DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 151244
SWODY1
SPC AC 151242

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT THU OCT 15 2009

VALID 151300Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS THE LOWER MS
VALLEY...

...SYNOPSIS...
A SERIES OF MID-UPPER SPEED MAXIMA OVER THE CENTRAL PLAINS AND
MIDWEST WILL CONTRIBUTE TO AMPLIFICATION OF A TROUGH OVER THE MS/OH
VALLEY REGION...AS UPSTREAM HEIGHTS RISE OVER THE GREAT BASIN IN
ADVANCE OF ANOTHER ERN PAC TROUGH. WITH RESPECT TO THUNDERSTORM
POTENTIAL...THE MOST RELEVANT FEATURES WILL BE THE ESEWD PROGRESSION
OF AN EMBEDDED SPEED MAX FROM CO/KS THIS MORNING TO THE LOWER MS AND
TN VALLEY REGION TONIGHT. THIS SPEED MAX WILL BE PRECEDED BY A WEAK
REMNANT LEE CYCLONE WHICH WILL DEVELOP EWD FROM NE TX ALONG THE
SLOW-MOVING BAROCLINIC ZONE ACROSS SRN AR...CENTRAL MS/AL...AND SRN
GA. IN THE WAKE OF THIS WAVE...THE BAROCLINIC ZONE WILL MOVE SEWD
AS A COLD FRONT AND REACH THE NW AND N CENTRAL GULF COAST EARLY
FRIDAY.

...LOWER MS VALLEY AREA TODAY...
A CLUSTER OF THUNDERSTORMS IS ONGOING OVER SRN AR...IN ADVANCE OF
THE WEAK SURFACE WAVE ON THE FRONT...WHERE LOW-LEVEL WAA IS
STRONGEST. PRESENT INDICATIONS ARE THAT THIS CONVECTION WILL LIKELY
PERSIST AND DEVELOP SEWD ACROSS LA/MS DURING THE DAY...FED BY AN
INFLUX OF RICH LOW-LEVEL MOISTURE FROM THE W/SW...AND MLCAPE VALUES
AOA 2000 J/KG. MEANWHILE...DEEP LAYER VERTICAL SHEAR WILL REMAIN
SUFFICIENT FOR ORGANIZED SEVERE STORMS...INCLUDING EMBEDDED
BOW/SUPERCELL STRUCTURES. LOW-LEVEL SHEAR HAS ALREADY PEAKED THIS
MORNING AND WILL WEAKEN GRADUALLY THROUGH THE DAY AS LOW-LEVEL FLOW
VEERS TO WLY AND SPEEDS DIMINISH...THUS THE THREAT FOR TORNADOES
WILL BE MARGINAL AT BEST. WARM PROFILES ALOFT SUGGEST THAT THE HAIL
THREAT WILL CONTINUE TO BE LIMITED...WHILE THE MODERATE
INSTABILITY/DRYING ALOFT WILL CONTINUE TO SUPPORT DAMAGING WINDS AS
THE PRIMARY SEVERE STORM THREAT THROUGH THE AFTERNOON.

..THOMPSON/HURLBUT.. 10/15/2009

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