SWODY1
SPC AC 011230
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0730 AM CDT THU OCT 01 2009
VALID 011300Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE MID MS VALLEY
INTO CENTRAL TX...
A LARGE UPPER TROUGH CONTINUES TO TRACK EASTWARD ACROSS THE
PLAINS...WITH A SERIES OF SHORTWAVE TROUGHS AND AN 80+ KT MID LEVEL
JET EXPECTED TO ROTATE ACROSS THE SOUTHERN PLAINS AND INTO THE MID
MS VALLEY TODAY. LATEST SURFACE ANALYSIS SHOWS THE PRIMARY COLD
FRONT SURGING EAST-SOUTHEASTWARD ACROSS KS/OK. STRONG SOUTHWESTERLY
LOW LEVEL WINDS HAVE TRANSPORTED MID 60S DEWPOINTS INTO CENTRAL KS
AHEAD OF THE FRONT...AND SHOULD ALLOW SIGNIFICANT MOISTENING TO
SPREAD INTO PARTS OF MO/AR BY EARLY AFTERNOON. THIS WILL LEAD TO
WIDESPREAD THUNDERSTORMS AND SCATTERED STRONG/SEVERE STORMS FROM
CENTRAL MO INTO EAST TX LATER TODAY.
...MO/AR/OK...
A BAND OF ONGOING CONVECTION CURRENTLY EXTENDS FROM MO INTO EASTERN
OK AND CENTRAL TX. THIS PRE-FRONTAL BAND IS ASSOCIATED WITH WARM
ADVECTION AND LIFT ALONG THE LOW LEVEL JET AXIS...AND WILL PROBABLY
BE MAINTAINED THROUGH MUCH OF THE DAY. BEHIND THIS
ACTIVITY...STRONG HEATING WILL YIELD MODERATE INSTABILITY ALONG THE
FRONT...ALTHOUGH 12Z RAOBS CONFIRM THAT CAP WILL LIKELY RETARD
SURFACE-BASED STORMS UNTIL AT LEAST EARLY AFTERNOON. INITIAL
ACTIVITY OVER WESTERN MO/NORTHWEST AR/EASTERN OK MAY BE
SUPERCELLULAR WITH A RISK OF LARGE HAIL AND DAMAGING WINDS. STORMS
WILL LIKELY CONGEAL INTO A SQUALL LINE BY EARLY EVENING AND SPREAD
ACROSS MO/AR WITH A CONTINUED RISK OF HAIL AND WIND DAMAGE.
...TX/LA...
CONSIDERABLE UNCERTAINTY REMAINS REGARDING THE SOUTH/WEST EXTENT OF
THUNDERSTORM DEVELOPMENT LATER TODAY. AMPLE MOISTURE AND MODERATE
CAPE VALUES WILL BE IN PLACE...BUT FORECAST SOUNDINGS SHOW
SUBSTANTIAL CAPPING WILL ALSO BE PRESENT. HAVE MAINTAINED SLIGHT
RISK OF SEVERE STORMS INTO CENTRAL TX DUE TO UNCERTAINTY...BUT
THREAT INCREASES TO THE EAST OVER EAST TX AND NORTHERN LA AS COLD
FRONT AND ASSOCIATED SQUALL LINE AFFECTS THIS REGION AFTER DARK.
ANY ISOLATED STORM THAT CAN DEVELOP ALONG THE FRONT OVER CENTRAL TX
WILL POSE A RISK OF LARGE HAIL AND DAMAGING WINDS.
...IA/NORTHERN MO...
WIDESPREAD PRECIPITATION HAS BEEN AFFECTING MUCH OF IA/NORTHERN MO
OVERNIGHT...BUT BACK EDGE HAS CROSSED THE MO RIVER AND A FEW BREAKS
IN THE CLOUDS ARE LIKELY THIS MORNING AHEAD OF THE FRONT. LOW LEVEL
MOISTURE REMAINS LIMITED IN THIS REGION...BUT MAY INCREASE INTO THE
LOWER 60S PRIOR TO FRONTAL PASSAGE. DESPITE ONLY MARGINAL
INSTABILITY...STRONG LARGE SCALE FORCING FOR ASCENT IN LEFT EXIT
REGION OF MID/UPPER LEVEL JET PROVIDES SOME CONCERN FOR ISOLATED
STRONG STORMS. HAIL WOULD BE THE MAIN THREAT...BUT COVERAGE IS NOT
ANTICIPATED TO MEET CATEGORICAL OUTLOOK CRITERIA.
..HART/GRAMS.. 10/01/2009
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