[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 130513
SWODY1
SPC AC 130511

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1211 AM CDT SAT MAY 13 2006

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM CNTRL AND SRN AL THROUGH
CNTRL AND SRN GA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN TX THROUGH THE LOWER
MS VALLEY...

...SYNOPSIS...

STAGNANT UPPER PATTERN WILL PERSIST THROUGH SATURDAY WITH A LARGE
UPPER LOW OVER THE ERN U.S. AND SHORTWAVE RIDGING OVER THE ROCKIES.
SERIES OF VORTICITY MAXIMA WILL CONTINUE TO ROTATE THROUGH THE UPPER
LOW. ONE SUCH FEATURE WILL MOVE SEWD INTO THE SERN STATES DURING THE
DAY. A COLD FRONT WILL MOVE PROGRESSIVELY SWD AND BY LATE AFTERNOON
SHOULD EXTEND FROM A SURFACE LOW OVER THE OH VALLEY SWWD INTO THE TN
VALLEY...THEN WNWWD INTO SRN KS.

...CNTRL AL THROUGH CNTRL AND SRN GA...

LOW LEVEL MOISTURE WILL REMAIN SOMEWHAT LIMITED THROUGH SATURDAY
OVER THE SERN STATES...AND THIS WILL LIKELY SERVE AS AN OVERALL
LIMITING FACTOR FOR A MORE ROBUST SEVERE WEATHER THREAT. CURRENT
OBSERVATIONS SHOW SURFACE DEWPOINTS GENERALLY IN THE UPPER 40S TO
LOWER 50S AND MUCH OF THIS MOISTURE IS CONFINED TO NEAR THE SURFACE.
RICHER LOW LEVEL MOISTURE IS WELL SW OF THIS AREA IN SRN TX. WITH
LITTLE IN THE WAY OF SIGNIFICANT MOISTURE ADVECTION...BOUNDARY LAYER
MIXING SHOULD RESULT IN DEWPOINTS REMAINING IN THE UPPER 40S TO NEAR
50 DURING THE DAY. DESPITE THE LIMITED LOW LEVEL MOISTURE...STEEP
LAPSE RATES AND SURFACE HEATING WILL RESULT IN SOME DESTABILIZATION
WITH MLCAPE AOB 500 J/KG. A FEW ELEVATED STORMS MAY BE ONGOING
WITHIN ZONE OF WARM ADVECTION AND ASCENT ASSOCIATED WITH A WLY LOW
LEVEL JET AND SEWD ADVANCING SHORTWAVE TROUGH. POTENTIAL WILL EXIST
FOR SOME OF THIS ACTIVITY TO INTENSIFY AND BECOME SURFACE BASED AS
THE DOWNSTREAM ATMOSPHERE DESTABILIZES. THERMODYNAMIC PROFILES WILL
LIKELY BE CHARACTERIZED BY INVERTED-V BOUNDARY LAYERS WITH UPDRAFTS
HAVING RELATIVELY HIGH BASES. PRIMARY THREAT WILL BE ISOLATED
DAMAGING WIND AND MARGINALLY SEVERE HAIL AS ACTIVITY SPREADS ESEWD.
THREAT SHOULD DIMINISH BY EARLY EVENING. 

...NERN TX...EXTREME SERN OK THROUGH THE LOWER MS VALLEY...

PARTIALLY MODIFIED GULF AIR WITH DEWPOINTS IN THE LOWER 60S SHOULD
BEGIN RETURNING NWD THROUGH TX BENEATH STEEP MID LEVEL LAPSE RATES
BY SATURDAY NIGHT AS THE NOCTURNAL LOW LEVEL JET INCREASES. STORMS
ARE EXPECTED TO DEVELOP WITHIN ZONE OF INCREASING WARM ADVECTION AND
LIFT FROM NERN TX SPREADING EWD INTO THE LOWER MS VALLEY REGION.
ACTIVITY WILL LIKELY BE ELEVATED...BUT THERMODYNAMIC PROFILES APPEAR
SUFFICIENT FOR A THREAT FOR HAIL WITHIN THE STRONGER STORMS.

..DIAL/CROSBY.. 05/13/2006