DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 110457
SWODY1
SPC AC 110455

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1155 PM CDT MON SEP 10 2012

VALID 111200Z - 121200Z

...NO SVR TSTM AREAS FORECAST...

...LOWER CO RIVER VALLEY/AZ...
THE PERSISTENT UPPER LOW OVER NORTHERN BAJA EARLY THIS MORNING IS
EXPECTED TO BECOME A BIT MORE PROGRESSIVE AS IT SPREADS EASTWARD AND
OTHERWISE WEAKENS. MEANWHILE...ANOTHER SHORTWAVE TROUGH CURRENTLY
MOVING INLAND OVER NORTHERN CA IS EXPECTED TO ALSO WEAKEN AS IT
MOVES INTO THE GREAT BASIN REGION. DESPITE THEIR WEAKENING
NATURE...THESE SYSTEMS /AND OROGRAPHIC LIFT/ WILL AGAIN CONTRIBUTE
TO SCATTERED TSTMS WITHIN A VERY MOIST AIRMASS ACROSS THE LOWER CO
RIVER VALLEY/AZ.

LOCALLY HEAVY RAINFALL WILL BE THE MORE PREVALENT HAZARD...BUT
STRONG/POTENTIALLY SEVERE DOWNBURST POTENTIAL CANNOT BE ENTIRELY
DISCOUNTED THIS AFTERNOON/EARLY EVENING ACROSS THE REGION.
HOWEVER...CLOUD COVER/PRIOR CONVECTIVE OVERTURNING SUGGESTS THAT
SURFACE HEATING/DESTABILIZATION WILL BE WEAKER THIS AFTERNOON AS
COMPARED TO PRIOR DAYS. THUS...CURRENT THINKING IS THAT SEVERE WIND
PROBABILITIES ARE NOT WARRANTED.

...CENTRAL PLAINS TO UPPER MIDWEST...
AS A COLD FRONT SPREADS EAST-SOUTHEASTWARD THROUGH TONIGHT ACROSS
THE CENTRAL PLAINS/UPPER MIDWEST...VERY ISOLATED TSTMS MAY FORM NEAR
THE FRONT...AND/OR HIGH PLAINS LEE TROUGH...LATE THIS
AFTERNOON/EARLY EVENING. EVEN WITH CONSEQUENTIAL FORCING FOR ASCENT
IN ASSOCIATION WITH AN UPPER TROUGH CROSSING CENTRAL CANADA...THE
PRIMARY LIMITING FACTORS FOR TSTM /AND SEVERE/ POTENTIAL WILL BE
MINIMAL BOUNDARY LAYER MOISTURE CONTENT...ALONG WITH A STOUT
ELEVATED MIXED LAYER ATOP THE WARM SECTOR.

...FL...
SHOWERS AND ISOLATED TSTMS WILL REMAIN POSSIBLE ACROSS SOUTH FL
ESPECIALLY THIS AFTERNOON ALONG AND SOUTH OF A STALLING/WEAKENING
FRONT. NO SEVERE TSTMS ARE EXPECTED.

..GUYER/LEITMAN.. 09/11/2012

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