SWODY1
SPC AC 151621
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT WED OCT 15 2008
VALID 151630Z - 161200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A PROGRESSIVE SHORTWAVE TROUGH WILL MOVE EWD FROM THE CENTRAL PLAINS
INTO THE ERN GREAT LAKES THROUGH TONIGHT. AN ASSOCIATED COLD FRONT
EXTENDED LATE THIS MORNING FROM NEAR ORD TO STL SWWD TO NEAR DFW AND
INTO SWRN TX. THIS FRONT WILL STEADILY MOVE SEWD AND EXTEND FROM THE
ERN GREAT LAKES INTO THE LOWER MS VALLEY/SERN TX BY 12Z THU. A
CONVECTIVE LINE IS EXPECTED TO DEVELOP IN THE NEXT FEW HOURS ALONG
THIS FRONT FROM PORTIONS OF ERN IL INTO SERN MO WITH THE POTENTIAL
FOR ISOLATED MARGINAL SVR WIND GUSTS AS THE ACTIVITY MOVES THROUGH
THE OHIO VALLEY. ADDITIONAL STRONG TSTMS ARE EXPECTED THROUGH THE
AFTERNOON FURTHER SOUTH ACROSS PORTIONS OF SRN/ERN TX AND LA
ASSOCIATED WITH A WEAKENING TROPICAL WAVE OVER SRN TX/NWRN GULF OF
MEXICO.
...MID MS/OHIO VALLEYS...
AS TEMPERATURES CONTINUE TO WARM INTO THE UPPER 70S/LOWER 80S
F...MUCAPE VALUES WILL RISE TO BETWEEN 500 AND 1000 J/KG BY 20Z
DEVELOPING CONVECTION ALONG THE FRONT FROM SWRN MO INTO WCENTRAL IL
WILL CONTINUE TO INTENSIFY AS IT ENCOUNTERS THE INCREASING
INSTABILITY OVER SERN MO...CENTRAL/SRN IL. 12Z SOUNDINGS INDICATE
POOR MID LEVEL LAPSE RATES OVER AND UPSTREAM OF THE AREA /OWING TO
AN INVERSION LAYER CENTERED NEAR 500 MB/. THIS WILL LIMIT UPDRAFT
STRENGTH...DESPITE MODESTLY STRONG MID LVL SWLY FLOW AND CONSEQUENT
MODERATE VERTICAL SHEAR /30-40 KTS FROM 0-6 KM/. MODERATE
UNIDIRECTIONAL LOW-MID LEVEL WIND FIELDS WILL SUPPORT CONVECTION
BECOMING ORGANIZED LINEARLY...WITH THE POTENTIAL FOR MARGINAL SVR
WIND GUSTS /ESP INVOF OF ANY SMALLER-SCALE BOWING SEGMENTS/. THE
THREAT FOR ISOLATED SVR WIND WILL DEVELOP INTO CENTRAL/SRN IN /SOUTH
OF A STATIONARY FRONT/ AND INTO FAR WRN OH/NWRN KY BEFORE WEAKENING
AROUND 00Z. GIVEN MARGINAL INSTABILITY GREATER SVR COVERAGE IS NOT
EXPECTED AND A SLIGHT RISK/15 PERCENT WIND PROBABILITIES/ WILL NOT
BE ISSUED.
...SERN/SRN TX...
ASSOCIATED WITH THE REMNANTS OF A WEAKENING ELY TROPICAL WAVE AND ON
THE SRN FRINGE OF THE WLYS...SCT TSTMS ARE EXPECTED OVER MUCH OF
SRN/SERN TX THIS AFTERNOON. ALTHOUGH MID LEVEL VERTICAL SHEAR WILL
REMAIN MODEST...MODERATELY INSTABILITY /MUCAPES AROUND 2500 J/KG//
WILL SUPPORT STRONG TSTMS CAPABLE OF PRODUCING GUSTY WINDS.
HOWEVER...WEAK LOW-MID LEVEL LAPSE RATES AND LIMITED VERTICAL SHEAR
SHOULD PRECLUDE ANY SVR WIND/HAIL THREAT.
THIS IS MY LAST PRODUCT AS AN SPC FORECASTER. IT HAS BEEN A PLEASURE
WORKING WITH EVERYONE AT SPC FOR THE LAST 7 YEARS.
..CROSBIE.. 10/15/2008
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