DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 120532
SWODY1
SPC AC 120530

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 AM CDT WED SEP 12 2012

VALID 121200Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
THE PRIMARY WESTERLIES WILL REMAIN OVER CANADA AND THE NORTH-CENTRAL
CONUS THROUGH THE PERIOD...IN ASSOCIATION WITH A CONSIDERABLE
EAST-NORTHEASTWARD MOVING UPPER TROUGH OVER EAST-CENTRAL
CANADA...AND A SECONDARY/CLIPPER-TYPE SHORTWAVE TROUGH THAT WILL
SPREAD SOUTHEASTWARD FROM THE CANADIAN ROCKIES AND REACH THE UPPER
MIDWEST BY EARLY THURSDAY. THE MAIN LOW-LEVEL FEATURE OF NOTE WILL
BE A SOUTHEASTWARD MOVING COLD FRONT...EXTENDING FROM THE GREAT
LAKES REGION TO THE LOWER MO VALLEY AND CENTRAL/SOUTHERN PLAINS BY
THIS EVENING.

...SOUTH-CENTRAL PLAINS...
A COLD FRONT WILL CONTINUE TO SETTLE SOUTH-SOUTHEASTWARD THROUGH THE
PERIOD ACROSS THE REGION. SOUTH OF THE FRONT...A MODEST DEGREE OF
MOISTURE RETURN WILL OCCUR TODAY ACROSS THE SOUTHERN PLAINS WARM
SECTOR /MAINLY 50S SURFACE DEWPOINTS INTO NORTH TX AND
OK/...ALTHOUGH THIS WILL BE OFFSET BY AMPLE HEATING/AGGRESSIVE
MIXING THIS AFTERNOON. NEAR THE NORTHEAST-SOUTHWEST ORIENTED FRONT
/AND LEE TROUGH ACROSS THE TX PANHANDLE/...ISOLATED TSTMS WILL BE
POSSIBLE BY LATE AFTERNOON/EARLY EVENING.

WHILE CAPE /500 J PER KG ML/ AND VERTICAL SHEAR /20 KT OR LESS 0-6
KM/ WILL BE WEAK OVERALL...SUFFICIENT MOISTURE/BUOYANCY MAY EXIST
FOR SOME STRONGER/SUSTAINED UPDRAFTS...WITH STRONG DOWNDRAFTS
POSSIBLE IN ASSOCIATION WITH A RELATIVELY HOT/DEEPLY MIXED BOUNDARY
LAYER. LOW SEVERE WIND PROBABILITIES SEEM PRUDENT GIVEN THE
POSSIBILITY OF SPORADIC STRONG/PERHAPS LOCALLY SEVERE WIND GUSTS FOR
A TIME LATE THIS AFTERNOON/EARLY EVENING.

...SOUTHERN ROCKIES...
AS THE UPPER LOW PROGRESSES EASTWARD TODAY...ASSOCIATED FORCING FOR
ASCENT/STEEP LAPSE RATES ALOFT AND A MOIST AIRMASS MAY CONTRIBUTE TO
SOME STRONGER TSTMS THIS AFTERNOON/EARLY EVENING FOR AREAS INCLUDING
NORTHERN AZ INTO NM. HOWEVER...MINIMAL OVERALL BUOYANCY SHOULD CURB
THE SEVERE TSTM POTENTIAL...AND PROBABILITIES DO NOT CURRENTLY
APPEAR WARRANTED FOR THE REGION.

..GUYER/LEITMAN.. 09/12/2012

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