From mcd at goshenarc.org Fri Dec 1 04:21:41 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 30 Nov 2006 23:21:41 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010423 SWOMCD SPC MCD 010423 ALZ000-010600- MESOSCALE DISCUSSION 2252 NWS STORM PREDICTION CENTER NORMAN OK 1023 PM CST THU NOV 30 2006 AREAS AFFECTED...WCNTRL AL CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010423Z - 010600Z AN ISOLATED TORNADO THREAT SHOULD CONTINUE FOR ANOTHER HOUR OR SO ACROSS PARTS OF WCNTRL AL. HOWEVER...THE THREAT SHOULD REMAIN TOO ISOLATED TO WARRANT A TORNADO WATCH LATE THIS EVENING. A LINE OF LOW-TOPPED CONVECTION IS CURRENTLY LOCATED ACROSS WRN AL WITH A LINE-ECHO WAVE PATTERN SHOWING UP SOUTH OF TUSCALOOSA AL. THE LINE IS LIKELY LOCATED ALONG A PRE-FRONTAL TROUGH AXIS AND IS MOST LIKELY ASSOCIATED WITH A SUBTLE LEAD SHORTWAVE-TROUGH AHEAD OF THE MAIN UPPER-LOW. SFC DEWPOINTS IN THE MID 60S F AHEAD OF THE LINE AND STRONG VERTICAL SHEAR MAY BE SUFFICIENT TO CONTINUE AN ISOLATED SEVERE THREAT OVER THE NEXT HOUR. ALTHOUGH INSTABILITY IS WEAK /100-300 J/KG BELOW 600 MB WITH MOIST ADIABATIC LAPSE RATES/...FORECAST SOUNDINGS SHOW STRONG SPEED SHEAR AND DIRECTIONAL SHEAR BELOW 3 KM. THIS SUGGESTS THE WIND PROFILE SHOULD BE FAVORABLE FOR A BRIEF TORNADO THREAT WITH ROTATING CELLS IN THE CONVECTIVE LINE. ALTHOUGH LESS OF A THREAT...A FEW STRONG WIND GUSTS MAY ALSO OCCUR WITH THE BETTER ORGANIZED STORMS. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...HUN... 32628714 32858754 33138782 33928765 34018680 33668623 32868631  From mcd at goshenarc.org Fri Dec 1 05:44:02 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 00:44:02 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010546 SWOMCD SPC MCD 010545 KYZ000-TNZ000-GAZ000-ALZ000-010715- MESOSCALE DISCUSSION 2253 NWS STORM PREDICTION CENTER NORMAN OK 1145 PM CST THU NOV 30 2006 AREAS AFFECTED...SRN KY...MIDDLE TN...NE AL CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 010545Z - 010715Z AN ISOLATED SEVERE THREAT MAY DEVELOP OVER THE NEXT 1 TO 3 HOURS ACROSS NE AL...MIDDLE TN AND SRN KY. A WW IS NOT ANTICIPATED BUT THE LINE OF CONVECTION WILL STILL BE MONITORED IN CASE INTENSIFICATION OCCURS. LATEST SFC ANALYSIS SHOWS A DEEPENING LOW SOUTH OF PADUCAH KY WITH A COLD FRONT EXTENDING SWD FROM THE LOW AND A NEARLY STATIONARY FRONT EXTENDING NEWD INTO THE UPPER OH VALLEY. A PREFRONTAL TROUGH LIKELY EXISTS SSEWD ACROSS THE WARM SECTOR WHERE STRONG PRESSURE FALLS ARE OCCURRING ATTM. A NARROW LINE OF CONVECTION IS CURRENTLY ONGOING ALONG THE PRESSURE TROUGH. ALTHOUGH INSTABILITY IS VERY WEAK AHEAD OF THE LINE...SHEAR PROFILES ARE STRONG (0-6 KM SHEAR OF 70KT AND 0-1 KM SHEAR AROUND 40 KT) WHICH COMBINED WITH INCREASING LARGE-SCALE ASCENT AHEAD OF AN APPROACHING UPPER-LOW MAY RESULT IN INTENSIFICATION OF THE LINE TONIGHT. ANY SEVERE THREAT THAT ACCOMPANIES THE LINE SHOULD REMAIN ISOLATED. A BRIEF TORNADO AND/OR STRONG WIND GUSTS MAY OCCUR WITH ROTATING CELLS AS THE LINE CROSS THE REGION OVERNIGHT. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MRX...JKL...FFC...LMK...OHX...BMX...HUN... 33668522 33548670 35098673 36208654 36938609 36768472 35388475  From mcd at goshenarc.org Fri Dec 1 05:48:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 00:48:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010550 SWOMCD SPC MCD 010550 ILZ000-WIZ000-MOZ000-IAZ000-KSZ000-OKZ000-011015- MESOSCALE DISCUSSION 2254 NWS STORM PREDICTION CENTER NORMAN OK 1150 PM CST THU NOV 30 2006 AREAS AFFECTED...EXTREME SERN KS...MUCH OF NRN/CNTRL MO...NRN/W-CNTRL IL...EXTREME SERN IA CONCERNING...HEAVY SNOW VALID 010550Z - 011015Z MODERATE TO HEAVY SNOW WITH LOCAL RATES UP TO 3 IN/HR WILL SPREAD NEWD FROM SERN KS/NERN OK/WRN MO ACROSS NERN MO INTO W-CNTRL AND NRN IL BY 12Z. AS THE SURFACE LOW ACROSS FAR WRN KY LIFTS NORTH AND DEEPENS...GRADIENT WINDS WILL INCREASE...AIDING IN BLOWING/DRIFTING SNOW AS WELL. POWERFUL UPPER LOW CENTERED AT 500 MB NEAR FAYETTEVILLE AR WILL TRACK NEWD TO NEAR SPRINGFIELD IL BY 12Z. DEFORMATION BAND OF MODERATE TO HEAVY SNOW WILL CONTINUE TO THE NW OF MID-LEVEL DRY SLOT...PARALLEL TO TRACK OF UPPER LOW. 00Z/RUC AND 03Z/NAM FORECAST SOUNDINGS INDICATE LARGE DENDRITIC GROWTH ZONES /IN EXCESS OF 100 MB/ WILL OCCUR ACROSS MUCH OF CNTRL MO FROM AROUND 50 N OF SGF TO COU TO UIN THROUGH 10Z. ISOLATED CG STRIKES HAVE OCCURRED WITHIN THIS ZONE...LIKELY SUPPORTING VERY HEAVY BURSTS OF SNOWFALL AT TIMES FROM 2 TO 3 IN/HR. FURTHER NE...VERY STRONG UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL OCCUR TO THE N/NW OF A 100+ KT 500 MB JET CURLING E/SE OF UPPER LOW. A MIX OF SLEET/FREEZING RAIN/SNOW ACROSS MUCH OF WRN/NRN IL WILL GRADUALLY TURN TO ALL SNOW FROM W TO E AS LOW-LEVEL TEMPS SLOWLY COOL WITH TIME. SNOWFALL RATES OF 1 TO 2 IN/HR WILL BE LIKELY IN THE 09-12Z TIME FRAME FROM THE NRN STL METRO/UIN AREA NEWD TOWARDS PIA AND THE WRN CHICAGO METRO AREA. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LOT...ILX...MKX...LSX...DVN...SGF...EAX...TSA...TOP...ICT... 38619053 37489215 36869405 36849542 37989516 39539357 40909171 41839019 42208951 42558832 41648761 40868811 40068899 WWWW From mcd at goshenarc.org Fri Dec 1 06:40:05 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 01:40:05 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010642 SWOMCD SPC MCD 010641 MIZ000-011045- MESOSCALE DISCUSSION 2255 NWS STORM PREDICTION CENTER NORMAN OK 1241 AM CST FRI DEC 01 2006 AREAS AFFECTED...SRN LOWER MI CONCERNING...WINTER MIXED PRECIPITATION VALID 010641Z - 011045Z FREEZING RAIN MIXED WITH SLEET WILL LIKELY INTENSIFY OVERNIGHT. ICE ACCUMULATION RATES SHOULD EXCEED 0.10 IN/HR. TEMPERATURES HAVE SLOWLY FALLEN TO SLIGHTLY BELOW FREEZING ACROSS MUCH OF SRN LOWER MI OVER THE PAST FEW HOURS. 00Z DTX/06Z ILX OBSERVED SOUNDINGS INDICATE A WARM NOSE OF SLIGHTLY ABOVE FREEZING TEMPERATURES CENTERED AROUND 850 MB. 00Z NAM/GFS AND 03Z RUC GUIDANCE INDICATE THIS WARM LAYER WILL BE MAINTAINED THROUGH 12Z...TO THE NE OF AN APPROACHING 850 MB LOW TRACKING FROM SRN MO INTO E-CNTRL IL. INTENSE LOW/MID-LEVEL ISENTROPIC LIFT AND WARM THETA-E ADVECTION IS EXPECTED TO CONTINUE SUPPORTING PRECIPITATION GENERATION. IN ADDITION...UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL INCREASE...ESPECIALLY TOWARDS 12Z AS A POTENT 100+ KT 500 MB JET CURLS EWD OF UPPER LOW APPROACHING SRN IL. CONVECTIVE SHOWERS OF FREEZING RAIN/SLEET WILL LIKELY OCCUR...WITH ICE ACCUMULATIONS IN EXCESS OF 0.10 IN/HR POSSIBLE. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...IWX...GRR... 42458390 42188486 42078558 42078616 42228639 42868617 43068541 43308466 43298389 42798331  From mcd at goshenarc.org Fri Dec 1 07:21:44 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 02:21:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010723 SWOMCD SPC MCD 010723 GAZ000-FLZ000-ALZ000-010830- MESOSCALE DISCUSSION 2256 NWS STORM PREDICTION CENTER NORMAN OK 0123 AM CST FRI DEC 01 2006 AREAS AFFECTED...SERN AL/PARTS OF CENTRAL-ERN FL PANHANDLE/SWRN GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010723Z - 010830Z ISOLATED STRONG WIND GUSTS WILL BE POSSIBLE THROUGH 09-10Z AS LOW- TOPPED CONVECTIVE LINE MOVES QUICKLY NEWD ACROSS THE CENTRAL-ERN FL PANHANDLE AND SERN AL INTO SWRN GA. REGIONAL RADARS SHOWED A BOW SHAPED CONVECTIVE LINE EXTENDING FROM SERN AL /GENEVA COUNTY/ TO BAY COUNTY FL. THIS LINE WAS MOVING NEWD AT 40 KT. 06Z RUC POINT FORECAST SOUNDINGS SUGGEST AIR MASS IMMEDIATELY DOWNSTREAM INTO SERN AL/CENTRAL FL PANHANDLE AND SWRN GA IS MARGINALLY UNSTABLE /MUCAPE 100-200 J/KG/ WITH THIS INSTABILITY CONFINED GENERALLY BELOW 600 MB. GIVEN SPEED OF THE CONVECTIVE LINE WITH AREA VADS INDICATING DEEP SWLY WINDS MAINTAINING LINEAR STRUCTURE WITH 40 KT JUST OFF THE SURFACE...ISOLATED STRONG WIND GUSTS WILL BE POSSIBLE WITHIN WEAKLY UNSTABLE AIR MASS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX... 30108583 30478568 30808577 30988592 31338569 31678538 31938492 31868424 31008404 30498423 30138456 29858534  From mcd at goshenarc.org Fri Dec 1 08:09:56 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 03:09:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010811 SWOMCD SPC MCD 010811 OHZ000-KYZ000-INZ000-010915- MESOSCALE DISCUSSION 2257 NWS STORM PREDICTION CENTER NORMAN OK 0211 AM CST FRI DEC 01 2006 AREAS AFFECTED...CENTRAL AND PARTS OF ERN KY/SERN IND/SWRN OH CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 010811Z - 010915Z TORNADO WATCH IS LIKELY FOR CENTRAL AND PARTS OF ERN KY...SERN IND...AND SWRN OH. SURFACE LOW...NOW LOCATED ALONG OH RIVER NEAR EVV...WILL CONTINUE TO INTENSIFY AS STRONG UPPER LOW OVER SERN MO UNDERGOES FURTHER DEEPENING AS IT TRACKS NEWD INTO IL BY 12Z. WARM FRONT EXTENDING NEWD FROM LOW TO JUST S OF CVG TO JUST S OF CMH IS EXPECTED TO RETREAT SLOWLY NWD AS WARM SECTOR CONTINUES TO MODIFY WITH SURFACE DEWPOINTS RISING THROUGH THE UPPER 50S AND LOWER 60S ACROSS CENTRAL KY TO SERN IND/SWRN OH. DESPITE WEAK INSTABILITY AND LOW-TOPPED LINE OF CONVECTION ALONG COLD FRONT...INCREASING DEEP LAYER SHEAR WITH BACKED LOW LEVEL WINDS SUGGESTS POTENTIAL FOR ISOLATED TORNADOES...IN ADDITION TO STRONG/DAMAGING WIND GUSTS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...RLX...JKL...ILN...LMK...IND... 36758594 38028593 39038559 39698458 39758346 38978311 37358356 36618451 36678593 WWWW From mcd at goshenarc.org Fri Dec 1 10:14:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 05:14:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011015 SWOMCD SPC MCD 011014 OHZ000-KYZ000-TNZ000-INZ000-011115- MESOSCALE DISCUSSION 2258 NWS STORM PREDICTION CENTER NORMAN OK 0414 AM CST FRI DEC 01 2006 AREAS AFFECTED...SERN IND/CENTRAL KY/SWRN OH AND INTO PARTS OF WRN AND CENTRAL OH CONCERNING...SEVERE THUNDERSTORM WATCH 872... VALID 011014Z - 011115Z WW BEING CONSIDERED FOR PARTS OF WRN AND CENTRAL OH TO THE N AND NE OF WW 872. SEVERE WEATHER THREAT CONTINUES ACROSS WW 872. LATEST SURFACE ANALYSES INDICATED STRONGEST AREA OF PRESSURE FALLS OVER EAST CENTRAL IL/WRN IND...WITH A SECONDARY AREA OF PRESSURE FALLS OVER SWRN OH. THESE TRENDS ARE INDICATIVE OF OBSERVED SECONDARY LOW CONTINUING TO DEVELOP OVER SERN IND...WHILE PRIMARY LOW OCCLUDES NWD INTO ERN IL. SURFACE OBSERVATIONS SHOWED WARM SECTOR IS DEVELOPING NWD ACROSS SWRN-CENTRAL OH AS THE WARM FRONT MOVES NWD...THUS SUPPORTING POTENTIAL FOR NEW WW AS AIR MASS SHOULD CONTINUE TO DESTABILIZE N OF WW 872. REGIONAL RADARS INDICATED A LINE OF LOW-TOPPED CONVECTION EXTENDING FROM FRANKLIN COUNTY IN SERN IND SWD ALONG THE COLD FRONT INTO CENTRAL KY...WITH THIS LINE MOVING NEWD AT 50 KT. GIVEN THIS SPEED COMBINED WITH 55-65 KT SSWLY WINDS JUST OFF THE SURFACE PER AREA VADS WITHIN WW 872...SUGGESTS CONTINUED POTENTIAL FOR DAMAGING WINDS WITH THE LINE. IN ADDITION...ISOLATED TORNADO THREAT REMAINS AS BACKED SURFACE WINDS ARE RESULTING IN STRONG LOW LEVEL SHEAR... ESPECIALLY IN VICINITY OF SURFACE LOW AND ENEWD ALONG SURFACE WARM FRONT. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PBZ...RLX...CLE...MRX...JKL...ILN...LMK...IWX...OHX...IND... 40408154 39508223 38018307 37088374 36588476 36578596 37458566 38358599 39158548 39648496 39948480 40638483 40728405 40768294 41008154  From mcd at goshenarc.org Fri Dec 1 12:40:16 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 07:40:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011242 SWOMCD SPC MCD 011242 MIZ000-WIZ000-ILZ000-011715- MESOSCALE DISCUSSION 2259 NWS STORM PREDICTION CENTER NORMAN OK 0642 AM CST FRI DEC 01 2006 AREAS AFFECTED...NRN IL...FAR SERN WI...NRN LOWER MI CONCERNING...HEAVY SNOW VALID 011242Z - 011715Z MODERATE TO HEAVY SNOW WILL QUICKLY EXPAND NEWD THROUGH 18Z AS POTENT UPPER LOW EJECTS RAPIDLY NEWD. SNOWFALL RATES OF 1 TO 2 IN/HR WILL BE COMMON...WITH THE HEAVIEST BAND OF SNOW FROM PIA NEWD TO RFD/MKE MOVING ACROSS LK MI INTO W-CNTRL LOWER MI. AN INTENSE PRESSURE GRADIENT WILL LEAD TO SUBSTANTIAL BLOWING AND DRIFTING SNOW. W/V IMAGERY DEPICTS THE UPPER LOW CENTERED NEAR DECATUR IL HAS ACCELERATED NEWD OVER THE PAST SEVERAL HOURS. PRIMARY SURFACE CYCLONE NEAR CHAMPAIGN IL HAS RAPIDLY DEEPENED BY 9 MB OVER THE PAST 8 HOURS. 06Z NAM/GFS AND 09Z RUC GUIDANCE ARE VERY SIMILAR IN TRACKING THE 500 MB LOW TO NEAR DETROIT MI BY 18Z. DEFORMATION BAND OF MODERATE TO HEAVY SNOW WILL PARALLEL THE TRACK OF THIS LOW FROM NRN/CNTRL IL AND FAR SERN WI NEWD ACROSS MUCH OF NRN/WRN LOWER MI. SUBSTANTIAL VERTICAL MOTION WITHIN THE SATURATED DENDRITIC GROWTH ZONE NW OF PUNCHING DRY SLOT...WILL CONTINUE TO PRODUCE SNOWFALL RATES AROUND 1 IN/HR. ISOLATED CG LIGHTNING STRIKES WILL ALSO LEAD TO CONVECTIVE BURSTS OF HEAVY SNOW OF AROUND 2 IN/HR. ACROSS NRN LOWER MI...12Z APX OBSERVED SOUNDING SHOWS A SUBSTANTIAL DRY POCKET REMAINS BETWEEN 700 TO 850 MB. HOWEVER...STRONG LOW-LEVEL ISENTROPIC LIFT AND FRONTOGENETICAL FORCING WILL QUICKLY SATURATE THE COLUMN. PRONOUNCED UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL OCCUR AS 120 KT 500 MB JET SPREADS NEWD ACROSS OH/LK ERIE...AIDING IN HEAVY SNOW DEVELOPMENT AFTER 15Z. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...APX...GRR...GRB...LOT...ILX...MKX...DVN... 45728401 45088301 43908326 43168525 42568633 41848758 41308825 40928857 40108934 40038977 40329022 40949024 41988973 43018879 43968766 45088591  From mcd at goshenarc.org Fri Dec 1 13:43:26 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 08:43:26 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011345 SWOMCD SPC MCD 011344 PAZ000-WVZ000-OHZ000-011445- MESOSCALE DISCUSSION 2260 NWS STORM PREDICTION CENTER NORMAN OK 0744 AM CST FRI DEC 01 2006 AREAS AFFECTED...ERN OH/WRN PA/FAR NRN WV PANHANDLE CONCERNING...SEVERE THUNDERSTORM WATCH 873... VALID 011344Z - 011445Z ISOLATED THREAT FOR DAMAGING WINDS WITH LOW-TOPPED CONVECTION ALONG FAST MOVING COLD FRONT TO CONTINUE THIS MORNING. REGIONAL RADARS INDICATED LOW-TOPPED LINE OF CONVECTION CONTINUED TO ACCOMPANY THE STRONG COLD FRONT MOVING ENEWD AT 40 KT AT THIS TIME INTO ERN OH AND WRN WV. VADS AT CLE AND CRW...JUST AHEAD OF THE CONVECTIVE LINE...INDICATED 45-55 KT SSWLY WINDS JUST OFF THE SURFACE. WARM FRONT HAS CONTINUED TO MOVE NWD THIS MORNING AND NOW EXTENDS ENEWD FROM SURFACE LOW OVER NORTH CENTRAL OH TO FAR NWRN AND NRN PA INTO SERN NY. WARM SECTOR AIR MASS WILL CONTINUE TO SLOWLY DESTABILIZE WITH LOW LEVEL LAPSE RATES POTENTIALLY BECOMING SUFFICIENTLY STEEP TO ALLOW STRONGER WINDS JUST OFF THE SURFACE TO MIX DOWNWARD AND PRODUCE LOCALLY STRONG DAMAGING WINDS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PBZ...RLX...CLE...ILN... 39668224 40528225 41488254 41688155 41698072 41607956 41157956 40747971 40248053 39838077 39518132  From mcd at goshenarc.org Fri Dec 1 16:36:46 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 11:36:46 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011638 SWOMCD SPC MCD 011638 CTZ000-MAZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-WVZ000-011845- MESOSCALE DISCUSSION 2261 NWS STORM PREDICTION CENTER NORMAN OK 1038 AM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS PA...WRN/SRN NY...DE...ERN WV...NJ...MD...NRN/CENTRAL VA...DC. CONCERNING...SEVERE THUNDERSTORM WATCH 874... VALID 011638Z - 011845Z BROKEN BAND OF LOW-TOPPED CONVECTION -- INCLUDING SPORADIC TSTMS -- IS FCST TO CONTINUE MOVING ENEWD 40-45 KT ACROSS WW AREA...AND PERHAPS ADJACENT PORTIONS WRN NY AND WRN/CENTRAL VA. ACTIVITY CONSISTS OF SEVERAL QUASI-LINEAR SEGMENTS THAT ARE DISCRETE AT 50 DBZ REFLECTIVITY LEVELS. SEVERAL REPORTS OF DAMAGE FROM NON-TSTM GUSTS -- BUT STILL CONVECTIVE IN ORIGIN -- HAVE BEEN RECEIVED FROM WRN PA AND NRN WV WITH THIS ACTIVITY. EXPECT SVR POTENTIAL TO PERSIST EWD THROUGH WW AND ALSO EXTEND INTO PORTIONS SRN NY..ERN PA AND NJ WITHIN 3-4 HOURS. ADDITIONAL WW MAY BE REQUIRED FOR THOSE AREAS ADJACENT TO WW 874. SFC MESOANALYSIS SHOWS MAIN CYCLONE OVER WRN LE...OCCLUDED FRONT EWD ACROSS LE TO TRIPLE POINT NEAR WRN TIP NY. WARM FRONT CONTINUES EWD INVOF NY/PA BORDER THEN ENEWD ACROSS SERN NY TO JUST S ALB...THEN EXTREME SRN VT. PRIND WARM FRONT WILL LIFT SLOWLY NWD ACROSS WRN NY AND SPREAD NEUTRALLY TO MRGLLY UNSTABLE WARM SECTOR INTO ELM/BGM/ALB AND PERHAPS ITH/GFL AREAS. GIVEN STRONG STATIC STABILITY EVIDENT N OF WARM FRONT...THIS BOUNDARY SHOULD SERVE AS NRN BOUND OF SVR WIND POTENTIAL. WAA AND WEAK SFC DIABATIC HEATING E OF FRONT WILL DESTABILIZE PRE-STORM BOUNDARY LAYER SOMEWHAT...RESULTING IN PATCHY MUCAPES 100-400 J/KG...SOME OF WHICH WILL REACH INTO ICING LAYERS SUITABLE FOR LIGHTNING PRODUCTION. GIVEN INTENSITY OF KINEMATIC FIELDS JUST ABOVE SFC AND POTENTIAL FOR DOWNWARD MOMENTUM TRANSFER...DAMAGING GUST POTENTIAL WILL EXIST ALMOST ANYWHERE WITHIN THIS ACTIVITY...BUT WILL BE ENHANCED LOCALLY INVOF LEWP/BOW FORMATIONS THAT SHOULD DEVELOP WITHIN THOSE SEGMENTS. QLCS-TYPE TORNADIC SPINUP ALSO CANNOT BE RULED OUT. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OKX...ALY...PHI...BGM...AKQ...BUF...CTP...LWX...RNK...PBZ...RLX... 38228023 39687965 41687937 42357950 42417718 42687540 42937387 42667335 41797352 40457397 39837405 39427428 38957482 38757538 38047789 37927995  From mcd at goshenarc.org Fri Dec 1 17:24:49 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 12:24:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011726 SWOMCD SPC MCD 011726 VTZ000-NYZ000-012300- MESOSCALE DISCUSSION 2262 NWS STORM PREDICTION CENTER NORMAN OK 1126 AM CST FRI DEC 01 2006 AREAS AFFECTED...NRN VT/ FAR NRN NY CONCERNING...FREEZING RAIN VALID 011726Z - 012300Z FREEZING RAIN WITH HRLY RATES FROM 0.05 TO 0.10 INCH WILL DEVELOP AND LAST FOR THE NEXT 3-5 HRS...BEFORE CHANGING BACK OVER TO RAIN DURING THE LATE AFTERNOON. SFC ANALYSIS AND RECENT OBS INDICATE LOW LEVEL COLD ADVECTION/DRAINAGE CONTINUES ALONG THE ST LAWRENCE AND CHAMPLAIN VALLEYS WITH TEMPERATURES RECENTLY FALLING TO 32F AT BOTH PLATTSBURGH AND MASSENA. WITH DWPTS RANGING FROM 29-31F...A FEW MORE DEGREES OF COOLING IS ANTICIPATED. STRONG WAA NORTH OF THE SFC WARM FRONT LOCATED OVER SRN NY WILL MAINTAIN AN ELEVATED WARM LAYER OVER THE REGION...ALONG WITH SUPPORTING MODERATE PRECIPITATION. AS THE 994 MB SFC LOW OVER SWRN NY MOVES NEWD INTO NRN NY LATER THIS AFTERNOON ...SUFFICIENT VEERING OF THE LOW LEVEL WIND FIELDS SHOULD OCCUR AND AID IN A TRANSITION OF P-TYPE BACK TO COLD RAIN AFTER 22Z. ..CROSBIE.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BTV... 44977255 44567288 44407334 44507383 44987421 45087404  From mcd at goshenarc.org Fri Dec 1 17:27:57 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 12:27:57 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011729 SWOMCD SPC MCD 011729 MDZ000-VAZ000-NCZ000-SCZ000-011930- MESOSCALE DISCUSSION 2263 NWS STORM PREDICTION CENTER NORMAN OK 1129 AM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS CENTRAL/SRN/ERN VA...EXTREME SERN MD...ERN NC...NERN SC. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 011729Z - 011930Z CONVECTION MAY STRENGTHEN THROUGH MID AFTERNOON ALONG PREFRONTAL CONVERGENCE BAND -- EVIDENT AS OF 1715Z FROM ABOUT 50 SW RIC TO 20 NW SAV. MAIN THREAT WILL BE DAMAGING GUSTS. ALSO...LINE OF SVR CONVECTION CLOSER TO COLD FRONT...AND NOW IN WWS 874-875 MAY BACKBUILD SWD AND AFFECT PORTIONS CENTRAL VA. AIR MASS WILL CONTINUE TO DESTABILIZE ACROSS COASTAL PLAIN AND TIDEWATER REGION FROM MD TO ERN NC...PERHAPS INTO PORTIONS NERN SC. SFC DIABATIC HEATING AND DEW POINTS MID 60S TO NEAR 70 F WILL COUNTERACT WEAK MIDLEVEL LAPSE RATES ENOUGH TO RAISE MLCAPES TO 500 J/KG...PERHAPS AS HIGH AS 1000 J/KG. VERTICAL WIND PROFILES WILL BE NEARLY UNIDIRECTIONAL...BUT WITH VERY STRONG SPEED SHEAR...AS TIGHTEST GRADIENT FLOW ALOFT PASSES OVER REGION SE OF EJECTING MID-UPPER LOW OVER GREAT LAKES REGION. 30-40 KT OF 0-1 KM VECTOR SHEAR IS EVIDENT OVER NC/VA PORTION OF DISCUSSION AREA...BASED ON VWP AND RUC SOUNDINGS. SVR PROBABILITIES DIMINISH WITH SWD EXTENT THROUGH SC BECAUSE OF WEAKER CONVERGENCE...AND BECAUSE OF EXPECTED VEERING TREND IN PRE-STORM BOUNDARY LAYER FLOW RELATED TO ISALLOBARIC FORCING. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...RNK... 33577990 36657842 37877831 38367760 38447500 37897531 37107588 36917598 36057566 35677545 35197550 35117592 34557652 34707680 34567722 34227777 33827794 33867854 33507903 33107922  From mcd at goshenarc.org Fri Dec 1 18:11:25 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 13:11:25 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011813 SWOMCD SPC MCD 011812 MEZ000-012345- MESOSCALE DISCUSSION 2264 NWS STORM PREDICTION CENTER NORMAN OK 1212 PM CST FRI DEC 01 2006 AREAS AFFECTED...NWRN/NERN ME CONCERNING...WINTER MIXED PRECIPITATION VALID 011812Z - 012345Z A MIXTURE OF LIGHT TO MODERATE FREEZING RAIN/SLEET WILL DEVELOP OVER PORTIONS OF ME THROUGH 21Z...WITH FREEZING RAIN BEING THE MORE PREDOMINANT P-TYPE SOUTH OF A LINE FROM HUL TO BML. HVY SNOW MAY BE THE PREDOMINANT P-TYPE OVER FAR NRN ME...DEVELOPING TOWARDS 00Z. HRLY LIQUID ACCUMULATION RATES AROUND 0.10 INCH WILL BE LIKELY...MAINLY AFTER 21Z. STRONG WAA WILL CONTINUE TO SPREAD NEWD INTO THE REGION OVER THE NEXT 6 HRS AHEAD OF STRONG 80 KT LOW LEVEL JET AND WARM FRONT LOCATED PRESENTLY OVER SRN NY AND NEW ENGLAND. AN ELEVATED WARM LAYER /NOTED BY 40 DEG F OBSERVATION AT MT. WASHINGTON/ WILL CONTINUE TO OVERSPREAD THE AREA. MEANWHILE...LOW LEVEL COLD/DRY AIR ADVECTION SUPPORTED BY NLY WINDS EMANATING FROM A LARGE AREA OF SFC HIGH PRESSURE OVER ERN QUEBEC WILL CONTINUE FOR SEVERAL MORE HRS. AS PRECIPITATION MOVES INTO PORTIONS OF NRN ME...WET-BULB COOLING EFFECTS WILL SUPPORT TEMPERATURES FALLING BELOW FREEZING OVER ALL OF NRN ME BY MID AFTERNOON. GIVEN THE RELATIVELY LARGE WARM LAYER NOTED ON FCST SOUNDINGS SUPPORTED BY STRONG WAA MOVING INTO THE REGION...FREEZING RAIN WILL BE THE PRIMARY P-TYPE SOUTH OF A LINE FROM HUL TO BML. NORTH OF THIS LINE...SLEET WILL BE THE PRIMARY P-TYPE FOR MOST OF THE REST OF NRN ME. THERE IS SOME UNCERTAINTY AS TO HOW FAR NORTH THE ELEVATED WARM LAYER CAN MOVE. ATTM...THERE IS SOME POSSIBILITY THAT FAR NRN ME WILL NEVER SEE A CHANGEOVER FROM THE MOD/HVY SNOWFALL WHICH SHOULD BEGIN BETWEEN 21-00Z. ..CROSBIE.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAR...GYX... 45546748 44916958 44747067 45217094 46597017 47276943 47376820 46826764  From mcd at goshenarc.org Fri Dec 1 21:07:12 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 16:07:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 012108 SWOMCD SPC MCD 012108 MAZ000-NYZ000-NHZ000-CTZ000-VTZ000-NJZ000-PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-012315- MESOSCALE DISCUSSION 2265 NWS STORM PREDICTION CENTER NORMAN OK 0308 PM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS NRN VA...SRN/ERN NY...MD...ERN PA...DC...NJ...WRN CT...SRN VT...WRN MA. CONCERNING...SEVERE THUNDERSTORM WATCH 874...875...876... VALID 012108Z - 012315Z SEGMENTED/LINEAR CONVECTION GENERALLY HAS REINVIGORATED OVER ERN PA AND SRN NY...AS ACTIVITY MOVES INTO BOUNDARY LAYER AIR MASS DESTABILIZED BY DIURNAL HEATING AND BY BOUNDARY LAYER THETAE ADVECTION. ADDITIONAL ADVECTIVE PROCESSES AND WEAK HEATING -- DURING NEXT 2-3 HOURS -- MAY MRGLLY DESTABILIZE RAIN-COOLED AIR NOW EVIDENT OVER EXTREME NERN PA...OVER MOST OF NJ...AND SERN NY. PRE-STORM MLCAPES SHOULD BE PEAKING AT 250-500 J/KG...CENTERED NEAR AXIS FROM BGM-FDK. DAMAGING WIND WILL REMAIN MAIN THREAT...AND QLCS-TYPE TORNADIC SPINUP STILL CANNOT BE RULED OUT. DEEP-LAYER KINEMATIC FIELDS AND INTENSE LLJ JUST ABOVE SFC WILL CONTINUE TO CONTRIBUTE TO FAVORABLE SHEAR PROFILES....EVEN AS INSTABILITY BECOMES MORE CONSTRAINED ON THREE SIDES BY COLD FRONT...WARM FRONT AND MARINE LAYER. DAMAGING WIND POTENTIAL WILL DECREASE SHARPLY POLEWARD OF WARM FRONT...CORRESPONDING TO STRONGER/DEEPER LAYER OF NEAR-SFC STATIC STABILITY WITH NWD EXTENT. SVR PROBABILITIES WILL DIMINISH GRADUALLY WITH EWD EXTENT ACROSS NEW ENGLAND AS CONVECTIVE FORCING ZONE PENETRATES INTO AIR MASS PROGRESSIVELY MORE STABILIZED BOTH BY MARINE LAYER TRAJECTORIES...AND BY SFC DIABATIC COOLING. STILL...SOME DAMAGING GUST POTENTIAL MAY EXTEND E OF WW 876...SO THIS AREA WILL BE MONITORED. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BOX...BTV...OKX...ALY...PHI...BGM...CTP...LWX... 39137767 40587702 42557628 43047578 43607440 43297268 42937246 42717224 42157220 41217269 40717283 40527392 40137402 39517423 38907530 38837740  From mcd at goshenarc.org Fri Dec 1 23:14:31 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 18:14:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 012316 SWOMCD SPC MCD 012315 MAZ000-RIZ000-NHZ000-CTZ000-NYZ000-VTZ000-020015- MESOSCALE DISCUSSION 2266 NWS STORM PREDICTION CENTER NORMAN OK 0515 PM CST FRI DEC 01 2006 AREAS AFFECTED...SRN NEW ENGLAND CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 012315Z - 020015Z THE SEVERE THREAT WILL INCREASE ACROSS SRN NEW ENGLAND OVER THE NEXT FEW HOURS. WIND DAMAGE WOULD BE THE PRIMARY THREAT ALTHOUGH AN ISOLATED TORNADO THREAT CANNOT BE OUTRULED. A WW WILL MAY BE NEEDED ACROSS THE REGION. LATEST SFC ANALYSIS SHOWS A 992 MB LOW OVER NERN NY. A STATIONARY FRONT EXTENDS EWD FROM THE LOW WITH A COLD FRONT EXTENDING SSWWD ACROSS ERN NY...ERN PA INTO WRN MD. A WELL-DEVELOPED SQUALL-LINE IS ONGOING JUST AHEAD OF THE FRONT AND THIS LINE WILL MOVE QUICKLY ACROSS SRN NEW ENGLAND THIS EVENING. OBJECTIVE ANALYSIS CURRENTLY SHOWS AN IMPRESSIVE 80 KT LOW-LEVEL JET CENTERED NEAR SRN NJ AND THIS FEATURE WILL CONTINUE TO NOSE INTO SRN NEW ENGLAND OVER THE NEXT FEW HOURS CREATING A VERY STRONG LOW-LEVEL SHEAR ENVIRONMENT. THIS WILL BE FAVORABLE FOR DAMAGING WINDS AS THE WELL-DEVELOPED LINE MOVES ACROSS SRN NEW ENGLAND. HOWEVER...UNCERTAINTY REMAINS CONCERNING HOW WIDESPREAD THE WIND DAMAGE POTENTIAL WILL BE DUE TO THE WEAK INSTABILITY CURRENTLY IN PLACE. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BOX...OKX...ALY... 41227135 41027292 41037343 41387368 42477343 42897229 42627075 41607044 WWWW From mcd at goshenarc.org Sat Dec 2 00:28:19 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 19:28:19 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 020030 SWOMCD SPC MCD 020029 MEZ000-020630- MESOSCALE DISCUSSION 2267 NWS STORM PREDICTION CENTER NORMAN OK 0629 PM CST FRI DEC 01 2006 AREAS AFFECTED...NRN/CENTRAL AND ERN ME CONCERNING...WINTER MIXED PRECIPITATION VALID 020029Z - 020630Z A MIX OF FREEZING RAIN/SLEET AND SNOW WILL CONTINUE TO DEVELOP OVER THE AREA IN THE NEXT COUPLE OF HRS. HEAVY ACCUMULATIONS WILL BE POSSIBLE MAINLY BETWEEN 02-05Z...AS THE STRONGEST BAND OF PRECIPITATION AND VERTICAL MOTION MOVES RAPIDLY ACROSS THE REGION. HRLY ACCUMULATION RATES MAY EXCEED 0.25 IN. FOR UP TO A HALF HR AT ANY LOCATION DURING THIS PERIOD. PRECIPITATION SHOULD BEGIN TO DIMINISH AROUND OR SHORTLY AFTER 06Z. LATEST SFC ANALYSIS SHOWS A 994 SFC LOW RAPIDLY MOVING ENEWD THROUGH NRN VT. THIS LOW SHOULD CONTINUE TO MOVE ENEWD ALONG A WARM FRONT INTO SRN/DOWNEAST ME THROUGH 06Z. LOW LEVEL COLD ADVECTION HAS AIDED IN MAINTAINING SUB-FREEZING TEMPERATURES ALONG AND NORTH OF AN AXIS FROM SRN FRANKLIN COUNTY INTO NRN WASHINGTON COUNTY ACROSS PORTIONS OF CENTRAL/ERN ME. WITH ANTICIPATED TRACK/MVMNT OF THE SFC LOW...THIS AXIS IS ANTICIPATED TO REMAIN NEARLY STATIONARY FOR THE NEXT 6 HRS. AS THE STRONG COLD FRONT AND LOW LEVEL WAA /85 KT LOW LEVEL JET/ CONTINUES TO APPROACH THE REGION...THE DEEP ELEVATED WARM LAYER NOTED ON THE 19Z AND 00Z GYX SOUNDING WILL SUPPORT FREEZING RAIN 50-75 MILES NORTH OF THE AFOREMENTIONED AXIS. NORTH OF THIS ZONE...THE ELEVATED WARM LAYER DIMINISHES IN DEPTH...WHICH WILL SUPPORT A MIX OF FREEZING RAIN AND SLEET ACROSS NRN ME. THE 00Z CAR SOUNDING INDICATED THAT THE ELEVATED WARM LAYER REMAINED JUST SLIGHTLY BELOW 0 DEG C. HOWEVER GIVEN THE APPROACHING LOW LEVEL SPEED MAX...A PERIOD OF SLEET SHOULD OCCUR AMONGST THE HVY SNOWFALL EXPECTED TO DEVELOP IN THE NEXT FEW HRS. ELEVATED INSTABILITY /MUCAPES FROM 50-100 J/KG/ MAY SUPPORT A FEW LIGHTNING STRIKES IN THE REGION ALLOWING FOR HVY PRECIPITATION RATES OVER 0.25 IN/HR FOR A 1/2 HR PERIOD OR LONGER. ..CROSBIE.. 12/02/2006 ...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... 47076775 45456778 44736951 45197047 46556998 47486884  From mcd at goshenarc.org Sun Dec 3 01:01:04 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 02 Dec 2006 20:01:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 030102 SWOMCD SPC MCD 030102 MIZ000-WIZ000-030700- MESOSCALE DISCUSSION 2268 NWS STORM PREDICTION CENTER NORMAN OK 0702 PM CST SAT DEC 02 2006 AREAS AFFECTED...WRN PORTIONS OF THE U.P OF MI CONCERNING...HEAVY SNOW VALID 030102Z - 030700Z HEAVY LAKE EFFECT SNOW BANDS ARE ANTICIPATED TO DEVELOP SWD INTO THE WRN PORTION OF THE U.P OF MI /INCLUDING THE KEWEENAW PENINSULA/ OVER THE NEXT FEW HRS. HRLY SNOWFALL RATES UP TO 2 INCHES WILL BE POSSIBLE ALONG THE N-NE FACING SLOPES OF THE HIGHER TERRAIN BY 06Z. IR SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS OVER WRN LAKE SUPERIOR. THIS WAS INDICATIVE OF INCREASING MID LEVEL VERTICAL MOTION AHEAD OF AN UPPER LOW CENTERED NEAR THE BWCA IN NERN MN. THE 00Z INL SOUNDING INDICATED COOLER THAN MODEL FCST 850 MB TEMPERATURES /AROUND -18 DEG C/. AS A 1020 MB SFC LOW OVER ERN LAKE SUPERIOR CONTINUES TO MOVE EWD AWAY FROM THE REGION...A SFC FRONT AND ASSOCIATED COOLING WILL AID IN STEEPENING LOW LEVEL LAPSE RATES AND INCREASING DELTA-T/S TO BETWEEN 18-20 DEG C BY 06Z OVER WRN LK SUPERIOR. AS THE LOW LEVEL FLOW BECOMES N-NELY...THE FETCH WILL BE ORIENTED ROUGHLY ALONG THE MINOR-AXIS OF LK SUPERIOR. THUS...A MULTI-BANDED LES REGIME WILL DEVELOP. LOW LEVEL UPSLOPE FLOW INTO THE N-NELY FACING SLOPES OF THE HIGHER TERRAIN COMBINED WITH AFOREMENTIONED THERMODYNAMIC PARAMETERS WILL FAVOR SNOWFALL RATES IN EXCESS OF 1 IN PER HR BEFORE 06Z. ..CROSBIE.. 12/03/2006 ...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...MQT...DLH... 47578786 47418925 46979073 46669080 46489030 46418930 46618791 46978730  From mcd at goshenarc.org Mon Dec 4 17:57:58 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 04 Dec 2006 12:57:58 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 041759 SWOMCD SPC MCD 041758 NYZ000-050000- MESOSCALE DISCUSSION 2269 NWS STORM PREDICTION CENTER NORMAN OK 1158 AM CST MON DEC 04 2006 AREAS AFFECTED...FAR SWRN NY...INCLUDING PORTIONS OF THE BUFFALO METRO AREA CONCERNING...HEAVY SNOW VALID 041758Z - 050000Z A PRE-EXISTING LAKE EFFECT SNOW BAND IS EXPECTED TO BECOME ORIENTED IN A MORE FAVORABLE ORIENTATION TO UP TO 2 IN/HR SNOWFALL RATES BEGINNING AFTER 22Z OVER PORTIONS OF SWRN NY. A VIGOROUS MID LEVEL VORT MAX AND UPPER LEVEL JET NOTED ON IR/WV SATELLITE IMAGERY WERE MOVING ACROSS SRN WI DURING THE EARLY AFTERNOON. STRONG AND DEEP VERTICAL MOTION AHEAD OF AND TO THE LEFT OF THE UPPER LEVEL JET ENTRANCE REGION HAS SUPPORTED MODERATE TO HVY SNOWFALL OVER SWRN LOWER MI. AS THIS SYSTEM MOVES EWD...LOW LEVEL FLOW OVER LAKE ERIE WILL CONTINUE TO BACK AND STRENGTHEN. IN RESPONSE...THE PRE-EXISTING SNOWBAND OVER LAKE ERIE WILL LIFT NWD. RELATIVELY UNIDIRECTIONAL SHEAR SHOULD CONTINUE TO SUPPORT A SINGLE BAND TYPE STRUCTURE. HOWEVER SPEED SHEAR MAY CREATE OCCASIONAL BREAKS IN THIS BAND. AS THIS BAND BECOMES ORIENTED SW-NE...AN INCREASING FETCH DOWN LAKE ERIE WILL OCCUR LATER THIS AFTERNOON. INCREASING VERTICAL MOTION WILL SUPPORT MID LEVEL COOLING AND RISING INVERSION HEIGHTS FROM THE PRESENT 7000 FT TO OVER 10000 FT...ALONG WITH INCREASING LAKE INDUCED CAPE VALUES TO OVER 300 J/KG. THIS WILL FAVOR HVY SNOWFALL DEVELOPING OVER SWRN NY SNOWBELT REGION AND PORTIONS OF THE BUFFALO METRO AREA BY EARLY EVENING /AFTER 22Z/. COMBINED WITH A FAVORABLE UPSLOPE COMPONENT INTO THE HIGHER TERRAIN...SNOWFALL RATES UP TO 2 IN/HR ARE POSSIBLE BY 00Z. THE HEAVIEST SNOWFALL BAND IS EXPECTED TO EFFECT NRN CHAUTAUQUA/CATTARAUGUS AND NRN/CENTRAL ERIE COUNTIES. ..CROSBIE.. 12/04/2006 ...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...BUF... 42997850 42927902 42397972 42247963 42247871 42337841  From mcd at goshenarc.org Tue Dec 5 01:01:59 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 04 Dec 2006 20:01:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050103 SWOMCD SPC MCD 050103 NYZ000-PAZ000-050600- MESOSCALE DISCUSSION 2270 NWS STORM PREDICTION CENTER NORMAN OK 0703 PM CST MON DEC 04 2006 AREAS AFFECTED...LAKE EFFECT SNOW BELTS OF WRN NY AND FAR NWRN PA CONCERNING...HEAVY SNOW VALID 050103Z - 050600Z HEAVY SNOW BAND OVER LAKE ERIE AND THE CANADA/NY BORDER WILL SHIFT SWD THROUGH THE BUFFALO METRO AREA AND INTO SWRN NY AND EXTREME NWRN PA BETWEEN 03-06Z. AN ADDITIONAL HVY SNOW BAND OVER LAKE ONTARIO WILL GRADUALLY SHIFT NWD AND AFFECTS AREAS BETWEEN ART AND SYR. HRLY ACCUMULATION RATES IN BOTH AREAS WILL BE UP TO 2 INCHES ...ESPECIALLY IN FAVORABLE UPSLOPE AREAS. RECENT VWP DATA FROM CLE INDICATES AN INCREASING AND VEERING OF THE LOW LEVEL FLOW COMPARED TO THE 00Z BUF SOUNDING. THIS IS ASSOCIATED WITH MID LEVEL SHORTWAVE TROUGH THAT HAS JUST RECENTLY PASSED THROUGH THE AREA /PER RADAR AND SAT IMAGERY/. AS A RESULT...THE HVY SNOW BAND WHICH HAS RECENTLY MOVED NORTH OF THE BUF AREA INTO SWRN ONTARIO CANADA AND EXTREME NRN/WRN NIAGARA COUNTY NY WILL BEGIN TO SHIFT SWD THROUGH THE BUF METRO AREA IN THE NEXT 3-6 HRS AS THE MEAN FLOW VEERS TO AROUND 240 DEG. AS THE LOW LEVEL FLOW CONTINUES TO VEER /PER THE 00Z DTX SOUNDING/ THIS HEAVY SNOW BAND SHOULD SHIFT SWD OF THE BUF AREA AND EFFECT PORTIONS OF SWRN NY AND FAR NWRN PA TOWARDS 06Z. HIGH INVERSION LEVELS /10 KFT PER THE 00Z BUF SOUNDING/ ALONG WITH AN INCREASING LAKE FETCH LENGTH WILL SUPPORT GREATER THAN 1 INCH/HR SNOWFALL RATES. IN UPSLOPE AREAS...RATES MAY APPROACH 2 IN/HR. FURTHER NORTH...THE HVY SNOW BAND OVER LAKE ONTARIO...BEING SEEDED FROM THE LAKE ERIE SNOW BAND...WILL SHIFT SLOWLY NWD THROUGH 03Z AS THE LOW LEVEL FLOW CONTINUES TO BACK TO AROUND 210 DEG /PER THE BUF 00Z SOUNDING/ AHEAD OF THE MID LEVEL SHORTWAVE/SFC TROUGH. HEAVIEST SNOW RATES WILL THEREFORE AFFECT NRN OSWEGO...SRN JEFFERSON...WRN LEWIS/ONEIDA COUNTIES THROUGH 06Z. EVENTUALLY THIS SNOW BAND WILL SHIFT BACK SWD AROUND OR AFTER 06Z...AS LOW LEVEL FLOW VEERS. SIMILAR TO AREAS SOUTH...HVY SNOW RATES UP TO 2 IN/HR WILL BE POSSIBLE IN THE HIGHEST TERRAIN/FAVORABLE UPSLOPE AREAS. ..CROSBIE.. 12/05/2006 ...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...BGM...BUF...CLE... 43207672 43477675 43867652 43897609 43687569 43377563 43267615 43207880 42717906 42068048 41948017 41987982 42097898 42487849 43077821  From mcd at goshenarc.org Tue Dec 5 10:47:22 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 05 Dec 2006 05:47:22 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051048 SWOMCD SPC MCD 051048 NYZ000-051545- MESOSCALE DISCUSSION 2271 NWS STORM PREDICTION CENTER NORMAN OK 0448 AM CST TUE DEC 05 2006 AREAS AFFECTED...ALONG AND JUST SOUTH OF TUG HILL REGION CONCERNING...HEAVY SNOW VALID 051048Z - 051545Z LAKE EFFECT SNOW BAND WITH RATES OF 1-3 INCHES WILL CONTINUE TO BECOME ORIENTED ALONG THE MAJOR-AXIS OF LAKE ONTARIO THROUGH MID MORNING...WITH THE GREATER SNOWFALL RATES BEGINNING TO AFFECT SRN JEFFERSON AND OSWEGO COUNTIES BY 11-12Z. THIS BAND IS EXPECTED TO REMAIN FOCUSED INTO THE TUG HILL REGION THIS MORNING. THE SRN PART OF THIS BAND MAY SHIFT JUST S OF TUG HILL REGION INTO NRN PARTS OF ONONDAGA TO ERN WAYNE COUNTIES LATER THIS MORNING AS LOW LEVEL WINDS SHIFT TO THE WNW. SINCE 08-09Z...RADAR AND SATELLITE IMAGERY INDICATED A LAKE EFFECT SNOW BAND DEVELOPING ALONG THE MAJOR-AXIS OF LAKE ONTARIO /CENTRAL PORTIONS OF THE LAKE/. LOW LEVEL CONVERGENCE...PER STREAMLINE ANALYSIS...HAS INCREASED THUS FAR AS LOW LEVEL WINDS OVER THE WRN AND CENTRAL PARTS OF LAKE ONTARIO HAVE SHIFTED TO THE WEST WITH THE PASSAGE OF A SHORT WAVE TROUGH. AS THIS TROUGH CONTINUES TO TRACK E TOWARD NEW ENGLAND THIS MORNING...THE LOW LEVEL WINDS OVER ERN LAKE ONTARIO WILL ALSO SHIFT TO THE W ALLOWING THIS SNOW BAND TO SPREAD INLAND OVER JEFFERSON AND OSWEGO COUNTIES BY 11-12Z. THE TUG HILL REGION SHOULD BE THE PRIMARY FOCUS FOR THIS BAND THROUGH 17-18Z... THOUGH A WIND SHIFT TO THE WNW MAY ALLOW THE BAND TO SETTLE SLIGHTLY SWD INTO NRN PARTS OF ONONDAGA...CAYUGA TO ERN WAYNE COUNTIES DURING THE LATE MORNING. IR IMAGERY INDICATED COOLING CLOUD TOPS WITH THIS DEVELOPING SNOW BAND OVER LAKE ONTARIO...WITH CLOUD TOPS ESTIMATED IN EXCESS OF 12-14 KFT AND THUS FAVORABLE FOR CHARGE SEPARATION /I.E. LIGHTNING PRODUCTION/. ALTHOUGH INVERSION HEIGHTS ARE EXPECTED TO FALL TO AROUND 8 KFT BY 18Z...STEEP LOW LEVEL LAPSE RATES AND LAKE-INDUCED CAPE OF 100-300 J/KG SUGGESTS POTENTIAL FOR GREATER SNOWFALL RATES WITH CONVECTIVE ELEMENTS. ..PETERS.. 12/05/2006 ...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...BGM...BUF... 43357672 43477645 43527634 43557621 43767621 43877606 43917568 43517556 43197571 43017587 42867622 42827642 42887667 43027688 43287693  From mcd at goshenarc.org Thu Dec 7 00:39:27 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 06 Dec 2006 19:39:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 070040 SWOMCD SPC MCD 070040 MIZ000-070615- MESOSCALE DISCUSSION 2272 NWS STORM PREDICTION CENTER NORMAN OK 0640 PM CST WED DEC 06 2006 AREAS AFFECTED...UPPER PENINSULA OF MICHIGAN CONCERNING...HEAVY SNOW VALID 070040Z - 070615Z BANDS OF LAKE EFFECT SNOW ARE LIKELY TO INCREASE ACROSS PORTIONS OF THE U.P. OF MICHIGAN BY LATE TONIGHT. LOCALIZED SNOW RATES OF 2 IN/HR OR GREATER WILL BE POSSIBLE ACROSS ALGER/WESTERN SCHOOLCRAFT/FAR EASTERN MARQUETTE/DELTA COUNTIES...ESPECIALLY TOWARD/AFTER 06Z. IN THE WAKE OF THE SURFACE COLD FRONT/PASSING MID LEVEL TROUGH...INCREASING CYCLONIC FLOW AND OFF-LAKE SUPERIOR TRAJECTORIES COUPLED WITH UPSLOPE/FRICTIONAL CONVERGENCE WILL FAVOR INCREASINGLY ORGANIZED LAKE EFFECT SNOW THROUGH THE NIGHT ACROSS THE EAST CENTRAL U.P. OF MICHIGAN. RECENT TAMDAR SOUNDINGS FROM NEAR MARQUETTE DEPICT AN INVERSION HEIGHT AROUND 2.5 KM/750 MB EARLY THIS EVENING...WITH 850 MB TEMPS AROUND -19 C. INCREASINGLY COLD AIR ALOFT WILL FAVOR STRONG LAKE-DRIVEN INSTABILITY OFF OF LAKE SUPERIOR...WITH 850 MB DELTA-T VALUES AROUND 25 C. ONLY MODEST DIRECTIONAL SHEAR IN THE BOUNDARY LAYER PER TAMDAR DATA/MARQUETTE WSR-88D VWP DATA WILL SUPPORT THE GRADUAL EVOLUTION/INTENSIFICATION OF SEVERAL LAKE EFFECT BANDS...WITH SOME POTENTIAL FOR CONSOLIDATION OVERNIGHT. LATEST RUC/4KM WRF-NMM GUIDANCE SUGGESTS INTENSIFICATION OF SNOW RATES TOWARD/AFTER 06Z...ESPECIALLY ACROSS ALGER AND SCHOOLCRAFT COUNTIES INCLUDING HIGHWAYS 28/94. HIGH SNOW-TO-LIQUID WATER EQUIVALENTS WILL FURTHER PROMOTE POTENTIAL FOR 2 IN/HR OR GREATER SNOW RATES. ..GUYER.. 12/07/2006 ...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...MQT... 46648700 46608610 46388611 46048636 46018661 46248713 46508727  From mcd at goshenarc.org Sun Dec 10 03:26:33 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 09 Dec 2006 22:26:33 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 100327 SWOMCD SPC MCD 100327 CAZ000-100930- MESOSCALE DISCUSSION 2274 NWS STORM PREDICTION CENTER NORMAN OK 0927 PM CST SAT DEC 09 2006 AREAS AFFECTED...WRN SLOPES OF CENTRAL AND SRN SIERRA NEVADA MTNS ABOVE 6000 FT CONCERNING...HEAVY SNOW VALID 100327Z - 100930Z HEAVY SNOW WITH ACCUMULATION RATES UP TO 3 IN/HR FOR A SEVERAL HR PERIOD WILL OVERSPREAD THE CENTRAL/SRN SIERRA NEVADA MTNS OF CA BEGINNING BETWEEN 04-06Z. SNOW LEVELS WILL INITIALLY START AROUND 6500 FT BEFORE FALLING TO AROUND 5000 FT WITH A COLD FRONTAL PASSAGE. MOD/HVY RAINFALL RATES HAVE BEEN OBSERVED AT SEVERAL SITES IN THE SFO/MRY BAY AREAS AND CENTRAL COAST REGION SINCE 01Z...ASSOCIATED WITH A STRONG UPPER TROUGH MOVING INTO THE CA COAST. THIS PRECIPITATION WAS BEING SUPPORTED BY STRONG VERTICAL MOTION ASSOCIATED WITH DIFFLUENT UPPER LEVEL FLOW AND A STRONG VORTICITY CENTER MOVING INTO THE CENTRAL CA COAST. ADDITIONAL STRONG MESOSCALE VERTICAL MOTION WAS OCCURRING ALONG/AHEAD OF A SFC-850 MB FRONTAL ZONE WHICH RECENTLY PASSED THROUGH KSFO. THE 00Z OAK SOUNDING AND RECENT BLU SFC OBS INDICATED SNOWFALL LEVELS SHOULD START OUT BETWEEN 6000-6500 FT. HIGH PWAT VALUES AHEAD OF THE FRONT ALONG WITH MDT /30 KT/ SSWLY LOW LEVEL FLOW WILL SUPPORT ENHANCED SNOWFALL RATES ON THE WRN UPSLOPE REGION OF THE CENTRAL/SRN SIERRA NEVADA. GIVEN THE RECENT PRECIP RATES/TRENDS AROUND 0.25-0.30 IN/HR AT SNS...MRY AND PRB...2-3 IN/HR SNOWFALL RATES WILL BE POSSIBLE FOR A SEVERAL HR PERIOD PRIOR TO FRONTAL PASSAGE OVER THE WRN SLOPES OF THE CENTRAL/SRN SIERRA. CURRENT EXTRAPOLATION OF THE FRONTAL MOVEMENT /EWD AROUND 30 KTS/ TAKE THE FRONT THROUGH THE SIERRA BETWEEN 06-09Z. AFTER THE FRONTAL PASSAGE...SNOW LEVELS WILL FALL TO AROUND 5000 FT...AND FORCING WILL BE PRIMARILY DRIVEN BY MDT UPSLOPE FLOW...WITH RATES DECREASING TO LESS THAN 2 INCH/HR BY 09Z. ..CROSBIE.. 12/10/2006 ...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...VEF...REV...HNX...STO... 38551964 39072006 39852019 40112072 39882099 39512077 38702036 38382012 38132001 37181928 36821906 36281873 35931859 35451845 35341843 35251824 35371802 35561809 36181811 36301821 37401869  From mcd at goshenarc.org Tue Dec 12 01:20:50 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 11 Dec 2006 20:20:50 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 120121 SWOMCD SPC MCD 120121 IAZ000-MOZ000-KSZ000-NEZ000-120345- MESOSCALE DISCUSSION 2275 NWS STORM PREDICTION CENTER NORMAN OK 0721 PM CST MON DEC 11 2006 AREAS AFFECTED...PORTIONS SERN NEB...EXTREME NERN KS...NWRN MO...SWRN IA. CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 120121Z - 120345Z TSTMS ARE FCST TO CONTINUE TO DEVELOP...AND INCREASE IN COVERAGE ACROSS THIS REGION DURING NEXT FEW HOURS -- INITIALLY SPREADING NWD ACROSS KS/NEB BORDER THEN ACROSS MO/IA BORDER AREA. MAIN SVR CONCERN WILL BE HAIL...WITH OCCASIONAL STG/DAMAGING GUSTS POSSIBLE. SFC MESOANALYSIS SHOWS MAIN CYCLONE BETWEEN CNK-MHK...WITH ONE WARM FRONTAL STRUCTURE EXTENDING EWD THROUGH MKC AREA AND ANOTHER CORRESPONDING TO INVERTED TROUGH NEWD NEAR OMA. SFC LOW SHOULD LIFT NEWD TOWARD SRN IA. LIKEWISE...STRONGEST LOW-MIDDLE LEVEL FORCING WILL SHIFT NEWD WITH TIME...PRIMARILY N OF SRN WARM FRONTAL SEGMENT. TOP RAOB...WHICH WAS WELL LOCATED TO SAMPLE MIDLEVEL AIR MASS ASSOCIATED WITH THIS EVENT...ALONG WITH AIRCRAFT SOUNDINGS AND RUC FCST SOUNDINGS...INDICATE PLUME OF FAVORABLY STEEP LAPSE RATES AROUND 8 DEG C/KM WILL SHIFT EWD AND NEWD ACROSS DISCUSSION AREA THROUGH ABOUT 06Z. MOISTURE AND ISENTROPIC LIFT EACH SHOULD INCREASE IN LOW LEVELS...NEAR NWRN PERIPHERY OF 35-45 KT LLJ. THIS SHOULD LEAD TO AREA OF MUCAPES AROUND 500-700 J/KG THAT WILL EXPAND ACROSS THIS REGION WITH WEAKENING CINH. VERTICAL SHEAR PROFILES SUPPORT POTENTIAL FOR WELL-ORGANIZED AND OCCASIONALLY ROTATING UPDRAFTS...WITH 35-45 KT EFFECTIVE SHEAR. FAVORABLE DEEPER-LAYER SHEARS -- I.E. 0-6 KM VALUES 50-75 KT THAT COVER MOST OF CAPE-BEARING LAYER -- ALSO WILL BE LIKELY ACROSS THIS REGION AS STRONG HEIGHT GRADIENT MOVES OVERHEAD IN ADVANCE OF KS/NEB UPPER CYCLONE. ..EDWARDS.. 12/12/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DMX...EAX...OAX...TOP... 39399466 39559617 39899721 40599700 41739581 41959434 41049325 40029360 39529425  From mcd at goshenarc.org Tue Dec 12 21:40:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 12 Dec 2006 16:40:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 122141 SWOMCD SPC MCD 122140 INZ000-ILZ000-122345- MESOSCALE DISCUSSION 2276 NWS STORM PREDICTION CENTER NORMAN OK 0340 PM CST TUE DEC 12 2006 AREAS AFFECTED...CNTRL AND ERN IL...FAR WRN IN CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 122140Z - 122345Z A FEW STRONG STORMS ARE LIKELY THROUGH EARLY EVENING...WITH SMALL/MARGINALLY SVR HAIL POSSIBLE. SURFACE HEATING AHEAD OF SURGING COLD FRONT HAS ALLOWED FOR SURFACE BASED INSTABILITY TO DEVELOP FROM IL SWD THROUGH THE LOWER MS VALLEY. UPPER SHORTWAVE EMBEDDED WITHIN TROUGH IS NOW MOVING ACROSS THE REGION...WITH FAVORABLE DEEP LAYER LIFT NOW ACROSS IL. GIVEN VERY COLD AIR ALOFT AND NARROW PLUME OF RELATIVELY STEEP LOW LEVEL LAPSE RATES...A FEW CELLS ARE EXPECTED TO BECOME STRONG AND/OR MARGINALLY SEVERE WITH HAIL THE MAIN THREAT. POTENTIAL DOES EXIST FOR A STORM OR TWO TO BECOME A SUPERCELL GIVEN FAVORABLE LOW LEVEL SHEAR AND DEEP FORCING. GIVEN NARROW WARM SECTOR...OVERALL THREAT SHOULD REMAIN RATHER LOCALIZED. ..JEWELL.. 12/12/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...IND...PAH...LOT...ILX...LSX... 38928737 38258817 38108981 39458933 41058905 41158765 40748720 39988718 WWWW From mcd at goshenarc.org Tue Dec 19 05:48:44 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 00:48:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190549 SWOMCD SPC MCD 190548 TXZ000-OKZ000-KSZ000-NMZ000-191015- MESOSCALE DISCUSSION 2277 NWS STORM PREDICTION CENTER NORMAN OK 1148 PM CST MON DEC 18 2006 AREAS AFFECTED...TX AND OK PANHANDLES...EXTREME E-CNTRL NM CONCERNING...WINTER MIXED PRECIPITATION VALID 190548Z - 191015Z SHOWERS/ISOLATED TSTMS OF FREEZING RAIN MIXED WITH SLEET WILL CONTINUE ACROSS THE TX/OK PANHANDLES THROUGH 12Z. ICE ACCUMULATIONS SHOULD GENERALLY REACH .05 IN/HR WITHIN MOST SHOWERS. HOWEVER...A MORE INTENSE/CONCENTRATED AREA OF FREEZING RAIN MAY DEVELOP FROM AROUND 50 W PVW TO AMA TO 50 SE GUY. JUST SE OF THIS LINE...STRONGLY FOCUSED LOW-LEVEL WARM/MOIST ADVECTION WILL BE MAXIMIZED THROUGH THE OVERNIGHT HOURS. IN ADDITION...WEAK ELEVATED INSTABILITY...EVIDENCED BY RECENT CG LIGHTNING STRIKES...WILL AID IN PRODUCING ICE ACCUMULATION RATES AROUND .10 IN/HR AT TIMES. 05Z SURFACE ANALYSIS PLACES THE FREEZING LINE FROM ABOUT 60 W LBB NNEWD TO 10 S AMA TO LBL. LOW-LEVEL TEMPERATURES WILL COOL FURTHER MAINLY ACROSS THE NRN TX AND OK PANHANDLES AS SURFACE TEMPERATURE/DEW POINT SPREADS REMAIN AROUND 10 TO 20 DEGREES. PER 00Z AMA/MAF AND 03Z LBB OBSERVED SOUNDINGS...LARGE WARM NOSE OF ABOVE FREEZING TEMPERATURES EXISTS BETWEEN 750-850 MB ATOP THE SURFACE-BASED COLD DOME. 00Z MODEL GUIDANCE IS VERY CONSISTENT IN MAINTAINING THIS STRUCTURE OVERNIGHT WITH 25 TO 35 KTS OF SELY FLOW FEEDING INTO A SSW TO NNE ORIENTED 800 MB STATIONARY FRONT. THIS WILL RESULT IN FOCUSED LOW-LEVEL WARM/MOIST ADVECTION ABOVE THE COLDER NEAR-SURFACE LAYER. 03Z RUC/00Z NAM FORECAST SOUNDINGS INDICATE FREEZING RAIN WILL BE THE PRIMARY PTYPE. SLEET WILL BE MORE PREVALENT FURTHER NW FROM TCC TO DHT TO LBL WHERE THE WARM NOSE WILL REMAIN COOLER THAN 2 TO 3 DEG C. ..GRAMS.. 12/19/2006 ...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...DDC...LUB...AMA...ABQ... 37190033 36520004 35250103 34350199 33930276 33750339 34290361 35120337 36360239 37050157 37220104 WWWW From mcd at goshenarc.org Tue Dec 19 12:15:01 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 07:15:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191215 SWOMCD SPC MCD 191215 TXZ000-OKZ000-191615- MESOSCALE DISCUSSION 2278 NWS STORM PREDICTION CENTER NORMAN OK 0615 AM CST TUE DEC 19 2006 AREAS AFFECTED...CNTRL/ERN PORTIONS OF THE TX/OK PNHDLS CONCERNING...WINTER MIXED PRECIPITATION VALID 191215Z - 191615Z SHOWERS OF FREEZING RAIN MIXED AT TIMES WITH SLEET WILL CONTINUE THROUGH THE MORNING ACROSS THE SRN HIGH PLAINS. THE MOST PERSISTENT REGENERATION OF SHOWERS WITH HEAVIEST PCPN RATES /UP TO 0.15 INCH PER HOUR/ WILL LIKELY EXIST IN A 50-60 NM WIDE AREA CENTERED ON A LINE EXTENDING FROM NEAR KPVW-KBGD-30SE KLBL. UPPER LOW WAS BEGINNING TO TURN EWD OVER THE LWR CO RVR VLY THIS MORNING WITH AN EXPANSIVE WARM CONVEYOR STREAMING FROM THE SUB-TROPICAL PAC NEWD TO THE SRN HIGH PLAINS. A DRY SLOT WAS EVIDENT IN WATER VAPOR IMAGERY OVER SCNTRL NM AND SHORT TERM MODELS SUGGEST THAT THIS MAY ENCROACH ON THE WRN TX PNHDL WITH TIME THIS MORNING. HOWEVER...INSPECTION OF THE 295-305K LAYERS SUGGESTS THAT ISENTROPIC LIFT WILL REMAIN STRONG FROM THE CNTRL S PLAINS NEWD INTO THE CNTRL/ERN TX/OK PNHDLS THROUGH AT LEAST 18Z. IN FACT...MUCAPES OF A COUPLE HUNDRED J PER KG WILL MAINTAIN THE TSTM THREAT...LOCALLY ENHANCING PCPN RATES. 12Z TEXAS MESONET OBS PLACE THE SFC FREEZING LINE FROM SEMINOLE NEWD THROUGH TAHOKA-SPUR-MEMPHIS AND INTO ROGER MILLS COUNTY OK. THE FREEZING LINE MAY RETREAT A BIT NWWD THIS MORNING AS LOW-LEVEL WARM ADVECTION CONTINUES...BUT AREAS ROUGHLY FROM KLBB-KAMA TO THE OK PNHDL SHOULD REMAIN FIRMLY AOB 30 DEG F WHERE PCPN CONTINUES TO COUNTERACT A FLOW OF RELATIVELY DRY NEAR-SFC AIR TRAJECTORIES. P-TYPE SHOULD MOSTLY REMAIN FREEZING RAIN OWING TO THE PLUS 4-5 DEG C WARM LAYER JUST ABOVE H8 NOTED ON THE 12Z AMA SOUNDING. SLEET MAY MIX WITH THE FREEZING RAIN IN THE HEAVIER TSTMS. ..RACY.. 12/19/2006 ...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... 35080200 35850170 36800113 36890021 36540006 35310056 34720088 34080119 33880156 34130200 34680212  From mcd at goshenarc.org Tue Dec 19 16:47:45 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 11:47:45 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191648 SWOMCD SPC MCD 191648 NEZ000-KSZ000-COZ000-192245- MESOSCALE DISCUSSION 2279 NWS STORM PREDICTION CENTER NORMAN OK 1048 AM CST TUE DEC 19 2006 AREAS AFFECTED...FAR ERN CO...WRN KS AND FAR SWRN NEB CONCERNING...FREEZING RAIN VALID 191648Z - 192245Z FREEZING RAIN SHOWERS...HVY AT TIMES...WILL CONTINUE TO DEVELOP NWD THROUGH MUCH OF WRN KS...FAR ERN CO AND FAR SWRN NEB THROUGH THE LATE AFTERNOON. SIGNIFICANT ICING MAY OCCUR WITH HRLY ACCUMULATIONS UP TO 0.10 IN WITH THE HEAVIEST SHOWERS OVER WRN KS. AREAS OF SLEET WILL MIX IN WITH THE FREEZING RAIN...ESPECIALLY ACROSS FAR ERN CO AND SWRN NEB. LATEST GDA PROFILER INDICATES A STRENGTHENING LOW LEVEL WAA PROFILE. 12Z AMA SOUNDING SHOWED MID LEVEL INSTABILITY WITH MUCAPES AROUND 300 J/KG. MEANWHILE WV IMAGERY SHOWS UPPER LEVEL ASCENT HAS BEGUN TO INCREASE OVER NERN NM UNDER STRONGLY DIFFLUENT PATTERN. THIS ASCENT SHOULD SPREAD NWD INTO ERN CO AND WRN KS THROUGH THE AFTERNOON AS THE SHORTWAVE TROUGH AXIS MOVES SLOWLY ACROSS NM. THE COMBINATION OF THESE INGREDIENTS WILL SUPPORT SCT MDT/HVY SHOWERS DEVELOPING AND MOVING INTO THE AREA. A SHALLOW SUB-FREEZING LAYER /< 1 KM DEEP/ WILL CONTINUE TO SUPPORT THE MAIN P-TYPE AS FREEZING RAIN AS PRECIPITATION DEVELOPS INTO WRN KS AND FAR ERN CO. THROUGH 00Z...THE NWD EXTENT OF THE HEAVIEST FREEZING RAIN ACCUMULATIONS WILL LIKELY BE AROUND I-70...AS MUCH DRIER AIR IN THE LOWER LEVELS WILL INITIALLY OFFSET PRECIP RATES ACROSS NWRN KS...FAR ECENTRAL/NERN CO AND FAR SWRN NEB. ..CROSBIE.. 12/19/2006 ...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...LBF...DDC...GLD...PUB...BOU... 37010034 39010032 40560037 40460276 39430276 38430285 36990262  From mcd at goshenarc.org Tue Dec 19 18:24:31 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 13:24:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191825 SWOMCD SPC MCD 191824 OKZ000-KSZ000-TXZ000-COZ000-NMZ000-200030- MESOSCALE DISCUSSION 2280 NWS STORM PREDICTION CENTER NORMAN OK 1224 PM CST TUE DEC 19 2006 AREAS AFFECTED...PORTIONS OF ERN NM...WRN TX...THE TX/OK PANHANDLES AND NWRN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 191824Z - 200030Z MDT/HVY FREEZING RAIN WILL CONTINUE OVER PORTIONS OF THE CENTRAL/ERN TX AND OK PANHANDLES...NRN TX SOUTH PLAINS THROUGH MOST OF THE AFTERNOON. HRLY FREEZING RAIN AMTS UP TO 0.25 INCH WILL BE POSSIBLE WITH THE HEAVIEST SHOWERS/TSTMS. FREEZING RAIN SHOULD CHANGEOVER TO RAIN IN NWRN OK...AND PORTIONS OF THE ERN OK/TX PANHANDLES...ERN/SRN TX SOUTH PLAINS OVER THE NEXT 3-6 HRS. MEANWHILE...WINTER MIXED PRECIPITATION WILL REMAIN LIGHT AND/OR DIMINISH OVER THE WRN TX PANHANDLE...AND MUCH OF ERN NM. MDT TO HVY CONVECTIVE FREEZING RAIN SHOWERS/TSTMS CONTINUE TO DEVELOP IN AN AREA OF STRONG WAA AND WEAK MID LEVEL INSTABILITY OVER WRN TX. THE STRONGEST ACTIVITY WAS DEVELOPING JUST AHEAD OF A SUBTLE SHORTWAVE TROUGH MOVING OUT OF ERN NM INTO THE TX PANHANDLE PER WV SAT IMAGERY. IN THE WAKE OF THIS SHORTWAVE...A MID LEVEL DRYSLOT WAS PRONOUNCED OVER ERN NM. ALTHOUGH LOW LEVELS REMAIN MOIST AND UPSLOPE FLOW WILL SUSTAIN FZDZ...THE MID LEVEL DRYING SHOULD LIMIT THE DEVELOPMENT ANY ADDITIONAL LT/MDT FREEZING RAIN/SLEET FOR THE REST OF THE AFTERNOON IN MOST OF ERN NM. AS THIS DRYSLOT MOVES INTO WRN TX...FREEZING RAIN RATES WILL GRADUALLY TAPER OFF OVER THE WRN TX SOUTH PLAINS AND WRN TX/OK PANHANDLES THROUGH 00Z. FURTHER EAST...LOW LEVEL FLOW WILL CONTINUE TO BECOME ELY OVER THE ERN/SRN TX SOUTH PLAINS...ERN TX PANHANDLE AND WRN OK IN RESPONSE TO THE APPROACHING UPPER LOW/SHORTWAVE TROUGH. AS THIS OCCURS...LOW LEVEL WARMING SHOULD SUPPORT A CHANGEOVER FROM FREEZING RAIN TO RAIN IN THESE AREAS DURING THE REST OF THE AFTERNOON. CURRENT EXTRAPOLATION OF RECENT TRENDS INDICATES FREEZING RAIN/RAIN TRANSITION ZONE SHOULD EXTEND FROM W OF GAG TO SE OF AMA TO NEAR LBB BY 22Z. ..CROSBIE.. 12/19/2006 ...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...DDC...LUB...AMA...MAF...PUB...ABQ... 36340407 37120208 36969925 36519895 35789939 33900109 33200213 32960380 33480460 34520463 35990432 WWWW From mcd at goshenarc.org Wed Dec 20 00:38:28 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 19:38:28 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200039 SWOMCD SPC MCD 200038 OKZ000-TXZ000-KSZ000-COZ000-NMZ000-200445- MESOSCALE DISCUSSION 2281 NWS STORM PREDICTION CENTER NORMAN OK 0638 PM CST TUE DEC 19 2006 AREAS AFFECTED...ERN NM....EXTREME SERN CO AND SWRN KS...WRN SECTIONS OF THE TX/OK PNHDLS CONCERNING...WINTER MIXED PRECIPITATION VALID 200038Z - 200445Z SNOWFALL RATES ARE FORECAST TO LOCALLY APPROACH 1 INCH PER HOUR THROUGH MIDNIGHT ACROSS PARTS OF SCNTRL AND ERN NM. MEANWHILE... FREEZING RAIN WILL PROBABLY INCREASE THROUGH LATE THIS EVENING ACROSS THE NWRN PART OF THE TX PNHDL...NWD ACROSS THE OK PNHDL AND INTO SWRN KS. POTENT UPPER LOW CONTINUES TO MAKE STEADY EWD PROGRESS ACROSS AZ THIS EVENING WITH NOSE OF 80-90KT MID LEVEL JET NOW EMERGING OVER THE UPPER RIO GRANDE VALLEY/SERN NM. INTENSE DYNAMIC FORCING FOR ASCENT WAS RESULTING IN AN INCREASING AREA OF TSTM ACTIVITY FROM FAR WEST TX NNEWD ACROSS SERN NM ATTM. LATEST ANALYSIS INDICATES SUBFREEZING SURFACE CONDITIONS PERSIST ALONG A GDP-ROW-AMA-LBL LINE. STRONG INFLUX OF LOW LEVEL MOISTURE AND PRONOUNCED WARM NOSE EVIDENT ON EVENING SOUNDINGS FROM MAF AND AMA SHOULD CONTINUE TO SUPPORT AN AXIS OF FREEZING RAIN...WITHIN THIS CORRIDOR THROUGH MIDNIGHT. GLAZE ACCUMULATIONS MAY BE LOCALLY ENHANCED BY CONVECTION AND COULD OCCASIONALLY EXCEED 0.10 INCH PER HOUR OVER THE NEXT 6 HOURS. FARTHER WEST AND DEEPER INTO THE COLD AIR...AREAS HEAVY SNOW SHOULD BECOME INCREASINGLY LIKELY THROUGH THE EVENING AS DEEP-LAYER ASCENT SPREADS EWD AHEAD OF THE UPPER LOW. SATELLITE AND RADAR IMAGERY CURRENTLY INDICATE A N-S BAND OF ENHANCED LIFT WAS MOVING EAST FROM CNTRL NM. THE ARRIVAL OF STRONGER FORCING AND MOISTENING WILL ALSO COINCIDE WITH AN INCREASINGLY FAVORABLE THERMODYNAMIC REGIME FOR SNOW CRYSTAL GROWTH AS TEMPERATURES IN THE LAYER OF STRONGEST LIFT COOL TO BELOW -12C. LATEST GUIDANCE INDICATES SNOWFALL RATES OF UP TO 1 INCH PER HOUR APPEAR MOST LIKELY ACROSS PARTS OF ECNTRL NM BY 06Z. ..CARBIN.. 12/20/2006 ...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...DDC...LUB...AMA...MAF...PUB...ABQ...EPZ... 37850167 37550100 37240081 36700064 36020076 35460105 34890154 34240228 33080348 32680448 32440513 33420546 34320542 35240528 35590488 36200444 36710356 37120277 37160269 37750236  From mcd at goshenarc.org Wed Dec 20 00:50:59 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 19:50:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200051 SWOMCD SPC MCD 200051 NEZ000-KSZ000-COZ000-200645- MESOSCALE DISCUSSION 2282 NWS STORM PREDICTION CENTER NORMAN OK 0651 PM CST TUE DEC 19 2006 AREAS AFFECTED...WRN AND CENTRAL NEB CONCERNING...WINTER MIXED PRECIPITATION VALID 200051Z - 200645Z FREEZING RAIN MIXED WITH SLEET AT TIMES IS EXPECTED TO DEVELOP NWD INTO WRN NEB THROUGH 06Z. MDT ACCUMULATION RATES /UP TO 0.05 IN PER HR/ OF FREEZING RAIN WILL BE POSSIBLE...ESPECIALLY OVER SWRN AND PORTIONS OF SCENTRAL NEB. STRONG WAA COMBINED WITH UPPER LEVEL DIFFLUENCE WILL CONTINUE TO SUPPORT NWD MOVEMENT OF PRECIPITATION OUT OF FAR ERN CO AND WRN KS INTO SWRN/SCENTRAL NEB OVER THE NEXT SEVERAL HRS. THE 00Z DDC SOUNDING INDICATED A SUBSTANTIAL ELEVATED WARM LAYER ATOP A SHALLOW SUBFREEZING LAYER WHICH WOULD SUPPORT FREEZING RAIN AS THE PRIMARY PTYPE. PORTIONS OF WCENTRAL/NCENTRAL NEB MAY SEE A MIX OF SLEET AS THE WARM LAYER WILL BE LESSER IN VERTICAL EXTENT IN THIS AREA INITIALLY. THE 00Z LBF SOUNDING ALONG WITH SFC OBS INDICATE DRY AIR IN THE LOWEST 1 KM. THIS LAYER WILL INITIALLY LIMIT ACCUMULATIONS/RATES ACROSS PORTIONS OF CENTRAL NEB. HOWEVER GIVEN THE STRENGTH OF THE WARM ADVECTION /AND MODERATE PRECIP RATES FALLING OUT OF CONVECTIVE SHOWERS/ SATURATION SHOULD CONTINUE STEADILY NWD THROUGH 06Z. ..CROSBIE.. 12/20/2006 ...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...GID...LBF...GLD...BOU... 40189920 40999916 42329971 42600073 42140212 40690206 39990169  From mcd at goshenarc.org Wed Dec 20 06:00:39 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 01:00:39 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200601 SWOMCD SPC MCD 200601 NEZ000-SDZ000-KSZ000-OKZ000-TXZ000-201200- MESOSCALE DISCUSSION 2283 NWS STORM PREDICTION CENTER NORMAN OK 1201 AM CST WED DEC 20 2006 AREAS AFFECTED...MUCH OF CNTRL NEBRASKA...WRN KS AND PORTIONS OF THE OK/TX PANHANDLES CONCERNING...FREEZING RAIN VALID 200601Z - 201200Z AREAS OF MDT TO OCCASIONALLY HEAVY FREEZING RAIN WILL CONTINUE FOR A FEW MORE HOURS ACROSS WRN KS...THE ERN OK PANHANDLE AND NERN TX PANHANDLE WITH HRLY ACCUMULATIONS OF 0.10 - 0.20". FARTHER N...FREEZING RAIN WILL SPREAD NEWD ACROSS CNTRL NEBRASKA...WITH HRLY RATES OF 0.05-0.10". LARGE AREA OF WARM ADVECTION PRECIPITATION CONTINUES TO SPREAD NWD AHEAD OF UPPER TROUGH. COOLING ALOFT WILL EVENTUALLY ALLOW FOR A CHANGEOVER TO SNOW ACROSS WRN TX/OK PANHANDLES...BUT NOT BEFORE 1-3 MORE HOURS OF SIGNIFICANT ICING. FARTHER N...STRONG SELY 850 MB FLOW WILL MAINTAIN FREEZING RAIN PROFILES FOR SEVERAL MORE HOURS FROM WRN KS INTO NEBRASKA. LOW LEVEL PROFILES CONTINUE TO SATURATE OVER CNTRL NEBRASKA...WITH SURFACE WET BULB TEMPERATURES BELOW FREEZING. THUS...FREEZING RAIN IS LIKELY TO MATERIALIZE OVERNIGHT WITH 0.05 - 0.10"/HR POSSIBLE...CONTINUING AFTER SUNRISE. ..JEWELL.. 12/20/2006 ...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...FSD...OAX...GID...LBF...DDC...GLD...AMA... 42930059 42879827 41859712 41379691 40859797 40299871 39179928 37869995 36590064 36300077 36330118 36790126 38270123 39780117 40560122 41140116 42320154  From mcd at goshenarc.org Wed Dec 20 12:08:57 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 07:08:57 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201209 SWOMCD SPC MCD 201209 NEZ000-KSZ000-COZ000-WYZ000-201615- MESOSCALE DISCUSSION 2284 NWS STORM PREDICTION CENTER NORMAN OK 0609 AM CST WED DEC 20 2006 AREAS AFFECTED...ERN CO PLAINS...URBAN CORRIDOR...SWRN NEB AND NWRN KS CONCERNING...HEAVY SNOW VALID 201209Z - 201615Z SNOW WILL CONTINUE TO SPREAD/DEVELOP NWWD FROM THE ECNTRL/SERN CO PLAINS AND WRN KS TO THE DEN URBAN CORRIDOR...NERN CO AND SWRN NEB THROUGH 18Z. HOURLY SNOWFALL RATES OF 1-2 INCHES CAN BE EXPECTED WITH A BLIZZARD LIKELY DEVELOPING LATER THIS MORNING. WATER VAPOR IMAGERY SHOWS THE CENTER OF UPPER LOW IN CNTRL NM. H7 LOW WAS FORMING OVER NERN NM WITH INCREASING NLY FLOW NOTED ON VWP/PROFILERS OVER ERN CO. THE H7 LOW WILL INTENSIFY AND MOVE VERY SLOWLY INTO SERN CO BY THIS AFTN. STRONG H5-H3 QVEC CONVERGENCE WILL SPREAD NWD ACROSS ERN CO...WRN KS AND SWRN NEB BY MID-MORNING...WITH STRONGEST UNDERLYING H7-H6 FRONTOGENESIS SHIFTING TO THE DEN URBAN CORRIDOR/PALMER DIVIDE AND NERN CO PLAINS BY 18Z. INCREASING QG ASCENT SHOULD BEGIN TO OVERWHELM THE DRY AIR/DOWNSLOPING OFF THE CHEYENNE RIDGE AND HEAVY SNOWFALL RATES SHOULD ENSUE AS THE MORNING PROGRESSES FARTHER NORTH AND WEST. POTENTIAL EXISTS FOR INTENSE MESOSCALE BANDING AS NEGATIVE MPVG/POTENTIAL SLANTWISE CONVECTION BECOMES COINCIDENT WITH THE FRONTOGENESIS BETWEEN 15-18Z. MOREOVER...AS THE SYSTEM BECOMES MORE VERTICALLY STACKED OVER SERN CO...EVIDENCE OF A TROWAL DEVELOPS INTO NERN CO BY 18Z...FURTHER LENDING CONFIDENCE OF VERY HEAVY SNOWFALL. BEST COMBINATION OF LARGE SCALE SUPPORT AND POTENTIAL MESOSCALE BANDING VCNTY MOST INTENSE UPSLOPE COMPONENT WILL OCCUR ALONG THE PALMER DIVIDE. FINALLY...INCREASING PRESSURE GRADIENTS WILL CONTRIBUTE TO ACCELERATING WINDS WITH H7 SPEEDS FORECAST TO 55 KTS ALONG THE PALMER DIVIDE AT 18Z. GIVEN VERY HEAVY SNOWFALL RATES AND THE DRY NATURE OF THE SNOW...EVOLUTION INTO A BLIZZARD IS LIKELY BY AFTN AND ESPECIALLY ALONG THE PALMER DIVIDE. ..RACY.. 12/20/2006 ...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...LBF...GLD...PUB...BOU...CYS... 38480412 38910433 39120453 39210499 39330545 39720575 40330578 40640574 40750474 41090382 41440295 41440245 41390209 41230164 41010126 40670098 40100077 39670084 39410116 39330182 39310213 39060225 38750229 38590237 38510270 38470314 38470353  From mcd at goshenarc.org Wed Dec 20 12:11:53 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 07:11:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201212 SWOMCD SPC MCD 201211 NEZ000-KSZ000-201615- MESOSCALE DISCUSSION 2285 NWS STORM PREDICTION CENTER NORMAN OK 0611 AM CST WED DEC 20 2006 AREAS AFFECTED...NCNTRL KS AND CNTRL NEB CONCERNING...FREEZING RAIN VALID 201211Z - 201615Z FREEZING RAIN...AT TIMES MIXED WITH SLEET...WILL CONTINUE ACROSS NCNTRL KS AND CNTRL NEB THROUGH THE MORNING. HRLY RATES WILL GENERALLY BE AROUND 0.10 INCH...BUT COULD APPROACH 0.25 INCH IN THE HEAVY SHOWERS. PROFILERS/VWPS CONTINUE TO SHOW A VERY STRONG WARM ADVECTION PATTERN ACROSS THE CNTRL PLAINS THIS MORNING. A LARGE SHIELD OF PCPN CONTINUES TO SURGE NWD ASSOCD WITH THE WARM CONVEYOR AHEAD OF THE NM UPPER LOW. WHILE A DRY SLOT BEGINS TO ENCROACH ON SWRN/CNTRL KS THROUGH MID-MORNING...DEVELOPMENT OF LIGHT-MDT RAIN WILL LIKELY CONTINUE OVER NCNTRL KS INTO CNTRL NEB COINCIDENT WITH LOW-LEVEL FRONTOGENESIS. SFC FREEZING LINE WILL LIKELY CREEP NWWD THROUGH LATE MORNING AS LOW-LEVEL WARM/MOIST ADVECTION CONTINUES. BUT...AREAS NW OF A KOFK-KGRI-KHLC LINE WILL HAVE HIGH PROBABILITIES OF REMAINING AOB FREEZING THROUGH THE MORNING. COLDEST SFC TEMPERATURES WILL REMAIN OVER CNTRL NEB. RUC FORECAST SOUNDINGS SUGGEST THAT A WARM NOSE CENTERED JUST ABOVE H8 OF 4-6 DEG C WILL REMAIN IN PLACE THROUGH LATE MORNING. LATEST SREF SHOWS HIGH PROBABILITIES FOR A FREEZING RAIN EVENT ACROSS ESPECIALLY CNTRL NEB THROUGH 18Z AT LEAST. AS STRONGER QVEC CONVERGENCE APPROACHES THE REGION NEAR 18Z...PRIND THAT THE COLUMN WILL BEGIN TO COOL SUFFICIENTLY FOR MORE OF A SLEET AND/OR SNOW PROFILE ACROSS WRN PORTIONS OF THE MCD AREA. THE HEAVIER SNOWFALL WILL BE LOCATED FARTHER WEST...SEE MCD #2284 FOR FURTHER DETAILS. ..RACY.. 12/20/2006 ...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...OAX...GID...LBF...GLD... 39490055 40110074 40490090 40700097 40980119 41240151 41850140 42410026 42789855 42709774 42289742 41839742 41019817 40529859 39979912 39599953 39280001 WWWW From mcd at goshenarc.org Wed Dec 20 17:44:14 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 12:44:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201745 SWOMCD SPC MCD 201744 COZ000-NMZ000-202345- MESOSCALE DISCUSSION 2286 NWS STORM PREDICTION CENTER NORMAN OK 1144 AM CST WED DEC 20 2006 AREAS AFFECTED...SE CO...ECNTRL CO...FAR NE NM CONCERNING...BLIZZARD VALID 201744Z - 202345Z HEAVY SNOW WILL CONTINUE ACROSS SE CO...ECNTRL CO AND FAR NE NM THIS AFTERNOON INTO THIS EVENING. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE LIKELY ESPECIALLY IN THE HIGHER TERRAIN. BLIZZARD CONDITIONS WILL ACCOMPANY THE HEAVY SNOW ESPECIALLY NEAR AND IN THE HIGHER TERRAIN. LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW OVER NE NM WITH A DEFORMATION ZONE LOCATED FROM JUST NORTHWEST OF THE LOW CENTER NEAR RATON NM EXTENDING NWD TO EAST OF PUEBLO CO. AN INVERTED TROUGH IS LOCATED ALONG THIS LINE WHERE HEAVY SNOWFALL IS ONGOING AND SHOULD PERSIST INTO THE EVENING. SEVERAL FACTORS ARE ENHANCING SNOWFALL RATES IN SE CO AND ECNTRL CO. FORECAST SOUNDINGS SHOW STEEP MID-LEVEL LAPSE RATES IN PLACE AND THE GRANADA CO PROFILER SHOWS BACKED ELY FLOW FROM ABOVE THE SFC TO NEAR 2 KM AGL. THIS ALONG WITH STRONG FRONTOGENETICAL FORCING ESPECIALLY IN THE FOOTHILLS OF SE CO AND IN THE HIGHER TERRAIN NEAR THE NM-CO STATE-LINE WILL ENHANCE SNOWFALL RATES OVER THE NEXT 3 TO 6 HOURS. IN ADDITION...OBJECTIVE ANALYSIS SHOWS 700 MB FLOW INCREASING ACROSS SE CO AND ECNTRL CO AND RESULTANT WINDS NEAR THE SFC SHOULD REMAIN STRONG OR INCREASE SLIGHTLY THIS AFTERNOON. AS A RESULT...HEAVY SNOW ALONG WITH BLIZZARD CONDITIONS ESPECIALLY NEAR THE FOOTHILLS WILL PERSIST. SNOWFALL RATES MAY DECREASE SOME THIS EVENING ESPECIALLY IN THE LOWER ELEVATIONS AS THE UPPER-SYSTEM BEGINS TO PULL AWAY FROM THE REGION. ..BROYLES.. 12/20/2006 ...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...GLD...PUB...BOU...ABQ... 36760363 36740469 37290533 37990555 38550546 39690519 39950418 39970354 39830316 39080252 37850258 37070284  From mcd at goshenarc.org Wed Dec 20 18:48:56 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 13:48:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201849 SWOMCD SPC MCD 201849 NEZ000-SDZ000-COZ000-WYZ000-210045- MESOSCALE DISCUSSION 2287 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST WED DEC 20 2006 AREAS AFFECTED...SERN WY...WRN AND NCENTRAL NEB...SCENTRAL SD CONCERNING...WINTER MIXED PRECIPITATION VALID 201849Z - 210045Z HEAVY SNOW WITH HRLY RATES OVER 1 INCH COMBINED WITH STRONG NLY WINDS /SUPPORTING BLIZZARD CONDITIONS/ WILL CONTINUE TO DEVELOP NWD OVER SERN WY AND THE NEB PANHANDLE THROUGH 21Z. ACROSS NCENTRAL NEB/SCENTRAL SD...FREEZING RAIN WILL INITIALLY BE THE PRIMARY P-TYPE THROUGH 21Z. A CHANGEOVER TO SLEET AND/OR HEAVY SNOW IS ANTICIPATED TO DEVELOP EWD ACROSS WRN/NCENTRAL NEB AND SCENTRAL SD IN THE 21-00Z PERIOD. RECENT MBW AND MRR PROFILERS INDICATE INCREASING WIND FIELDS IN THE 2-4 KM LAYER. MID LEVEL WINDS HAVE ALSO RECENTLY BACKED AT THE MRR PROFILER FURTHER INDICATING A RESPONSE TO STRONG FRONTOGENESIS OCCURRING OVER SERN WY AND THE NEB PANHANDLE. AS THE MID LEVEL LOW OVER NERN NM CONTINUES TO LIFT SLOWLY NEWD INTO WRN KS THROUGH THE AFTERNOON...THE MID LEVEL DRYSLOT WILL CONTINUE TO MOVE INTO NERN CO. THIS WILL FURTHER AID IN MAINTAINING STRONG FRONTOGENETIC FORCING SUPPORTING HEAVY SNOWFALL DEVELOPMENT. MODERATE SFC PRESSURE FALLS WILL CONTINUE TO OCCUR OVER NWRN KS AND SWRN NEB IN ADVANCE OF THE UPPER LOW ASSOCIATED WITH STRONG UPPER TROPOSPHERIC WARM ADVECTION. THIS WILL SUPPORT AN INCREASE IN SFC WINDS OVER MUCH OF WRN/CENTRAL NEB...SERN WY AND EVENTUALLY SCENTRAL SD TOWARD 00Z. SHALLOW SUBFREEZING AIR WILL CONTINUE TO EXIST OVER PORTIONS OF NCENTRAL NEB AND SCENTRAL SD...SUPPORTED BY LOW LEVEL DRY AIR ADVECTION. AS MODERATE LOW LEVEL WARM ADVECTION CONTINUES... FREEZING RAIN WILL BE THE PRIMARY PTYPE IN THIS AREA FOR THE NEXT SEVERAL HRS BEFORE A CHANGEOVER TO SLEET OCCURS AFTER 21Z AS THE MID LEVEL SYSTEM GRADUALLY SHIFTS NEWD AND LOW LEVEL COOLING OCCURS. IN ADDITION..MODERATE RAINFALL FALLING ACROSS PORTIONS OF WRN NEB SHOULD CHANGEOVER TO HVY SNOW AFTER 21Z. THE ANTICIPATED HVY SNOW/RAIN LINE SHOULD EXTEND FROM ANW TO LBF TO MCK BY 00Z. ..CROSBIE.. 12/20/2006 ...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...ABR...LBF...UNR...BOU...CYS... 43669957 42910243 42150533 40840505 41040252 41390081 42939953  From mcd at goshenarc.org Thu Dec 21 00:21:37 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 19:21:37 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210022 SWOMCD SPC MCD 210022 NEZ000-KSZ000-COZ000-WYZ000-210615- MESOSCALE DISCUSSION 2288 NWS STORM PREDICTION CENTER NORMAN OK 0622 PM CST WED DEC 20 2006 AREAS AFFECTED...NERN CO / FAR SERN WY / SWRN NEB CONCERNING...BLIZZARD VALID 210022Z - 210615Z PERIODS OF HEAVY SNOW WITH HOURLY RATES OF UP TO 1-1.5 INCHES ARE EXPECTED TO CONTINUE THROUGH 21/06Z. WHEN COUPLED WITH NLY/NELY WINDS OF 30-40 MPH...BLIZZARD OR NEAR BLIZZARD CONDITIONS WILL CONTINUE FROM THE CHEYENNE RIDGE AND CO FRONT RANGE EWD INTO THE HIGH PLAINS. LATE AFTERNOON/EARLY EVENING WATER VAPOR IMAGERY INDICATES DEEP UPPER LOW BEGINNING TO DEVELOP MORE NEWD INTO SWRN KS WITH STRONGEST HEIGHT FALLS SHIFTING THROUGH CNTRL/ERN KS AND SRN NEB. INITIAL DEFORMATION BAND OVER MUCH OF NEB WWD ACROSS ERN CO HAS WEAKENED THIS AFTERNOON...PERHAPS IN ASSOCIATION WITH NWD DEVELOPMENT OF SYSTEM DRY SLOT ALONG ERN PERIPHERY OF MID-LEVEL CIRCULATION. HOWEVER...IR CLOUD TOP TEMPERATURES AND RADAR REFLECTIVITY DATA SHOW THE INITIAL STAGES OF SECONDARY DEFORMATION ZONE DEVELOPMENT FROM NEAR AKO EWD THROUGH IML TO NEAR BBW. WATER VAPOR IMAGERY AND SHORT TERM GUIDANCE SUGGEST THAT THIS EVOLUTION IS LIKELY IN RESPONSE TO STRONG VORTICITY MAXIMUM ROTATING AROUND UPPER LOW. AS THIS VORTICITY MAXIMUM CONTINUES N AND THEN NW OF UPPER TONIGHT...EXPECT THAT PRECIPITATION SHIELD WILL EXPAND/INTENSIFY FROM NERN CO EWD INTO CNTRL NEB WITH HOURLY SNOW RATES APPROACHING 1-1.5 INCHES. 21/00Z DEN SOUNDING INDICATES A SHALLOW LAYER /BETWEEN 550-500 MB/ OF CONDITIONALLY UNSTABLE LAPSE RATES WITH ISOLATED LIGHTNING STRIKES OBSERVED ALONG THE FRONT RANGE THIS AFTERNOON AND EARLY EVENING. ANY EMBEDDED CONVECTIVE ELEMENTS WILL BE CAPABLE OF SNOW RATES APPROACHING TWO INCHES/HOUR. IN ADDITION TO THE HEAVY SNOW...STRONG NLY/NELY WINDS OF 25-35 MPH GUSTING TO 40-45 MPH ARE RESULTING IN BLIZZARD OR NEAR BLIZZARD CONDITIONS ACROSS THE REGION...A TREND WHICH SHOULD CONTINUE THROUGH 21/06Z. EXPECT SNOW RATES TO BEGIN TO DIMINISH ALONG THE FRONT RANGE THEREAFTER. ..MEAD.. 12/21/2006 ...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...LBF...GLD...PUB...BOU...CYS... 39240473 40540506 41410494 42080420 42090304 41200197 40710160 39730172 38980230 38710372  From mcd at goshenarc.org Thu Dec 21 00:56:58 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 19:56:58 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210057 SWOMCD SPC MCD 210057 NEZ000-SDZ000-COZ000-210700- MESOSCALE DISCUSSION 2289 NWS STORM PREDICTION CENTER NORMAN OK 0657 PM CST WED DEC 20 2006 AREAS AFFECTED...CNTRL INTO N-CNTRL NEB CONCERNING...HEAVY SNOW VALID 210057Z - 210700Z HEAVY SNOW WITH HOURLY RATES OF 1-1.5 INCHES IS FORECAST TO BECOME INCREASING COMMON ACROSS DISCUSSION AREA THROUGH 21/06Z. EMBEDDED POCKETS OF FREEZING RAIN WILL ALSO REMAIN POSSIBLE...MAINLY FROM BBW NEWD THROUGH BUB AND ONL. AS MENTIONED IN MCD 2288...A SECONDARY DEFORMATION BAND/PRECIPITATION SHIELD APPEARS TO BE DEVELOPING FROM NEAR AKO ENEWD THROUGH LBF/BBW WITH SOME REINTENSIFICATION NOTED WITHIN INITIAL BAND OVER CHERRY COUNTY. THIS ENHANCEMENT IN CLOUDS/PRECIPITATION APPEARS TO BE ARISING FROM STRONG VORTICITY MAXIMUM ROTATING NWD AROUND UPPER LOW OVER SWRN CO...COUPLED WITH LOW-LEVEL WAA OCCURRING TO THE N OF SURFACE FRONTAL OCCLUSION. CURRENTLY...SURFACE OBSERVATIONS INDICATE A NARROW CORRIDOR OF FREEZING RAIN FROM LBF/BBW NEWD TOWARD ANW/ONL...WITH A CHANGE OVER TO SNOW FORECAST THIS EVENING FROM W-E AS COLD AIR DEEPENS ON BACKSIDE OF SYNOPTIC SYSTEM. PERIODS OF FREEZING RAIN WITH HOURLY RATES OF .01 TO .05 INCHES MAY PERSIST THROUGH 21/06Z FROM BBW TO ONL. OTHERWISE...EXPECT THAT THE STRENGTHENING LARGE SCALE FORCING AHEAD OF VORTICITY MAXIMUM WILL SUPPORT AN INCREASE IN SNOW COVERAGE AND INTENSITY IN A BAND FROM IML AND SNY EWD THROUGH LBF/MHN/ANW AREAS WITH SNOW RATES APPROACHING 1-1.5 INCHES THROUGH MIDNIGHT CST. ..MEAD.. 12/21/2006 ...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...GID...LBF...UNR...BOU...CYS... 41580285 42310279 42740218 42990115 43000044 42979885 42509836 41559842 41119930 40910063 40930230 41220255  From mcd at goshenarc.org Sun Dec 31 19:45:19 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 14:45:19 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 311949 SWOMCD SPC MCD 311949 GAZ000-FLZ000-312145- MESOSCALE DISCUSSION 2342 NWS STORM PREDICTION CENTER NORMAN OK 0149 PM CST SUN DEC 31 2006 AREAS AFFECTED...SRN GA THROUGH NRN FL CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 311949Z - 312145Z LINE OF STORMS MOVING E THROUGH SRN GA AND THE ERN FL PANHANDLE MAY BE CAPABLE OF PRODUCING MAINLY ISOLATED DAMAGING WIND ALONG WITH AN OUTSIDE CHANCE OF A BRIEF TORNADO THROUGH EARLY EVENING. PRE-FRONTAL LINE OF STORMS FROM SWRN GA THROUGH THE ERN FL PANHANDLE IS MOVING E AT AROUND 15 TO 20 KT. ACTIVITY IS DEVELOPING ALONG WARM CONVEYOR BELT WITHIN ZONE OF 850 MB CONFLUENCE. WARMING AND MOISTENING OF THE BOUNDARY LAYER JUST DOWNSTREAM FROM THE LINE HAS CONTRIBUTED TO SOME DESTABILIZATION. HOWEVER...MLCAPE REMAINS AOB 500 J/KG DUE TO MODEST MID LEVEL LAPSE RATES. RECENT VWP DATA STILL SHOW SUFFICIENT VERTICAL WIND PROFILES FOR ORGANIZED STORM STRUCTURES WITHIN THE LINE WITH 0-1 KM STORM RELATIVE HELICITY AROUND 200 M2/S2 AND DEEP LAYER SHEAR ON THE ORDER OF 35 KT. HOWEVER...LIMITING FACTORS WILL BE WEAK INSTABILITY AND A TENDENCY FOR THE BOUNDARY LAYER FLOW TO GRADUALLY VEER AND WEAKEN WITH TIME AS STRONGER FORCING ASSOCIATED WITH UPPER JET LIFTS TOWARD THE TN AND OH VALLEYS. ..DIAL.. 12/31/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...JAX...FFC...TAE... 32058167 30738202 30018310 30148424 31118405 32438348 WWWW From mcd at goshenarc.org Sun Dec 31 20:56:13 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 15:56:13 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 312100 SWOMCD SPC MCD 312100 GAZ000-ALZ000-312330- MESOSCALE DISCUSSION 2343 NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CST SUN DEC 31 2006 AREAS AFFECTED...EXTREME ERN AL...NWRN GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 312100Z - 312330Z THERE IS A CONDITIONAL THREAT FOR AN ISOLATED TORNADO ACROSS EXTREME NERN AL INTO NRN/WRN GA THIS AFTERNOON. 20Z SURFACE ANALYSIS SHOWS COLD FRONT NOW MOVING ACROSS E-CNTRL AL...WITH A WARM FRONT DRAPED ACROSS NRN GA INTO CNTRL SC. SOUTH OF THIS BOUNDARY...AN INITIAL SQUALL LINE CONTINUES TO MOVE EWD ACROSS CNTRL/SRN GA INTO NRN FL. MEANWHILE...THE AIR MASS IS ATTEMPTING TO RECOVER W OF THE SQUALL LINE WITH TEMPERATURES INTO THE LOWER 70S OVER ERN AL/SWRN GA...AND DEWPOINTS IN THE MID 60S. SMALL STORM CELLS ARE CURRENTLY DEVELOPING OVER ERN AL ALONG THE FRONT...AIDED BY UPPER LEVEL DIVERGENCE. INSTABILITY LEVELS ARE CURRENTLY LOW...BUT MAY INCREASE A BIT WITH SSWLY 850 MB FLOW AHEAD OF THE WIND SHIFT. SHEAR PROFILES ARE QUITE STRONG AROUND ATLANTA WITH 200-300 M2/S2 EFFECTIVE SRH SOUTH OF THE WARM FRONT...AND INCREASED MID LEVEL JET SPEEDS NOTED RECENTLY ON VWP. GIVEN CONTINUED FORCING COMING OUT OF AL...PRESENCE OF WARM FRONT...AND SURFACE BASED INSTABILITY...AN ISOLATED STRONG/SEVERE STORM WILL BE POSSIBLE WITH THE THREAT OF A TORNADO AND/OR LOCALLY DAMAGING WIND GUST. ..JEWELL.. 12/31/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GSP...FFC...BMX...HUN... 32638589 33298582 34138576 34768571 34888515 34648383 34218315 33818319 33408352 33188371 32948403 32728433 32638492 32558558  From mcd at goshenarc.org Fri Dec 1 04:21:41 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Thu, 30 Nov 2006 23:21:41 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010423 SWOMCD SPC MCD 010423 ALZ000-010600- MESOSCALE DISCUSSION 2252 NWS STORM PREDICTION CENTER NORMAN OK 1023 PM CST THU NOV 30 2006 AREAS AFFECTED...WCNTRL AL CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010423Z - 010600Z AN ISOLATED TORNADO THREAT SHOULD CONTINUE FOR ANOTHER HOUR OR SO ACROSS PARTS OF WCNTRL AL. HOWEVER...THE THREAT SHOULD REMAIN TOO ISOLATED TO WARRANT A TORNADO WATCH LATE THIS EVENING. A LINE OF LOW-TOPPED CONVECTION IS CURRENTLY LOCATED ACROSS WRN AL WITH A LINE-ECHO WAVE PATTERN SHOWING UP SOUTH OF TUSCALOOSA AL. THE LINE IS LIKELY LOCATED ALONG A PRE-FRONTAL TROUGH AXIS AND IS MOST LIKELY ASSOCIATED WITH A SUBTLE LEAD SHORTWAVE-TROUGH AHEAD OF THE MAIN UPPER-LOW. SFC DEWPOINTS IN THE MID 60S F AHEAD OF THE LINE AND STRONG VERTICAL SHEAR MAY BE SUFFICIENT TO CONTINUE AN ISOLATED SEVERE THREAT OVER THE NEXT HOUR. ALTHOUGH INSTABILITY IS WEAK /100-300 J/KG BELOW 600 MB WITH MOIST ADIABATIC LAPSE RATES/...FORECAST SOUNDINGS SHOW STRONG SPEED SHEAR AND DIRECTIONAL SHEAR BELOW 3 KM. THIS SUGGESTS THE WIND PROFILE SHOULD BE FAVORABLE FOR A BRIEF TORNADO THREAT WITH ROTATING CELLS IN THE CONVECTIVE LINE. ALTHOUGH LESS OF A THREAT...A FEW STRONG WIND GUSTS MAY ALSO OCCUR WITH THE BETTER ORGANIZED STORMS. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...HUN... 32628714 32858754 33138782 33928765 34018680 33668623 32868631  From mcd at goshenarc.org Fri Dec 1 05:44:02 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 00:44:02 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010546 SWOMCD SPC MCD 010545 KYZ000-TNZ000-GAZ000-ALZ000-010715- MESOSCALE DISCUSSION 2253 NWS STORM PREDICTION CENTER NORMAN OK 1145 PM CST THU NOV 30 2006 AREAS AFFECTED...SRN KY...MIDDLE TN...NE AL CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 010545Z - 010715Z AN ISOLATED SEVERE THREAT MAY DEVELOP OVER THE NEXT 1 TO 3 HOURS ACROSS NE AL...MIDDLE TN AND SRN KY. A WW IS NOT ANTICIPATED BUT THE LINE OF CONVECTION WILL STILL BE MONITORED IN CASE INTENSIFICATION OCCURS. LATEST SFC ANALYSIS SHOWS A DEEPENING LOW SOUTH OF PADUCAH KY WITH A COLD FRONT EXTENDING SWD FROM THE LOW AND A NEARLY STATIONARY FRONT EXTENDING NEWD INTO THE UPPER OH VALLEY. A PREFRONTAL TROUGH LIKELY EXISTS SSEWD ACROSS THE WARM SECTOR WHERE STRONG PRESSURE FALLS ARE OCCURRING ATTM. A NARROW LINE OF CONVECTION IS CURRENTLY ONGOING ALONG THE PRESSURE TROUGH. ALTHOUGH INSTABILITY IS VERY WEAK AHEAD OF THE LINE...SHEAR PROFILES ARE STRONG (0-6 KM SHEAR OF 70KT AND 0-1 KM SHEAR AROUND 40 KT) WHICH COMBINED WITH INCREASING LARGE-SCALE ASCENT AHEAD OF AN APPROACHING UPPER-LOW MAY RESULT IN INTENSIFICATION OF THE LINE TONIGHT. ANY SEVERE THREAT THAT ACCOMPANIES THE LINE SHOULD REMAIN ISOLATED. A BRIEF TORNADO AND/OR STRONG WIND GUSTS MAY OCCUR WITH ROTATING CELLS AS THE LINE CROSS THE REGION OVERNIGHT. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MRX...JKL...FFC...LMK...OHX...BMX...HUN... 33668522 33548670 35098673 36208654 36938609 36768472 35388475  From mcd at goshenarc.org Fri Dec 1 05:48:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 00:48:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010550 SWOMCD SPC MCD 010550 ILZ000-WIZ000-MOZ000-IAZ000-KSZ000-OKZ000-011015- MESOSCALE DISCUSSION 2254 NWS STORM PREDICTION CENTER NORMAN OK 1150 PM CST THU NOV 30 2006 AREAS AFFECTED...EXTREME SERN KS...MUCH OF NRN/CNTRL MO...NRN/W-CNTRL IL...EXTREME SERN IA CONCERNING...HEAVY SNOW VALID 010550Z - 011015Z MODERATE TO HEAVY SNOW WITH LOCAL RATES UP TO 3 IN/HR WILL SPREAD NEWD FROM SERN KS/NERN OK/WRN MO ACROSS NERN MO INTO W-CNTRL AND NRN IL BY 12Z. AS THE SURFACE LOW ACROSS FAR WRN KY LIFTS NORTH AND DEEPENS...GRADIENT WINDS WILL INCREASE...AIDING IN BLOWING/DRIFTING SNOW AS WELL. POWERFUL UPPER LOW CENTERED AT 500 MB NEAR FAYETTEVILLE AR WILL TRACK NEWD TO NEAR SPRINGFIELD IL BY 12Z. DEFORMATION BAND OF MODERATE TO HEAVY SNOW WILL CONTINUE TO THE NW OF MID-LEVEL DRY SLOT...PARALLEL TO TRACK OF UPPER LOW. 00Z/RUC AND 03Z/NAM FORECAST SOUNDINGS INDICATE LARGE DENDRITIC GROWTH ZONES /IN EXCESS OF 100 MB/ WILL OCCUR ACROSS MUCH OF CNTRL MO FROM AROUND 50 N OF SGF TO COU TO UIN THROUGH 10Z. ISOLATED CG STRIKES HAVE OCCURRED WITHIN THIS ZONE...LIKELY SUPPORTING VERY HEAVY BURSTS OF SNOWFALL AT TIMES FROM 2 TO 3 IN/HR. FURTHER NE...VERY STRONG UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL OCCUR TO THE N/NW OF A 100+ KT 500 MB JET CURLING E/SE OF UPPER LOW. A MIX OF SLEET/FREEZING RAIN/SNOW ACROSS MUCH OF WRN/NRN IL WILL GRADUALLY TURN TO ALL SNOW FROM W TO E AS LOW-LEVEL TEMPS SLOWLY COOL WITH TIME. SNOWFALL RATES OF 1 TO 2 IN/HR WILL BE LIKELY IN THE 09-12Z TIME FRAME FROM THE NRN STL METRO/UIN AREA NEWD TOWARDS PIA AND THE WRN CHICAGO METRO AREA. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LOT...ILX...MKX...LSX...DVN...SGF...EAX...TSA...TOP...ICT... 38619053 37489215 36869405 36849542 37989516 39539357 40909171 41839019 42208951 42558832 41648761 40868811 40068899 WWWW From mcd at goshenarc.org Fri Dec 1 06:40:05 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 01:40:05 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010642 SWOMCD SPC MCD 010641 MIZ000-011045- MESOSCALE DISCUSSION 2255 NWS STORM PREDICTION CENTER NORMAN OK 1241 AM CST FRI DEC 01 2006 AREAS AFFECTED...SRN LOWER MI CONCERNING...WINTER MIXED PRECIPITATION VALID 010641Z - 011045Z FREEZING RAIN MIXED WITH SLEET WILL LIKELY INTENSIFY OVERNIGHT. ICE ACCUMULATION RATES SHOULD EXCEED 0.10 IN/HR. TEMPERATURES HAVE SLOWLY FALLEN TO SLIGHTLY BELOW FREEZING ACROSS MUCH OF SRN LOWER MI OVER THE PAST FEW HOURS. 00Z DTX/06Z ILX OBSERVED SOUNDINGS INDICATE A WARM NOSE OF SLIGHTLY ABOVE FREEZING TEMPERATURES CENTERED AROUND 850 MB. 00Z NAM/GFS AND 03Z RUC GUIDANCE INDICATE THIS WARM LAYER WILL BE MAINTAINED THROUGH 12Z...TO THE NE OF AN APPROACHING 850 MB LOW TRACKING FROM SRN MO INTO E-CNTRL IL. INTENSE LOW/MID-LEVEL ISENTROPIC LIFT AND WARM THETA-E ADVECTION IS EXPECTED TO CONTINUE SUPPORTING PRECIPITATION GENERATION. IN ADDITION...UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL INCREASE...ESPECIALLY TOWARDS 12Z AS A POTENT 100+ KT 500 MB JET CURLS EWD OF UPPER LOW APPROACHING SRN IL. CONVECTIVE SHOWERS OF FREEZING RAIN/SLEET WILL LIKELY OCCUR...WITH ICE ACCUMULATIONS IN EXCESS OF 0.10 IN/HR POSSIBLE. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...IWX...GRR... 42458390 42188486 42078558 42078616 42228639 42868617 43068541 43308466 43298389 42798331  From mcd at goshenarc.org Fri Dec 1 07:21:44 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 02:21:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010723 SWOMCD SPC MCD 010723 GAZ000-FLZ000-ALZ000-010830- MESOSCALE DISCUSSION 2256 NWS STORM PREDICTION CENTER NORMAN OK 0123 AM CST FRI DEC 01 2006 AREAS AFFECTED...SERN AL/PARTS OF CENTRAL-ERN FL PANHANDLE/SWRN GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 010723Z - 010830Z ISOLATED STRONG WIND GUSTS WILL BE POSSIBLE THROUGH 09-10Z AS LOW- TOPPED CONVECTIVE LINE MOVES QUICKLY NEWD ACROSS THE CENTRAL-ERN FL PANHANDLE AND SERN AL INTO SWRN GA. REGIONAL RADARS SHOWED A BOW SHAPED CONVECTIVE LINE EXTENDING FROM SERN AL /GENEVA COUNTY/ TO BAY COUNTY FL. THIS LINE WAS MOVING NEWD AT 40 KT. 06Z RUC POINT FORECAST SOUNDINGS SUGGEST AIR MASS IMMEDIATELY DOWNSTREAM INTO SERN AL/CENTRAL FL PANHANDLE AND SWRN GA IS MARGINALLY UNSTABLE /MUCAPE 100-200 J/KG/ WITH THIS INSTABILITY CONFINED GENERALLY BELOW 600 MB. GIVEN SPEED OF THE CONVECTIVE LINE WITH AREA VADS INDICATING DEEP SWLY WINDS MAINTAINING LINEAR STRUCTURE WITH 40 KT JUST OFF THE SURFACE...ISOLATED STRONG WIND GUSTS WILL BE POSSIBLE WITHIN WEAKLY UNSTABLE AIR MASS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX... 30108583 30478568 30808577 30988592 31338569 31678538 31938492 31868424 31008404 30498423 30138456 29858534  From mcd at goshenarc.org Fri Dec 1 08:09:56 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 03:09:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 010811 SWOMCD SPC MCD 010811 OHZ000-KYZ000-INZ000-010915- MESOSCALE DISCUSSION 2257 NWS STORM PREDICTION CENTER NORMAN OK 0211 AM CST FRI DEC 01 2006 AREAS AFFECTED...CENTRAL AND PARTS OF ERN KY/SERN IND/SWRN OH CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 010811Z - 010915Z TORNADO WATCH IS LIKELY FOR CENTRAL AND PARTS OF ERN KY...SERN IND...AND SWRN OH. SURFACE LOW...NOW LOCATED ALONG OH RIVER NEAR EVV...WILL CONTINUE TO INTENSIFY AS STRONG UPPER LOW OVER SERN MO UNDERGOES FURTHER DEEPENING AS IT TRACKS NEWD INTO IL BY 12Z. WARM FRONT EXTENDING NEWD FROM LOW TO JUST S OF CVG TO JUST S OF CMH IS EXPECTED TO RETREAT SLOWLY NWD AS WARM SECTOR CONTINUES TO MODIFY WITH SURFACE DEWPOINTS RISING THROUGH THE UPPER 50S AND LOWER 60S ACROSS CENTRAL KY TO SERN IND/SWRN OH. DESPITE WEAK INSTABILITY AND LOW-TOPPED LINE OF CONVECTION ALONG COLD FRONT...INCREASING DEEP LAYER SHEAR WITH BACKED LOW LEVEL WINDS SUGGESTS POTENTIAL FOR ISOLATED TORNADOES...IN ADDITION TO STRONG/DAMAGING WIND GUSTS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...RLX...JKL...ILN...LMK...IND... 36758594 38028593 39038559 39698458 39758346 38978311 37358356 36618451 36678593 WWWW From mcd at goshenarc.org Fri Dec 1 10:14:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 05:14:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011015 SWOMCD SPC MCD 011014 OHZ000-KYZ000-TNZ000-INZ000-011115- MESOSCALE DISCUSSION 2258 NWS STORM PREDICTION CENTER NORMAN OK 0414 AM CST FRI DEC 01 2006 AREAS AFFECTED...SERN IND/CENTRAL KY/SWRN OH AND INTO PARTS OF WRN AND CENTRAL OH CONCERNING...SEVERE THUNDERSTORM WATCH 872... VALID 011014Z - 011115Z WW BEING CONSIDERED FOR PARTS OF WRN AND CENTRAL OH TO THE N AND NE OF WW 872. SEVERE WEATHER THREAT CONTINUES ACROSS WW 872. LATEST SURFACE ANALYSES INDICATED STRONGEST AREA OF PRESSURE FALLS OVER EAST CENTRAL IL/WRN IND...WITH A SECONDARY AREA OF PRESSURE FALLS OVER SWRN OH. THESE TRENDS ARE INDICATIVE OF OBSERVED SECONDARY LOW CONTINUING TO DEVELOP OVER SERN IND...WHILE PRIMARY LOW OCCLUDES NWD INTO ERN IL. SURFACE OBSERVATIONS SHOWED WARM SECTOR IS DEVELOPING NWD ACROSS SWRN-CENTRAL OH AS THE WARM FRONT MOVES NWD...THUS SUPPORTING POTENTIAL FOR NEW WW AS AIR MASS SHOULD CONTINUE TO DESTABILIZE N OF WW 872. REGIONAL RADARS INDICATED A LINE OF LOW-TOPPED CONVECTION EXTENDING FROM FRANKLIN COUNTY IN SERN IND SWD ALONG THE COLD FRONT INTO CENTRAL KY...WITH THIS LINE MOVING NEWD AT 50 KT. GIVEN THIS SPEED COMBINED WITH 55-65 KT SSWLY WINDS JUST OFF THE SURFACE PER AREA VADS WITHIN WW 872...SUGGESTS CONTINUED POTENTIAL FOR DAMAGING WINDS WITH THE LINE. IN ADDITION...ISOLATED TORNADO THREAT REMAINS AS BACKED SURFACE WINDS ARE RESULTING IN STRONG LOW LEVEL SHEAR... ESPECIALLY IN VICINITY OF SURFACE LOW AND ENEWD ALONG SURFACE WARM FRONT. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PBZ...RLX...CLE...MRX...JKL...ILN...LMK...IWX...OHX...IND... 40408154 39508223 38018307 37088374 36588476 36578596 37458566 38358599 39158548 39648496 39948480 40638483 40728405 40768294 41008154  From mcd at goshenarc.org Fri Dec 1 12:40:16 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 07:40:16 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011242 SWOMCD SPC MCD 011242 MIZ000-WIZ000-ILZ000-011715- MESOSCALE DISCUSSION 2259 NWS STORM PREDICTION CENTER NORMAN OK 0642 AM CST FRI DEC 01 2006 AREAS AFFECTED...NRN IL...FAR SERN WI...NRN LOWER MI CONCERNING...HEAVY SNOW VALID 011242Z - 011715Z MODERATE TO HEAVY SNOW WILL QUICKLY EXPAND NEWD THROUGH 18Z AS POTENT UPPER LOW EJECTS RAPIDLY NEWD. SNOWFALL RATES OF 1 TO 2 IN/HR WILL BE COMMON...WITH THE HEAVIEST BAND OF SNOW FROM PIA NEWD TO RFD/MKE MOVING ACROSS LK MI INTO W-CNTRL LOWER MI. AN INTENSE PRESSURE GRADIENT WILL LEAD TO SUBSTANTIAL BLOWING AND DRIFTING SNOW. W/V IMAGERY DEPICTS THE UPPER LOW CENTERED NEAR DECATUR IL HAS ACCELERATED NEWD OVER THE PAST SEVERAL HOURS. PRIMARY SURFACE CYCLONE NEAR CHAMPAIGN IL HAS RAPIDLY DEEPENED BY 9 MB OVER THE PAST 8 HOURS. 06Z NAM/GFS AND 09Z RUC GUIDANCE ARE VERY SIMILAR IN TRACKING THE 500 MB LOW TO NEAR DETROIT MI BY 18Z. DEFORMATION BAND OF MODERATE TO HEAVY SNOW WILL PARALLEL THE TRACK OF THIS LOW FROM NRN/CNTRL IL AND FAR SERN WI NEWD ACROSS MUCH OF NRN/WRN LOWER MI. SUBSTANTIAL VERTICAL MOTION WITHIN THE SATURATED DENDRITIC GROWTH ZONE NW OF PUNCHING DRY SLOT...WILL CONTINUE TO PRODUCE SNOWFALL RATES AROUND 1 IN/HR. ISOLATED CG LIGHTNING STRIKES WILL ALSO LEAD TO CONVECTIVE BURSTS OF HEAVY SNOW OF AROUND 2 IN/HR. ACROSS NRN LOWER MI...12Z APX OBSERVED SOUNDING SHOWS A SUBSTANTIAL DRY POCKET REMAINS BETWEEN 700 TO 850 MB. HOWEVER...STRONG LOW-LEVEL ISENTROPIC LIFT AND FRONTOGENETICAL FORCING WILL QUICKLY SATURATE THE COLUMN. PRONOUNCED UPPER-LEVEL DIVERGENCE/DIFFLUENCE WILL OCCUR AS 120 KT 500 MB JET SPREADS NEWD ACROSS OH/LK ERIE...AIDING IN HEAVY SNOW DEVELOPMENT AFTER 15Z. ..GRAMS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...APX...GRR...GRB...LOT...ILX...MKX...DVN... 45728401 45088301 43908326 43168525 42568633 41848758 41308825 40928857 40108934 40038977 40329022 40949024 41988973 43018879 43968766 45088591  From mcd at goshenarc.org Fri Dec 1 13:43:26 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 08:43:26 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011345 SWOMCD SPC MCD 011344 PAZ000-WVZ000-OHZ000-011445- MESOSCALE DISCUSSION 2260 NWS STORM PREDICTION CENTER NORMAN OK 0744 AM CST FRI DEC 01 2006 AREAS AFFECTED...ERN OH/WRN PA/FAR NRN WV PANHANDLE CONCERNING...SEVERE THUNDERSTORM WATCH 873... VALID 011344Z - 011445Z ISOLATED THREAT FOR DAMAGING WINDS WITH LOW-TOPPED CONVECTION ALONG FAST MOVING COLD FRONT TO CONTINUE THIS MORNING. REGIONAL RADARS INDICATED LOW-TOPPED LINE OF CONVECTION CONTINUED TO ACCOMPANY THE STRONG COLD FRONT MOVING ENEWD AT 40 KT AT THIS TIME INTO ERN OH AND WRN WV. VADS AT CLE AND CRW...JUST AHEAD OF THE CONVECTIVE LINE...INDICATED 45-55 KT SSWLY WINDS JUST OFF THE SURFACE. WARM FRONT HAS CONTINUED TO MOVE NWD THIS MORNING AND NOW EXTENDS ENEWD FROM SURFACE LOW OVER NORTH CENTRAL OH TO FAR NWRN AND NRN PA INTO SERN NY. WARM SECTOR AIR MASS WILL CONTINUE TO SLOWLY DESTABILIZE WITH LOW LEVEL LAPSE RATES POTENTIALLY BECOMING SUFFICIENTLY STEEP TO ALLOW STRONGER WINDS JUST OFF THE SURFACE TO MIX DOWNWARD AND PRODUCE LOCALLY STRONG DAMAGING WINDS. ..PETERS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PBZ...RLX...CLE...ILN... 39668224 40528225 41488254 41688155 41698072 41607956 41157956 40747971 40248053 39838077 39518132  From mcd at goshenarc.org Fri Dec 1 16:36:46 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 11:36:46 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011638 SWOMCD SPC MCD 011638 CTZ000-MAZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-WVZ000-011845- MESOSCALE DISCUSSION 2261 NWS STORM PREDICTION CENTER NORMAN OK 1038 AM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS PA...WRN/SRN NY...DE...ERN WV...NJ...MD...NRN/CENTRAL VA...DC. CONCERNING...SEVERE THUNDERSTORM WATCH 874... VALID 011638Z - 011845Z BROKEN BAND OF LOW-TOPPED CONVECTION -- INCLUDING SPORADIC TSTMS -- IS FCST TO CONTINUE MOVING ENEWD 40-45 KT ACROSS WW AREA...AND PERHAPS ADJACENT PORTIONS WRN NY AND WRN/CENTRAL VA. ACTIVITY CONSISTS OF SEVERAL QUASI-LINEAR SEGMENTS THAT ARE DISCRETE AT 50 DBZ REFLECTIVITY LEVELS. SEVERAL REPORTS OF DAMAGE FROM NON-TSTM GUSTS -- BUT STILL CONVECTIVE IN ORIGIN -- HAVE BEEN RECEIVED FROM WRN PA AND NRN WV WITH THIS ACTIVITY. EXPECT SVR POTENTIAL TO PERSIST EWD THROUGH WW AND ALSO EXTEND INTO PORTIONS SRN NY..ERN PA AND NJ WITHIN 3-4 HOURS. ADDITIONAL WW MAY BE REQUIRED FOR THOSE AREAS ADJACENT TO WW 874. SFC MESOANALYSIS SHOWS MAIN CYCLONE OVER WRN LE...OCCLUDED FRONT EWD ACROSS LE TO TRIPLE POINT NEAR WRN TIP NY. WARM FRONT CONTINUES EWD INVOF NY/PA BORDER THEN ENEWD ACROSS SERN NY TO JUST S ALB...THEN EXTREME SRN VT. PRIND WARM FRONT WILL LIFT SLOWLY NWD ACROSS WRN NY AND SPREAD NEUTRALLY TO MRGLLY UNSTABLE WARM SECTOR INTO ELM/BGM/ALB AND PERHAPS ITH/GFL AREAS. GIVEN STRONG STATIC STABILITY EVIDENT N OF WARM FRONT...THIS BOUNDARY SHOULD SERVE AS NRN BOUND OF SVR WIND POTENTIAL. WAA AND WEAK SFC DIABATIC HEATING E OF FRONT WILL DESTABILIZE PRE-STORM BOUNDARY LAYER SOMEWHAT...RESULTING IN PATCHY MUCAPES 100-400 J/KG...SOME OF WHICH WILL REACH INTO ICING LAYERS SUITABLE FOR LIGHTNING PRODUCTION. GIVEN INTENSITY OF KINEMATIC FIELDS JUST ABOVE SFC AND POTENTIAL FOR DOWNWARD MOMENTUM TRANSFER...DAMAGING GUST POTENTIAL WILL EXIST ALMOST ANYWHERE WITHIN THIS ACTIVITY...BUT WILL BE ENHANCED LOCALLY INVOF LEWP/BOW FORMATIONS THAT SHOULD DEVELOP WITHIN THOSE SEGMENTS. QLCS-TYPE TORNADIC SPINUP ALSO CANNOT BE RULED OUT. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OKX...ALY...PHI...BGM...AKQ...BUF...CTP...LWX...RNK...PBZ...RLX... 38228023 39687965 41687937 42357950 42417718 42687540 42937387 42667335 41797352 40457397 39837405 39427428 38957482 38757538 38047789 37927995  From mcd at goshenarc.org Fri Dec 1 17:24:49 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 12:24:49 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011726 SWOMCD SPC MCD 011726 VTZ000-NYZ000-012300- MESOSCALE DISCUSSION 2262 NWS STORM PREDICTION CENTER NORMAN OK 1126 AM CST FRI DEC 01 2006 AREAS AFFECTED...NRN VT/ FAR NRN NY CONCERNING...FREEZING RAIN VALID 011726Z - 012300Z FREEZING RAIN WITH HRLY RATES FROM 0.05 TO 0.10 INCH WILL DEVELOP AND LAST FOR THE NEXT 3-5 HRS...BEFORE CHANGING BACK OVER TO RAIN DURING THE LATE AFTERNOON. SFC ANALYSIS AND RECENT OBS INDICATE LOW LEVEL COLD ADVECTION/DRAINAGE CONTINUES ALONG THE ST LAWRENCE AND CHAMPLAIN VALLEYS WITH TEMPERATURES RECENTLY FALLING TO 32F AT BOTH PLATTSBURGH AND MASSENA. WITH DWPTS RANGING FROM 29-31F...A FEW MORE DEGREES OF COOLING IS ANTICIPATED. STRONG WAA NORTH OF THE SFC WARM FRONT LOCATED OVER SRN NY WILL MAINTAIN AN ELEVATED WARM LAYER OVER THE REGION...ALONG WITH SUPPORTING MODERATE PRECIPITATION. AS THE 994 MB SFC LOW OVER SWRN NY MOVES NEWD INTO NRN NY LATER THIS AFTERNOON ...SUFFICIENT VEERING OF THE LOW LEVEL WIND FIELDS SHOULD OCCUR AND AID IN A TRANSITION OF P-TYPE BACK TO COLD RAIN AFTER 22Z. ..CROSBIE.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BTV... 44977255 44567288 44407334 44507383 44987421 45087404  From mcd at goshenarc.org Fri Dec 1 17:27:57 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 12:27:57 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011729 SWOMCD SPC MCD 011729 MDZ000-VAZ000-NCZ000-SCZ000-011930- MESOSCALE DISCUSSION 2263 NWS STORM PREDICTION CENTER NORMAN OK 1129 AM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS CENTRAL/SRN/ERN VA...EXTREME SERN MD...ERN NC...NERN SC. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 011729Z - 011930Z CONVECTION MAY STRENGTHEN THROUGH MID AFTERNOON ALONG PREFRONTAL CONVERGENCE BAND -- EVIDENT AS OF 1715Z FROM ABOUT 50 SW RIC TO 20 NW SAV. MAIN THREAT WILL BE DAMAGING GUSTS. ALSO...LINE OF SVR CONVECTION CLOSER TO COLD FRONT...AND NOW IN WWS 874-875 MAY BACKBUILD SWD AND AFFECT PORTIONS CENTRAL VA. AIR MASS WILL CONTINUE TO DESTABILIZE ACROSS COASTAL PLAIN AND TIDEWATER REGION FROM MD TO ERN NC...PERHAPS INTO PORTIONS NERN SC. SFC DIABATIC HEATING AND DEW POINTS MID 60S TO NEAR 70 F WILL COUNTERACT WEAK MIDLEVEL LAPSE RATES ENOUGH TO RAISE MLCAPES TO 500 J/KG...PERHAPS AS HIGH AS 1000 J/KG. VERTICAL WIND PROFILES WILL BE NEARLY UNIDIRECTIONAL...BUT WITH VERY STRONG SPEED SHEAR...AS TIGHTEST GRADIENT FLOW ALOFT PASSES OVER REGION SE OF EJECTING MID-UPPER LOW OVER GREAT LAKES REGION. 30-40 KT OF 0-1 KM VECTOR SHEAR IS EVIDENT OVER NC/VA PORTION OF DISCUSSION AREA...BASED ON VWP AND RUC SOUNDINGS. SVR PROBABILITIES DIMINISH WITH SWD EXTENT THROUGH SC BECAUSE OF WEAKER CONVERGENCE...AND BECAUSE OF EXPECTED VEERING TREND IN PRE-STORM BOUNDARY LAYER FLOW RELATED TO ISALLOBARIC FORCING. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...RNK... 33577990 36657842 37877831 38367760 38447500 37897531 37107588 36917598 36057566 35677545 35197550 35117592 34557652 34707680 34567722 34227777 33827794 33867854 33507903 33107922  From mcd at goshenarc.org Fri Dec 1 18:11:25 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 13:11:25 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 011813 SWOMCD SPC MCD 011812 MEZ000-012345- MESOSCALE DISCUSSION 2264 NWS STORM PREDICTION CENTER NORMAN OK 1212 PM CST FRI DEC 01 2006 AREAS AFFECTED...NWRN/NERN ME CONCERNING...WINTER MIXED PRECIPITATION VALID 011812Z - 012345Z A MIXTURE OF LIGHT TO MODERATE FREEZING RAIN/SLEET WILL DEVELOP OVER PORTIONS OF ME THROUGH 21Z...WITH FREEZING RAIN BEING THE MORE PREDOMINANT P-TYPE SOUTH OF A LINE FROM HUL TO BML. HVY SNOW MAY BE THE PREDOMINANT P-TYPE OVER FAR NRN ME...DEVELOPING TOWARDS 00Z. HRLY LIQUID ACCUMULATION RATES AROUND 0.10 INCH WILL BE LIKELY...MAINLY AFTER 21Z. STRONG WAA WILL CONTINUE TO SPREAD NEWD INTO THE REGION OVER THE NEXT 6 HRS AHEAD OF STRONG 80 KT LOW LEVEL JET AND WARM FRONT LOCATED PRESENTLY OVER SRN NY AND NEW ENGLAND. AN ELEVATED WARM LAYER /NOTED BY 40 DEG F OBSERVATION AT MT. WASHINGTON/ WILL CONTINUE TO OVERSPREAD THE AREA. MEANWHILE...LOW LEVEL COLD/DRY AIR ADVECTION SUPPORTED BY NLY WINDS EMANATING FROM A LARGE AREA OF SFC HIGH PRESSURE OVER ERN QUEBEC WILL CONTINUE FOR SEVERAL MORE HRS. AS PRECIPITATION MOVES INTO PORTIONS OF NRN ME...WET-BULB COOLING EFFECTS WILL SUPPORT TEMPERATURES FALLING BELOW FREEZING OVER ALL OF NRN ME BY MID AFTERNOON. GIVEN THE RELATIVELY LARGE WARM LAYER NOTED ON FCST SOUNDINGS SUPPORTED BY STRONG WAA MOVING INTO THE REGION...FREEZING RAIN WILL BE THE PRIMARY P-TYPE SOUTH OF A LINE FROM HUL TO BML. NORTH OF THIS LINE...SLEET WILL BE THE PRIMARY P-TYPE FOR MOST OF THE REST OF NRN ME. THERE IS SOME UNCERTAINTY AS TO HOW FAR NORTH THE ELEVATED WARM LAYER CAN MOVE. ATTM...THERE IS SOME POSSIBILITY THAT FAR NRN ME WILL NEVER SEE A CHANGEOVER FROM THE MOD/HVY SNOWFALL WHICH SHOULD BEGIN BETWEEN 21-00Z. ..CROSBIE.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAR...GYX... 45546748 44916958 44747067 45217094 46597017 47276943 47376820 46826764  From mcd at goshenarc.org Fri Dec 1 21:07:12 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 16:07:12 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 012108 SWOMCD SPC MCD 012108 MAZ000-NYZ000-NHZ000-CTZ000-VTZ000-NJZ000-PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-012315- MESOSCALE DISCUSSION 2265 NWS STORM PREDICTION CENTER NORMAN OK 0308 PM CST FRI DEC 01 2006 AREAS AFFECTED...PORTIONS NRN VA...SRN/ERN NY...MD...ERN PA...DC...NJ...WRN CT...SRN VT...WRN MA. CONCERNING...SEVERE THUNDERSTORM WATCH 874...875...876... VALID 012108Z - 012315Z SEGMENTED/LINEAR CONVECTION GENERALLY HAS REINVIGORATED OVER ERN PA AND SRN NY...AS ACTIVITY MOVES INTO BOUNDARY LAYER AIR MASS DESTABILIZED BY DIURNAL HEATING AND BY BOUNDARY LAYER THETAE ADVECTION. ADDITIONAL ADVECTIVE PROCESSES AND WEAK HEATING -- DURING NEXT 2-3 HOURS -- MAY MRGLLY DESTABILIZE RAIN-COOLED AIR NOW EVIDENT OVER EXTREME NERN PA...OVER MOST OF NJ...AND SERN NY. PRE-STORM MLCAPES SHOULD BE PEAKING AT 250-500 J/KG...CENTERED NEAR AXIS FROM BGM-FDK. DAMAGING WIND WILL REMAIN MAIN THREAT...AND QLCS-TYPE TORNADIC SPINUP STILL CANNOT BE RULED OUT. DEEP-LAYER KINEMATIC FIELDS AND INTENSE LLJ JUST ABOVE SFC WILL CONTINUE TO CONTRIBUTE TO FAVORABLE SHEAR PROFILES....EVEN AS INSTABILITY BECOMES MORE CONSTRAINED ON THREE SIDES BY COLD FRONT...WARM FRONT AND MARINE LAYER. DAMAGING WIND POTENTIAL WILL DECREASE SHARPLY POLEWARD OF WARM FRONT...CORRESPONDING TO STRONGER/DEEPER LAYER OF NEAR-SFC STATIC STABILITY WITH NWD EXTENT. SVR PROBABILITIES WILL DIMINISH GRADUALLY WITH EWD EXTENT ACROSS NEW ENGLAND AS CONVECTIVE FORCING ZONE PENETRATES INTO AIR MASS PROGRESSIVELY MORE STABILIZED BOTH BY MARINE LAYER TRAJECTORIES...AND BY SFC DIABATIC COOLING. STILL...SOME DAMAGING GUST POTENTIAL MAY EXTEND E OF WW 876...SO THIS AREA WILL BE MONITORED. ..EDWARDS.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BOX...BTV...OKX...ALY...PHI...BGM...CTP...LWX... 39137767 40587702 42557628 43047578 43607440 43297268 42937246 42717224 42157220 41217269 40717283 40527392 40137402 39517423 38907530 38837740  From mcd at goshenarc.org Fri Dec 1 23:14:31 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 18:14:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 012316 SWOMCD SPC MCD 012315 MAZ000-RIZ000-NHZ000-CTZ000-NYZ000-VTZ000-020015- MESOSCALE DISCUSSION 2266 NWS STORM PREDICTION CENTER NORMAN OK 0515 PM CST FRI DEC 01 2006 AREAS AFFECTED...SRN NEW ENGLAND CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 012315Z - 020015Z THE SEVERE THREAT WILL INCREASE ACROSS SRN NEW ENGLAND OVER THE NEXT FEW HOURS. WIND DAMAGE WOULD BE THE PRIMARY THREAT ALTHOUGH AN ISOLATED TORNADO THREAT CANNOT BE OUTRULED. A WW WILL MAY BE NEEDED ACROSS THE REGION. LATEST SFC ANALYSIS SHOWS A 992 MB LOW OVER NERN NY. A STATIONARY FRONT EXTENDS EWD FROM THE LOW WITH A COLD FRONT EXTENDING SSWWD ACROSS ERN NY...ERN PA INTO WRN MD. A WELL-DEVELOPED SQUALL-LINE IS ONGOING JUST AHEAD OF THE FRONT AND THIS LINE WILL MOVE QUICKLY ACROSS SRN NEW ENGLAND THIS EVENING. OBJECTIVE ANALYSIS CURRENTLY SHOWS AN IMPRESSIVE 80 KT LOW-LEVEL JET CENTERED NEAR SRN NJ AND THIS FEATURE WILL CONTINUE TO NOSE INTO SRN NEW ENGLAND OVER THE NEXT FEW HOURS CREATING A VERY STRONG LOW-LEVEL SHEAR ENVIRONMENT. THIS WILL BE FAVORABLE FOR DAMAGING WINDS AS THE WELL-DEVELOPED LINE MOVES ACROSS SRN NEW ENGLAND. HOWEVER...UNCERTAINTY REMAINS CONCERNING HOW WIDESPREAD THE WIND DAMAGE POTENTIAL WILL BE DUE TO THE WEAK INSTABILITY CURRENTLY IN PLACE. ..BROYLES.. 12/01/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BOX...OKX...ALY... 41227135 41027292 41037343 41387368 42477343 42897229 42627075 41607044 WWWW From mcd at goshenarc.org Sat Dec 2 00:28:19 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Fri, 01 Dec 2006 19:28:19 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 020030 SWOMCD SPC MCD 020029 MEZ000-020630- MESOSCALE DISCUSSION 2267 NWS STORM PREDICTION CENTER NORMAN OK 0629 PM CST FRI DEC 01 2006 AREAS AFFECTED...NRN/CENTRAL AND ERN ME CONCERNING...WINTER MIXED PRECIPITATION VALID 020029Z - 020630Z A MIX OF FREEZING RAIN/SLEET AND SNOW WILL CONTINUE TO DEVELOP OVER THE AREA IN THE NEXT COUPLE OF HRS. HEAVY ACCUMULATIONS WILL BE POSSIBLE MAINLY BETWEEN 02-05Z...AS THE STRONGEST BAND OF PRECIPITATION AND VERTICAL MOTION MOVES RAPIDLY ACROSS THE REGION. HRLY ACCUMULATION RATES MAY EXCEED 0.25 IN. FOR UP TO A HALF HR AT ANY LOCATION DURING THIS PERIOD. PRECIPITATION SHOULD BEGIN TO DIMINISH AROUND OR SHORTLY AFTER 06Z. LATEST SFC ANALYSIS SHOWS A 994 SFC LOW RAPIDLY MOVING ENEWD THROUGH NRN VT. THIS LOW SHOULD CONTINUE TO MOVE ENEWD ALONG A WARM FRONT INTO SRN/DOWNEAST ME THROUGH 06Z. LOW LEVEL COLD ADVECTION HAS AIDED IN MAINTAINING SUB-FREEZING TEMPERATURES ALONG AND NORTH OF AN AXIS FROM SRN FRANKLIN COUNTY INTO NRN WASHINGTON COUNTY ACROSS PORTIONS OF CENTRAL/ERN ME. WITH ANTICIPATED TRACK/MVMNT OF THE SFC LOW...THIS AXIS IS ANTICIPATED TO REMAIN NEARLY STATIONARY FOR THE NEXT 6 HRS. AS THE STRONG COLD FRONT AND LOW LEVEL WAA /85 KT LOW LEVEL JET/ CONTINUES TO APPROACH THE REGION...THE DEEP ELEVATED WARM LAYER NOTED ON THE 19Z AND 00Z GYX SOUNDING WILL SUPPORT FREEZING RAIN 50-75 MILES NORTH OF THE AFOREMENTIONED AXIS. NORTH OF THIS ZONE...THE ELEVATED WARM LAYER DIMINISHES IN DEPTH...WHICH WILL SUPPORT A MIX OF FREEZING RAIN AND SLEET ACROSS NRN ME. THE 00Z CAR SOUNDING INDICATED THAT THE ELEVATED WARM LAYER REMAINED JUST SLIGHTLY BELOW 0 DEG C. HOWEVER GIVEN THE APPROACHING LOW LEVEL SPEED MAX...A PERIOD OF SLEET SHOULD OCCUR AMONGST THE HVY SNOWFALL EXPECTED TO DEVELOP IN THE NEXT FEW HRS. ELEVATED INSTABILITY /MUCAPES FROM 50-100 J/KG/ MAY SUPPORT A FEW LIGHTNING STRIKES IN THE REGION ALLOWING FOR HVY PRECIPITATION RATES OVER 0.25 IN/HR FOR A 1/2 HR PERIOD OR LONGER. ..CROSBIE.. 12/02/2006 ...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... 47076775 45456778 44736951 45197047 46556998 47486884  From mcd at goshenarc.org Sun Dec 3 01:01:04 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 02 Dec 2006 20:01:04 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 030102 SWOMCD SPC MCD 030102 MIZ000-WIZ000-030700- MESOSCALE DISCUSSION 2268 NWS STORM PREDICTION CENTER NORMAN OK 0702 PM CST SAT DEC 02 2006 AREAS AFFECTED...WRN PORTIONS OF THE U.P OF MI CONCERNING...HEAVY SNOW VALID 030102Z - 030700Z HEAVY LAKE EFFECT SNOW BANDS ARE ANTICIPATED TO DEVELOP SWD INTO THE WRN PORTION OF THE U.P OF MI /INCLUDING THE KEWEENAW PENINSULA/ OVER THE NEXT FEW HRS. HRLY SNOWFALL RATES UP TO 2 INCHES WILL BE POSSIBLE ALONG THE N-NE FACING SLOPES OF THE HIGHER TERRAIN BY 06Z. IR SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS OVER WRN LAKE SUPERIOR. THIS WAS INDICATIVE OF INCREASING MID LEVEL VERTICAL MOTION AHEAD OF AN UPPER LOW CENTERED NEAR THE BWCA IN NERN MN. THE 00Z INL SOUNDING INDICATED COOLER THAN MODEL FCST 850 MB TEMPERATURES /AROUND -18 DEG C/. AS A 1020 MB SFC LOW OVER ERN LAKE SUPERIOR CONTINUES TO MOVE EWD AWAY FROM THE REGION...A SFC FRONT AND ASSOCIATED COOLING WILL AID IN STEEPENING LOW LEVEL LAPSE RATES AND INCREASING DELTA-T/S TO BETWEEN 18-20 DEG C BY 06Z OVER WRN LK SUPERIOR. AS THE LOW LEVEL FLOW BECOMES N-NELY...THE FETCH WILL BE ORIENTED ROUGHLY ALONG THE MINOR-AXIS OF LK SUPERIOR. THUS...A MULTI-BANDED LES REGIME WILL DEVELOP. LOW LEVEL UPSLOPE FLOW INTO THE N-NELY FACING SLOPES OF THE HIGHER TERRAIN COMBINED WITH AFOREMENTIONED THERMODYNAMIC PARAMETERS WILL FAVOR SNOWFALL RATES IN EXCESS OF 1 IN PER HR BEFORE 06Z. ..CROSBIE.. 12/03/2006 ...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...MQT...DLH... 47578786 47418925 46979073 46669080 46489030 46418930 46618791 46978730  From mcd at goshenarc.org Mon Dec 4 17:57:58 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 04 Dec 2006 12:57:58 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 041759 SWOMCD SPC MCD 041758 NYZ000-050000- MESOSCALE DISCUSSION 2269 NWS STORM PREDICTION CENTER NORMAN OK 1158 AM CST MON DEC 04 2006 AREAS AFFECTED...FAR SWRN NY...INCLUDING PORTIONS OF THE BUFFALO METRO AREA CONCERNING...HEAVY SNOW VALID 041758Z - 050000Z A PRE-EXISTING LAKE EFFECT SNOW BAND IS EXPECTED TO BECOME ORIENTED IN A MORE FAVORABLE ORIENTATION TO UP TO 2 IN/HR SNOWFALL RATES BEGINNING AFTER 22Z OVER PORTIONS OF SWRN NY. A VIGOROUS MID LEVEL VORT MAX AND UPPER LEVEL JET NOTED ON IR/WV SATELLITE IMAGERY WERE MOVING ACROSS SRN WI DURING THE EARLY AFTERNOON. STRONG AND DEEP VERTICAL MOTION AHEAD OF AND TO THE LEFT OF THE UPPER LEVEL JET ENTRANCE REGION HAS SUPPORTED MODERATE TO HVY SNOWFALL OVER SWRN LOWER MI. AS THIS SYSTEM MOVES EWD...LOW LEVEL FLOW OVER LAKE ERIE WILL CONTINUE TO BACK AND STRENGTHEN. IN RESPONSE...THE PRE-EXISTING SNOWBAND OVER LAKE ERIE WILL LIFT NWD. RELATIVELY UNIDIRECTIONAL SHEAR SHOULD CONTINUE TO SUPPORT A SINGLE BAND TYPE STRUCTURE. HOWEVER SPEED SHEAR MAY CREATE OCCASIONAL BREAKS IN THIS BAND. AS THIS BAND BECOMES ORIENTED SW-NE...AN INCREASING FETCH DOWN LAKE ERIE WILL OCCUR LATER THIS AFTERNOON. INCREASING VERTICAL MOTION WILL SUPPORT MID LEVEL COOLING AND RISING INVERSION HEIGHTS FROM THE PRESENT 7000 FT TO OVER 10000 FT...ALONG WITH INCREASING LAKE INDUCED CAPE VALUES TO OVER 300 J/KG. THIS WILL FAVOR HVY SNOWFALL DEVELOPING OVER SWRN NY SNOWBELT REGION AND PORTIONS OF THE BUFFALO METRO AREA BY EARLY EVENING /AFTER 22Z/. COMBINED WITH A FAVORABLE UPSLOPE COMPONENT INTO THE HIGHER TERRAIN...SNOWFALL RATES UP TO 2 IN/HR ARE POSSIBLE BY 00Z. THE HEAVIEST SNOWFALL BAND IS EXPECTED TO EFFECT NRN CHAUTAUQUA/CATTARAUGUS AND NRN/CENTRAL ERIE COUNTIES. ..CROSBIE.. 12/04/2006 ...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...BUF... 42997850 42927902 42397972 42247963 42247871 42337841  From mcd at goshenarc.org Tue Dec 5 01:01:59 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 04 Dec 2006 20:01:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 050103 SWOMCD SPC MCD 050103 NYZ000-PAZ000-050600- MESOSCALE DISCUSSION 2270 NWS STORM PREDICTION CENTER NORMAN OK 0703 PM CST MON DEC 04 2006 AREAS AFFECTED...LAKE EFFECT SNOW BELTS OF WRN NY AND FAR NWRN PA CONCERNING...HEAVY SNOW VALID 050103Z - 050600Z HEAVY SNOW BAND OVER LAKE ERIE AND THE CANADA/NY BORDER WILL SHIFT SWD THROUGH THE BUFFALO METRO AREA AND INTO SWRN NY AND EXTREME NWRN PA BETWEEN 03-06Z. AN ADDITIONAL HVY SNOW BAND OVER LAKE ONTARIO WILL GRADUALLY SHIFT NWD AND AFFECTS AREAS BETWEEN ART AND SYR. HRLY ACCUMULATION RATES IN BOTH AREAS WILL BE UP TO 2 INCHES ...ESPECIALLY IN FAVORABLE UPSLOPE AREAS. RECENT VWP DATA FROM CLE INDICATES AN INCREASING AND VEERING OF THE LOW LEVEL FLOW COMPARED TO THE 00Z BUF SOUNDING. THIS IS ASSOCIATED WITH MID LEVEL SHORTWAVE TROUGH THAT HAS JUST RECENTLY PASSED THROUGH THE AREA /PER RADAR AND SAT IMAGERY/. AS A RESULT...THE HVY SNOW BAND WHICH HAS RECENTLY MOVED NORTH OF THE BUF AREA INTO SWRN ONTARIO CANADA AND EXTREME NRN/WRN NIAGARA COUNTY NY WILL BEGIN TO SHIFT SWD THROUGH THE BUF METRO AREA IN THE NEXT 3-6 HRS AS THE MEAN FLOW VEERS TO AROUND 240 DEG. AS THE LOW LEVEL FLOW CONTINUES TO VEER /PER THE 00Z DTX SOUNDING/ THIS HEAVY SNOW BAND SHOULD SHIFT SWD OF THE BUF AREA AND EFFECT PORTIONS OF SWRN NY AND FAR NWRN PA TOWARDS 06Z. HIGH INVERSION LEVELS /10 KFT PER THE 00Z BUF SOUNDING/ ALONG WITH AN INCREASING LAKE FETCH LENGTH WILL SUPPORT GREATER THAN 1 INCH/HR SNOWFALL RATES. IN UPSLOPE AREAS...RATES MAY APPROACH 2 IN/HR. FURTHER NORTH...THE HVY SNOW BAND OVER LAKE ONTARIO...BEING SEEDED FROM THE LAKE ERIE SNOW BAND...WILL SHIFT SLOWLY NWD THROUGH 03Z AS THE LOW LEVEL FLOW CONTINUES TO BACK TO AROUND 210 DEG /PER THE BUF 00Z SOUNDING/ AHEAD OF THE MID LEVEL SHORTWAVE/SFC TROUGH. HEAVIEST SNOW RATES WILL THEREFORE AFFECT NRN OSWEGO...SRN JEFFERSON...WRN LEWIS/ONEIDA COUNTIES THROUGH 06Z. EVENTUALLY THIS SNOW BAND WILL SHIFT BACK SWD AROUND OR AFTER 06Z...AS LOW LEVEL FLOW VEERS. SIMILAR TO AREAS SOUTH...HVY SNOW RATES UP TO 2 IN/HR WILL BE POSSIBLE IN THE HIGHEST TERRAIN/FAVORABLE UPSLOPE AREAS. ..CROSBIE.. 12/05/2006 ...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...BGM...BUF...CLE... 43207672 43477675 43867652 43897609 43687569 43377563 43267615 43207880 42717906 42068048 41948017 41987982 42097898 42487849 43077821  From mcd at goshenarc.org Tue Dec 5 10:47:22 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 05 Dec 2006 05:47:22 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 051048 SWOMCD SPC MCD 051048 NYZ000-051545- MESOSCALE DISCUSSION 2271 NWS STORM PREDICTION CENTER NORMAN OK 0448 AM CST TUE DEC 05 2006 AREAS AFFECTED...ALONG AND JUST SOUTH OF TUG HILL REGION CONCERNING...HEAVY SNOW VALID 051048Z - 051545Z LAKE EFFECT SNOW BAND WITH RATES OF 1-3 INCHES WILL CONTINUE TO BECOME ORIENTED ALONG THE MAJOR-AXIS OF LAKE ONTARIO THROUGH MID MORNING...WITH THE GREATER SNOWFALL RATES BEGINNING TO AFFECT SRN JEFFERSON AND OSWEGO COUNTIES BY 11-12Z. THIS BAND IS EXPECTED TO REMAIN FOCUSED INTO THE TUG HILL REGION THIS MORNING. THE SRN PART OF THIS BAND MAY SHIFT JUST S OF TUG HILL REGION INTO NRN PARTS OF ONONDAGA TO ERN WAYNE COUNTIES LATER THIS MORNING AS LOW LEVEL WINDS SHIFT TO THE WNW. SINCE 08-09Z...RADAR AND SATELLITE IMAGERY INDICATED A LAKE EFFECT SNOW BAND DEVELOPING ALONG THE MAJOR-AXIS OF LAKE ONTARIO /CENTRAL PORTIONS OF THE LAKE/. LOW LEVEL CONVERGENCE...PER STREAMLINE ANALYSIS...HAS INCREASED THUS FAR AS LOW LEVEL WINDS OVER THE WRN AND CENTRAL PARTS OF LAKE ONTARIO HAVE SHIFTED TO THE WEST WITH THE PASSAGE OF A SHORT WAVE TROUGH. AS THIS TROUGH CONTINUES TO TRACK E TOWARD NEW ENGLAND THIS MORNING...THE LOW LEVEL WINDS OVER ERN LAKE ONTARIO WILL ALSO SHIFT TO THE W ALLOWING THIS SNOW BAND TO SPREAD INLAND OVER JEFFERSON AND OSWEGO COUNTIES BY 11-12Z. THE TUG HILL REGION SHOULD BE THE PRIMARY FOCUS FOR THIS BAND THROUGH 17-18Z... THOUGH A WIND SHIFT TO THE WNW MAY ALLOW THE BAND TO SETTLE SLIGHTLY SWD INTO NRN PARTS OF ONONDAGA...CAYUGA TO ERN WAYNE COUNTIES DURING THE LATE MORNING. IR IMAGERY INDICATED COOLING CLOUD TOPS WITH THIS DEVELOPING SNOW BAND OVER LAKE ONTARIO...WITH CLOUD TOPS ESTIMATED IN EXCESS OF 12-14 KFT AND THUS FAVORABLE FOR CHARGE SEPARATION /I.E. LIGHTNING PRODUCTION/. ALTHOUGH INVERSION HEIGHTS ARE EXPECTED TO FALL TO AROUND 8 KFT BY 18Z...STEEP LOW LEVEL LAPSE RATES AND LAKE-INDUCED CAPE OF 100-300 J/KG SUGGESTS POTENTIAL FOR GREATER SNOWFALL RATES WITH CONVECTIVE ELEMENTS. ..PETERS.. 12/05/2006 ...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...BGM...BUF... 43357672 43477645 43527634 43557621 43767621 43877606 43917568 43517556 43197571 43017587 42867622 42827642 42887667 43027688 43287693  From mcd at goshenarc.org Thu Dec 7 00:39:27 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 06 Dec 2006 19:39:27 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 070040 SWOMCD SPC MCD 070040 MIZ000-070615- MESOSCALE DISCUSSION 2272 NWS STORM PREDICTION CENTER NORMAN OK 0640 PM CST WED DEC 06 2006 AREAS AFFECTED...UPPER PENINSULA OF MICHIGAN CONCERNING...HEAVY SNOW VALID 070040Z - 070615Z BANDS OF LAKE EFFECT SNOW ARE LIKELY TO INCREASE ACROSS PORTIONS OF THE U.P. OF MICHIGAN BY LATE TONIGHT. LOCALIZED SNOW RATES OF 2 IN/HR OR GREATER WILL BE POSSIBLE ACROSS ALGER/WESTERN SCHOOLCRAFT/FAR EASTERN MARQUETTE/DELTA COUNTIES...ESPECIALLY TOWARD/AFTER 06Z. IN THE WAKE OF THE SURFACE COLD FRONT/PASSING MID LEVEL TROUGH...INCREASING CYCLONIC FLOW AND OFF-LAKE SUPERIOR TRAJECTORIES COUPLED WITH UPSLOPE/FRICTIONAL CONVERGENCE WILL FAVOR INCREASINGLY ORGANIZED LAKE EFFECT SNOW THROUGH THE NIGHT ACROSS THE EAST CENTRAL U.P. OF MICHIGAN. RECENT TAMDAR SOUNDINGS FROM NEAR MARQUETTE DEPICT AN INVERSION HEIGHT AROUND 2.5 KM/750 MB EARLY THIS EVENING...WITH 850 MB TEMPS AROUND -19 C. INCREASINGLY COLD AIR ALOFT WILL FAVOR STRONG LAKE-DRIVEN INSTABILITY OFF OF LAKE SUPERIOR...WITH 850 MB DELTA-T VALUES AROUND 25 C. ONLY MODEST DIRECTIONAL SHEAR IN THE BOUNDARY LAYER PER TAMDAR DATA/MARQUETTE WSR-88D VWP DATA WILL SUPPORT THE GRADUAL EVOLUTION/INTENSIFICATION OF SEVERAL LAKE EFFECT BANDS...WITH SOME POTENTIAL FOR CONSOLIDATION OVERNIGHT. LATEST RUC/4KM WRF-NMM GUIDANCE SUGGESTS INTENSIFICATION OF SNOW RATES TOWARD/AFTER 06Z...ESPECIALLY ACROSS ALGER AND SCHOOLCRAFT COUNTIES INCLUDING HIGHWAYS 28/94. HIGH SNOW-TO-LIQUID WATER EQUIVALENTS WILL FURTHER PROMOTE POTENTIAL FOR 2 IN/HR OR GREATER SNOW RATES. ..GUYER.. 12/07/2006 ...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...MQT... 46648700 46608610 46388611 46048636 46018661 46248713 46508727  From mcd at goshenarc.org Sun Dec 10 03:26:33 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sat, 09 Dec 2006 22:26:33 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 100327 SWOMCD SPC MCD 100327 CAZ000-100930- MESOSCALE DISCUSSION 2274 NWS STORM PREDICTION CENTER NORMAN OK 0927 PM CST SAT DEC 09 2006 AREAS AFFECTED...WRN SLOPES OF CENTRAL AND SRN SIERRA NEVADA MTNS ABOVE 6000 FT CONCERNING...HEAVY SNOW VALID 100327Z - 100930Z HEAVY SNOW WITH ACCUMULATION RATES UP TO 3 IN/HR FOR A SEVERAL HR PERIOD WILL OVERSPREAD THE CENTRAL/SRN SIERRA NEVADA MTNS OF CA BEGINNING BETWEEN 04-06Z. SNOW LEVELS WILL INITIALLY START AROUND 6500 FT BEFORE FALLING TO AROUND 5000 FT WITH A COLD FRONTAL PASSAGE. MOD/HVY RAINFALL RATES HAVE BEEN OBSERVED AT SEVERAL SITES IN THE SFO/MRY BAY AREAS AND CENTRAL COAST REGION SINCE 01Z...ASSOCIATED WITH A STRONG UPPER TROUGH MOVING INTO THE CA COAST. THIS PRECIPITATION WAS BEING SUPPORTED BY STRONG VERTICAL MOTION ASSOCIATED WITH DIFFLUENT UPPER LEVEL FLOW AND A STRONG VORTICITY CENTER MOVING INTO THE CENTRAL CA COAST. ADDITIONAL STRONG MESOSCALE VERTICAL MOTION WAS OCCURRING ALONG/AHEAD OF A SFC-850 MB FRONTAL ZONE WHICH RECENTLY PASSED THROUGH KSFO. THE 00Z OAK SOUNDING AND RECENT BLU SFC OBS INDICATED SNOWFALL LEVELS SHOULD START OUT BETWEEN 6000-6500 FT. HIGH PWAT VALUES AHEAD OF THE FRONT ALONG WITH MDT /30 KT/ SSWLY LOW LEVEL FLOW WILL SUPPORT ENHANCED SNOWFALL RATES ON THE WRN UPSLOPE REGION OF THE CENTRAL/SRN SIERRA NEVADA. GIVEN THE RECENT PRECIP RATES/TRENDS AROUND 0.25-0.30 IN/HR AT SNS...MRY AND PRB...2-3 IN/HR SNOWFALL RATES WILL BE POSSIBLE FOR A SEVERAL HR PERIOD PRIOR TO FRONTAL PASSAGE OVER THE WRN SLOPES OF THE CENTRAL/SRN SIERRA. CURRENT EXTRAPOLATION OF THE FRONTAL MOVEMENT /EWD AROUND 30 KTS/ TAKE THE FRONT THROUGH THE SIERRA BETWEEN 06-09Z. AFTER THE FRONTAL PASSAGE...SNOW LEVELS WILL FALL TO AROUND 5000 FT...AND FORCING WILL BE PRIMARILY DRIVEN BY MDT UPSLOPE FLOW...WITH RATES DECREASING TO LESS THAN 2 INCH/HR BY 09Z. ..CROSBIE.. 12/10/2006 ...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...VEF...REV...HNX...STO... 38551964 39072006 39852019 40112072 39882099 39512077 38702036 38382012 38132001 37181928 36821906 36281873 35931859 35451845 35341843 35251824 35371802 35561809 36181811 36301821 37401869  From mcd at goshenarc.org Tue Dec 12 01:20:50 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Mon, 11 Dec 2006 20:20:50 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 120121 SWOMCD SPC MCD 120121 IAZ000-MOZ000-KSZ000-NEZ000-120345- MESOSCALE DISCUSSION 2275 NWS STORM PREDICTION CENTER NORMAN OK 0721 PM CST MON DEC 11 2006 AREAS AFFECTED...PORTIONS SERN NEB...EXTREME NERN KS...NWRN MO...SWRN IA. CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 120121Z - 120345Z TSTMS ARE FCST TO CONTINUE TO DEVELOP...AND INCREASE IN COVERAGE ACROSS THIS REGION DURING NEXT FEW HOURS -- INITIALLY SPREADING NWD ACROSS KS/NEB BORDER THEN ACROSS MO/IA BORDER AREA. MAIN SVR CONCERN WILL BE HAIL...WITH OCCASIONAL STG/DAMAGING GUSTS POSSIBLE. SFC MESOANALYSIS SHOWS MAIN CYCLONE BETWEEN CNK-MHK...WITH ONE WARM FRONTAL STRUCTURE EXTENDING EWD THROUGH MKC AREA AND ANOTHER CORRESPONDING TO INVERTED TROUGH NEWD NEAR OMA. SFC LOW SHOULD LIFT NEWD TOWARD SRN IA. LIKEWISE...STRONGEST LOW-MIDDLE LEVEL FORCING WILL SHIFT NEWD WITH TIME...PRIMARILY N OF SRN WARM FRONTAL SEGMENT. TOP RAOB...WHICH WAS WELL LOCATED TO SAMPLE MIDLEVEL AIR MASS ASSOCIATED WITH THIS EVENT...ALONG WITH AIRCRAFT SOUNDINGS AND RUC FCST SOUNDINGS...INDICATE PLUME OF FAVORABLY STEEP LAPSE RATES AROUND 8 DEG C/KM WILL SHIFT EWD AND NEWD ACROSS DISCUSSION AREA THROUGH ABOUT 06Z. MOISTURE AND ISENTROPIC LIFT EACH SHOULD INCREASE IN LOW LEVELS...NEAR NWRN PERIPHERY OF 35-45 KT LLJ. THIS SHOULD LEAD TO AREA OF MUCAPES AROUND 500-700 J/KG THAT WILL EXPAND ACROSS THIS REGION WITH WEAKENING CINH. VERTICAL SHEAR PROFILES SUPPORT POTENTIAL FOR WELL-ORGANIZED AND OCCASIONALLY ROTATING UPDRAFTS...WITH 35-45 KT EFFECTIVE SHEAR. FAVORABLE DEEPER-LAYER SHEARS -- I.E. 0-6 KM VALUES 50-75 KT THAT COVER MOST OF CAPE-BEARING LAYER -- ALSO WILL BE LIKELY ACROSS THIS REGION AS STRONG HEIGHT GRADIENT MOVES OVERHEAD IN ADVANCE OF KS/NEB UPPER CYCLONE. ..EDWARDS.. 12/12/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DMX...EAX...OAX...TOP... 39399466 39559617 39899721 40599700 41739581 41959434 41049325 40029360 39529425  From mcd at goshenarc.org Tue Dec 12 21:40:29 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 12 Dec 2006 16:40:29 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 122141 SWOMCD SPC MCD 122140 INZ000-ILZ000-122345- MESOSCALE DISCUSSION 2276 NWS STORM PREDICTION CENTER NORMAN OK 0340 PM CST TUE DEC 12 2006 AREAS AFFECTED...CNTRL AND ERN IL...FAR WRN IN CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 122140Z - 122345Z A FEW STRONG STORMS ARE LIKELY THROUGH EARLY EVENING...WITH SMALL/MARGINALLY SVR HAIL POSSIBLE. SURFACE HEATING AHEAD OF SURGING COLD FRONT HAS ALLOWED FOR SURFACE BASED INSTABILITY TO DEVELOP FROM IL SWD THROUGH THE LOWER MS VALLEY. UPPER SHORTWAVE EMBEDDED WITHIN TROUGH IS NOW MOVING ACROSS THE REGION...WITH FAVORABLE DEEP LAYER LIFT NOW ACROSS IL. GIVEN VERY COLD AIR ALOFT AND NARROW PLUME OF RELATIVELY STEEP LOW LEVEL LAPSE RATES...A FEW CELLS ARE EXPECTED TO BECOME STRONG AND/OR MARGINALLY SEVERE WITH HAIL THE MAIN THREAT. POTENTIAL DOES EXIST FOR A STORM OR TWO TO BECOME A SUPERCELL GIVEN FAVORABLE LOW LEVEL SHEAR AND DEEP FORCING. GIVEN NARROW WARM SECTOR...OVERALL THREAT SHOULD REMAIN RATHER LOCALIZED. ..JEWELL.. 12/12/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...IND...PAH...LOT...ILX...LSX... 38928737 38258817 38108981 39458933 41058905 41158765 40748720 39988718 WWWW From mcd at goshenarc.org Tue Dec 19 05:48:44 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 00:48:44 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 190549 SWOMCD SPC MCD 190548 TXZ000-OKZ000-KSZ000-NMZ000-191015- MESOSCALE DISCUSSION 2277 NWS STORM PREDICTION CENTER NORMAN OK 1148 PM CST MON DEC 18 2006 AREAS AFFECTED...TX AND OK PANHANDLES...EXTREME E-CNTRL NM CONCERNING...WINTER MIXED PRECIPITATION VALID 190548Z - 191015Z SHOWERS/ISOLATED TSTMS OF FREEZING RAIN MIXED WITH SLEET WILL CONTINUE ACROSS THE TX/OK PANHANDLES THROUGH 12Z. ICE ACCUMULATIONS SHOULD GENERALLY REACH .05 IN/HR WITHIN MOST SHOWERS. HOWEVER...A MORE INTENSE/CONCENTRATED AREA OF FREEZING RAIN MAY DEVELOP FROM AROUND 50 W PVW TO AMA TO 50 SE GUY. JUST SE OF THIS LINE...STRONGLY FOCUSED LOW-LEVEL WARM/MOIST ADVECTION WILL BE MAXIMIZED THROUGH THE OVERNIGHT HOURS. IN ADDITION...WEAK ELEVATED INSTABILITY...EVIDENCED BY RECENT CG LIGHTNING STRIKES...WILL AID IN PRODUCING ICE ACCUMULATION RATES AROUND .10 IN/HR AT TIMES. 05Z SURFACE ANALYSIS PLACES THE FREEZING LINE FROM ABOUT 60 W LBB NNEWD TO 10 S AMA TO LBL. LOW-LEVEL TEMPERATURES WILL COOL FURTHER MAINLY ACROSS THE NRN TX AND OK PANHANDLES AS SURFACE TEMPERATURE/DEW POINT SPREADS REMAIN AROUND 10 TO 20 DEGREES. PER 00Z AMA/MAF AND 03Z LBB OBSERVED SOUNDINGS...LARGE WARM NOSE OF ABOVE FREEZING TEMPERATURES EXISTS BETWEEN 750-850 MB ATOP THE SURFACE-BASED COLD DOME. 00Z MODEL GUIDANCE IS VERY CONSISTENT IN MAINTAINING THIS STRUCTURE OVERNIGHT WITH 25 TO 35 KTS OF SELY FLOW FEEDING INTO A SSW TO NNE ORIENTED 800 MB STATIONARY FRONT. THIS WILL RESULT IN FOCUSED LOW-LEVEL WARM/MOIST ADVECTION ABOVE THE COLDER NEAR-SURFACE LAYER. 03Z RUC/00Z NAM FORECAST SOUNDINGS INDICATE FREEZING RAIN WILL BE THE PRIMARY PTYPE. SLEET WILL BE MORE PREVALENT FURTHER NW FROM TCC TO DHT TO LBL WHERE THE WARM NOSE WILL REMAIN COOLER THAN 2 TO 3 DEG C. ..GRAMS.. 12/19/2006 ...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...DDC...LUB...AMA...ABQ... 37190033 36520004 35250103 34350199 33930276 33750339 34290361 35120337 36360239 37050157 37220104 WWWW From mcd at goshenarc.org Tue Dec 19 12:15:01 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 07:15:01 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191215 SWOMCD SPC MCD 191215 TXZ000-OKZ000-191615- MESOSCALE DISCUSSION 2278 NWS STORM PREDICTION CENTER NORMAN OK 0615 AM CST TUE DEC 19 2006 AREAS AFFECTED...CNTRL/ERN PORTIONS OF THE TX/OK PNHDLS CONCERNING...WINTER MIXED PRECIPITATION VALID 191215Z - 191615Z SHOWERS OF FREEZING RAIN MIXED AT TIMES WITH SLEET WILL CONTINUE THROUGH THE MORNING ACROSS THE SRN HIGH PLAINS. THE MOST PERSISTENT REGENERATION OF SHOWERS WITH HEAVIEST PCPN RATES /UP TO 0.15 INCH PER HOUR/ WILL LIKELY EXIST IN A 50-60 NM WIDE AREA CENTERED ON A LINE EXTENDING FROM NEAR KPVW-KBGD-30SE KLBL. UPPER LOW WAS BEGINNING TO TURN EWD OVER THE LWR CO RVR VLY THIS MORNING WITH AN EXPANSIVE WARM CONVEYOR STREAMING FROM THE SUB-TROPICAL PAC NEWD TO THE SRN HIGH PLAINS. A DRY SLOT WAS EVIDENT IN WATER VAPOR IMAGERY OVER SCNTRL NM AND SHORT TERM MODELS SUGGEST THAT THIS MAY ENCROACH ON THE WRN TX PNHDL WITH TIME THIS MORNING. HOWEVER...INSPECTION OF THE 295-305K LAYERS SUGGESTS THAT ISENTROPIC LIFT WILL REMAIN STRONG FROM THE CNTRL S PLAINS NEWD INTO THE CNTRL/ERN TX/OK PNHDLS THROUGH AT LEAST 18Z. IN FACT...MUCAPES OF A COUPLE HUNDRED J PER KG WILL MAINTAIN THE TSTM THREAT...LOCALLY ENHANCING PCPN RATES. 12Z TEXAS MESONET OBS PLACE THE SFC FREEZING LINE FROM SEMINOLE NEWD THROUGH TAHOKA-SPUR-MEMPHIS AND INTO ROGER MILLS COUNTY OK. THE FREEZING LINE MAY RETREAT A BIT NWWD THIS MORNING AS LOW-LEVEL WARM ADVECTION CONTINUES...BUT AREAS ROUGHLY FROM KLBB-KAMA TO THE OK PNHDL SHOULD REMAIN FIRMLY AOB 30 DEG F WHERE PCPN CONTINUES TO COUNTERACT A FLOW OF RELATIVELY DRY NEAR-SFC AIR TRAJECTORIES. P-TYPE SHOULD MOSTLY REMAIN FREEZING RAIN OWING TO THE PLUS 4-5 DEG C WARM LAYER JUST ABOVE H8 NOTED ON THE 12Z AMA SOUNDING. SLEET MAY MIX WITH THE FREEZING RAIN IN THE HEAVIER TSTMS. ..RACY.. 12/19/2006 ...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... 35080200 35850170 36800113 36890021 36540006 35310056 34720088 34080119 33880156 34130200 34680212  From mcd at goshenarc.org Tue Dec 19 16:47:45 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 11:47:45 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191648 SWOMCD SPC MCD 191648 NEZ000-KSZ000-COZ000-192245- MESOSCALE DISCUSSION 2279 NWS STORM PREDICTION CENTER NORMAN OK 1048 AM CST TUE DEC 19 2006 AREAS AFFECTED...FAR ERN CO...WRN KS AND FAR SWRN NEB CONCERNING...FREEZING RAIN VALID 191648Z - 192245Z FREEZING RAIN SHOWERS...HVY AT TIMES...WILL CONTINUE TO DEVELOP NWD THROUGH MUCH OF WRN KS...FAR ERN CO AND FAR SWRN NEB THROUGH THE LATE AFTERNOON. SIGNIFICANT ICING MAY OCCUR WITH HRLY ACCUMULATIONS UP TO 0.10 IN WITH THE HEAVIEST SHOWERS OVER WRN KS. AREAS OF SLEET WILL MIX IN WITH THE FREEZING RAIN...ESPECIALLY ACROSS FAR ERN CO AND SWRN NEB. LATEST GDA PROFILER INDICATES A STRENGTHENING LOW LEVEL WAA PROFILE. 12Z AMA SOUNDING SHOWED MID LEVEL INSTABILITY WITH MUCAPES AROUND 300 J/KG. MEANWHILE WV IMAGERY SHOWS UPPER LEVEL ASCENT HAS BEGUN TO INCREASE OVER NERN NM UNDER STRONGLY DIFFLUENT PATTERN. THIS ASCENT SHOULD SPREAD NWD INTO ERN CO AND WRN KS THROUGH THE AFTERNOON AS THE SHORTWAVE TROUGH AXIS MOVES SLOWLY ACROSS NM. THE COMBINATION OF THESE INGREDIENTS WILL SUPPORT SCT MDT/HVY SHOWERS DEVELOPING AND MOVING INTO THE AREA. A SHALLOW SUB-FREEZING LAYER /< 1 KM DEEP/ WILL CONTINUE TO SUPPORT THE MAIN P-TYPE AS FREEZING RAIN AS PRECIPITATION DEVELOPS INTO WRN KS AND FAR ERN CO. THROUGH 00Z...THE NWD EXTENT OF THE HEAVIEST FREEZING RAIN ACCUMULATIONS WILL LIKELY BE AROUND I-70...AS MUCH DRIER AIR IN THE LOWER LEVELS WILL INITIALLY OFFSET PRECIP RATES ACROSS NWRN KS...FAR ECENTRAL/NERN CO AND FAR SWRN NEB. ..CROSBIE.. 12/19/2006 ...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...LBF...DDC...GLD...PUB...BOU... 37010034 39010032 40560037 40460276 39430276 38430285 36990262  From mcd at goshenarc.org Tue Dec 19 18:24:31 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 13:24:31 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 191825 SWOMCD SPC MCD 191824 OKZ000-KSZ000-TXZ000-COZ000-NMZ000-200030- MESOSCALE DISCUSSION 2280 NWS STORM PREDICTION CENTER NORMAN OK 1224 PM CST TUE DEC 19 2006 AREAS AFFECTED...PORTIONS OF ERN NM...WRN TX...THE TX/OK PANHANDLES AND NWRN OK CONCERNING...WINTER MIXED PRECIPITATION VALID 191824Z - 200030Z MDT/HVY FREEZING RAIN WILL CONTINUE OVER PORTIONS OF THE CENTRAL/ERN TX AND OK PANHANDLES...NRN TX SOUTH PLAINS THROUGH MOST OF THE AFTERNOON. HRLY FREEZING RAIN AMTS UP TO 0.25 INCH WILL BE POSSIBLE WITH THE HEAVIEST SHOWERS/TSTMS. FREEZING RAIN SHOULD CHANGEOVER TO RAIN IN NWRN OK...AND PORTIONS OF THE ERN OK/TX PANHANDLES...ERN/SRN TX SOUTH PLAINS OVER THE NEXT 3-6 HRS. MEANWHILE...WINTER MIXED PRECIPITATION WILL REMAIN LIGHT AND/OR DIMINISH OVER THE WRN TX PANHANDLE...AND MUCH OF ERN NM. MDT TO HVY CONVECTIVE FREEZING RAIN SHOWERS/TSTMS CONTINUE TO DEVELOP IN AN AREA OF STRONG WAA AND WEAK MID LEVEL INSTABILITY OVER WRN TX. THE STRONGEST ACTIVITY WAS DEVELOPING JUST AHEAD OF A SUBTLE SHORTWAVE TROUGH MOVING OUT OF ERN NM INTO THE TX PANHANDLE PER WV SAT IMAGERY. IN THE WAKE OF THIS SHORTWAVE...A MID LEVEL DRYSLOT WAS PRONOUNCED OVER ERN NM. ALTHOUGH LOW LEVELS REMAIN MOIST AND UPSLOPE FLOW WILL SUSTAIN FZDZ...THE MID LEVEL DRYING SHOULD LIMIT THE DEVELOPMENT ANY ADDITIONAL LT/MDT FREEZING RAIN/SLEET FOR THE REST OF THE AFTERNOON IN MOST OF ERN NM. AS THIS DRYSLOT MOVES INTO WRN TX...FREEZING RAIN RATES WILL GRADUALLY TAPER OFF OVER THE WRN TX SOUTH PLAINS AND WRN TX/OK PANHANDLES THROUGH 00Z. FURTHER EAST...LOW LEVEL FLOW WILL CONTINUE TO BECOME ELY OVER THE ERN/SRN TX SOUTH PLAINS...ERN TX PANHANDLE AND WRN OK IN RESPONSE TO THE APPROACHING UPPER LOW/SHORTWAVE TROUGH. AS THIS OCCURS...LOW LEVEL WARMING SHOULD SUPPORT A CHANGEOVER FROM FREEZING RAIN TO RAIN IN THESE AREAS DURING THE REST OF THE AFTERNOON. CURRENT EXTRAPOLATION OF RECENT TRENDS INDICATES FREEZING RAIN/RAIN TRANSITION ZONE SHOULD EXTEND FROM W OF GAG TO SE OF AMA TO NEAR LBB BY 22Z. ..CROSBIE.. 12/19/2006 ...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...DDC...LUB...AMA...MAF...PUB...ABQ... 36340407 37120208 36969925 36519895 35789939 33900109 33200213 32960380 33480460 34520463 35990432 WWWW From mcd at goshenarc.org Wed Dec 20 00:38:28 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 19:38:28 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200039 SWOMCD SPC MCD 200038 OKZ000-TXZ000-KSZ000-COZ000-NMZ000-200445- MESOSCALE DISCUSSION 2281 NWS STORM PREDICTION CENTER NORMAN OK 0638 PM CST TUE DEC 19 2006 AREAS AFFECTED...ERN NM....EXTREME SERN CO AND SWRN KS...WRN SECTIONS OF THE TX/OK PNHDLS CONCERNING...WINTER MIXED PRECIPITATION VALID 200038Z - 200445Z SNOWFALL RATES ARE FORECAST TO LOCALLY APPROACH 1 INCH PER HOUR THROUGH MIDNIGHT ACROSS PARTS OF SCNTRL AND ERN NM. MEANWHILE... FREEZING RAIN WILL PROBABLY INCREASE THROUGH LATE THIS EVENING ACROSS THE NWRN PART OF THE TX PNHDL...NWD ACROSS THE OK PNHDL AND INTO SWRN KS. POTENT UPPER LOW CONTINUES TO MAKE STEADY EWD PROGRESS ACROSS AZ THIS EVENING WITH NOSE OF 80-90KT MID LEVEL JET NOW EMERGING OVER THE UPPER RIO GRANDE VALLEY/SERN NM. INTENSE DYNAMIC FORCING FOR ASCENT WAS RESULTING IN AN INCREASING AREA OF TSTM ACTIVITY FROM FAR WEST TX NNEWD ACROSS SERN NM ATTM. LATEST ANALYSIS INDICATES SUBFREEZING SURFACE CONDITIONS PERSIST ALONG A GDP-ROW-AMA-LBL LINE. STRONG INFLUX OF LOW LEVEL MOISTURE AND PRONOUNCED WARM NOSE EVIDENT ON EVENING SOUNDINGS FROM MAF AND AMA SHOULD CONTINUE TO SUPPORT AN AXIS OF FREEZING RAIN...WITHIN THIS CORRIDOR THROUGH MIDNIGHT. GLAZE ACCUMULATIONS MAY BE LOCALLY ENHANCED BY CONVECTION AND COULD OCCASIONALLY EXCEED 0.10 INCH PER HOUR OVER THE NEXT 6 HOURS. FARTHER WEST AND DEEPER INTO THE COLD AIR...AREAS HEAVY SNOW SHOULD BECOME INCREASINGLY LIKELY THROUGH THE EVENING AS DEEP-LAYER ASCENT SPREADS EWD AHEAD OF THE UPPER LOW. SATELLITE AND RADAR IMAGERY CURRENTLY INDICATE A N-S BAND OF ENHANCED LIFT WAS MOVING EAST FROM CNTRL NM. THE ARRIVAL OF STRONGER FORCING AND MOISTENING WILL ALSO COINCIDE WITH AN INCREASINGLY FAVORABLE THERMODYNAMIC REGIME FOR SNOW CRYSTAL GROWTH AS TEMPERATURES IN THE LAYER OF STRONGEST LIFT COOL TO BELOW -12C. LATEST GUIDANCE INDICATES SNOWFALL RATES OF UP TO 1 INCH PER HOUR APPEAR MOST LIKELY ACROSS PARTS OF ECNTRL NM BY 06Z. ..CARBIN.. 12/20/2006 ...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...DDC...LUB...AMA...MAF...PUB...ABQ...EPZ... 37850167 37550100 37240081 36700064 36020076 35460105 34890154 34240228 33080348 32680448 32440513 33420546 34320542 35240528 35590488 36200444 36710356 37120277 37160269 37750236  From mcd at goshenarc.org Wed Dec 20 00:50:59 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Tue, 19 Dec 2006 19:50:59 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200051 SWOMCD SPC MCD 200051 NEZ000-KSZ000-COZ000-200645- MESOSCALE DISCUSSION 2282 NWS STORM PREDICTION CENTER NORMAN OK 0651 PM CST TUE DEC 19 2006 AREAS AFFECTED...WRN AND CENTRAL NEB CONCERNING...WINTER MIXED PRECIPITATION VALID 200051Z - 200645Z FREEZING RAIN MIXED WITH SLEET AT TIMES IS EXPECTED TO DEVELOP NWD INTO WRN NEB THROUGH 06Z. MDT ACCUMULATION RATES /UP TO 0.05 IN PER HR/ OF FREEZING RAIN WILL BE POSSIBLE...ESPECIALLY OVER SWRN AND PORTIONS OF SCENTRAL NEB. STRONG WAA COMBINED WITH UPPER LEVEL DIFFLUENCE WILL CONTINUE TO SUPPORT NWD MOVEMENT OF PRECIPITATION OUT OF FAR ERN CO AND WRN KS INTO SWRN/SCENTRAL NEB OVER THE NEXT SEVERAL HRS. THE 00Z DDC SOUNDING INDICATED A SUBSTANTIAL ELEVATED WARM LAYER ATOP A SHALLOW SUBFREEZING LAYER WHICH WOULD SUPPORT FREEZING RAIN AS THE PRIMARY PTYPE. PORTIONS OF WCENTRAL/NCENTRAL NEB MAY SEE A MIX OF SLEET AS THE WARM LAYER WILL BE LESSER IN VERTICAL EXTENT IN THIS AREA INITIALLY. THE 00Z LBF SOUNDING ALONG WITH SFC OBS INDICATE DRY AIR IN THE LOWEST 1 KM. THIS LAYER WILL INITIALLY LIMIT ACCUMULATIONS/RATES ACROSS PORTIONS OF CENTRAL NEB. HOWEVER GIVEN THE STRENGTH OF THE WARM ADVECTION /AND MODERATE PRECIP RATES FALLING OUT OF CONVECTIVE SHOWERS/ SATURATION SHOULD CONTINUE STEADILY NWD THROUGH 06Z. ..CROSBIE.. 12/20/2006 ...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...GID...LBF...GLD...BOU... 40189920 40999916 42329971 42600073 42140212 40690206 39990169  From mcd at goshenarc.org Wed Dec 20 06:00:39 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 01:00:39 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 200601 SWOMCD SPC MCD 200601 NEZ000-SDZ000-KSZ000-OKZ000-TXZ000-201200- MESOSCALE DISCUSSION 2283 NWS STORM PREDICTION CENTER NORMAN OK 1201 AM CST WED DEC 20 2006 AREAS AFFECTED...MUCH OF CNTRL NEBRASKA...WRN KS AND PORTIONS OF THE OK/TX PANHANDLES CONCERNING...FREEZING RAIN VALID 200601Z - 201200Z AREAS OF MDT TO OCCASIONALLY HEAVY FREEZING RAIN WILL CONTINUE FOR A FEW MORE HOURS ACROSS WRN KS...THE ERN OK PANHANDLE AND NERN TX PANHANDLE WITH HRLY ACCUMULATIONS OF 0.10 - 0.20". FARTHER N...FREEZING RAIN WILL SPREAD NEWD ACROSS CNTRL NEBRASKA...WITH HRLY RATES OF 0.05-0.10". LARGE AREA OF WARM ADVECTION PRECIPITATION CONTINUES TO SPREAD NWD AHEAD OF UPPER TROUGH. COOLING ALOFT WILL EVENTUALLY ALLOW FOR A CHANGEOVER TO SNOW ACROSS WRN TX/OK PANHANDLES...BUT NOT BEFORE 1-3 MORE HOURS OF SIGNIFICANT ICING. FARTHER N...STRONG SELY 850 MB FLOW WILL MAINTAIN FREEZING RAIN PROFILES FOR SEVERAL MORE HOURS FROM WRN KS INTO NEBRASKA. LOW LEVEL PROFILES CONTINUE TO SATURATE OVER CNTRL NEBRASKA...WITH SURFACE WET BULB TEMPERATURES BELOW FREEZING. THUS...FREEZING RAIN IS LIKELY TO MATERIALIZE OVERNIGHT WITH 0.05 - 0.10"/HR POSSIBLE...CONTINUING AFTER SUNRISE. ..JEWELL.. 12/20/2006 ...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...FSD...OAX...GID...LBF...DDC...GLD...AMA... 42930059 42879827 41859712 41379691 40859797 40299871 39179928 37869995 36590064 36300077 36330118 36790126 38270123 39780117 40560122 41140116 42320154  From mcd at goshenarc.org Wed Dec 20 12:08:57 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 07:08:57 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201209 SWOMCD SPC MCD 201209 NEZ000-KSZ000-COZ000-WYZ000-201615- MESOSCALE DISCUSSION 2284 NWS STORM PREDICTION CENTER NORMAN OK 0609 AM CST WED DEC 20 2006 AREAS AFFECTED...ERN CO PLAINS...URBAN CORRIDOR...SWRN NEB AND NWRN KS CONCERNING...HEAVY SNOW VALID 201209Z - 201615Z SNOW WILL CONTINUE TO SPREAD/DEVELOP NWWD FROM THE ECNTRL/SERN CO PLAINS AND WRN KS TO THE DEN URBAN CORRIDOR...NERN CO AND SWRN NEB THROUGH 18Z. HOURLY SNOWFALL RATES OF 1-2 INCHES CAN BE EXPECTED WITH A BLIZZARD LIKELY DEVELOPING LATER THIS MORNING. WATER VAPOR IMAGERY SHOWS THE CENTER OF UPPER LOW IN CNTRL NM. H7 LOW WAS FORMING OVER NERN NM WITH INCREASING NLY FLOW NOTED ON VWP/PROFILERS OVER ERN CO. THE H7 LOW WILL INTENSIFY AND MOVE VERY SLOWLY INTO SERN CO BY THIS AFTN. STRONG H5-H3 QVEC CONVERGENCE WILL SPREAD NWD ACROSS ERN CO...WRN KS AND SWRN NEB BY MID-MORNING...WITH STRONGEST UNDERLYING H7-H6 FRONTOGENESIS SHIFTING TO THE DEN URBAN CORRIDOR/PALMER DIVIDE AND NERN CO PLAINS BY 18Z. INCREASING QG ASCENT SHOULD BEGIN TO OVERWHELM THE DRY AIR/DOWNSLOPING OFF THE CHEYENNE RIDGE AND HEAVY SNOWFALL RATES SHOULD ENSUE AS THE MORNING PROGRESSES FARTHER NORTH AND WEST. POTENTIAL EXISTS FOR INTENSE MESOSCALE BANDING AS NEGATIVE MPVG/POTENTIAL SLANTWISE CONVECTION BECOMES COINCIDENT WITH THE FRONTOGENESIS BETWEEN 15-18Z. MOREOVER...AS THE SYSTEM BECOMES MORE VERTICALLY STACKED OVER SERN CO...EVIDENCE OF A TROWAL DEVELOPS INTO NERN CO BY 18Z...FURTHER LENDING CONFIDENCE OF VERY HEAVY SNOWFALL. BEST COMBINATION OF LARGE SCALE SUPPORT AND POTENTIAL MESOSCALE BANDING VCNTY MOST INTENSE UPSLOPE COMPONENT WILL OCCUR ALONG THE PALMER DIVIDE. FINALLY...INCREASING PRESSURE GRADIENTS WILL CONTRIBUTE TO ACCELERATING WINDS WITH H7 SPEEDS FORECAST TO 55 KTS ALONG THE PALMER DIVIDE AT 18Z. GIVEN VERY HEAVY SNOWFALL RATES AND THE DRY NATURE OF THE SNOW...EVOLUTION INTO A BLIZZARD IS LIKELY BY AFTN AND ESPECIALLY ALONG THE PALMER DIVIDE. ..RACY.. 12/20/2006 ...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...LBF...GLD...PUB...BOU...CYS... 38480412 38910433 39120453 39210499 39330545 39720575 40330578 40640574 40750474 41090382 41440295 41440245 41390209 41230164 41010126 40670098 40100077 39670084 39410116 39330182 39310213 39060225 38750229 38590237 38510270 38470314 38470353  From mcd at goshenarc.org Wed Dec 20 12:11:53 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 07:11:53 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201212 SWOMCD SPC MCD 201211 NEZ000-KSZ000-201615- MESOSCALE DISCUSSION 2285 NWS STORM PREDICTION CENTER NORMAN OK 0611 AM CST WED DEC 20 2006 AREAS AFFECTED...NCNTRL KS AND CNTRL NEB CONCERNING...FREEZING RAIN VALID 201211Z - 201615Z FREEZING RAIN...AT TIMES MIXED WITH SLEET...WILL CONTINUE ACROSS NCNTRL KS AND CNTRL NEB THROUGH THE MORNING. HRLY RATES WILL GENERALLY BE AROUND 0.10 INCH...BUT COULD APPROACH 0.25 INCH IN THE HEAVY SHOWERS. PROFILERS/VWPS CONTINUE TO SHOW A VERY STRONG WARM ADVECTION PATTERN ACROSS THE CNTRL PLAINS THIS MORNING. A LARGE SHIELD OF PCPN CONTINUES TO SURGE NWD ASSOCD WITH THE WARM CONVEYOR AHEAD OF THE NM UPPER LOW. WHILE A DRY SLOT BEGINS TO ENCROACH ON SWRN/CNTRL KS THROUGH MID-MORNING...DEVELOPMENT OF LIGHT-MDT RAIN WILL LIKELY CONTINUE OVER NCNTRL KS INTO CNTRL NEB COINCIDENT WITH LOW-LEVEL FRONTOGENESIS. SFC FREEZING LINE WILL LIKELY CREEP NWWD THROUGH LATE MORNING AS LOW-LEVEL WARM/MOIST ADVECTION CONTINUES. BUT...AREAS NW OF A KOFK-KGRI-KHLC LINE WILL HAVE HIGH PROBABILITIES OF REMAINING AOB FREEZING THROUGH THE MORNING. COLDEST SFC TEMPERATURES WILL REMAIN OVER CNTRL NEB. RUC FORECAST SOUNDINGS SUGGEST THAT A WARM NOSE CENTERED JUST ABOVE H8 OF 4-6 DEG C WILL REMAIN IN PLACE THROUGH LATE MORNING. LATEST SREF SHOWS HIGH PROBABILITIES FOR A FREEZING RAIN EVENT ACROSS ESPECIALLY CNTRL NEB THROUGH 18Z AT LEAST. AS STRONGER QVEC CONVERGENCE APPROACHES THE REGION NEAR 18Z...PRIND THAT THE COLUMN WILL BEGIN TO COOL SUFFICIENTLY FOR MORE OF A SLEET AND/OR SNOW PROFILE ACROSS WRN PORTIONS OF THE MCD AREA. THE HEAVIER SNOWFALL WILL BE LOCATED FARTHER WEST...SEE MCD #2284 FOR FURTHER DETAILS. ..RACY.. 12/20/2006 ...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...OAX...GID...LBF...GLD... 39490055 40110074 40490090 40700097 40980119 41240151 41850140 42410026 42789855 42709774 42289742 41839742 41019817 40529859 39979912 39599953 39280001 WWWW From mcd at goshenarc.org Wed Dec 20 17:44:14 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 12:44:14 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201745 SWOMCD SPC MCD 201744 COZ000-NMZ000-202345- MESOSCALE DISCUSSION 2286 NWS STORM PREDICTION CENTER NORMAN OK 1144 AM CST WED DEC 20 2006 AREAS AFFECTED...SE CO...ECNTRL CO...FAR NE NM CONCERNING...BLIZZARD VALID 201744Z - 202345Z HEAVY SNOW WILL CONTINUE ACROSS SE CO...ECNTRL CO AND FAR NE NM THIS AFTERNOON INTO THIS EVENING. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE LIKELY ESPECIALLY IN THE HIGHER TERRAIN. BLIZZARD CONDITIONS WILL ACCOMPANY THE HEAVY SNOW ESPECIALLY NEAR AND IN THE HIGHER TERRAIN. LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW OVER NE NM WITH A DEFORMATION ZONE LOCATED FROM JUST NORTHWEST OF THE LOW CENTER NEAR RATON NM EXTENDING NWD TO EAST OF PUEBLO CO. AN INVERTED TROUGH IS LOCATED ALONG THIS LINE WHERE HEAVY SNOWFALL IS ONGOING AND SHOULD PERSIST INTO THE EVENING. SEVERAL FACTORS ARE ENHANCING SNOWFALL RATES IN SE CO AND ECNTRL CO. FORECAST SOUNDINGS SHOW STEEP MID-LEVEL LAPSE RATES IN PLACE AND THE GRANADA CO PROFILER SHOWS BACKED ELY FLOW FROM ABOVE THE SFC TO NEAR 2 KM AGL. THIS ALONG WITH STRONG FRONTOGENETICAL FORCING ESPECIALLY IN THE FOOTHILLS OF SE CO AND IN THE HIGHER TERRAIN NEAR THE NM-CO STATE-LINE WILL ENHANCE SNOWFALL RATES OVER THE NEXT 3 TO 6 HOURS. IN ADDITION...OBJECTIVE ANALYSIS SHOWS 700 MB FLOW INCREASING ACROSS SE CO AND ECNTRL CO AND RESULTANT WINDS NEAR THE SFC SHOULD REMAIN STRONG OR INCREASE SLIGHTLY THIS AFTERNOON. AS A RESULT...HEAVY SNOW ALONG WITH BLIZZARD CONDITIONS ESPECIALLY NEAR THE FOOTHILLS WILL PERSIST. SNOWFALL RATES MAY DECREASE SOME THIS EVENING ESPECIALLY IN THE LOWER ELEVATIONS AS THE UPPER-SYSTEM BEGINS TO PULL AWAY FROM THE REGION. ..BROYLES.. 12/20/2006 ...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...GLD...PUB...BOU...ABQ... 36760363 36740469 37290533 37990555 38550546 39690519 39950418 39970354 39830316 39080252 37850258 37070284  From mcd at goshenarc.org Wed Dec 20 18:48:56 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 13:48:56 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 201849 SWOMCD SPC MCD 201849 NEZ000-SDZ000-COZ000-WYZ000-210045- MESOSCALE DISCUSSION 2287 NWS STORM PREDICTION CENTER NORMAN OK 1249 PM CST WED DEC 20 2006 AREAS AFFECTED...SERN WY...WRN AND NCENTRAL NEB...SCENTRAL SD CONCERNING...WINTER MIXED PRECIPITATION VALID 201849Z - 210045Z HEAVY SNOW WITH HRLY RATES OVER 1 INCH COMBINED WITH STRONG NLY WINDS /SUPPORTING BLIZZARD CONDITIONS/ WILL CONTINUE TO DEVELOP NWD OVER SERN WY AND THE NEB PANHANDLE THROUGH 21Z. ACROSS NCENTRAL NEB/SCENTRAL SD...FREEZING RAIN WILL INITIALLY BE THE PRIMARY P-TYPE THROUGH 21Z. A CHANGEOVER TO SLEET AND/OR HEAVY SNOW IS ANTICIPATED TO DEVELOP EWD ACROSS WRN/NCENTRAL NEB AND SCENTRAL SD IN THE 21-00Z PERIOD. RECENT MBW AND MRR PROFILERS INDICATE INCREASING WIND FIELDS IN THE 2-4 KM LAYER. MID LEVEL WINDS HAVE ALSO RECENTLY BACKED AT THE MRR PROFILER FURTHER INDICATING A RESPONSE TO STRONG FRONTOGENESIS OCCURRING OVER SERN WY AND THE NEB PANHANDLE. AS THE MID LEVEL LOW OVER NERN NM CONTINUES TO LIFT SLOWLY NEWD INTO WRN KS THROUGH THE AFTERNOON...THE MID LEVEL DRYSLOT WILL CONTINUE TO MOVE INTO NERN CO. THIS WILL FURTHER AID IN MAINTAINING STRONG FRONTOGENETIC FORCING SUPPORTING HEAVY SNOWFALL DEVELOPMENT. MODERATE SFC PRESSURE FALLS WILL CONTINUE TO OCCUR OVER NWRN KS AND SWRN NEB IN ADVANCE OF THE UPPER LOW ASSOCIATED WITH STRONG UPPER TROPOSPHERIC WARM ADVECTION. THIS WILL SUPPORT AN INCREASE IN SFC WINDS OVER MUCH OF WRN/CENTRAL NEB...SERN WY AND EVENTUALLY SCENTRAL SD TOWARD 00Z. SHALLOW SUBFREEZING AIR WILL CONTINUE TO EXIST OVER PORTIONS OF NCENTRAL NEB AND SCENTRAL SD...SUPPORTED BY LOW LEVEL DRY AIR ADVECTION. AS MODERATE LOW LEVEL WARM ADVECTION CONTINUES... FREEZING RAIN WILL BE THE PRIMARY PTYPE IN THIS AREA FOR THE NEXT SEVERAL HRS BEFORE A CHANGEOVER TO SLEET OCCURS AFTER 21Z AS THE MID LEVEL SYSTEM GRADUALLY SHIFTS NEWD AND LOW LEVEL COOLING OCCURS. IN ADDITION..MODERATE RAINFALL FALLING ACROSS PORTIONS OF WRN NEB SHOULD CHANGEOVER TO HVY SNOW AFTER 21Z. THE ANTICIPATED HVY SNOW/RAIN LINE SHOULD EXTEND FROM ANW TO LBF TO MCK BY 00Z. ..CROSBIE.. 12/20/2006 ...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...ABR...LBF...UNR...BOU...CYS... 43669957 42910243 42150533 40840505 41040252 41390081 42939953  From mcd at goshenarc.org Thu Dec 21 00:21:37 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 19:21:37 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210022 SWOMCD SPC MCD 210022 NEZ000-KSZ000-COZ000-WYZ000-210615- MESOSCALE DISCUSSION 2288 NWS STORM PREDICTION CENTER NORMAN OK 0622 PM CST WED DEC 20 2006 AREAS AFFECTED...NERN CO / FAR SERN WY / SWRN NEB CONCERNING...BLIZZARD VALID 210022Z - 210615Z PERIODS OF HEAVY SNOW WITH HOURLY RATES OF UP TO 1-1.5 INCHES ARE EXPECTED TO CONTINUE THROUGH 21/06Z. WHEN COUPLED WITH NLY/NELY WINDS OF 30-40 MPH...BLIZZARD OR NEAR BLIZZARD CONDITIONS WILL CONTINUE FROM THE CHEYENNE RIDGE AND CO FRONT RANGE EWD INTO THE HIGH PLAINS. LATE AFTERNOON/EARLY EVENING WATER VAPOR IMAGERY INDICATES DEEP UPPER LOW BEGINNING TO DEVELOP MORE NEWD INTO SWRN KS WITH STRONGEST HEIGHT FALLS SHIFTING THROUGH CNTRL/ERN KS AND SRN NEB. INITIAL DEFORMATION BAND OVER MUCH OF NEB WWD ACROSS ERN CO HAS WEAKENED THIS AFTERNOON...PERHAPS IN ASSOCIATION WITH NWD DEVELOPMENT OF SYSTEM DRY SLOT ALONG ERN PERIPHERY OF MID-LEVEL CIRCULATION. HOWEVER...IR CLOUD TOP TEMPERATURES AND RADAR REFLECTIVITY DATA SHOW THE INITIAL STAGES OF SECONDARY DEFORMATION ZONE DEVELOPMENT FROM NEAR AKO EWD THROUGH IML TO NEAR BBW. WATER VAPOR IMAGERY AND SHORT TERM GUIDANCE SUGGEST THAT THIS EVOLUTION IS LIKELY IN RESPONSE TO STRONG VORTICITY MAXIMUM ROTATING AROUND UPPER LOW. AS THIS VORTICITY MAXIMUM CONTINUES N AND THEN NW OF UPPER TONIGHT...EXPECT THAT PRECIPITATION SHIELD WILL EXPAND/INTENSIFY FROM NERN CO EWD INTO CNTRL NEB WITH HOURLY SNOW RATES APPROACHING 1-1.5 INCHES. 21/00Z DEN SOUNDING INDICATES A SHALLOW LAYER /BETWEEN 550-500 MB/ OF CONDITIONALLY UNSTABLE LAPSE RATES WITH ISOLATED LIGHTNING STRIKES OBSERVED ALONG THE FRONT RANGE THIS AFTERNOON AND EARLY EVENING. ANY EMBEDDED CONVECTIVE ELEMENTS WILL BE CAPABLE OF SNOW RATES APPROACHING TWO INCHES/HOUR. IN ADDITION TO THE HEAVY SNOW...STRONG NLY/NELY WINDS OF 25-35 MPH GUSTING TO 40-45 MPH ARE RESULTING IN BLIZZARD OR NEAR BLIZZARD CONDITIONS ACROSS THE REGION...A TREND WHICH SHOULD CONTINUE THROUGH 21/06Z. EXPECT SNOW RATES TO BEGIN TO DIMINISH ALONG THE FRONT RANGE THEREAFTER. ..MEAD.. 12/21/2006 ...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...LBF...GLD...PUB...BOU...CYS... 39240473 40540506 41410494 42080420 42090304 41200197 40710160 39730172 38980230 38710372  From mcd at goshenarc.org Thu Dec 21 00:56:58 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Wed, 20 Dec 2006 19:56:58 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 210057 SWOMCD SPC MCD 210057 NEZ000-SDZ000-COZ000-210700- MESOSCALE DISCUSSION 2289 NWS STORM PREDICTION CENTER NORMAN OK 0657 PM CST WED DEC 20 2006 AREAS AFFECTED...CNTRL INTO N-CNTRL NEB CONCERNING...HEAVY SNOW VALID 210057Z - 210700Z HEAVY SNOW WITH HOURLY RATES OF 1-1.5 INCHES IS FORECAST TO BECOME INCREASING COMMON ACROSS DISCUSSION AREA THROUGH 21/06Z. EMBEDDED POCKETS OF FREEZING RAIN WILL ALSO REMAIN POSSIBLE...MAINLY FROM BBW NEWD THROUGH BUB AND ONL. AS MENTIONED IN MCD 2288...A SECONDARY DEFORMATION BAND/PRECIPITATION SHIELD APPEARS TO BE DEVELOPING FROM NEAR AKO ENEWD THROUGH LBF/BBW WITH SOME REINTENSIFICATION NOTED WITHIN INITIAL BAND OVER CHERRY COUNTY. THIS ENHANCEMENT IN CLOUDS/PRECIPITATION APPEARS TO BE ARISING FROM STRONG VORTICITY MAXIMUM ROTATING NWD AROUND UPPER LOW OVER SWRN CO...COUPLED WITH LOW-LEVEL WAA OCCURRING TO THE N OF SURFACE FRONTAL OCCLUSION. CURRENTLY...SURFACE OBSERVATIONS INDICATE A NARROW CORRIDOR OF FREEZING RAIN FROM LBF/BBW NEWD TOWARD ANW/ONL...WITH A CHANGE OVER TO SNOW FORECAST THIS EVENING FROM W-E AS COLD AIR DEEPENS ON BACKSIDE OF SYNOPTIC SYSTEM. PERIODS OF FREEZING RAIN WITH HOURLY RATES OF .01 TO .05 INCHES MAY PERSIST THROUGH 21/06Z FROM BBW TO ONL. OTHERWISE...EXPECT THAT THE STRENGTHENING LARGE SCALE FORCING AHEAD OF VORTICITY MAXIMUM WILL SUPPORT AN INCREASE IN SNOW COVERAGE AND INTENSITY IN A BAND FROM IML AND SNY EWD THROUGH LBF/MHN/ANW AREAS WITH SNOW RATES APPROACHING 1-1.5 INCHES THROUGH MIDNIGHT CST. ..MEAD.. 12/21/2006 ...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...GID...LBF...UNR...BOU...CYS... 41580285 42310279 42740218 42990115 43000044 42979885 42509836 41559842 41119930 40910063 40930230 41220255  From mcd at goshenarc.org Sun Dec 31 19:45:19 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 14:45:19 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 311949 SWOMCD SPC MCD 311949 GAZ000-FLZ000-312145- MESOSCALE DISCUSSION 2342 NWS STORM PREDICTION CENTER NORMAN OK 0149 PM CST SUN DEC 31 2006 AREAS AFFECTED...SRN GA THROUGH NRN FL CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 311949Z - 312145Z LINE OF STORMS MOVING E THROUGH SRN GA AND THE ERN FL PANHANDLE MAY BE CAPABLE OF PRODUCING MAINLY ISOLATED DAMAGING WIND ALONG WITH AN OUTSIDE CHANCE OF A BRIEF TORNADO THROUGH EARLY EVENING. PRE-FRONTAL LINE OF STORMS FROM SWRN GA THROUGH THE ERN FL PANHANDLE IS MOVING E AT AROUND 15 TO 20 KT. ACTIVITY IS DEVELOPING ALONG WARM CONVEYOR BELT WITHIN ZONE OF 850 MB CONFLUENCE. WARMING AND MOISTENING OF THE BOUNDARY LAYER JUST DOWNSTREAM FROM THE LINE HAS CONTRIBUTED TO SOME DESTABILIZATION. HOWEVER...MLCAPE REMAINS AOB 500 J/KG DUE TO MODEST MID LEVEL LAPSE RATES. RECENT VWP DATA STILL SHOW SUFFICIENT VERTICAL WIND PROFILES FOR ORGANIZED STORM STRUCTURES WITHIN THE LINE WITH 0-1 KM STORM RELATIVE HELICITY AROUND 200 M2/S2 AND DEEP LAYER SHEAR ON THE ORDER OF 35 KT. HOWEVER...LIMITING FACTORS WILL BE WEAK INSTABILITY AND A TENDENCY FOR THE BOUNDARY LAYER FLOW TO GRADUALLY VEER AND WEAKEN WITH TIME AS STRONGER FORCING ASSOCIATED WITH UPPER JET LIFTS TOWARD THE TN AND OH VALLEYS. ..DIAL.. 12/31/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...JAX...FFC...TAE... 32058167 30738202 30018310 30148424 31118405 32438348 WWWW From mcd at goshenarc.org Sun Dec 31 20:56:13 2006 From: mcd at goshenarc.org (Mesoscale Convective Discussions) Date: Sun, 31 Dec 2006 15:56:13 -0500 Subject: [MCD] SWOMCD Message-ID: ACUS11 KWNS 312100 SWOMCD SPC MCD 312100 GAZ000-ALZ000-312330- MESOSCALE DISCUSSION 2343 NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CST SUN DEC 31 2006 AREAS AFFECTED...EXTREME ERN AL...NWRN GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 312100Z - 312330Z THERE IS A CONDITIONAL THREAT FOR AN ISOLATED TORNADO ACROSS EXTREME NERN AL INTO NRN/WRN GA THIS AFTERNOON. 20Z SURFACE ANALYSIS SHOWS COLD FRONT NOW MOVING ACROSS E-CNTRL AL...WITH A WARM FRONT DRAPED ACROSS NRN GA INTO CNTRL SC. SOUTH OF THIS BOUNDARY...AN INITIAL SQUALL LINE CONTINUES TO MOVE EWD ACROSS CNTRL/SRN GA INTO NRN FL. MEANWHILE...THE AIR MASS IS ATTEMPTING TO RECOVER W OF THE SQUALL LINE WITH TEMPERATURES INTO THE LOWER 70S OVER ERN AL/SWRN GA...AND DEWPOINTS IN THE MID 60S. SMALL STORM CELLS ARE CURRENTLY DEVELOPING OVER ERN AL ALONG THE FRONT...AIDED BY UPPER LEVEL DIVERGENCE. INSTABILITY LEVELS ARE CURRENTLY LOW...BUT MAY INCREASE A BIT WITH SSWLY 850 MB FLOW AHEAD OF THE WIND SHIFT. SHEAR PROFILES ARE QUITE STRONG AROUND ATLANTA WITH 200-300 M2/S2 EFFECTIVE SRH SOUTH OF THE WARM FRONT...AND INCREASED MID LEVEL JET SPEEDS NOTED RECENTLY ON VWP. GIVEN CONTINUED FORCING COMING OUT OF AL...PRESENCE OF WARM FRONT...AND SURFACE BASED INSTABILITY...AN ISOLATED STRONG/SEVERE STORM WILL BE POSSIBLE WITH THE THREAT OF A TORNADO AND/OR LOCALLY DAMAGING WIND GUST. ..JEWELL.. 12/31/2006 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GSP...FFC...BMX...HUN... 32638589 33298582 34138576 34768571 34888515 34648383 34218315 33818319 33408352 33188371 32948403 32728433 32638492 32558558