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ACUS02 KWNS 090556
SWODY2
SPC AC 090554
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT THU SEP 09 2010
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MO
VALLEY/SOUTH-CENTRAL PLAINS...
...SYNOPSIS...
CURRENT WESTERN STATES UPPER TROUGH IS EXPECTED TO ADVANCE
EAST-NORTHEASTWARD FROM THE NORTHERN/CENTRAL ROCKIES TO THE CANADIAN
PRAIRIES/UPPER MIDWEST ON FRIDAY. AN ASSOCIATED EAST-SOUTHEAST
ADVANCING COLD FRONT ACROSS THE PLAINS WILL PROVIDE A FOCUS FOR
STRONG TO SEVERE TSTM DEVELOPMENT...MAINLY ACROSS PORTIONS OF THE
LOWER MO VALLEY/LOWER PORTIONS OF THE SOUTH-CENTRAL PLAINS.
...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS...
BASAL PORTION OF THE AFOREMENTIONED UPPER TROUGH WILL OVERSPREAD THE
CENTRAL PLAINS BY AFTERNOON/EVENING...WITH STRENGTHENING WIND FIELDS
/40-50 KT AT 500 MB/ AND COOLING ALOFT GENERALLY EXPECTED TO LAG /TO
THE NORTHWEST/ THE EAST-SOUTHEAST ADVANCING SURFACE COLD FRONT. IT
SEEMS PROBABLE THAT SURFACE BASED TSTMS WILL DEVELOP/INCREASE BY
LATE AFTERNOON/EARLY EVENING ALONG THE COLD FRONT NEAR A SURFACE
TRIPLE POINT/NORTHEAST OF A KS SURFACE LOW. THIS INITIAL
DEVELOPMENT/BRUNT OF THE SEVERE RISK APPEARS MOST LIKELY ACROSS
PORTIONS OF EASTERN KS/WESTERN MO...AND PERHAPS SOUTHEAST
NEB/SOUTHWEST IA. A NEAR-FRONTAL FAVORABLE JUXTAPOSITION OF VERTICAL
SHEAR AND MODERATE TO STRONG BUOYANCY /UPWARDS OF 2000-3000 J PER KG
MLCAPE/...AMID A RELATIVELY HIGH MOISTURE CONTENT AIRMASS /SURFACE
DEWPOINTS UPPER 60S TO LOWER 70S F/...WILL SUPPORT
ORGANIZED/SUSTAINED SEVERE STORMS CAPABLE OF MAINLY DAMAGING
WINDS/HAIL ESPECIALLY DURING THE LATE AFTERNOON/EARLY EVENING HOURS.
STORMS SHOULD CONTINUE TO INCREASE/CONGEAL AND SPREAD
EAST-SOUTHEASTWARD ACROSS THE OZARKS/MIDDLE MS VALLEY
VICINITIES...ALTHOUGH THE SEVERE THREAT SHOULD GENERALLY WANE BY
LATE EVENING AS NEAR-SURFACE BUOYANCY BECOMES EXHAUSTED.
...EASTERN DAKOTAS/MIDDLE MO VALLEY/UPPER MIDWEST...
FARTHER NORTH...A CONSIDERABLY LESSER OPPORTUNITY/DEGREE OF
DESTABILIZATION IS ANTICIPATED IN VICINITY OF THE NORTH-SOUTH
ORIENTED OCCLUDING FRONTAL ZONE. NONETHELESS...A FEW EARLY DAY
ELEVATED TSTMS COULD POSE A SEVERE HAIL THREAT. ADDITIONAL
STRONG/PERHAPS SEVERE TSTM DEVELOPMENT /CAPABLE OF HAIL AND WIND/
MAY OCCUR ALONG THE OCCLUDING FRONTAL ZONE DURING THE AFTERNOON
ACROSS EAST-CENTRAL DAKOTAS...PROVIDED SUFFICIENT /ALBEIT MODEST/
DESTABILIZATION OCCURS. IN EITHER CASE...CURRENT THINKING IS THAT
THE OVERALL SEVERE THREAT WILL REMAIN TOO MARGINAL/ISOLATED TO
WARRANT A CATEGORICAL SLIGHT RISK.
..GUYER.. 09/09/2010
