[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210046
SWODY1
SPC AC 210043

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0643 PM CST TUE FEB 20 2007

VALID 210100Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT ACROSS PARTS OF THE MID
SOUTH...

...MID SOUTH...

00Z MESOANALYSIS INDICATED SURFACE LOW JUST SE OF UNO WITH ATTENDANT
COLD FRONT EXTENDING NEWD ALONG THE OH RIVER.  THIS BOUNDARY THEN
EXTENDED SWWD FROM THIS LOW INTO W-CNTRL AR.  TSTMS HAVE DEVELOPED
WITHIN THE PAST COUPLE OF HOURS INVOF OF THIS SURFACE LOW /POF TO
CGI/ WITHIN ZONE OF SUSTAINED CONVERGENCE AND ON THE NERN FRINGE OF
STEEPER LOW LEVEL LAPSE RATES AXIS FROM N-CNTRL AR INTO SERN OK. 
STORMS SHOULD INCREASE IN COVERAGE OVER THE NEXT FEW HOURS AS
LARGE-SCALE FORCING FOR ASCENT ASSOCIATED WITH APPROACHING SHORT
WAVE TROUGH OVERSPREADS REGION.

INFLOW AIR MASS FOR THESE STORMS APPEARS TO BE RELATIVELY WELL
SAMPLED BY THE 00Z LIT SOUNDING WITH SBCAPES OF 600-700 J/KG AND
VERY LITTLE CONVECTIVE INHIBITION.  CURRENT BLOOMFIELD MO PROFILER
INDICATES LARGELY UNDIRECTIONAL WIND FIELDS WITH 60-65 KTS OF 0-6 KM
BULK SHEAR.  THIS KINEMATIC PROFILE SHOULD CONTINUE TO SUPPORT
SPLITTING STORMS AS EVIDENCED BY PERSISTENT LEFT-MOVING SUPERCELL
APPROACHING CGI AS OF 0020Z.  HOWEVER...MEM VWP SUGGESTS THAT
VERTICAL SHEAR BECOMES MORE FAVORABLE FOR RIGHT-MOVING SUPERCELLS
WITH SWD EXTENT WITH 300-350 M2/S2 0-1 KM SRH.

BASED ON RELATIVELY STEEP MID-LEVEL LAPSE RATES OBSERVED ON 00Z LIT
SOUNDING AND ANTICIPATED SUPERCELL STORM STRUCTURES...EXPECT THAT
LARGE HAIL WILL BE THE PRIMARY SEVERE WEATHER THREAT WITH THE MOST
INTENSE STORMS.  A TORNADO OR TWO STILL REMAINS POSSIBLE THIS
EVENING WITH ANY SUPERCELLS THAT CAN MOVE/DEVELOP MORE SEWD INTO
STRONGER SHEARED LOW-LEVEL ENVIRONMENT OVER FAR NERN AR...THE MO
BOOTHEEL INTO WRN TN.

STORMS WILL LIKELY PERSIST FOR THE NEXT SEVERAL HOURS...GRADUALLY
GROWING UPSCALE INTO CLUSTERS INTO PORTIONS OF WRN KY AND WRN/MIDDLE
TN.  STORMS SHOULD TEND TO DIMINISH IN INTENSITY AFTER 21/06Z AS
BOUNDARY LAYER COOLS AND CAP BECOMES INCREASINGLY STRONG.

..MEAD.. 02/21/2007