SWODY2
SPC AC 151724
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1224 PM CDT THU APR 15 2010
VALID 161200Z - 171200Z
...NO SVR TSTM AREAS FORECAST...
...OH VALLEY...
UPPER TROUGH MOVING EWD INTO NRN ONTARIO AND UPPER MS VALLEY DURING
DAY 1 IS EXPECTED TO AMPLIFY ACROSS THE GREAT LAKES AND INTO THE OH
VALLEY ON FRIDAY. AT 12Z FRIDAY...A COLD FRONT ASSOCIATED WITH THIS
TROUGH SHOULD EXTEND FROM THE LOWER GREAT LAKES THROUGH NRN MO TO
SRN KS AND THE OK PANHANDLE. THIS FRONT WILL MOVE STEADILY S/SEWD
INTO THE OH VALLEY...WHILE A NNW-SSE ORIENTED WARM FRONT MOVES
SLOWLY EWD INTO ERN PA/SERN NY. MODELS REMAIN CONSISTENT IN SHOWING
AN INCREASE IN WLY MID LEVEL WINDS /50-60 KT/ WITHIN THE 700-500 MB
LAYER ACROSS THE UPPER OH VALLEY TO THE CENTRAL APPALACHIANS WITH
THE APPROACH OF THE UPPER TROUGH. THIS INCREASE IN DEEP LAYER WIND
FIELDS...WITH A WLY LLJ AROUND 40 KT THROUGH THE UPPER OH
VALLEY...SUPPORT STRONG EFFECTIVE BULK SHEAR AND LOW LEVEL SPEED
SHEAR FOR BOTH STRONG WIND GUSTS AND AN ISOLATED TORNADO POTENTIAL.
HOWEVER...THE PRIMARY LIMITING FACTOR FOR GREATER SEVERE
PROBABILITIES AND THE INTRODUCTION OF A CATEGORICAL OUTLOOK REMAINS
WITH THE RELATIVELY POOR THERMODYNAMICS. SURFACE DEWPOINTS IN THE
MID 50S AND DIABATIC HEATING WILL SUPPORT SUFFICIENT DESTABILIZATION
FOR TSTMS ALONG THE COLD FRONT...BUT WEAK LAPSE RATES SHOULD TEND TO
PRECLUDE THE DEVELOPMENT OF STRONGER INSTABILITY. IF GREATER
INSTABILITY IS EXPECTED...THEN A SLIGHT RISK MAY BE NEEDED IN
UPCOMING DAY 1 OUTLOOKS.
...PACIFIC NW TO ERN UT/WRN CO TO WRN NM...
COMPACT LOW/SHORT WAVE TROUGH...CURRENTLY LOCATED OVER THE ERN
PACIFIC /W OF CA/ AT 34N/135W PER WATER VAPOR IMAGERY...IS EXPECTED
TO REACH THE CA COAST BY 12Z FRIDAY. THIS TROUGH WILL SPLIT DURING
DAY 2 WITH THE NRN PORTION TRACKING NNEWD INTO ORE/WA...WHILE THE
SRN EXTENT MOVES THROUGH THE GREAT BASIN TO FOUR CORNERS. STEEP
LAPSE RATES EXTENDING NWWD FROM WRN NM TO THE PACIFIC NW AND FORCING
FOR ASCENT ATTENDANT TO THE TWO TROUGHS WILL SUPPORT TSTM
DEVELOPMENT FRIDAY AFTERNOON INTO THE EVENING. ALTHOUGH SURFACE
MOISTURE WILL BE MEAGER...STRONG SURFACE HEATING AND STEEP LAPSE
RATES SHOULD SUPPORT AT LEAST VERY WEAK INSTABILITY /SBCAPE OF A FEW
HUNDRED J PER KG/. INVERTED-V THERMODYNAMIC PROFILES SUGGEST THE
POTENTIAL FOR A FEW STRONG WIND GUSTS THROUGHOUT THIS GENERAL TSTM
AREA. THE GREATEST POTENTIAL...THOUGH TOO LOW TO INTRODUCE SEVERE
PROBABILITIES...WOULD BE ACROSS SWRN NM AND NERN ORE/ERN WA WHERE
EFFECTIVE BULK SHEAR 25-30 KT SUPPORTS POTENTIAL FOR A FEW ORGANIZED
STORMS. HOWEVER...THE VERY WEAK INSTABILITY SHOULD GREATLY LIMIT
THE OVERALL COVERAGE OF THIS THREAT.
..PETERS.. 04/15/2010
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