[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 201243
SWODY1
SPC AC 201241

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CDT WED SEP 20 2006

VALID 201300Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE TX PANHANDLE NORTHWARD
INTO WESTERN KS...

MORNING WATER VAPOR IMAGERY SHOWS POWERFUL UPPER TROUGH ROTATING
ACROSS NV/UT.  THIS FEATURE IS EXPECTED TO MOVE RAPIDLY EASTWARD
ACROSS THE CENTRAL ROCKIES TODAY...AND INTO THE CENTRAL/SOUTHERN
PLAINS TONIGHT.  A VERY DYNAMIC PATTERN WILL DEVELOP ACROSS THE
CENTRAL HIGH PLAINS FOR STRONG CONVECTION.  THE MAIN FORECAST
PROBLEM WILL BE THE QUALITY/TIMING OF LOW LEVEL MOISTURE RETURN.

...TX PANHANDLE...
FULL SUNSHINE IS EXPECTED THIS AFTERNOON OVER THE TX
PANHANDLE...WHERE WEAK SURFACE DRYLINE IS EXPECTED TO SLOWLY
DEVELOP.  WEAK LEAD IMPULSE CURRENTLY MOVING ACROSS NORTHERN AZ IS
FORECAST TO APPROACH THIS REGION BY LATE AFTERNOON...PROVIDING
SUFFICIENT FORCING FOR UPWARD VERTICAL MOTION FOR ISOLATED
THUNDERSTORM DEVELOPMENT.  SURFACE DEWPOINTS IN THE MID-UPPER 50S TO
THE EAST OF THE DRYLINE...COUPLED WITH STEEP LOW/MID LEVEL LAPSE
RATES SHOULD RESULT IN MLCAPE VALUES OF 500-1000 J/KG. DESPITE
RELATIVELY WEAK CAPE VALUES...VERTICAL SHEAR PROFILES ARE EXPECTED
TO BE QUITE FAVORABLE FOR ORGANIZED/SEVERE STORMS BY 00Z.  LARGE
HAIL AND GUSTY WINDS ARE EXPECTED IN STRONGEST CELLS OVER THIS
REGION.

...WESTERN KS...
EXIT REGION OF MID/UPPER JET WILL OVERSPREAD WESTERN KS AFTER
00Z...RESULTING IN RAPID/WIDESPREAD CONVECTIVE DEVELOPMENT. 
POTENTIAL FOR SEVERE STORMS IN THIS AREA IS MORE COMPLICATED DUE TO
UNCERTAINTIES REGARDING MOISTURE RETURN.  CURRENT INDICATIONS ARE
THAT DEWPOINTS IN THE LOWER 50S WILL BE PRESENT...RESULTING IN CAPE
VALUES BELOW 500 J/KG. HOWEVER...STRENGTH OF UPPER SYSTEM...STEEP
MID LEVEL LAPSE RATES...AND VERY STRONG LOW LEVEL VERTICAL SHEAR
SUGGEST THE THREAT OF INTENSE ELEVATED SEVERE STORMS OVERNIGHT. 
LARGE HAIL WILL BE POSSIBLE WITH INITIAL STORMS ACROSS WESTERN KS
DURING THE LATE EVENING...BEFORE ACTIVITY BECOMES WIDESPREAD AND
LESS INTENSE AFTER MIDNIGHT.

..HART/GRAMS.. 09/20/2006