[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 201738
SWODY2
SPC AC 201737

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT WED SEP 20 2006

VALID 211200Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
VERY STRONG/PROGRESSIVE UPPER LOW IS FORECAST TO MOVE ACROSS THE
CENTRAL AND SRN PLAINS THIS PERIOD...ACCOMPANIED BY VERY STRONG
LOWER AND MID TROPOSPHERIC FLOW.  ACCOMPANYING SURFACE LOW INITIALLY
OVER ERN CO/WRN KS SHOULD MOVE SLOWLY EWD ACROSS KS...THOUGH LEE
TROUGHING AND EVENTUAL CYCLOGENESIS ARE FORECAST TO PERSIST ACROSS
ERN CO AHEAD OF NEXT SHORT-WAVE TROUGH AS IT ROTATES RAPIDLY SEWD
INTO CO LATE.

MAIN CONVECTIVE THREAT THIS PERIOD WILL EXIST OVER THE CENTRAL
CONUS. HOWEVER...SEVERE POTENTIAL ACROSS THIS REGION REMAINS HIGHLY
CONDITIONAL UPON DEGREE OF LOW-LEVEL MOISTURE ADVECTION AND
ASSOCIATED AIRMASS DESTABILIZATION AHEAD OF SURFACE TROUGH/DRY LINE
OVER KS/OK/N TX DURING THE DAY.  

...SRN NEB SWD INTO N TX AND EWD INTO WRN MO/WRN AR...
ELEVATED CONVECTION SHOULD BE ONGOING AT THE START OF THE PERIOD
WITHIN REGION OF STRONG WARM ADVECTION.  SURFACE TROUGH/DRYLINE IS
FORECAST TO MOVE EWD ACROSS KS/OK/N TX THIS PERIOD...AS VERY STRONG
KINEMATICS OVERSPREAD THE REGION AHEAD OF POTENT UPPER SYSTEM. 
MID-LEVEL JET STREAK NEAR 80 KT IS FORECAST...ABOVE 50 TO 60 KT SLY
LOW-LEVEL JET. RESULTING SHEAR WOULD BE VERY SUPPORTIVE OF
SUPERCELLS...AND ACCOMPANYING SEVERE/TORNADO THREAT.

HOWEVER...POTENTIAL FOR DEEP/SURFACE-BASED CONVECTIVE DEVELOPMENT
REMAINS HIGHLY CONDITIONAL ATTM...AS RICH BOUNDARY-LAYER MOISTURE
REMAINS S OF BAROCLINIC ZONE ACROSS THE CENTRAL GULF.  LATEST
NAM/GFS AS WELL AS SREF GUIDANCE ALL INDICATE VERY MEAGER BOUNDARY
LAYER MOISTURE RETURN AND ASSOCIATED AIRMASS DESTABILIZATION AHEAD
OF SURFACE TROUGH AS IT SHIFTS RAPIDLY ACROSS THE REGION THROUGH THE
AFTERNOON.  GIVEN THESE QUESTIONS...WILL MAINTAIN A 5% SEVERE
PROBABILITY ATTM.  HOWEVER...AN UPGRADE IN RISK LEVEL MAY BE
NEEDED...AS CERTAINTY REGARDING DEGREE OF LOW-LEVEL MOISTURE RETURN
AND ASSOCIATED DESTABILIZATION INCREASES WITH TIME.

..GOSS.. 09/20/2006