DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121957
SWODY1
SPC AC 121955

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 PM CDT WED SEP 12 2012

VALID 122000Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

NO APPRECIABLE CHANGES HAVE BEEN MADE TO THE 1630Z OUTLOOK. HAVE
OPTED TO EXPAND THUNDERSTORM PROBABILITIES A BIT FARTHER NORTH
ACROSS PORTIONS OF CNTRL/NERN NEB TO ACCOUNT FOR THE POST-FRONTAL
LIGHTNING ACTIVITY ACROSS THIS REGION.

OTHERWISE...REF SWOMCD 1946 AND 1945 REGARDING THE CONVECTIVE THREAT
ALONG COLD FRONT FROM SCNTRL KS INTO NWRN TX AND FOR TSTMS ACROSS
SWRN LA TO THE MIDDLE/UPPER TX COAST.

..DARROW.. 09/12/2012

.PREV DISCUSSION... /ISSUED 1124 AM CDT WED SEP 12 2012/

...S-CNTRL KS SSWWD INTO THE TX SOUTH PLAINS...
A SHARP COLD FRONT WILL CONTINUE MOVING SEWD/SSEWD ACROSS THE SRN
PLAINS TODAY...EXTENDING FROM THE I-44 CORRIDOR IN OK TO SERN NM BY
LATE TONIGHT. FRONTAL ASCENT...LOCALLY AUGMENTED BY THE BAROCLINIC
CIRCULATION ACCOMPANYING A N/S DIFFERENTIAL HEATING ZONE OVER THE TX
PANHANDLE/SOUTH PLAINS...MAY BE SUFFICIENT FOR ISOLATED SFC-BASED
STORM DEVELOPMENT INVOF THE FRONT. THE INFLUX OF ONLY PARTIALLY
MODIFIED LOW-LEVEL MOISTURE BENEATH AN EML/DRY PROFILES ALOFT WILL
SUPPORT AROUND 500 J/KG OF MLCAPE PER 12Z RAOBS. AND...WITH SFC
TEMPERATURE-DEWPOINT SPREADS AOA 30F...ISOLATED MICROBURSTS WITH
VERY SPORADIC SVR WIND GUSTS CANNOT BE RULED OUT. REGARDLESS...THE
DURATION OF ANY SVR THREAT WILL BE CURTAILED BY THE UNDERCUTTING
FRONT. POST-FRONTAL THUNDERSTORM CHANCES WILL BE RELATIVELY
GREATER...THOUGH THE ANTICIPATED ANAFRONTAL CHARACTER OF THIS
CONVECTION SHOULD GREATLY LIMIT THE SVR THREAT.

...MIDDLE/UPPER TX COASTAL PLAIN AND SWRN/S-CNTRL LA...
RELATIVELY RICHER LOW-LEVEL MOISTURE SUCCEEDING A NWD-ADVANCING
MARINE SFC BOUNDARY CHARACTERIZED BY LOWER/MIDDLE-70S DEWPOINTS WILL
LIE BENEATH DRIER AIR ALOFT W OF AN UPPER LOW CENTERED OVER THE
ARKLAMISS REGION. THIS WILL SUPPORT MLCAPE VALUES OF 1500-2500 J/KG
AHEAD OF A CONVECTIVELY-AUGMENTED SEA-BREEZE CONVERGENCE ZONE. STEEP
LOW-LEVEL LAPSE RATES WITH DCAPE OF 1000-1300 J/KG PER FORECAST
SOUNDINGS...AND THE PRESENCE OF DRY AIR ALOFT...SHOULD AID IN
SPORADIC SVR WIND GUSTS THIS AFTERNOON WITH STORMS THAT REGENERATE
ALONG THE AFOREMENTIONED SEA BREEZE.

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