SWODY1
SPC AC 191247
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT TUE AUG 19 2008
VALID 191300Z - 201200Z
...THERE IS A SLGT RISK OF SVR TSTMS TODAY ALONG THE E COAST OF
FL...
...E CENTRAL AND SE FL TODAY...
TROPICAL STORM FAY HAS MADE LANDFALL ALONG THE SW FL COAST AND WILL
CONTINUE SLOWLY NNEWD TOWARD E CENTRAL FL BY EARLY WEDNESDAY /SEE
LATEST NHC ADVISORIES FOR DETAILS/. LOCAL VWP/S SHOW THE STRONGEST
LOW-LEVEL SHEAR E AND NE OF THE CYCLONE CORE...WHILE REGIONAL RADAR
MOSAICS CONFIRM THE PERSISTENCE OF A PRIMARY CONVECTIVE BAND FROM
THE SE FL COAST TO THE WRN BAHAMAS. CONTINUED NNEWD MOTION OF FAY
WILL RESULT IN A DECREASE IN THE SUPERCELL/TORNADO THREAT ACROSS S
FL LATER THIS MORNING...WHILE THE THREAT WILL PERSIST AND GRADUALLY
INCREASE NWD ACROSS THE E CENTRAL FL COAST DURING THE DAY.
...WRN MT THIS AFTERNOON/EVENING...
A MID LEVEL SHORTWAVE TROUGH FROM NRN CA TO ORE/WA THIS MORNING WILL
EJECT NEWD AND LOSE AMPLITUDE AS A STRONGER UPSTREAM TROUGH
APPROACHES THE PAC NW COAST EARLY WEDNESDAY. A SURFACE COLD FRONT
WILL ACCOMPANY THE MID LEVEL WAVE FROM ID INTO WRN/CENTRAL MT BY
EARLY TONIGHT. LOW-LEVEL MOISTURE IS LIMITED E OF THE MOUNTAINS IN
WRN MT...BUT VERY STEEP LAPSE RATES AND STRONG SURFACE HEATING/DEEP
MIXING WILL CONTRIBUTE TO INVERTED-V PROFILES THIS AFTERNOON/EVENING
FROM WRN INTO CENTRAL MT. EXPECT HIGH-BASED THUNDERSTORMS TO FORM
NEAR THE FRONT AND OVER THE HIGH TERRAIN ACROSS WRN MT THIS
AFTERNOON...AND THEN SPREAD EWD TO CENTRAL MT BY LATE EVENING. THE
STRONGEST STORMS MAY PRODUCE MARGINALLY SEVERE HAIL OVER THE HIGHER
TERRAIN...BUT ISOLATED DAMAGING WINDS WILL BE THE MAIN THREAT E OF
THE MOUNTAINS.
...SE NEW ENGLAND THROUGH EARLY AFTERNOON...
A MID LEVEL SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ARE MOVING
SEWD ACROSS NY/NRN NEW ENGLAND AS OF 12Z. THIS SYSTEM WILL TRAVERSE
SE NEW ENGLAND BY EARLY AFTERNOON. SURFACE HEATING AND BOUNDARY
LAYER DEWPOINTS IN THE LOW-MID 60S WILL CONTRIBUTE TO A NARROW
CORRIDOR OF MLCAPE VALUES OF 500-1000 J/KG FROM LATE MORNING INTO
EARLY AFTERNOON IMMEDIATELY IN ADVANCE OF THE COLD FRONT.
THUNDERSTORM DEVELOPMENT COULD OCCUR ALONG THE FRONT BEFORE IT MOVES
OFFSHORE...THUS THERE WILL BE A NARROW WINDOW OF OPPORTUNITY FOR
MARGINALLY SEVERE HAIL AND ISOLATED DAMAGING GUSTS ACROSS SE NEW
ENGLAND FROM ABOUT 15-19Z.
...E TX/OK THROUGH TONIGHT...
A MID LEVEL LOW OVER NW TX WILL MOVE ONLY SLOWLY EWD TODAY AS PART
OF A TEMPORARY REX BLOCK CONFIGURATION OVER THE PLAINS. DEEP MOIST
PROFILES /PW VALUES OF 1.75-2.25 INCHES/ AND AT LEAST WEAK
INSTABILITY WILL CONTRIBUTE TO WIDESPREAD CONVECTION TODAY FROM
CENTRAL OK SWD INTO N AND E TX. SEVERAL STORM CLUSTERS WILL LIKELY
BE FOCUSED BY EMBEDDED SMALLER SCALE VORTICITY MAXIMA ROTATING
AROUND THE LOW...AND LOCALLY HEAVY RAINFALL IS LIKELY. THE SEVERE
STORM THREAT WILL BE LIMITED...HOWEVER...BY THE WEAK INSTABILITY AND
RATHER WEAK TROPOSPHERIC FLOW NOTED IN 12Z SOUNDINGS. SOMEWHAT
STRONGER FLOW/STEEPER LAPSE RATES WILL BE PRESENT OVER SW TX...BUT
STORM COVERAGE SHOULD BE MUCH MORE ISOLATED COMPARED TO AREAS
FARTHER E IN TX.
..THOMPSON/GRAMS.. 08/19/2008
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