF .10 TO .20 IN/HR WILL CONTINUE FOR THE NEXT FEW HOURS. SIGNIFICANT PRECIPITATION WILL DIMINISH LATER THIS AFTERNOON. A LARGE AREA OF SHOWERS WITH EMBEDDED TSTMS HAS MOVED RAPIDLY INTO ERN OK...WITH THE BACK EDGE OF PRECIPITATION FROM AROUND ALVA OK TO MWL. MUCH OF THE SIGNIFICANT PRECIPITATION HAS BEEN SLEET WITH AN OCCASIONAL MIX OF FREEZING RAIN IN CNTRL OK. RUC OBJECTIVE ANALYSIS INDICATES MUCAPES OF AOB 500 J/KG OVER CNTRL/ERN OK AND N-CNTRL TX WILL CONTINUE TO SUPPORT ELEVATED TSTM POTENTIAL. AT 18Z...THE SURFACE FREEZING LINE WAS LOCATED FROM AROUND 20 W OF FYV TO NEAR DFW. SIGNIFICANT ICE ACCUMULATIONS WILL LIKELY CONTINUE JUST W OF THIS LINE...ALONG THE US-69 CORRIDOR IN ERN OK. MORNING MODEL GUIDANCE ARE CONSISTENT IN DIMINISHING PRECIPITATION THROUGH THE AFTERNOON. THIS SHOULD OCCUR AS 850 TO 700 MB WINDS BECOME MORE WLY WITH CORRESPONDING DECREASES IN RH AND INTENSIFYING ISENTROPIC DOWNGLIDE. ..GRAMS.. 01/14/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...TSA...FWD...OUN... 32899698 32629747 33469731 33959720 34629704 35739672 36539622 36799596 36939537 36739500 36579477 36199502 34899566 34469603 33449669 WWWW From mcd at goshenarc.org Mon Jan 15 00:34:46 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 19:34:46 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150037 SWOMCD SPC MCD 150037 MOZ000-ARZ000-TXZ000-OKZ000-150600- MESOSCALE DISCUSSION 0064 NWS STORM PREDICTION CENTER NORMAN OK 0637 PM CST SUN JAN 14 2007 AREAS AFFECTED...SW MO/SE OK/NE AND CNTRL TX/NW AR CONCERNING...WINTER MIXED PRECIPITATION VALID 150037Z - 150600Z PERIODS OF SLEET AND FREEZING RAIN ARE EXPECTED ACROSS SOUTHWEST MISSOURI...SOUTHEAST OKLAHOMA...NORTHEAST AND CENTRAL TEXAS...AND NORTHWEST ARKANSAS THIS EVENING. ACCUMULATIONS ARE EXPECTED TO BE AROUND .05 INCHES TO .10 INCHES PER HOUR. PRECIPITATION RATES HAVE BEEN DIMINISHING THROUGHOUT THE AFTERNOON OVER THE REGION...HOWEVER...SOME AREAS OF FROZEN PRECIPITATION ARE STILL OCCURRING AND WILL CONTINUE FOR THE NEXT SEVERAL HOURS...ESPECIALLY OVER NORTH CENTRAL TEXAS INCLUDING THE DALLAS/FT. WORTH METROPLEX. LATEST RADAR IMAGERY CONTINUES TO SHOW DEVELOPING PRECIPITATION BANDS THROUGHOUT THE REGION...AND AS THESE MOVE NEAR AND AROUND THE 32 F ISOTHERM...A MIX OF LIQUID AND FROZEN PRECIP WILL OCCUR...WITH SOME LOCALIZED HEAVY AMOUNTS. ADDITIONALLY...THE FROZEN PRECIP WILL CONTINUE TO MOVE AND DEVELOP SOUTHEASTWARD WITH THE 32 F LINE. BOTH THE RUC AND NAM AGREE THAT THE AREAS OF HEAVY SLEET AND FREEZING RAIN WILL CONTINUE TO DIMINISH INTO THE EVENING. THE LATEST NAM SHOWS A NARROW WINDOW OF FOCUSED VERTICAL MOTION FOR THE NEXT SEVERAL HOURS...AND THEN DIMINISHES BY ROUGHLY 06Z AND MOVES EASTWARD. THUS...THE PERIOD OF SIGNIFICANT FROZEN PRECIPITATION WILL MAINLY OCCUR WITHIN THAT TIME FRAME. ..LEVIT.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SGF...SHV...TSA...FWD...OUN...EWX...SJT... 30929853 31079922 31349961 31899962 33099848 34199700 36159499 38009344 37839234 37049194 35959282 34869371 32659518 31589636 31119773  From mcd at goshenarc.org Mon Jan 15 01:05:14 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 14 Jan 2007 20:05:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150108 SWOMCD SPC MCD 150107 MIZ000-OHZ000-INZ000-ILZ000-WIZ000-150600- MESOSCALE DISCUSSION 0065 NWS STORM PREDICTION CENTER NORMAN OK 0707 PM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS NRN IL...EXTREME SERN WI...SRN LM...EXTREME NRN INDIANA...EXTREME NWRN OH...SRN/CENTRAL LOWER MI. CONCERNING...WINTER MIXED PRECIPITATION VALID 150107Z - 150600Z NEWD MOVING AREA OF PRECIP NOW OVER CENTRAL PORTIONS INDIANA/IL WILL MOVE ATOP FREEZING SFC TEMPS IN MI/INDIANA AND ERN WI/IL BORDER REGIONS...AND PORTIONS N-CENTRAL/NERN IL...THROUGH 230Z. THIS ACTIVITY WILL BE PRIMARILY IN FORM OF LIGHT FREEZING RAIN WITH RATES GENERALLY AOB .10 INCH HOUR...BUT LOCALLY TO .25 INCH/HOUR. BETWEEN 3Z-6Z...FREEZING RAIN WITH RATES LOCALLY NEAR .25-.5 INCH/HOUR MAY MOVE NEWD ACROSS SRN LOWER MI. TRANSITION THROUGH MIXED PHASE WITH SLEET...THEN TO SLEET/SNOW MIX...IS POSSIBLE WITH NWD EXTENT ACROSS S-CENTRAL TO CENTRAL LOWER MI. ISOLATED SNOW RATES 1-2 INCH/HOUR MAY DEVELOP BY 6Z W-CENTRAL LOWER MI. LOW LEVEL WAA AND MOISTURE TRANSPORT WILL STRENGTHEN ACROSS THIS AREA FROM SW-NE AS MID-UPPER LEVEL PERTURBATION NOW OVER CENTRAL HIGH PLAINS CONTINUES TO EJECT NEWD. NRN PORTION OF MOST INTENSE ISENTROPIC ASCENT IN 291-297K LAYER WILL OVERLAP SFC FREEZING TEMPS ACROSS NERN IL...NRN INDIANA AND SRN LOWER MI BETWEEN 3Z AND 6Z...CONCURRENT WITH INCREASE IN 850 MB LLJ TO 40-50 KT JUST S OF AREA ACROSS CENTRAL/SRN INDIANA AND SRN IL. 850-750 MB LAYER FRONTOGENESIS REASONABLY IS PROGGED TO STRENGTHEN OVER THIS AREA THROUGH 6Z...AIDING LIFT. AT SFC...FREEZING LINE IS ANALYZED AT 0Z NEAR TOL...SBN...VPZ...NWD ACROSS RELATIVELY WARM LM WATERS...THEN SWWD AGAIN ACROSS NRN FRINGES CHI METRO...TO ABOUT 10 N PIA. PRIND CAA AND WEAK WET BULB EFFECTS WILL HELP TO DRIFT THIS LINE SWD OVER NRN INDIANA. HOWEVER FREEZING LINE MAY NOT CHANGE MUCH OVER IL DUE TO LACK OF SFC CAA...COMBINED WITH SENSIBLE WARMING FROM DESCENT OF RELATIVELY WARM PRECIP THROUGH SATURATED AIR. RUC FCST SOUNDINGS INDICATE THIS WILL LEAD TO SATURATED...ROUGHLY 7 KFT DEEP SUPERFREEZING LAYER ACROSS NRN INDIANA...ABOVE SHALLOW FREEZING LAYER NEAR SFC. SUPERFREEZING LAYER SHOULD TRANSITION TO 4-5 KFT DEPTH OVER SRN LOWER MI...ATOP DEEPER SUBFREEZING BOUNDARY LAYER MORE CONDUCIVE FOR SLEET. WITH NWWD EXTENT IN LOWER MI...THERMAL PROFILES ALOFT WILL SUPPORT SNOW. STEEP LAPSE RATES OF 6-7 DEG C/KM...IN PORTIONS OF MOST FAVORABLE THERMAL ZONES FOR DENDRITIC GROWTH...INDICATE SOME CONVECTIVE SNOW IS POSSIBLE WITH LOCALIZED HEAVY RATES. ..EDWARDS.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...APX...IWX...GRR...LOT...MKX...DVN... 41858983 43128761 44258652 44278507 42948295 42028310 41468363 41328525 41628648 42238670 42488728 42028825 41828888 41628964 41758988  From mcd at goshenarc.org Mon Jan 15 05:12:12 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 00:12:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150515 SWOMCD SPC MCD 150514 NYZ000-151115- MESOSCALE DISCUSSION 0066 NWS STORM PREDICTION CENTER NORMAN OK 1114 PM CST SUN JAN 14 2007 AREAS AFFECTED...SRN NY CONCERNING...FREEZING RAIN VALID 150514Z - 151115Z FREEZING RAIN WILL DEVELOP OVER SOUTHERN NEW YORK DURING THE NEXT SEVERAL HOURS. LOCALIZED AND HEAVIEST ACCUMULATION VALUES ARE EXPECTED TO BE AROUND ONE QUARTER INCH BY 12Z. NUMEROUS FREEZING RAIN REPORTS CONTINUE IN SOUTHERN MICHIGAN...AND THE AIR MASS OVER THE SOUTHERN NEW YORK AREA IS SIMILAR WITH TEMPERATURES EITHER AT FREEZING OR JUST BELOW. AS MOISTURE ADVECTS NORTHEASTWARD INTO NEW YORK...FREEZING RAIN WILL DEVELOP AND IS EXPECTED TO BE HEAVIEST FROM AROUND 09Z TO 12Z. OPERATIONAL MODELS AGREE THAT THE BROAD REGION OF UPWARD VERTICAL MOTION AHEAD OF THE LONGWAVE TROUGH CURRENTLY LOCATED OVER THE MIDWEST WILL CONTINUE TO MOVE TO THE EAST...PROVIDING A FAVORABLE ENVIRONMENT FOR PRECIPITATION IN THE REGION. THIS REGION OF LIFT WILL BE JUXTAPOSED WITH AN AIR MASS THAT IS CLOSE TO FREEZING...AIDING IN THE DEVELOPMENT OF SUPERCOOLED DROPLETS AS THE RAIN FALLS THROUGH THE SHALLOW COLD LAYER NEAR THE SURFACE. ADDITIONALLY...THE LATEST 21Z SREF RUN SHOWS A HIGH PROBABILITY FOR LOCALIZED FREEZING PRECIP RATES TO BE ABOVE .05 INCHES PER HOUR...ESPECIALLY DURING THE LATER HALF OF THE FORECAST PERIOD. FINALLY...SOME SLEET COULD BE MIXED IN WITH THE FREEZING RAIN...ALSO IN LOCALIZED AREAS...ESPECIALLY IN NORTHERN PORTIONS OF THE DISCUSSION AREA WHERE TEMPERATURES WILL BE A FEW DEGREES COOLER THAN 32 F. ..LEVIT.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...ALY...BGM...BUF... 43257890 43267785 43317673 43347621 43287571 43207511 42977455 42637385 42157366 42057393 41947432 41927482 42037550 42037694 42007770 42027840 42027882 42037922 42137951 42577899 42967890  From mcd at goshenarc.org Mon Jan 15 05:31:39 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 00:31:39 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 150534 SWOMCD SPC MCD 150534 MIZ000-OHZ000-INZ000-ILZ000-WIZ000-151030- MESOSCALE DISCUSSION 0067 NWS STORM PREDICTION CENTER NORMAN OK 1134 PM CST SUN JAN 14 2007 AREAS AFFECTED...PORTIONS CENTRAL/SRN LOWER MI...EXTREME SERN WI...EXTREME NWRN OH...EXTREME NRN INDIANA...SRN LM...AND NRN IL. CONCERNING...WINTER MIXED PRECIPITATION VALID 150534Z - 151030Z MAJOR SFC ICING EVENT POSSIBLE THROUGH 12Z ACROSS PORTIONS S-CENTRAL/SERN LOWER MI...EXTREME NRN INDIANA AND NWRN OH...WITH FREEZING RAIN CONTINUING THROUGH MUCH OF DISCUSSION PERIOD. RATES LOCALLY EXCEEDING .25 INCH/HOUR ARE POSSIBLE BRIEFLY...WITH .10-.25 INCH RATES COMMON. TRANSITION TO LIGHTER FREEZING RAIN RATES IS EXPECTED WITH WWD EXTENT ACROSS EXTREME SWRN LOWER MI...SRN LM INTO NRN IL...WHERE PRECIP SHOULD WEAKEN FROM SW-NE DURING NEXT 4-6 HOURS. MEANWHILE MIXED-PHASE TRANSITION IS EXPECTED FROM FREEZING RAIN TO SLEET TO SNOW -- FROM S-N ACROSS S-CENTRAL AND ERN LOWER MI. 5Z SFC MESOANALYSIS SHOWED FREEZING LINE NEAR NRN SHORE LE...THEN INVOF MI/OH AND MI/INDIANA BORDERS...ARCHING NWD OVER SRN LM...THEN WINDING ERRATICALLY SWWD ACROSS NRN IL. MODIFIED RAOBS AND RUC SOUNDINGS INDICATE 5-8 KFT DEEP SUPERFREEZING AIR MASS ABOVE SHALLOW NEAR-SFC FREEZING LAYER FROM MI/INDIANA AND MI/OH BORDER REGIONS NWD OVER S-CENTRAL/SWRN LOWER MI. THIS PROFILE GRADUALLY WILL COOL WITH TIME...AS APPARENT TOP-DOWN PRECIP COOLING OCCURS IN WARM LAYER THROUGH MELTING AND RELATED LATENT HEAT ABSORPTION PROCESSES. THIS WILL MAINTAIN FREEZING RAIN FOR SEVERAL MORE HOURS OVER SERN LOWER MI BUT AID IN TRANSITION TO MORE FROZEN PRECIP FARTHER W AND NW. MEANWHILE...WITH BOUNDARY LAYER NEARLY SATURATED...WET BULB COOLING EFFECTS NEAR SFC SHOULD BE MINIMAL...AND FREEZING LINE SHOULD MOVE LITTLE OVER MOST OF AREA THROUGH REMAINDER OVERNIGHT HOURS. STRONGEST ISENTROPIC ASCENT IN 288-294 K LAYER...AND GREATEST FRONTOGENETIC FORCING IN 800-850 MB PRESSURE LAYER...ARE FCST TO MOVE NEWD ACROSS REGION THROUGH 9Z...THEN DIMINISH THEREAFTER AS BULK OF STRONGEST FORCING SHIFTS EWD OVER SRN ONT AND INTO UPSTATE NY. REF SPC MESOSCALE DISCUSSION 676 FOR MORE DETAILS ON DOWNSTREAM FREEZING RAIN POTENTIAL. ..EDWARDS.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CLE...DTX...IWX...GRR...LOT...MKX...DVN... 42948787 43538557 43598409 43868251 43168234 41858309 41558342 41548499 41678653 42238670 42488728 42028825 41388844 41528968 41758988  From mcd at goshenarc.org Mon Jan 15 12:48:01 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 15 Jan 2007 07:48:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 151250 SWOMCD SPC MCD 151250 MEZ000-NHZ000-MAZ000-VTZ000-NYZ000-151645- MESOSCALE DISCUSSION 0068 NWS STORM PREDICTION CENTER NORMAN OK 0650 AM CST MON JAN 15 2007 AREAS AFFECTED...NY...NH...VT...MA CONCERNING...FREEZING RAIN VALID 151250Z - 151645Z FREEZING RAIN MIXED WITH SLEET WILL CONTINUE THROUGH LATE MORNING IN A WIDESPREAD AREA FROM BUFFALO NY EXTENDING EWD TO ALBANY NY AND TO JUST NORTH OF BOSTON MA. ADDITIONAL ICE ACCUMULATION SHOULD OCCUR WITH UP TO A HALF INCH OF FREEZING RAIN MIXED WITH SLEET POSSIBLE IN SOME AREAS. LATEST SFC ANALYSIS SHOWS A QUASI-STATIONARY FRONT LOCATED FROM NRN OH EXTENDING EWD INTO FAR NRN PA AND ACROSS TO SRN NEW ENGLAND. ATTM...THE FREEZING LINE IS LOCATED WITHIN 50 MILES NORTH OF THE BOUNDARY IN FAR SRN NY AND MA. 12Z SOUNDINGS FROM ALBANY NY AND BUFFALO NY SHOW A THICK WARM LAYER STARTING FROM 1500 TO 2500 FEET ABOVE GROUND LEVEL EXTENDING NEARLY TO THE 700 MB LEVEL IN BOTH SOUNDINGS. THE WARMEST AIR IS LOCATED NEAR 850 MB WITH TEMPS IN THE 4 TO 6 CELSIUS RANGE. FORECAST SOUNDINGS KEEP THE WARM LAYER INTACT THROUGH MIDDAY SUGGESTING A STRONG POTENTIAL FOR FREEZING RAIN AND TO A LESSER EXTENT SLEET. WIDESPREAD FREEZING RAIN SHOULD CONTINUE DUE TO STRONG ASCENT ASSOCIATED WITH A LOW-AMPLITUDE SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY MOVING EWD ACROSS THE REGION. PRECIPITATION MAY ALSO BECOME ENHANCED BY LATE MORNING DUE TO INCREASING LOW-LEVEL WARM ADVECTION NORTH OF THE FRONTAL BOUNDARY. THE SLEET POTENTIAL SHOULD BE GREATEST ACROSS THE NRN PART OF THE MCD AREA. FREEZING RAIN MAY DIMINISH BY LATE MORNING ACROSS THE FAR WRN PART OF THE MCD AREA AS THE SHORTWAVE TROUGH MOVES EWD. IN ADDITION...THE FREEZING LINE SHOULD MOVE SLOWLY NWD ALLOWING FOR SOME AREAS IN THE SRN PART OF THE MCD AREA TO CHANGEOVER TO RAIN. ..BROYLES.. 01/15/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF... 43547093 42677160 42367268 41937446 42097547 42067736 42167805 42377891 43027929 43777866 43927667 43977227 43687087 WWWW From mcd at goshenarc.org Tue Jan 16 05:44:12 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 16 Jan 2007 00:44:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 160546 SWOMCD SPC MCD 160546 TXZ000-161015- MESOSCALE DISCUSSION 0071 NWS STORM PREDICTION CENTER NORMAN OK 1146 PM CST MON JAN 15 2007 AREAS AFFECTED...SOUTH CENTRAL TX/TX HILL COUNTRY INTO SOUTHEAST TX CONCERNING...WINTER MIXED PRECIPITATION VALID 160546Z - 161015Z FREEZING RAIN/PERHAPS SOME SLEET IS LIKELY TO PERSIST OVERNIGHT ACROSS MUCH OF SOUTH CENTRAL TX/THE TX HILL COUNTRY INTO SOUTHEAST TX...INCLUDING A CORRIDOR FROM SAN ANTONIO/AUSTIN TO COLLEGE STATION AND LUFKIN. LIQUID EQUIVALENTS UP TO 0.05-0.10 IN/HR WILL CONTRIBUTE TO ADDITIONAL ICE GLAZE AND HAZARDOUS TRAVEL CONDITIONS. AS COLD ARCTIC AIR BECOMES PROGRESSIVELY ENTRENCHED ACROSS SOUTH TX...SURFACE WET BULB ZERO C LINE AT 05Z IS ANALYZED FROM NEAR THE UVALDE-HONDO-SAN ANTONIO CORRIDOR...TO NEAR VICTORIA AND THE NORTHWEST HOUSTON METRO WITH EASTERN EXTENT. COINCIDENT WITH DEEP PACIFIC MOISTURE PLUME AND ALIGNED WITH LOW TO MID LEVEL BAROCLINIC ZONE/FRONTOGENETICAL FORCING...VOLUMETRIC RADAR DATA AND SURFACE OBSERVATIONS HAVE SHOWN A PERSISTENT BELT OF PRECIPITATION STREAMING NORTHEASTWARD THIS EVENING OUT OF MEXICO INTO SOUTH CENTRAL/SOUTHEAST TX. ALTHOUGH SOMEWHAT LIMITED BY DRY AIR IN THE LOW LEVELS PER SURFACE OBSERVATIONS AND RECENT ACARS DATA FROM NEAR SAN ANTONIO...LIGHT FREEZING RAIN/ICE GLAZE HAS BEEN COMMON THIS EVENING ACROSS SOUTH CENTRAL/SOUTHEAST TX. PER MODEL SOUNDINGS AND THE AFOREMENTIONED ACARS DATA...FREEZING RAIN SHOULD REMAIN PREDOMINANT OVERNIGHT VIA A WARM/MELTING LAYER /5-7 DEG C/ ABOVE A SHALLOW SUB-FREEZING LAYER IN THE LOWEST 1 KM. LIQUID EQUIVALENTS AROUND 0.05 IN/HR HAVE BECOME MORE COMMON OVER THE PAST HOUR OR TWO PER RECENT OBSERVATIONS AROUND SAN ANTONIO /KSAT AND KSSF/...SUGGESTING THAT THE DRY LOW LEVELS HAVE BECOME SATURATED SIMILAR TO FORECAST TRENDS REFLECTED IN 00Z NAM SOUNDINGS. 00Z NAM/WRM-NMM 4KM GUIDANCE SUGGESTS THIS GENERAL SOUTHWEST-NORTHEAST BAND OF AT LEAST LIGHT MIXED PRECIPITATION SHOULD PERSIST THROUGH THE OVERNIGHT...WITH SOME INCREASE/NORTHWARD SPREAD SUGGESTED OVERNIGHT ACROSS THE HILL COUNTRY...INCLUDING THE JUNCTION/KERRVILLE TX VICINITIES. PREDOMINANT FREEZING RAIN WITH LIQUID EQUIVALENTS UP TO 0.10 IN/HR WILL CONTRIBUTE TO FURTHER ICE GLAZE OVERNIGHT. ..GUYER.. 01/16/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SHV...HGX...FWD...EWX...SJT... 29100042 29690085 30430016 30579750 31609481 30559490 28979807 28849902  From mcd at goshenarc.org Fri Jan 19 06:55:49 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 01:55:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190658 SWOMCD SPC MCD 190658 MEZ000-191300- MESOSCALE DISCUSSION 0080 NWS STORM PREDICTION CENTER NORMAN OK 1258 AM CST FRI JAN 19 2007 AREAS AFFECTED...PORTIONS OF SRN AND ERN ME CONCERNING...HEAVY SNOW VALID 190658Z - 191300Z ...SNOW WILL CONTINUE TO SPREAD ACROSS MUCH OF SRN AND CNTRL ME EARLY THIS MORNING... LATEST SFC ANALYSIS SHOWS WEAK SFC LOW JUST NORTH OF CAPE COD. SFC PRESSURE FALLS OF 1-2 MB/HR ARE OBSERVED FROM PORTIONS OF MA ACROSS NRN NEW ENGLAND...SUGGESTING THAT INTENSIFYING SFC LOW WILL LIFT NWD TOWARD GULF OF ME BY 12Z FRIDAY. RADAR LOOPS INDICATE PRECIPITATION HAS ALREADY SPREAD AS FAR NORTH AS BANGOR WITH RAIN OR FREEZING RAIN OBSERVED CLOSE TO THE COAST. LARGE SCALE ASCENT ASSOCIATED WITH ERN NY SHORTWAVE IS APPARENT ON SATELLITE LOOPS...AND THIS WILL LIKELY INTERACT WITH BAROCLINIC ZONE ALONG THE COAST. LOW LEVEL FRONTOGENESIS IS FORECAST TO INCREASE OVERNIGHT...AND THIS WILL SUPPORT THE DEVELOPMENT OF A MORE SUBSTANTIAL SNOW BAND BY 12Z...WITH HEAVIEST SNOW RATES EXPECTED AFTER 09Z. FORECAST SOUNDINGS SUGGEST PROFILES FROM AUGUSTA TO BANGOR ARE OR WILL BECOME SATURATED THROUGH A DEEP LAYER WITH DENDRITIC GROWTH ZONES FAVORABLE FOR MODERATE TO HEAVY SNOW PRODUCTION. ..TAYLOR.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...CAR...GYX... 45286784 43966978 43837074 44377095 45246986 45746891 45966837 45876783  From mcd at goshenarc.org Fri Jan 19 08:19:03 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 03:19:03 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190821 SWOMCD SPC MCD 190821 TXZ000-NMZ000-191215- MESOSCALE DISCUSSION 0081 NWS STORM PREDICTION CENTER NORMAN OK 0221 AM CST FRI JAN 19 2007 AREAS AFFECTED...EXTREME SOUTHEAST NM...PARTS OF WEST TX CONCERNING...FREEZING RAIN VALID 190821Z - 191215Z THE POTENTIAL FOR MORE WIDESPREAD FREEZING RAIN APPEARS TO BE ON THE INCREASE EARLY TODAY ACROSS PARTS OF WEST TX AND SOUTHEAST NM. THE GREATEST CHANCE FOR GLAZE AMOUNTS IN EXCESS OF 0.10 INCH PER 3H SHOULD EVOLVE GENERALLY NORTH OF I20/I10 AND WEST OF MAF THROUGH DAYBREAK. LATEST SATELLITE IMAGERY DEPICTS EXTENSIVE TROPICAL CONNECTION AND EVOLVING BAROCLINIC LEAF CLOUD PATTERN ACROSS NRN MEXICO...NM... AND WEST TX. BENEATH THE MID/UPPER LEVEL MOISTURE PLUME AND INCREASING MID LEVEL DYNAMICS WELL AHEAD OF BAJA CLOSED LOW...LOW LEVEL AIR MASS ACROSS THE PECOS VALLEY AND POINTS WEST WAS COOL/COLD AND RELATIVELY DRY. AN EXPANDING AREA OF PRECIPITATION ACROSS THE RIO GRANDE AND PECOS VALLEYS TO SERN NM HAS CONTRIBUTED TO DIABATIC COOLING IN THE BOUNDARY LAYER AND SURFACE WET BULB FREEZING LINE CURRENTLY EXTENDS FROM BIG SPRING WWD ACROSS THE PECOS VALLEY TO WEST OF GDP. THE SURFACE FREEZING LINE LAGS THE WET BULB FREEZING LINE TO THE NORTH BUT HAS BEEN SETTLING SWD EARLY TODAY AS PRECIPITATION RATES INCREASE. LATEST MODEL GUIDANCE IS SUGGESTING THAT A BAND OF FREEZING RAIN COULD BECOME ESTABLISHED ACROSS THE REGION OVER THE NEXT FEW HOURS. PERSISTENT ISENTROPIC LIFT ATOP THE SURFACE-BASED COLD DOME COULD RESULT IN FREEZING RAIN RATES UP TO A FEW HUNDREDTHS PER HOUR THROUGH 12Z. ..CARBIN.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SJT...MAF...EPZ... 31930556 31510537 31120471 31410354 31530174 31770092 32240071 32640101 32760189 32530393 32270551  From mcd at goshenarc.org Fri Jan 19 12:22:55 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 07:22:55 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191225 SWOMCD SPC MCD 191225 TXZ000-NMZ000-191830- MESOSCALE DISCUSSION 0082 NWS STORM PREDICTION CENTER NORMAN OK 0625 AM CST FRI JAN 19 2007 AREAS AFFECTED...SOUTHEAST NM...WEST TX CONCERNING...WINTER MIXED PRECIPITATION VALID 191225Z - 191830Z AREAS OF ICE PELLETS...FREEZING RAIN...AND LIGHT SNOW ARE EXPECTED TO PLAGUE PARTS OF SOUTHEAST NM AND WEST TX THROUGH THE MORNING. WHILE OVERALL ACCUMULATIONS WILL REMAIN LIGHT...GENERALLY LESS THAN 0.05 INCH LIQUID EQUIVALENT PER HOUR...ROAD SURFACES BETWEEN MAF AND LBB MAY BECOME SLICK. HIGHER ELEVATIONS ACROSS FAR WEST TX AND SERN NM COULD EXPERIENCE A MIX OF ICE PELLETS AND SNOW... PERHAPS CHANGING TO ALL SNOW AT SOME LOCATIONS DURING THE MORNING. WARM/MOIST CONVEYOR BELT HAS DEVELOPED ATOP COLD SURFACE-BASED AIR MASS FROM THE RIO GRANDE VALLEY TO THE TX SOUTH PLAINS THIS MORNING. LARGE SCALE JET COUPLING BETWEEN MID LEVEL CONFLUENCE ZONE ACROSS THE PLAINS AND UPPER LOW OVER BAJA WILL MAINTAIN STRONG LOW THROUGH MID LEVEL ISENTROPIC ASCENT OVER THESE AREAS THROUGH THE MORNING. LATEST 4KM WRF-NMM AND WRF-NSSL SUPPORT MAXIMUM HOURLY PRECIPITATION RATES BETWEEN 0.03 AND 0.05 INCH ACROSS THE AREA OF CONCERN THROUGH 18Z. RECENT RADAR AND OBSERVATIONAL TRENDS WOULD SUGGEST A RELATIVELY NARROW RIBBON OF FREEZING RAIN SHOULD DEVELOP CLOSEST TO THE SURFACE WET-BULB FREEZING LINE. THIS LINE CURRENTLY PARALLELS I20 FROM THE MAF AREA TO NORTH OF PECOS. FARTHER NORTH...RADAR REFLECTIVITY AND MODEL SOUNDING PROFILES INDICATE ICE PELLETS AND/OR FREEZING RAIN WILL BE POSSIBLE. FORECAST PROFILES ALSO INDICATE THAT WEAK ELEVATED WARM LAYER DIMINISHES IN STRENGTH NORTH OF A GDP-CNM-LBB LINE AS STRONGER ASCENT DEVELOPS ACROSS THESE AREAS THROUGH THE MORNING. THUS...A TRANSITION TO LIGHT SNOW...OR A MIX OF SNOW AND ICE PELLETS WOULD BE THE MOST LIKELY PRECIPITATION TYPES IN THE NRN/NWRN PORTIONS OF THE MESOSCALE DISCUSSION AREA. ..CARBIN.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SJT...LUB...MAF...ABQ...EPZ... 32410073 32130138 31730213 31690356 31390400 30990429 31030485 31490551 31720554 32490531 33080498 33480434 33700331 33830223 33920144 33860029 33380022 32740047  From mcd at goshenarc.org Fri Jan 19 19:01:09 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 14:01:09 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191903 SWOMCD SPC MCD 191903 TXZ000-NMZ000-200000- MESOSCALE DISCUSSION 0083 NWS STORM PREDICTION CENTER NORMAN OK 0103 PM CST FRI JAN 19 2007 AREAS AFFECTED...CAPROCK/SOUTH PLAINS OF WEST TX AND EASTERN NM CONCERNING...WINTER MIXED PRECIPITATION VALID 191903Z - 200000Z A MIX OF SLEET AND SOME FREEZING RAIN IS EXPECTED TO DEVELOP NORTHWARD AND INCREASE ACROSS THE WEST TX PLAINS/CAPROCK VICINITY THROUGH THE AFTERNOON...INCLUDING THE LUBBOCK AND PLAINVIEW AREAS...WITH SNOW BECOMING MORE PREDOMINANT BY LATE AFTERNOON. MAINLY SNOW WILL BECOME INCREASINGLY HEAVY ACROSS EAST CENTRAL NM...WHERE SNOW RATES COULD REACH 1 IN/HR AFTER 21Z. WATER VAPOR IMAGERY AND UPPER AIR DIAGNOSTICS FEATURE A CLOSED UPPER LOW CENTERED NEAR NORTHERN BAJA MEXICO...WITH A DEEP PACIFIC MOISTURE PLUME EXTENDING ACROSS NORTHERN MEXICO INTO NM AND THE ADJACENT SOUTHERN PLAINS. OBSERVATIONAL TRENDS AND LATEST NAM/RUC AND 4KM WRF NMM/NSSL GUIDANCE SUPPORTS A NORTHWARD EXPANSION/INCREASE OF WINTER MIXED PRECIPITATION ACROSS NORTHWEST TX THIS AFTERNOON. WHILE LOW LEVEL DRY AIR WILL INITIALLY DETER HEAVY PRECIPITATION DEVELOPMENT WITH NORTH EXTENT ACROSS THE TX PANHANDLE...AND LOW LEVEL TEMPERATURE PROFILES HAVE GENERALLY BEEN MARGINAL AROUND FREEZING ACROSS WEST TX...HIGHER PRECIPITATION RATES/EVAPORATIVE COOLING HAVE BEEN SUFFICIENT TO BRING TEMPERATURES DOWN TO BELOW 32F AMIDST MIXED PRECIPITATION. A MIX OF SLEET/LIGHT FREEZING RAIN HAS BEEN COMMON OVER THE PAST FEW HOURS IN OBSERVATIONS AT LUBBOCK TX/CLOVIS NM. WITH LARGE SCALE FORCING FOR ASCENT INCREASING THIS AFTERNOON...A SPECIAL 15Z OBSERVED RAOB FROM REESE CENTER /JUST WEST OF LUBBOCK/ SUPPORTS A MAINTENANCE OF MAINLY SLEET/SOME FREEZING RAIN THROUGH AT LEAST EARLY AFTERNOON PER THE PARTIAL MELTING LAYER OBSERVED BETWEEN 750-825 MB. OF NOTE...BASED ON THE OBSERVED REESE SOUNDING DATA...IT APPEARS THE 12Z NAM/GFS POINT SOUNDINGS MAY BE EXHIBITING A FEW DEGREE COOL BIAS WITHIN THE ELEVATED WARM LAYER. RUC/NAM FORECAST SOUNDINGS ULTIMATELY SUPPORT SNOW BECOMING MORE PREDOMINANT ACROSS NORTHWEST TX BY LATE AFTERNOON. ACROSS EAST CENTRAL NM...VERTICAL PROFILES APPEAR MORE FAVORABLE FOR SNOW AS THE PREDOMINANT PRECIPITATION TYPE...ESPECIALLY FROM CLOVIS WESTWARD. OBSERVATIONAL TRENDS/NUMERICAL GUIDANCE SUGGEST SNOW RATES COULD REACH 1 IN/HR AFTER 21Z ACROSS EAST CENTRAL NM...INCLUDING THE CLOVIS/FORT SUMNER AREAS TO NEAR/JUST SOUTH OF I-40. ..GUYER.. 01/19/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LUB...AMA...MAF...ABQ...EPZ... 34680528 35030440 34970273 34840162 34420065 34300057 33140077 32770107 31920210 31860270 32000368 31990515 33420579  From mcd at goshenarc.org Sat Jan 20 01:52:53 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 19 Jan 2007 20:52:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200155 SWOMCD SPC MCD 200154 OKZ000-TXZ000-200600- MESOSCALE DISCUSSION 0084 NWS STORM PREDICTION CENTER NORMAN OK 0754 PM CST FRI JAN 19 2007 AREAS AFFECTED...NORTHWEST TX/SOUTHWEST OK CONCERNING...WINTER MIXED PRECIPITATION VALID 200154Z - 200600Z A MIX OF FREEZING RAIN/SLEET IN ADDITION TO SOME SNOW WILL LIKELY PERSIST THROUGH MUCH OF THE EVENING FROM THE TX SOUTH PLAINS/CAPROCK VICINITY INTO PORTIONS OF NORTH CENTRAL TX AND SOUTHWEST/FAR SOUTH CENTRAL OK. A LIGHT ICE GLAZE IS POSSIBLE. IN ASSOCIATION WITH INCREASING PRECIPITATION RATES ACROSS MUCH OF NORTHWEST TX INTO FAR SOUTHWEST/SOUTH CENTRAL OK...WITH TEMPERATURES BORDERLINE AROUND FREEZING...SURFACE OBSERVATIONS CONTINUE TO GENERALLY REFLECT A MIX OF FREEZING RAIN/SOME SLEET ACROSS THIS CORRIDOR. THE 00Z AMARILLO RAOB FEATURES A 100 MB DEEP ELEVATED ABOVE-FREEZING LAYER CENTERED AROUND 750 MB...CONSISTENT WITH THE MIX OF SLEET/FREEZING RAIN AND SOME SNOW THAT HAS BEEN PREVALENT ACROSS NORTHWEST TX. FARTHER EAST...THE 00Z NORMAN OBSERVED RAOB FEATURES ABOVE FREEZING WARM LAYER /NEARLY 2 C/ CENTERED AROUND 770 MB...WITH AN ABUNDANCE OF DRY AIR IN THE LOW LEVELS BELOW 800 MB. BASED ON THESE OBSERVED SOUNDINGS...IT APPEARS 18Z NAM/18Z GFS POINT SOUNDINGS CONTINUE TO FEATURE A SLIGHT COOL BIAS /1-2 DEG C/ WITHIN THE CRITICAL ELEVATED WARM LAYER. WITH LITTLE THERMAL ADVECTION/FLUCTUATION...THIS SUGGESTS THE ONSET OF PREDOMINANT SNOW WILL REMAIN DELAYED AS THE ELEVATED WARM LAYER STRUGGLES TO COOL BELOW FREEZING...WITH A CONTINUANCE OF A FREEZING RAIN/SLEET MIX FROM THE CAPROCK/TX SOUTH PLAINS INTO SOUTHWEST OK THIS EVENING. THIS SCENARIO MAY SUPPORT LIGHT ICE ACCUMULATIONS. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OUN...LUB...AMA...MAF... 35420028 35389904 34769773 34049789 34199943 33580040 32550119 32670256 33960262 35150154  From mcd at goshenarc.org Sat Jan 20 06:21:44 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 01:21:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200624 SWOMCD SPC MCD 200623 TXZ000-201030- MESOSCALE DISCUSSION 0085 NWS STORM PREDICTION CENTER NORMAN OK 1223 AM CST SAT JAN 20 2007 AREAS AFFECTED...S PLAINS/CAPROCK OF NWRN TX CONCERNING...FREEZING RAIN VALID 200623Z - 201030Z LIGHT FREEZING RAIN OCCASIONALLY MIXED WITH SLEET WILL PERSIST THROUGH THE OVERNIGHT HOURS. 3-HR PRECIP ACCUMULATIONS FROM .05 TO .10 IN WILL BE LIKELY. SURFACE TEMPERATURES ACROSS THE S PLAINS/CAPROCK REGION HAVE LEVELED OFF FROM 30 TO 32 DEGREES. AT 06Z...THE SURFACE FREEZING LINE WAS LOCATED FROM MAF TO 20 W ABI TO 40 SE CDS. 06Z MAF AND 03Z REESE TX OBSERVED SOUNDINGS WERE INDICATIVE OF FREEZING RAIN WITH OCCASIONAL SLEET ACROSS THE S PLAINS/CAPROCK REGION. NAMELY...A 100 MB DEEP ABOVE FREEZING WARM NOSE BETWEEN 725 TO 825 MB IN THE 06Z MAF SOUNDING TO A LESS THAN 50 MB ABOVE FREEZING LAYER IN THE 03Z REESE SOUNDING. BOTH 00Z NAM AND 03Z RUC POINT FORECAST SOUNDINGS CONTINUE THE TREND OF A SLIGHT COOL BIAS /AROUND 1 DEG C/ WITH THE ELEVATED WARM LAYER. THE THERMODYNAMIC PROFILE FROM THE SURFACE TO 700 MB IS EXPECTED TO CHANGE LITTLE THROUGH 12Z...WITH OCCASIONAL PHASE CHANGES LIKELY A RESULT OF SUBTLE VARIATIONS IN UPWARD VERTICAL MOTION. EVENING SATELLITE IMAGERY HAS DEPICTED A WELL-DEFINED MID/UPPER-LEVEL SUB-TROPICAL MOISTURE PLUME FROM THE SRN TIP OF BAJA CA NEWD ACROSS THE SRN HIGH PLAINS. THIS PLUME WAS LOCATED DOWNSTREAM OF A QUASI-STATIONARY UPPER LOW IN FAR NWRN SONORA. ALTHOUGH THIS LOW WILL BEGIN TO ACCELERATE EWD BY 12Z...THE MOISTURE PLUME SHOULD ONLY SHIFT SLOWLY EWD. IN ADDITION...LOW-LEVEL WAA /AS INFERRED FROM VEERING IN 06Z MAF SOUNDING/ IN WARM/MOIST CONVEYOR BELT REGION IS EXPECTED TO REMAIN NEARLY STATIONARY OVERNIGHT. THUS...LIGHT PRECIPITATION FOR THE NEXT SEVERAL HOURS WILL CONTINUE. ..GRAMS.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...OUN...SJT...LUB...MAF... 33770170 34449996 34139979 33150010 32440036 32140076 31550131 31960209 32520269 33030255  From mcd at goshenarc.org Sat Jan 20 18:12:06 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 13:12:06 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201817 SWOMCD SPC MCD 201816 KSZ000-OKZ000-TXZ000-202215- MESOSCALE DISCUSSION 0087 NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CST SAT JAN 20 2007 AREAS AFFECTED...TX PANHANDLE/NORTHWEST OK INTO MUCH OF CENTRAL/EASTERN KS CONCERNING...HEAVY SNOW VALID 201816Z - 202215Z MODERATE/PERHAPS LOCALLY HEAVY SNOW WILL DEVELOP NORTHWARD AND BECOME MORE PREVALENT FROM NORTHWEST OK INTO MUCH OF CENTRAL AND EASTERN KS THROUGH THE AFTERNOON...INCLUDING THE WOODWARD OK AREA TO THE WICHITA/SALINA KS VICINITIES AND KS TURNPIKE. SNOW RATES UP TO 1 IN/HR ARE POSSIBLE. WITH UPPER LOW CONTINUING TO ADVANCE EASTWARD ACROSS NM...LARGELY COINCIDENT WITH THE EXIT REGION OF THE ASSOCIATED MID/UPPER LEVEL JET...MODERATE/LOCALLY HEAVY SNOW HAS BEEN PREVALENT FROM THE TX PANHANDLE/NORTHWEST OK INTO SOUTH CENTRAL KS THROUGH MIDDAY. IN FACT...1 IN/HR SNOW RATES HAVE BEEN RECENTLY REPORTED AT AMARILLO TX...WITH HEAVY SNOW ALSO REPORTED AT BORGER TX. WHILE SNOW SHOULD NOT BE PARTICULARLY FOCUSED ON THE MESOSCALE ACROSS NORTHWEST OK INTO CENTRAL/EASTERN KS THIS AFTERNOON...WEAKENING STATIC STABILITY /LARGELY COINCIDENT WITH NORTHEAST-ADVANCING DRY SLOT CURRENTLY ACROSS EASTERN NM INTO FAR WEST TX/ MAY TEND TO SOMEWHAT ENHANCE SNOW RATES IN A SCENARIO OTHERWISE CHARACTERIZED BY AMPLE FORCING FOR ASCENT/UVVS COINCIDENT WITH A FAVORABLE DENDRITIC GROWTH LAYER. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...SGF...EAX...TOP...ICT...OUN...GID...DDC...AMA... 38899554 38479494 38069471 37519485 37369544 37049662 36929720 36589819 36399869 36059957 35600078 36320111 36990083 37710011 39319825 WWWW From mcd at goshenarc.org Sat Jan 20 19:09:42 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 20 Jan 2007 14:09:42 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201914 SWOMCD SPC MCD 201914 MOZ000-ARZ000-OKZ000-KSZ000-202345- MESOSCALE DISCUSSION 0088 NWS STORM PREDICTION CENTER NORMAN OK 0114 PM CST SAT JAN 20 2007 AREAS AFFECTED...CENTRAL/NORTHEAST OK INTO FAR SOUTHEAST KS/FAR NORTHERN AR/SOUTHWEST MO CONCERNING...WINTER MIXED PRECIPITATION VALID 201914Z - 202345Z A MIX OF FREEZING RAIN/SLEET APPEARS LIKELY TO PERSIST MUCH OF THE AFTERNOON FROM THE OKC METRO AREA TO AREAS ALONG/NORTH OF THE I-44 TURNPIKE IN NORTHEAST OK...AND INTO EXTREME SOUTHEAST KS...WITH SOME LIGHT ICE ACCUMULATIONS POSSIBLE. MIXED PRECIPITATION WILL ALSO STEADILY INCREASE THIS AFTERNOON ALONG I-44 IN SOUTHWEST MO...INCLUDING THE JOPLIN/SPRINGFIELD VICINITIES. SPECIAL 18Z NORMAN OK OBSERVED RAOB AND RECENT ACARS SOUNDING DATA NEAR THE OKLAHOMA CITY AIRPORT SUGGEST THE VERTICAL THERMAL PROFILE HAS FLUCTUATED VERY LITTLE FROM THIS MORNING /REFERENCE 12Z NORMAN RAOB/ ACROSS CENTRAL OK. WITH SURFACE TEMPERATURES GENERALLY HOLDING NEAR 32F...AT LEAST A PARTIAL MELTING LAYER /NEARLY 2 DEG C PER THE 18Z RAOB/ AROUND 800 MB WILL REMAIN CONDUCIVE FOR A CONTINUANCE OF FREEZING RAIN AND SLEET THIS AFTERNOON ACROSS PORTIONS OF CENTRAL/NORTHEAST OK. FARTHER EAST...WET BULB PROFILES FROM THE 18Z OBSERVED RAOB FROM SPRINGFIELD MO SEEMS TO PRIMARILY SUPPORT SLEET WITH PRECIPITATION ONSET ACROSS SOUTHWEST MO. THE 18Z SPRINGFIELD SOUNDING ALSO REFLECTS A TOP-DOWN SATURATION BETWEEN 600-800 MB SINCE 12Z. WITH FURTHER SATURATION AND PRECIPITATION RATES EXPECTED TO INCREASE THROUGH MID/LATE AFTERNOON FROM NORTHWEST AR INTO SOUTHWEST MO...A MIX OF SLEET AND SOME SNOW/PERHAPS FREEZING RAIN APPEARS LIKELY. ..GUYER.. 01/20/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...LZK...SGF...TSA...ICT...OUN... 37369249 37109183 36879170 36609168 36199220 35989313 36249418 36299577 36149639 35549709 35329756 35529799 36319764 37409540 37569405  From mcd at goshenarc.org Sun Jan 21 06:21:27 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 01:21:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210626 SWOMCD SPC MCD 210625 KYZ000-INZ000-211130- MESOSCALE DISCUSSION 0089 NWS STORM PREDICTION CENTER NORMAN OK 1225 AM CST SUN JAN 21 2007 AREAS AFFECTED...PORTIONS OF CNTRL KY...EXTREME SRN IND CONCERNING...WINTER MIXED PRECIPITATION VALID 210625Z - 211130Z AN ASSORTMENT OF PTYPES SHOULD OCCUR THROUGH 12Z AS A LARGE PRECIPITATION AREA ALONG THE MID-MS RIVER VALLEY EXPANDS EWD. ALTHOUGH SNOW AND RAIN MAY OCCUR AT TIMES...FREEZING RAIN AND SLEET WILL LIKELY BECOME THE PRIMARY PTYPES. ICE ACCUMULATIONS IN EXCESS OF .05 IN/HR WILL BE POSSIBLE...ESPECIALLY TOWARDS 12Z. AT 06Z...THE SURFACE WET BULB FREEZING LINE WAS LOCATED FROM AROUND 40 NE PAH TO 25 NE BWG TO 25 W CSV. THIS LINE HAS REMAINED NEARLY STATIONARY OVER THE PAST FEW HOURS AND SHOULD REMAIN AS SUCH FOR THE NEXT SEVERAL HOURS. RECENT SURFACE OBSERVATIONS INDICATE LIGHT RAIN/SNOW HAS REACHED WRN KY AND FAR SRN IND. IT WILL CONTINUE A GRADUAL PROGRESSION EWD AS TOP-DOWN SATURATION OCCURS GIVEN THE DRY LOW-LEVELS /AS EVIDENCED BY 00Z BNA SOUNDING/. MORE SUBSTANTIAL PRECIPITATION SHOULD OCCUR TOWARDS 12Z AS A 50-60 KT LLJ FROM THE LOWER MS VALLEY FOCUSES STRONG WARM/MOIST ADVECTION INTO THE REGION. BOTH 03Z RUC AND 00Z NAM MODEL GUIDANCE INDICATE SLOW WARMING OF THE 700 TO 850 MB LAYER EVEN AS SATURATION/UPWARD VERTICAL MOTION OCCURS. POINT FORECAST SOUNDINGS SHOW AN ABOVE FREEZING WARM NOSE DEVELOPING...WHICH WOULD SUPPORT FREEZING RAIN AND/OR SLEET. THIS IS ALSO SUPPORTED IN THE 20/21Z SREF GUIDANCE WHICH INDICATE THESE AS THE MOST LIKELY PTYPES. IF THIS INDEED OCCURS...PRECIPITATION RATES WOULD CERTAINLY SUPPORT ICE ACCUMULATIONS IN EXCESS OF .05 IN/HR. ..GRAMS.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...JKL...LMK...PAH... 38498642 38518571 38388506 37948419 37378431 37028498 37348561 37828638 38148684 38378719  From mcd at goshenarc.org Sun Jan 21 08:48:17 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 03:48:17 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210853 SWOMCD SPC MCD 210852 INZ000-KYZ000-ILZ000-211215- MESOSCALE DISCUSSION 0090 NWS STORM PREDICTION CENTER NORMAN OK 0252 AM CST SUN JAN 21 2007 AREAS AFFECTED...ERN IL...CNTRL IND CONCERNING...HEAVY SNOW VALID 210852Z - 211215Z A BURST OF HEAVY SNOWFALL WITH RATES OF UP TO AN INCH AN HOUR APPEARS LIKELY EARLY THIS MORNING FROM EAST-CNTRL IL ACROSS CNTRL AND SCNTRL SECTIONS OF INDIANA. INTENSE ISENTROPIC LIFT AND RESULTANT ADIABATIC COOLING WILL CONTINUE TO COUNTER LOW LEVEL WARMING ON THE NOSE OF THE 850MB JET TRANSITIONING OVER THE LOWER OH VALLEY EARLY TODAY. GIVEN UPSTREAM PW VALUES AROUND AN 1 INCH...AND 30-40KT LOW LEVEL JET... STRONG MOISTURE TRANSPORT WILL SUPPORT HIGH PRECIPITATION RATES OVER THE NEXT FEW HOURS. ADDITIONALLY...MELTING-INDUCED THERMALLY INDIRECT CIRCULATIONS DEVELOPING ACROSS THE RAIN/SNOW LINE COULD FURTHER BOOST SNOWFALL ON THE COLD SIDE OF THE PRECIPITATION TRANSITION ZONE. DEEP ISOTHERMAL NEAR/BELOW 0C PROFILES WILL ALSO FAVOR SNOWFLAKE GROWTH THROUGH ACCRETION AND RIMING. LATEST MODEL GUIDANCE APPEARS TO SUGGEST AN AXIS OF 3-4 INCH SNOWFALL ALONG THE I70 CORRIDOR...FROM NEAR MATTOON IL TO INDIANAPOLIS THROUGH 12Z. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...ILN...LMK...IND...ILX... 38818818 39348874 40098880 40238806 40358669 40038548 39668499 39098502 38678543 38708664  From mcd at goshenarc.org Sun Jan 21 09:25:38 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 04:25:38 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210930 SWOMCD SPC MCD 210929 WIZ000-ILZ000-IAZ000-MNZ000-211530- MESOSCALE DISCUSSION 0091 NWS STORM PREDICTION CENTER NORMAN OK 0329 AM CST SUN JAN 21 2007 AREAS AFFECTED...NERN IA TO EXTREME SERN MN/SWRN WI/NWRN IL CONCERNING...HEAVY SNOW VALID 210929Z - 211530Z MDT TO HVY SNOW SHOULD DEVELOP NEWD FROM THE MO RIVER VALLEY AND ACROSS PARTS OF THE UPPER MS VALLEY THROUGH THE MORNING. SNOWFALL RATES UP TO AN INCH PER HOUR APPEAR POSSIBLE. STRONG DYNAMIC FORCING FOR ASCENT WITHIN COMMA-HEAD OF DEEP LAYER CYCLONE WILL CONTINUE TO TRANSITION NEWD FROM THE MID MO RIVER VALLEY THIS MORNING. PRONOUNCED ASCENT OCCURRING WITHIN LEFT EXIT REGION OF 100KT MID LEVEL JET WAS CURRENTLY SUPPORTING A BROAD AREA OF MDT TO HVY SNOW ACROSS PARTS OF ERN NEB AND WRN IA. MEANWHILE...MID LEVEL DRY INTRUSION..CLEARLY EVIDENT IN SATELLITE IMAGERY...WAS PROBABLY LIMITING SNOWFALL RATES ACROSS PARTS OF CNTRL AND ERN IA ATTM. EXPECT HEAVIER SNOW TO REDEVELOP TO THE NORTHEAST THROUGH THE MORNING AS THE MID LEVEL LOW BEGINS OPEN UP AND TRACK NEWD OVER IA. A ZONE OF MODEST MID/UPPER LEVEL FRONTOGENESIS/LIFT OCCURRING IN A THERMODYNAMIC REGIME FAVORABLE FOR BOTH VAPOR TO ICE TRANSPORT AND DENDRITE GROWTH SHOULD EVOLVE ALONG THE MID LEVEL LOW TRACK. THIS PROCESS IS EXPECTED TO CONTRIBUTE TO AN AXIS OF ENHANCED SNOWFALL FROM NCNTRL IA TO SWRN WI THROUGH ABOUT 15Z. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...MKX...DVN...ARX...MPX...DMX... 42149008 41999347 41839391 42679482 43429402 43659212 43569108 43068978 WWWW From mcd at goshenarc.org Sun Jan 21 12:22:43 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 07:22:43 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 211227 SWOMCD SPC MCD 211227 WVZ000-VAZ000-OHZ000-KYZ000-INZ000-211730- MESOSCALE DISCUSSION 0092 NWS STORM PREDICTION CENTER NORMAN OK 0627 AM CST SUN JAN 21 2007 AREAS AFFECTED...SRN OH...NERN KY...AND PARTS OF WV CONCERNING...WINTER MIXED PRECIPITATION VALID 211227Z - 211730Z A RANGE OF WINTER PRECIPITATION TYPES WILL SPREAD ACROSS PARTS OF THE CUMBERLAND PLATEAU AND UPPER OH VALLEY THROUGH EARLY AFTERNOON. NRN PORTIONS OF THE DISCUSSION AREA...FROM SWRN OH ACROSS MUCH OF CNTRL WV WILL EXPERIENCE SNOW...POSSIBLY CHANGING TO FREEZING RAIN IN SOME AREAS BY LATER THIS MORNING. SRN PARTS OF THE AREA...ALONG THE OH RIVER...NERN KY...AND SRN WV WILL EXPERIENCE A PERIOD OF FREEZING RAIN...PERHAPS MIXED WITH ICE PELLETS AT TIMES. STRONG WARM/MOIST CONVEYOR BELT CONTINUES TO IMPINGE UPON ENTRENCHED SURFACE-BASED COLD DOME FROM THE UPPER OH VALLEY TO THE WRN SLOPES OF THE APPALACHIANS THIS MORNING. GRADUAL SATURATION OF DRY LOW LEVEL AIR MASS...AND RESULTANT EVAPORATIVE COOLING FROM SWRN OH INTO WV...WILL SUPPORT SNOW ACROSS THESE AREAS THROUGH THE MORNING. LATEST MODEL GUIDANCE SUGGESTS MAXIMUM SNOWFALL RATES OF AROUND 0.5 TO 1 INCH PER HOUR COULD OCCUR NORTH OF A CVG-CRW-BKW LINE THROUGH ABOUT 18Z. INCREASINGLY STRONG LOW LEVEL JET DEVELOPING NEWD FROM THE TN AND LOWER OH VALLEYS WILL ADVECT A WARMER LAYER OF AIR NEWD ATOP THE SURFACE-BASED SUB-FREEZING AIRMASS FROM NERN KY INTO SRN WV. PRECIPITATION IN THESE AREAS IS LIKELY TO FALL IN THE FORM OF FREEZING RAIN...PERHAPS MIXED WITH SLEET AT TIMES. UPSTREAM HOURLY PRECIPITATION AMOUNTS WOULD SUPPORT GLAZE ACCUMULATIONS OF AS MUCH AS 0.10 INCH PER HOUR IN SOME AREAS OVER THE NEXT FEW HOURS. ..CARBIN.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...RNK...RLX...JKL...ILN...LMK... 37538236 37838282 37968359 38028463 38478520 39668440 39808281 39418165 39208102 38638029 38258006 37628048 37118079 37038129 37198191 WWWW From mcd at goshenarc.org Sun Jan 21 16:45:50 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 11:45:50 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 211650 SWOMCD SPC MCD 211650 VAZ000-WVZ000-NCZ000-212115- MESOSCALE DISCUSSION 0093 NWS STORM PREDICTION CENTER NORMAN OK 1050 AM CST SUN JAN 21 2007 AREAS AFFECTED...EASTERN WV/WESTERN VA AND NORTHERN PART OF WESTERN NC CONCERNING...WINTER MIXED PRECIPITATION VALID 211650Z - 212115Z A MIX OF FREEZING RAIN AND SOME SLEET IS EXPECTED TO BECOME PREDOMINANT THROUGH THE AFTERNOON ACROSS EASTERN WV/NORTHWEST NC INTO MUCH OF WESTERN VA...INCLUDING THE I-81 CORRIDOR AND THE BLACKSBURG/ROANOKE/LYNCHBURG AREAS...AS WELL AS I-64 FROM SOUTHEAST WV THROUGH THE STAUNTON/WAYNESBORO VA AREAS. ICE ACCUMULATIONS ARE LIKELY VIA LIQUID EQUIVALENTS OF 0.05-0.10 IN/HR. WHILE THE 12Z OBSERVED RAOB FROM ROANOKE VA EXHIBITED AN ENTIRELY SUB-FREEZING RELATIVE WARM LAYER ALOFT /700-850 MB 1-2 DEG C BELOW ZERO/...A PRONOUNCED WARM ADVECTION REGIME IS QUICKLY MODIFYING THE ELEVATED THERMODYNAMIC PROFILE. OVER THE PAST COUPLE OF HOURS...OBSERVATIONS OF FREEZING RAIN HAVE BECOME MORE COMMON FROM SOUTHERN WV TO THE ROANOKE VA VICINITY...WITH LIGHT FREEZING RAIN JUST REPORTED /16Z/ AS FAR EAST AS THE LYNCHBURG VA AREA. WITH A SUB-FREEZING BOUNDARY LAYER LOCKED IN PLACE IN THE LOWEST 1 KM ALONG/EAST OF THE APPALACHIANS /REFERENCE 12Z ROANOKE RAOB/...AND PARTIAL/FULL MELTING ALOFT BECOMING MORE LIKELY...FREEZING RAIN/SLEET SHOULD BECOME PREDOMINANT FROM EASTERN WV/NORTHWEST NC INTO MUCH OF WESTERN VA THROUGH THE AFTERNOON. THIS IS ALSO SUPPORTED BY 09Z SREF PROBABILISTIC PRECIP-TYPE GUIDANCE. REGARDING THE ELEVATED WARM LAYER...COMPARISONS BETWEEN REGIONAL OBSERVED 12Z RAOBS AND 12Z NAM/12Z GFS GUIDANCE SUGGESTS THE SHORT TERM MODEL DEPICTIONS MAY BE SLIGHTLY TOO COOL...PERHAPS SUGGESTIVE OF A RELATIVELY QUICKER CHANGE-OVER TO FREEZING RAIN THROUGH EARLY/MID AFTERNOON VIA THE WARMER TEMPERATURES ALOFT. ..GUYER.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...AKQ...LWX...RNK...RLX... 38677952 38427856 37777820 37307828 36747898 36288009 36378131 37668135 38488027  From mcd at goshenarc.org Sun Jan 21 23:04:16 2007 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 21 Jan 2007 18:04:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 212309 SWOMCD SPC MCD 212308 VAZ000-MDZ000-220345- MESOSCALE DISCUSSION 0094 NWS STORM PREDICTION CENTER NORMAN OK 0508 PM CST SUN JAN 21 2007 AREAS AFFECTED...MUCH OF VA AND FAR SOUTHERN MD CONCERNING...WINTER MIXED PRECIPITATION VALID 212308Z - 220345Z FREEZING RAIN WILL CONTINUE TO REMAIN DOMINANT/SHIFT EAST-NORTHEAST THIS EVENING ACROSS CENTRAL VA...ESPECIALLY ALONG/SOUTHWEST OF I-64...FROM LYNCHBURG/DANVILLE TO THE CHARLOTTESVILLE/RICHMOND AREAS. ICE ACCUMULATIONS WILL BE POSSIBLE INTO THE VA PIEDMONT VIA LIQUID EQUIVALENTS UP TO 0.05 IN/HR. FARTHER NORTH...MAINLY SNOW WILL LIKELY YIELD TO A MIX OF SLEET/FREEZING RAIN EARLY THIS EVENING WITH NORTH EXTENT ALONG I-95 THROUGH THE FREDERICKSBURG VICINITY AND PERHAPS PORTIONS OF THE DC METRO. WITH A COLD/SUB-FREEZING WEDGE REMAINING IN PLACE VIA EXITING HIGH PRESSURE...STRONG WARM ADVECTION REGIME INTO THE MID ATLANTIC STATES AND ASSOCIATED ELEVATED WARM/MELTING LAYER HAS PROVED FAVORABLE FOR FREEZING RAIN MUCH OF THE AFTERNOON ACROSS SOUTHWEST INTO CENTRAL VA. WELL REPRESENTATIVE OF THIS SCENARIO...THE WET BULB PROFILE FROM THE EARLIER 18Z OBSERVED SOUNDING FROM GREENSBORO SC FEATURED A 4.0 DEG C WARM NOSE AROUND 800 MB...FAVORABLE FOR MELTING AND RESULTANT FREEZING RAIN. FARTHER NORTH...OBSERVATIONAL TRENDS IN ACCORDANCE WITH RECENT ACARS DATA /NEAR CHARLOTTESVILLE AND THE DC AREA/ AND LATEST SREF PROBABILISTIC GUIDANCE SUGGEST BOUTS OF INITIAL SNOW WILL CHANGE OVER TO SOME SLEET AND FREEZING RAIN EARLY THIS EVENING ALONG I-95 NORTH OF RICHMOND...INCLUDING THE FREDERICKSBURG AREA AND PERHAPS PORTIONS OF THE DC METRO. ..GUYER.. 01/21/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ...NOTICE... SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS. ATTN...WFO...AKQ...LWX...RNK... 38637751 38627699 38077653 37707668 37087750 36617888 36698010 37318007 38237855