SPC AC 240559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1159 PM CST TUE NOV 23 2010
VALID 241200Z - 251200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN KS...MUCH
OF MO...ERN OK...NWRN HALF OF AR...AND PARTS OF NERN TX...
...SYNOPSIS...
VERY LARGE...POSITIVELY-TILTED UPPER TROUGH IS PROGGED TO SHIFT
SLOWLY EWD ACROSS THE ROCKIES THIS PERIOD...WITH THE EMBEDDED UPPER
LOW FORECAST TO RESIDE OVER THE DAKOTAS BY THE END OF THE PERIOD.
MEANWHILE...FASTER SWLY FLOW ALOFT ON THE SERN PERIPHERY OF THE
TROUGH WILL SPREAD ACROSS THE CENTRAL/SRN PLAINS INTO THE MID MS
VALLEY REGION.
AT THE SURFACE...AN ASSOCIATED COLD FRONT WILL MOVE OUT OF THE
ROCKIES AND INTO THE CENTRAL PLAINS/SRN HIGH PLAINS THROUGH THE DAY.
BY THE END OF THE PERIOD...AN OCCLUDED FRONT SHOULD ARC SEWD FROM
THE UPPER MS VALLEY ACROSS THE WRN UPPER GREAT LAKES TO A TRIPLE
POINT OVER THE LOWER OH VALLEY. FROM THE TRIPLE POINT...THE COLD
FRONT SHOULD EXTEND SWWD ACROSS AR INTO TX...WHILE THE WARM FRONT
REACHES THE MID OH VALLEY.
...ERN KS/MUCH OF MO/ERN OK/AR AND A SMALL PORTION OF NERN TX...
ELEVATED SHOWERS AND SCATTERED THUNDERSTORMS SHOULD BE ONGOING AT
THE START OF THE PERIOD ACROSS PARTS OF THE SLIGHT RISK AREA...IN
ZONE OF STRONG WARM ADVECTION N OF THE WARM FRONT RETREATING NWD
ACROSS THE SRN PLAINS INTO KS/MO. EXPECT MUCH OF THIS PRECIPITATION
TO SHIFT NEWD ACROSS THE LOWER MO/MID MS/LOWER OH VALLEYS THROUGH
THE DAY AS THE FRONT RETREATS...WHILE THE COLD FRONT ADVANCES SSEWD
ACROSS KS TOWARD MO/OK.
WITHIN THE WARM SECTOR...COMBINATION OF EARLIER PRECIPITATION AND
LINGERING EFFECTS OF SHORT-WAVE RIDGING SHOULD MAINTAIN WEAK LAPSE
RATES...AND GIVEN POSITIVELY-TILTED NATURE OF THE ADVANCING TROUGH
AND LACK OF A PRONOUNCED LEAD WAVE BUT RATHER SLOW STEADY HEIGHT
FALLS...SUBSTANTIAL MID-LEVEL COOLING IS NOT FORECAST AHEAD OF THE
FRONT. THUS...DESPITE NWD ADVECTION OF DECENT LOW-LEVEL MOISTURE
/UPPER 50S TO NEAR 60 DEWPOINTS INTO MO AND GENERALLY LOW 60S ACROSS
MOST OF THE REST OF THE SLIGHT RISK AREA/...MIXED-LAYER CAPE IS
FORECAST TO REMAIN LESS THAN 500 J/KG IN MOST AREAS.
WHILE MODEST...THE DEGREE OF INSTABILITY SHOULD BE SUFFICIENT TO
SUPPORT ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT ALONG THE COLD
FRONT AS IT ADVANCES ACROSS KS INTO MO/OK DURING THE AFTERNOON AND
EVENING...AND ALONG A PRE-FRONTAL CONFLUENCE BAND LIKELY TO RESIDE
OVER ERN OK. CAPPING SHOULD LIMIT SWD DEVELOPMENT INTO NERN
TX...BUT OTHER/ISOLATED STORMS MAY ALSO EVOLVE INVOF THE RETREATING
WARM FRONT INVOF THE MID MS/LOWER OH VALLEYS. FORCED STORMS ALONG
THE FRONT MAY CONTINUE INTO THE OVERNIGHT HOURS...SHIFTING ACROSS
PARTS OF NERN TX...ERN OK AND AR.
THOUGH MODEST INSTABILITY SHOULD LIMIT OVERALL CONVECTIVE
COVERAGE/INTENSITY...STRENGTH OF DEEP-LAYER WIND FIELD WILL BE QUITE
SUFFICIENT FOR ORGANIZED/ROTATING STORMS. IN FACT...DEGREE OF SHEAR
MAY BE DETRIMENTAL ACROSS PARTS OF THE REGION -- TOO STRONG FOR THE
AVAILABLE INSTABILITY. NONETHELESS...EXPECT A FEW STRONGER
STORMS/SMALL-SCALE LINE SEGMENTS TO ORGANIZE THROUGH THE AFTERNOON
AND EVENING...WITH ACCOMPANYING POTENTIAL FOR DAMAGING WINDS AND
POSSIBLY HAIL. LOW-LEVEL SHEAR WILL ALSO BE SUPPORTIVE OF TORNADOES
-- ESPECIALLY ACROSS PARTS OF MO...THOUGH THREAT WILL REMAIN
ISOLATED DUE TO OVERALL LIMITED STORM COVERAGE/INTENSITY EXPECTED
ATTM. OVERNIGHT...A DECREASE IN THE ALREADY LIMITED CAPE SUGGESTS A
WANE IN CONVECTIVE INTENSITY AND ASSOCIATED SEVERE POTENTIAL.
..GOSS/GARNER.. 11/24/2010
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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