SWODY1
SPC AC 121255
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT TUE AUG 12 2008
VALID 121300Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM E TX/LA INTO GA AND THE FL
PANHANDLE...
...SYNOPSIS...
UPR RIDGE WILL PERSIST OVER THE SWRN U.S. THIS PERIOD WHILE BLOCKY
PATTERN CONTINUES ACROSS THE NORTH AND EAST. BECAUSE OF BLOCK...AB
UPR LOW EXPECTED TO EDGE ONLY VERY SLOWLY E AS BROAD CYCLONIC
CIRCULATION REMAINS LARGELY STNRY OVER QUEBEC. FARTHER S...A BROAD
BAND OF DIFFLUENT CYCLONIC FLOW WILL PREVAIL FROM THE MS VLY TO THE
S ATLANTIC CST. SATELLITE AND VWP/PROFILER DATA INDICATE SEVERAL
DISTURBANCES IN THIS FLOW THAT LIKELY WILL CONSOLIDATE INTO AN
ANOMALOUSLY STRONG SHORTWAVE TROUGH OVER THE TN VLY BY 12Z
WEDNESDAY.
AT THE SFC...MAIN FEATURE OF NOTE IS FRONTAL ZONE NOW EXTENDING FROM
NE TX ESE TO THE FL PANHANDLE. THE FRONT SHOULD BECOME BETTER
DEFINED THROUGH THE PERIOD AS A SFC WAVE DEVELOPS ALONG IT AND
TRACKS E TO NEAR THE AL/GA BORDER AREA EARLY WEDNESDAY.
ELSEWHERE...COLD FRONT NOW EXTENDING FROM THE UPR MS VLY TO THE
CNTRL PLNS EXPECTED TO CONTINUE WEAKENING...WHILE A WEAK LEE TROUGH
LINGERS OVER THE CNTRL HI PLNS.
...E TX/LA TO GA/FL PANHANDLE...
BAND OF ENHANCED NNWLY MID LVL FLOW NOW OVER THE CNTRL PLNS SUGGESTS
THAT DOWNSTREAM DISTURBANCE NOW APPROACHING THE ARKLATEX WILL INDEED
AMPLIFY AS IT CONTINUES ESE ALONG STRENGTHENING FRONTAL ZONE OVER
THE GULF CST STATES. COMBINATION OF ANOMALOUS UPR AIR PATTERN WITH
BAND OF VERY RICH MOISTURE /PW AOA 2 INCHES/ COULD RESULT IN AN
INCREASING THREAT FOR SVR WX...IN ADDITION TO HEAVY RAIN...OVER THE
CNTRL GULF CST REGION AND N FL/GA AND SC THROUGH THE NEXT 24-36 HRS.
CLOUDS WILL LIMIT SFC HEATING ALONG AND S OF GULF STATES FRONTAL
ZONE TODAY...AND MID LVL LAPSE RATES WILL REMAIN WEAK. BUT
COMBINATION OF EVEN MODEST HEATING WITH RICH MOISTURE...INCREASING
UVV...AND STRENGTHENING LOW TO MID LVL WIND FIELD LIKELY WILL
SUPPORT SOME INTENSIFICATION OF EXISTING STORMS/STORM CLUSTERS FROM
E TX INTO LA...SRN AND CNTRL MS...SRN AL...AND THE FL PANHANDLE
LATER TODAY.
LARGELY UNIDIRECTIONAL WSWLY LOW TO MID LVL FLOW WILL LIMIT CLOUD
LAYER SHEAR...BUT COULD SUPPORT BOWING STRUCTURES WITH HIGH WIND.
ON THE OTHER HAND...FAIRLY SUBSTANTIAL LOW-LVL /0-1 KM/ SHEAR WILL
EXIST. GIVEN VERY RICH MOISTURE INFLOW /DEWPOINTS IN THE MID 70S
F/...THIS COULD ENHANCE POTENTIAL FOR LOW-LVL STORM ROTATION/
TORNADOES...ESPECIALLY IN THE PRESENCE OF ANY DISCRETE OR
SEMI-DISCRETE STORMS.
WITH SHORTWAVE IMPULSE AND ASSOCIATED WIND FIELD EXPECTED TO FURTHER
STRENGTHEN OVERNIGHT...AND WITH MINIMAL DIURNAL VARIATION EXPECTED
IN CONVECTIVE COVERAGE/STRENGTH...EXPECT THAT SVR THREAT WILL
CONTINUE AND POSSIBLY EVEN INCREASE THROUGH EARLY WEDNESDAY EWD
ACROSS AL INTO GA AND NW FL.
...CNTRL/SRN HI PLNS...
WDLY SCTD TSTMS EXPECTED TO FORM WITH AFTN HEATING INVOF WEAKENING
FRONT AND ALONG LEE TROUGH FROM WRN SD/WRN NEB INTO NW KS AND
POSSIBLY FAR NE CO. OTHERS MAY FORM OVER THE MOUNTAINS OF CNTRL/SRN
CO AND NRN NM. ALTHOUGH LOW-LVL WINDS WILL BE WEAK...30-40 KT WNWLY
FLOW ON NE FRINGE OF UPR RIDGE WILL YIELD AMPLE SHEAR FOR ORGANIZED
STORMS AND POSSIBLY A FEW WEAK SUPERCELLS. THESE COULD YIELD ISOLD
SVR HAIL AND LOCALLY DMGG WIND GIVEN STEEP LOW LVL LAPSE RATES.
SOME OF THE STORMS...ESPECIALLY THOSE IN SW NEB/NW KS...COULD
ORGANIZE INTO A SSE-MOVING CLUSTER THAT PERSISTS INTO THE EVENING.
OTHER STORMS MAY FORM LATER TONIGHT/EARLY WEDNESDAY OVER WRN KS/WRN
NEB ALONG STRENGTHENING SLY LLJ.
...WRN/NRN MO TO SE MN...
SFC HEATING ALONG WEAKENING COLD FRONT SHOULD SUPPORT MODEST
DESTABILIZATION /SBCAPE TO 1500 J PER KG/ IN WAKE OF ONGOING
CLOUDS/SHOWERS LATER TODAY. ALTHOUGH 30 KT DEEP NNWLY SHEAR WILL BE
SUFFICIENT FOR ORGANIZED/SUSTAINED STORMS...WEAK UVV AND DIMINISHING
FRONTAL CONVERGENCE SHOULD LIMIT OVERALL STRENGTH AND COVERAGE OF
STORMS. NEVERTHELESS...THOSE THAT DO FORM WILL BE CAPABLE OF
LOCALLY DMGG WIND AND POSSIBLY MARGINALLY SVR HAIL.
..CORFIDI/HURLBUT.. 08/12/2008
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