SWODY1
SPC AC 261609
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1109 AM CDT TUE AUG 26 2008
VALID 261630Z - 271200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SERN US...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL AND
NRN PLAINS...
...SERN STATES...
REMNANT CIRCULATION OF FAY OVER NRN AL DRIFTING NEWD AND BY 12Z WED
SHOULD BE INTO KY. LOW/MID LEVEL FLOW REMAINS SURPRISINGLY
STRONG/30-40KT/ E OF THE CENTER ACROSS GA CONSIDERING THE SYSTEM IS
MOVING FURTHER AWAY FROM THE GULF. AS A RESULT SHEAR IS SUPPORTIVE
OF LOW LEVEL ROTATION WITHIN ANY CONVECTIVE DEVELOPMENT AND IS
EXPECTED TO CONTINUE THRU MUCH OF THIS PERIOD.
ADDITIONALLY TODAY...THE AIR MASS AHEAD OF MAIN BAND OF
STRONG/SEVERE CONVECTION FROM GA TO SC WILL HEAT UP AND DESTABILIZE
THIS AFTERNOON GIVEN THE OBSERVED LIMITED CLOUD COVER. MLCAPES
EXPECTED TO RISE TO AOA 1500 J/G BY MID AFTERNOON WHICH ALONG WITH
THE FAVORABLE VEERING SHEAR PROFILES WILL CONTINUE TO SUPPORT
TORNADIC SUPERCELL POTENTIAL. AS LOW LEVEL FLOW GRADUALLY VEERS TO
MORE SWLY THE ROTATION/TORNADO THREAT SHOULD GRADUALLY DIMINISH FROM
W TO E ACROSS GA BY THIS EVENING. HOWEVER FURTHER N AND E INTO
SC/SRN NC BACKED LOW LEVEL FLOW VICINITY E/W BOUNDARY COULD MAINTAIN
SOME TORNADO CONCERN WELL INTO THE EVENING.
...NRN PLAINS...
STRONG COLD FRONT NOW ENTERING WRN DAKOTAS IS BEING SUPPORTED BY
VIGOROUS UPPER TROUGH CROSSING MT. THE WARM SECTOR AIR MASS AHEAD OF
THE FRONT IS CHARACTERIZED BY A MOIST LOW LEVEL SLY FLOW OF 30-40KT
...THAT IS CAPPED BY A PRONOUNCED EML IN THE MID/UPPER LEVELS WITH
LAPSE RATES NEAR 9C/KM. SINCE THE STRONG ASCENT AND MID LEVEL
COOLING WITH THE MT S/WV TROUGH SIGNIFICANTLY LAGS THE COLD
FRONT...IT WILL REQUIRE STRONG HEATING TO DISSIPATE THE CINH FOR
CONVECTIVE INITIATION. THIS SHOULD HAPPEN LATE THIS AFTERNOON AT
WHICH TIME MLCAPES TO 2000 J/KG WILL BE IN PLACE ACROSS THE DAKOTAS.
STRONG/SEVERE THUNDERSTORMS WILL FORM VICINITY THE COLD FRONT BY
MID/LATE AFTERNOON. SHEAR AND INSTABILITY WILL BE SUFFICIENT FOR
ISOLATED SUPERCELL POTENTIAL...HOWEVER GIVEN THE LAG TO THE UPPER
TROUGH THE SHEAR OF 30-40KT VICINITY FRONTAL ZONE WILL SUPPORT
MAINLY CLUSTERS AND SHORT LINE SEGMENTS. PRIMARY SEVERE THREAT WILL
BE LARGE HAIL AND LOCALIZED DAMAGING WINDS.
...SWRN DESERTS...
MONDAYS ACTIVE CONVECTION HAS SIGNIFICANTLY OVERTURNED THE AIRMASS
MUCH OF THE DESERT VALLEYS. HOWEVER IT APPEARS THAT THINNING CLOUD
COVER VICINITY LOWER CO RIVER VALLEY WILL ALLOW SUFFICIENT HEATING
OF THE NOW VERY MOIST AIR MASS FOR RENEWED THUNDERSTORM DEVELOPMENT
VICINITY HIGHER TERRAIN THIS AFTERNOON. STEERING FLOW IS
WEAK...HOWEVER WITH MLCAPES POTENTIALLY AS HIGH AS 2000
J/KG...LOCALIZED DOWNBURSTS WILL AGAIN BE A THREAT.
..HALES/CROSBIE.. 08/26/2008
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