SWODY1
SPC AC 201252
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT WED AUG 20 2008
VALID 201300Z - 211200Z
...THERE IS A SLGT RISK OF SVR TSTMS THROUGH TONIGHT FOR NE FL AND
SE GA...
...NE FL/SE GA THROUGH TONIGHT...
TROPICAL STORM FAY HAS STALLED ALONG THE E CENTRAL FL COAST...AND
ONLY A SLOW WWD/NWWD MOTION IS EXPECTED THROUGH TONIGHT AS A MID
LEVEL RIDGE BUILDS OVER THE SE STATES AND MID ATLANTIC /SEE LATEST
NHC ADVISORIES FOR DETAILS/. THE CYCLONE HAS WEAKENED SINCE
YESTERDAY...AND THE ASSOCIATED LOW-MID LEVEL FLOW FIELDS AND
LOW-LEVEL SHEAR HAVE WEAKENED ACCORDINGLY. STILL...AS FAY DRIFTS
ALONG THE COAST AND EVENTUALLY BACK INLAND...THE MORE FAVORABLE
ERN/NERN QUADRANTS OF THE STORM WILL SPREAD WWD WITH AN ATTENDANT
THREAT FOR RAINBAND SUPERCELLS AND A COUPLE OF BRIEF TORNADOES
ACROSS NE FL AND SE GA.
...FRONT RANGE OF SRN CO/NM THIS AFTERNOON...
REGIONAL 12Z SOUNDINGS SHOW BOUNDARY LAYER DEWPOINTS IN THE 50S
BENEATH STEEP MID LEVEL LAPSE RATES...A COMBINATION WHICH SHOULD BE
SUFFICIENT FOR WIDELY SCATTERED THUNDERSTORM DEVELOPMENT THIS
AFTERNOON WITH SURFACE TEMPERATURES IN THE LOW-MID 80S. MLCAPE
VALUES COULD APPROACH 1000 J/KG...AND WEAK WNWLY FLOW ALOFT WITH
WEAK SLY/SELY LOW-LEVEL WINDS WILL PROVIDE SUFFICIENT VERTICAL SHEAR
FOR A FEW ORGANIZED MULTICELL CLUSTERS. THE STRONGEST STORMS MAY
PRODUCE ISOLATED HAIL/STRONG OUTFLOW WINDS LATER THIS
AFTERNOON/EVENING.
...WRN MT TO THE WRN DAKOTAS THIS AFTERNOON INTO TONIGHT...
A LEAD SHORTWAVE TROUGH IS NOW EJECTING NEWD OVER CENTRAL MT...WITH
AN ACCOMPANYING SURFACE TROUGH/COLD FRONT ACROSS ERN MT. THIS
BOUNDARY WILL STALL NEAR THE MT/ND BORDER TODAY AS SURFACE PRESSURES
FALL ACROSS MT IN ADVANCE OF AN UPSTREAM/STRONGER MID LEVEL TROUGH
NOW MOVING EWD TOWARD WA. STEEP MID LEVEL LAPSE RATES AND STRONG
SURFACE HEATING WILL SUPPORT A NARROW CORRIDOR OF WEAK-MODERATE
INSTABILITY ALONG AND E OF THE SURFACE TROUGH ACROSS THE WRN DAKOTAS
THIS AFTERNOON. HOWEVER...VERTICAL SHEAR WILL BE RELATIVELY WEAK
OVER THIS AREA...AND THUNDERSTORM COVERAGE ALONG THE TROUGH SHOULD
BE RATHER SPARSE...LIMITING ANY SEVERE STORM THREAT. FARTHER
W...INSTABILITY WILL BE QUITE LIMITED ACROSS CENTRAL/WRN MT IN
ADVANCE OF THE STRONGER UPSTREAM WAVE. SOME CONVECTION WILL BE
POSSIBLE ACROSS WRN MT LATER THIS AFTERNOON INTO EARLY TONIGHT...BUT
VERY MARGINAL INSTABILITY AND UNIMPRESSIVE INVERTED-V PROFILES WITH
COOLER/MORE MOIST SURFACE CONDITIONS /COMPARED TO YESTERDAY/ SUGGEST
THAT ANY WIND DAMAGE THREAT IS LIKEWISE LIMITED.
..THOMPSON/GRAMS.. 08/20/2008
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