SWODY1
SPC AC 111614
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT MON AUG 11 2008
VALID 111630Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF SERN NY INTO ERN
PA/NRN NJ AND SRN NEW ENGLAND...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PART OF THE NRN/CNTRL
PLAINS...
...NORTHEAST...
STRONG UPPER LOW AND ASSOCIATED MID LEVEL COLD POCKET WILL CONTINUE
TO SUPPORT SCATTERED LOW-TOPPED THUNDERSTORMS FROM PORTIONS OF THE
NRN MID ATLANTIC INTO PARTS OF NEW ENGLAND TODAY. THE COLD AIR
ALOFT WILL COMPENSATE FOR SEASONABLY COOL SURFACE TEMPERATURES AND
MAINTAIN MARGINAL INSTABILITY...ALONG WITH POTENTIAL FOR HAIL IN THE
STRONGER CORES. ACTIVITY WILL LIKELY REMAIN WEAKLY
FOCUSED/ORGANIZED GIVEN WEAK MID/UPPER LEVEL FLOW AND LIMITED LOW
LEVEL CONVERGENCE. HOWEVER WITH POCKETS OF HEATING /TEMPERED ACROSS
SRN NEW ENGLAND BY ONSHORE FLOW OFF LONG ISLAND SOUND AND THE
ATLANTIC/...A FEW STRONGER STORMS CAPABLE OF MARGINALLY SEVERE
HAIL/STRONG WIND GUSTS ARE EXPECTED TO CONTINUE INTO THE EARLY
EVENING.
...NRN/CENTRAL PLAINS...
MESSY MID/UPPER LEVEL PATTERN OVER THE NRN AND CENTRAL PLAINS AHEAD
OF WELL DEFINED SHORTWAVE TROUGH NOW MOVING ESEWD AWAY FROM THE NRN
ROCKIES. SEVERAL LOW AMPLITUDE IMPULSES ARE EVIDENT OVER THIS
REGION EARLY TODAY WHICH SHOULD MAINTAIN AREAS OF MOIST CONVECTION
THIS AFTERNOON...ESPECIALLY ACROSS THE ERN PART OF THE NRN PLAINS.
HOWEVER...WEAK LAPSE RATES WITHIN DEEP MOIST PLUME OVER MUCH OF THE
GREAT PLAINS...ALONG WITH LIMITED SURFACE HEATING...WILL TEND TO
INHIBIT MORE THAN ISOLATED SEVERE THUNDERSTORMS OVER THIS REGION.
EXCEPTION MAY BE OVER CENTRAL/SERN SD WHERE HIGH RES MODELS CONTINUE
TO INCREASE STORMS THIS AFTERNOON ALONG WRN EDGE OF LEADING LOW
CLOUD SHIELD. DESPITE THE WEAK LAPSE RATES/MODEST
INSTABILITY...FAIRLY STRONG LOW-DEEP LAYER SHEAR /LARGELY DRIVEN BY
LOOPING LOW LEVEL HODOGRAPHS INVOF 20-30 KT H85 JET/ MAY SUPPORT A
FEW LONGER-LIVED STORMS/SUPERCELLS.
ADDITIONAL AREA OF STRONG/SEVERE THUNDERSTORM DEVELOPMENT SHOULD
OCCUR IN CLOSER PROXIMITY TO THE HIGH PLAINS ON WRN FRINGE OF DEEP
MOIST PLUME...WHERE GREATER HEATING/STEEPER LAPSE RATES WILL BE
FOUND. IN ADDITION...WNWLY FLOW WILL STRENGTHEN THROUGH THE DAY
AHEAD OF APPROACHING NRN ROCKIES SHORTWAVE TROUGH. EXPECT
THUNDERSTORMS WILL INCREASE WITHIN AXIS OF MODERATE INSTABILITY FROM
THE CENTRAL HIGH PLAINS INTO SD DURING THE MID TO LATE AFTERNOON AS
CAP WEAKENS. FORECAST SOUNDINGS STILL ONLY YIELD MODERATE
MLCAPE/LAPSE RATES ACROSS THIS REGION...BUT STORMS SHOULD PERSIST
WITHIN SUFFICIENT SHEAR FOR ORGANIZATION INTO LINES/CLUSTERS
SPREADING PRIMARY THREAT OF DAMAGING WINDS SSEWD THROUGH THE
EVENING. ISOLATED LARGE HAIL WILL ALSO LIKELY ACCOMPANY THE
STRONGER STORMS.
...TX INTO THE LOWER MS RIVER VALLEY...
RESIDUAL MCS AND ASSOCIATED OUTFLOW BOUNDARIES/MCVS WILL MAINTAIN
SUFFICIENT FOCUS FOR NEW DEVELOPMENT TODAY...ESPECIALLY AS WARM
SECTOR BECOMES VERY WARM/UNSTABLE. AS HAS BEEN THE CASE THE PAST
FEW DAYS...ISOLATED STORMS WILL LIKELY BRIEFLY BECOME SEVERE
...ALTHOUGH OVERALL THREAT SHOULD REMAIN LOW.
..EVANS/SMITH.. 08/11/2008
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