SWODY1
SPC AC 191223
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0723 AM CDT MON MAY 19 2008
VALID 191300Z - 201200Z
...NO SVR TSTM AREAS FORECAST...
...MID MS/OH RIVER VALLEYS...
FAST MOVING SHORTWAVE TROUGH DIGGING SEWD ALONG BACKSIDE OF
PRONOUNCED UPPER VORTEX OVER ONTARIO/NERN U.S. WILL OVERSPREAD THIS
REGION THIS AFTERNOON. THIS WILL AID IN MOVING SURFACE LOW AND
STRENGTHENING WSWLY LLJ...NOW OVER THE CENTRAL PLAINS...QUICKLY EWD
TOWARDS THE CONFLUENCE OF THE OH/MS RIVERS BY THE EARLY EVENING. A
WARM FRONT WILL BECOME BETTER DEFINED FROM THIS LOW ENEWD INTO NERN
KY WHICH WILL HANGUP ON THE ERN END OVER THE APPALACHIANS. MODELS
ARE QUITE LIKELY TOO AGGRESSIVE IN LOW LEVEL MOISTURE FORECASTS OVER
DEVELOPING WARM SECTOR. HOWEVER...COMBINATION OF ADVECTION AND
DOWNWARD MIXING SHOULD INCREASE SURFACE DEW POINTS INTO THE 50S
THROUGH THE AFTERNOON.
THUNDERSTORMS ARE EXPECTED TO INCREASE WITHIN STRONG LOW LEVEL WAA
REGIME OVER THE OH RIVER VALLEY INTO PORTIONS OF KY/TN THROUGH THE
EVENING...AIDED BY VERTICAL MOTION AHEAD OF APPROACHING SHORTWAVE
TROUGH. REGION WILL BE STRONGLY SHEARED...BUT ELEVATED NATURE OF
THE STORMS AND MEAGER FEED OF LOW LEVEL MOISTURE SHOULD LIMIT MORE
THAN AN ISOLATED ROBUST UPDRAFT OR TWO OVER THIS REGION.
ATTM...EXPECT CAP WILL LIMIT/INHIBIT SURFACE-BASED STORMS AND LIMIT
WWD THUNDERSTORM DEVELOPMENT LATER THIS EVENING. HOWEVER...GIVEN
STEEP LAPSE RATES AND CONSIDERABLE SHEAR...WILL MAINTAIN CONDITIONAL
THREAT /LOW SEVERE PROBABILITIES/ WWD INTO SRN MO/NRN AR.
...ERN SD/SWRN MN/NWRN IA...
NW-SE ORIENTED LOW-LEVEL BAROCLINIC ZONE IS EXPECTED TO FOCUS
LOW-TOPPED TSTMS THIS AFTERNOON INVOF MID LEVEL COLD POCKET AND
ASCENT ASSOCIATED WITH SHORTWAVE TROUGH NOW DIGGING SEWD INTO ERN
ND. WHILE CONVECTIVE INSTABILITY WILL REMAIN MARGINAL /SBCAPES AOB
300 J PER KG/...STEEP LAPSE RATES AND COOL THERMODYNAMIC PROFILES
MAY SUPPORT A FEW STRONGER STORMS CAPABLE OF SOME HAIL. LOCALLY
STRONG WIND GUSTS ARE ALSO POSSIBLE GIVEN THE RELATIVELY
STRONG...UNIDIRECTIONAL WIND PROFILES.
...CENTRAL HIGH PLAINS INTO KS...
MODELS CONTINUE TO DEVELOP SCATTERED THUNDERSTORMS INVOF SURFACE
BOUNDARY EXTENDING SE-NW OVER THE REGION AS HEATING/DEEP MIXING
SUPPORTS WEAK INSTABILITY. FORECAST SOUNDINGS NEAR THIS ACTIVITY
INDICATE LOW-TOPPED STORMS WILL DEVELOP WITHIN A DEEPLY MIXED
BOUNDARY LAYER AND STRONG NWLY SHEAR...FAVORING A RISK OF STRONG
GUSTS/HAIL AS THEY MOVE QUICKLY SSEWD INTO THE EARLY EVENING.
..EVANS/CROSBIE.. 05/19/2008
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