DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 091609
SWODY1
SPC AC 091607

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1007 AM CST MON JAN 09 2012

VALID 091630Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS THROUGH TONIGHT FOR PARTS OF SE
TX AND SW LA...

...UPPER TX AND SW LA COASTAL PLAIN THROUGH TONIGHT...
A MIDLEVEL LOW OVER THE TX BIG BEND THIS MORNING WILL PROGRESS ENEWD
OVER CENTRAL TX BY TONIGHT. DOWNSTREAM FROM THE MIDLEVEL LOW...A
SURFACE CYCLONE IS EXPECTED TO FORM ALONG A PRE-EXISTING FRONT
ACROSS SE TX BY THIS EVENING...AND THE LOW WILL DEVELOP NNEWD INTO E
TX OVERNIGHT. MEANWHILE...AN INFLUX OF MID-UPPER 60S BOUNDARY LAYER
DEWPOINTS WILL CONTINUE ACROSS THE MIDDLE/UPPER TX COAST INTO SW LA
IN ADVANCE OF THE WEAK SURFACE LOW. WIDESPREAD CLOUDS WILL LIMIT
DAYTIME HEATING...BUT THE RICH MOISTURE WILL HELP MAINTAIN MLCAPE
VALUES NEAR 1000 J/KG ALONG THE UPPER TX COAST THROUGH THIS
AFTERNOON.

THE VWP FROM HOUSTON AND MODIFIED 12Z SOUNDINGS SHOW AN ENVIRONMENT
SUPPORTIVE OF SUPERCELLS ACROSS THE UPPER TX COAST...WITHIN THE
LARGER AREA OF CONVECTION THAT IS EXPECTED TO PERSIST AND SPREAD EWD
THROUGH TONIGHT. THE STORM ENVIRONMENT IS NEAR ITS PEAK IN TERMS OF
INSTABILITY AND VERTICAL SHEAR...AND IT APPEARS THAT THE STRONGER
FORCING FOR ASCENT AND VERTICAL SHEAR WILL GRADUALLY SHIFT NWD/NEWD
AND AWAY FROM THE MOST UNSTABLE PART OF THE WARM SECTOR LATER THIS
AFTERNOON INTO TONIGHT. THUS...THE RISK FOR A TORNADO OR
TWO...ALONG WITH DAMAGING WINDS AND LARGE HAIL...WILL LIKELY PEAK
BETWEEN NOW AND EARLY AFTERNOON ACROSS THE UPPER TX COASTAL PLAIN
/NEAR AND S OF THE HOUSTON METRO AREA/...AND THEN DIMINISH SOME
LATER THIS AFTERNOON/EVENING. OVERNIGHT...THE RISK FOR A TORNADO OR
DAMAGING GUST WILL SPREAD INTO SW LA...WHERE THE STRONGER STORMS
WILL MOVE INLAND FROM THE NW GULF. THE MAGNITUDE OF INSTABILITY
WELL INLAND FROM THE COAST WILL BE IN QUESTION AS A RESULT OF
WIDESPREAD CONVECTION BETWEEN NOW AND TONIGHT FROM SE TX INTO W/SW
LA.

..THOMPSON/COHEN.. 01/09/2012

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