DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 041248
SWODY1
SPC AC 041246

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0646 AM CST SUN NOV 04 2012

VALID 041300Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS ALONG THE SE ATLANTIC COAST
THIS AFTERNOON/EVENING...

...SE ATLANTIC COAST THIS AFTERNOON/EVENING...
A WEAK SURFACE LOW ACROSS UPSTATE SC THIS MORNING WILL DEVELOP EWD
TO THE NC COAST BY LATE AFTERNOON/EVENING ALONG A LOW-LEVEL
BAROCLINIC ZONE...IN ADVANCE OF SHORTWAVE TROUGH PROGRESSING ESEWD
FROM THE MID MS/OH VALLEY REGION. TRAILING THE SURFACE LOW...A COLD
FRONT WILL MOVE SEWD TO THE NE GULF AND SE ATLANTIC COASTS BY EARLY
MONDAY. SOME LOW-LEVEL MOISTENING WILL OCCUR TODAY IN ADVANCE OF
THE COLD FRONT...WITH BOUNDARY LAYER DEWPOINTS OF 56-60 F EXPECTED
TO SPREAD NEWD WITH ADVECTION AND DAYTIME HEATING/MIXING. THE
DAYTIME HEATING WILL ALSO SUPPORT AFTERNOON SURFACE TEMPERATURES IN
THE 80S...WHICH COMBINED WITH THE MIDLEVEL LAPSE RATES NEAR 7
C/KM...WILL SUPPORT MLCAPE VALUES OF 500-1500 J/KG.

SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE FRONT IN
THE 21-00Z TIME FRAME AS CONVECTIVE INHIBITION DIMINISHES AND ASCENT
INCREASES ALONG THE FRONT WITH THE APPROACH OF THE MIDLEVEL TROUGH.
THE COMBINATION OF MODEST BUOYANCY AND DEEP-LAYER UNIDIRECTIONAL
WIND PROFILES /WITH 30-35 KT EFFECTIVE BULK WIND DIFFERENCES/ WILL
SUPPORT A FEW ORGANIZED MULTICELLS AND/OR LOW-END SPLITTING
SUPERCELLS BEFORE CONVECTION MOVES OFFSHORE AROUND 03Z. STEEP
LOW-LEVEL LAPSE RATES LATE THIS AFTERNOON AND DCAPE AOA 1000 J/KG
MAY BE SUFFICIENT FOR ISOLATED STRONG/DAMAGING GUSTS...WHILE THE
BUOYANCY/LAPSE RATES AND ORGANIZED STORM STRUCTURES COULD ALSO BE
SUFFICIENT FOR MARGINALLY SEVERE HAIL.

...TX TO THE LOWER MS VALLEY TODAY...
A FEW CLUSTERS OF THUNDERSTORMS ARE ONGOING FROM THE MIDDLE TX COAST
TO THE LOWER MS VALLEY IN ASSOCIATION WITH MOIST LOW LEVELS AND A
SERIES OF SMALL-SCALE/WEAK MIDLEVEL TROUGHS. THE COVERAGE OF STORMS
WILL LIKELY PEAK THIS MORNING FROM THE TX COAST INTO SW LA BEFORE
CONVECTION MOVES OFFSHORE THIS AFTERNOON. DESPITE MODERATE BUOYANCY
PER 12Z SOUNDINGS...WEAK LOW-LEVEL FLOW AND THE EARLY STORM
INITIATION SUGGEST THAT SEVERE STORMS ARE UNLIKELY.

..THOMPSON/LEITMAN.. 11/04/2012

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