[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 201814
SWODY1
SPC AC 201813

DAY 1 CONVECTIVE OUTLOOK RESENT 1
NWS STORM PREDICTION CENTER NORMAN OK
0113 PM CDT WED APR 20 2005

VALID 201630Z - 211200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 WNW
DRT CDS DDC 55 NNE GCK 20 NNE COS 50 SW LAR 45 SSW DGW 20 W CDR 25
ENE ANW 55 ESE SUX 30 E MMO TOL 25 NNE UCA 10 SW ALB 15 WSW POU 35 W
ABE 20 ESE ZZV 45 N SDF 35 NNE JLN 40 NW BVO 65 WSW COT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SSW P07 20 WNW BGS
65 NNE AMA 20 E LBL 25 W GCK 15 ESE ALS 4BL 20 SSW U24 40 ENE ELY
EKO 50 NNW OWY 65 N BOI 65 E S80 3DU 45 ESE GDV 40 NNW MBG 20 W ABR
30 E BKX 40 W LNR MKG 30 NE MBS ...CONT... 30 SSW WAL 30 E LYH 20 E
CSV 20 WNW CHA 15 ESE GAD 10 WNW DHN 30 SSE CEW ...CONT... 55 W 3B1
10 S EPM.

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL/SRN
PLAINS EWD ACROSS THE OH VALLEY INTO THE NERN STATES...

...SYNOPSIS...
MORNING WATER VAPOR IMAGERY SHOWS MID/UPPER-LEVEL LOW OVER NRN UT
WITH ASSOCIATED SHORTWAVE TROUGH/JET STREAK ROTATING NEWD AROUND
THIS LOW THROUGH NRN AZ/SRN UT INTO WRN CO. ADDITIONAL DOWNSTREAM
FEATURES OF NOTE WERE MCV OVER S-CNTRL IA INTO NRN MO AND SHORTWAVE
TROUGH OVER LOWER MI. MEANWHILE...PROGRESSIVE SUBTROPICAL BRANCH OF
WESTERLIES IS PRESENT FROM BAJA EWD ACROSS NRN MEXICO AND SRN TX
WITH AN APPARENT LOW-AMPLITUDE DISTURBANCE CURRENTLY OVER CHIHUAHUA
MEXICO.

IN THE LOW LEVELS...MESOANALYSIS INDICATES PRIMARY SURFACE LOW OVER
WRN KS WITH OUTFLOW BOUNDARY SLOWLY SAGGING SWD THROUGH CNTRL KS IN
WAKE OF TSTM CLUSTER OVER IA/MO. QUASI-STATIONARY BOUNDARY EXTENDED
ENEWD FROM THIS CONVECTIVE ACTIVITY ACROSS THE SRN GREAT LAKES INTO
CNTRL NEW ENGLAND.

...CNTRL HIGH PLAINS...
GIVEN WIDESPREAD STRATUS AND LOW-LEVEL RIDGING OBSERVED THIS MORNING
FROM ERN WY/WRN SD SWD INTO WRN NEB AND NERN CO...SEVERAL CONCERNS
EXIST REGARDING POTENTIAL FOR AIR MASS DESTABILIZATION TODAY AHEAD
OF APPROACHING SHORTWAVE TROUGH/SPEED MAX. WHILE SOME NWD EROSION OF
LOW CLOUDS WILL LIKELY OCCUR TODAY IN RESPONSE TO INCREASE PRESSURE
FALLS OVER NERN CO INTO NWRN KS...SWRN NEB...IT APPEARS THAT LATEST
SHORT TERM MODELS MAY BE TOO AGGRESSIVE IN DESTABILIZING AIR MASS
NWWD INTO THE CHEYENNE RIDGE.

CURRENT THINKING IS THAT TSTMS WILL INITIALLY DEVELOP AND INTENSIFY
BY AFTERNOON OVER THE FRONT RANGE WHERE LOCALLY STRONGER DIABATIC
HEATING AND RESULTANT STEEPENING OF LOW/MID-LEVEL LAPSE RATES WILL
CONTRIBUTE TO WEAK TO MODERATE INSTABILITY. TSTMS SHOULD GRADUALLY
MOVE/DEVELOP OFF THE HIGHER TERRAIN INTO ADJACENT PLAINS OF NERN CO
AND SWRN NEB/NEB PNHDL...THOUGH THE MAJORITY OF ACTIVITY MAY WELL
REMAIN SLIGHTLY ELEVATED. NONETHELESS... SUFFICIENT EFFECTIVE BULK
SHEAR WILL EXIST TO SUPPORT SUPERCELLS CAPABLE OF PRIMARILY LARGE
HAIL. GREATEST LIKELIHOOD FOR MORE SURFACE BASED DEVELOPMENT WILL
OCCUR ALONG SRN EDGE OF STRATUS OVER NERN CO...AS WELL AS OVER
DEVELOPING TRIPLE POINT OVER NWRN KS INTO SWRN NEB. COMBINATION OF
MODERATE INSTABILITY /MLCAPES OF 1000-1500 J/KG/ AND 40-50 KTS OF
DEEP-LAYER SHEAR SUGGEST THE POTENTIAL FOR SUPERCELLS CAPABLE OF
DAMAGING WINDS...LARGE HAIL AND ISOLATED TORNADOES.

UPSCALE GROWTH INTO AN MCS WILL LIKELY OCCUR TONIGHT ALONG
DEVELOPING 40-45 KT LLJ AXIS WITH ASSOCIATED WIND/HAIL THREAT
SPREADING EWD ACROSS NEB/NRN KS.

...IA/MO INTO THE OH VALLEY...
REMNANT NOCTURNAL MCS IS IN PROGRESS THIS MORNING OVER S-CNTRL IA
INTO N-CNTRL MO. THOUGH SWLY LLJ /PER 12Z UPPER-AIR OBSERVATIONS/ IS
FORECAST TO WEAKEN...EVOLVING MCV COUPLED WITH DESTABILIZING
DOWNSTREAM AIR MASS MAY WELL SUPPORT ONGOING ACTIVITY EWD INTO THE
OH VALLEY THIS AFTERNOON INTO TONIGHT. MODEST WLY MID-LEVEL FLOW
OBSERVED ON 12Z OAX SOUNDING IN CONJUNCTION WITH DEEPENING...
DESTABILIZING BOUNDARY LAYER WILL SUPPORT A FEW STRONG WIND GUSTS IN
ADDITION TO LARGE HAIL.

...UPPER OH VALLEY INTO THE HUDSON VALLEY...
A SECONDARY TSTM CLUSTER IS IN PROGRESS THIS MORNING FROM WRN LAKE
ERIE INTO N-CNTRL OH AHEAD OF SHORTWAVE TROUGH MOVING ACROSS LOWER
MI. PRESENCE OF MODERATELY STEEP MID-LEVEL LAPSE RATES AND STRONG
DIABATIC HEATING SHOULD SUPPORT DESTABILIZATION OF DOWNSTREAM AIR
MASS ACROSS PA/NY...WHICH SHOULD SUSTAIN ONGOING CONVECTION EWD
TODAY INTO THIS EVENING. DEEP WLY FLOW/MODEST DEEP-LAYER SPEED SHEAR
SHOULD ENHANCE DOWNDRAFT POTENTIAL/EWD ELONGATION OF SYSTEM COLD
POOL WITH A FEW DAMAGING WIND GUSTS POSSIBLE.

...KS/OK/TX DRYLINE...
12Z REGIONAL SOUNDINGS INDICATE THE PRESENCE OF GRADUALLY IMPROVING
LOW-LEVEL MOISTURE BENEATH STEEP MID-LEVEL LAPSE RATES OF 7.5-8.5
C/KM. CURRENT WATER VAPOR IMAGERY AND PROFILER TIME/HEIGHT PLOTS
INDICATE A WEAK SHORTWAVE TROUGH LIFTING NEWD THROUGH PORTIONS OF
WRN/W-CNTRL TX. ADDITIONALLY...A LOWER AMPLITUDE DISTURBANCE IS
EVIDENT OVER CHIHUAHUA MEXICO...EMBEDDED IN
PROGRESSIVE...SUBTROPICAL JET CHANNEL.

STRONG DAYTIME HEATING COUPLED WITH BOUNDARY-LAYER DEWPOINTS IN THE
60S ARE EXPECTED TO CONTRIBUTE TO MODERATE TO STRONG INSTABILITY E
OF THE DRYLINE WITH MLCAPES INCREASING TO 2000-3000 J/KG. PRIMARY
UNCERTAINTY IS WHETHER DEEP CONVECTION WILL INITIATE. WHILE LATEST
DETERMINISTIC MODEL GUIDANCE SUGGESTS THAT AIR MASS WILL REMAIN
CAPPED...SOME ENSEMBLE MEMBERS DO INDICATE CONVECTIVE PRECIPITATION
ALONG DRYLINE LATE THIS AFTERNOON INTO EVENING. SHOULD STORMS
INITIATE...COMBINATION OF MODERATE INSTABILITY AND MARGINALLY STRONG
DEEP-LAYER SHEAR WILL SUPPORT ORGANIZED SEVERE STORMS INCLUDING A
SUPERCELL OR TWO WITH LARGE HAIL BEING THE PRIMARY SEVERE WEATHER
THREAT.

..MEAD/GUYER.. 04/20/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
WILL PROVIDE DETAILS ON THE TRANSITION.