SPC AC 221621
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT TUE MAR 22 2011
VALID 221630Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM EASTERN PORTIONS OF
NEB/KS/OK TO THE UPPER MS RIVER VALLEY...
...CENTRAL/SOUTHERN PLAINS AND LOWER/MIDDLE MO VALLEY TO
MIDDLE/UPPER MS VALLEY...
ON THE PERIPHERY OF AN UPPER LOW CENTERED OVER THE NORTHERN
ROCKIES...MIDDAY WATER VAPOR IMAGERY REFLECTS A LEAD SHORTWAVE
TROUGH ADVANCING NORTHEASTWARD OVER THE CENTRAL/SOUTHERN HIGH
PLAINS...WITH LARGE SCALE HEIGHT FALLS ALREADY OVERSPREADING THE
MAJORITY OF THE PLAINS PER 12Z UPPER ANALYSIS. WITHIN THE LEFT EXIT
REGION OF A 100-130 KT UPPER JET...A SURFACE LOW WILL DEEPEN TO A
DEGREE WHILE OTHERWISE DEVELOPING EASTWARD ACROSS THE LOWER-MIDDLE
MO RIVER VALLEY.
MODEST LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE MIDDLE TO
UPPER 50S F...MAY PRECLUDE A MORE APPRECIABLE/WIDESPREAD
MODERATE-RISK CALIBER SEVERE THREAT ACROSS PORTIONS OF THE MO
VALLEY. THAT SAID...STRONG/SEVERE TSTMS ARE EXPECTED TO INITIALLY
DEVELOP NEAR/EAST OF THE SURFACE LOW AND ASSOCIATED DRYLINE/COLD
FRONT TRIPLE POINT ACROSS EASTERN NEB/EASTERN KS INTO WESTERN
IA/NORTHWEST MO...PERHAPS AS EARLY AS THE 20-21Z TIME FRAME. THIS
IDEA IS WELL SUPPORTED BY CONVECTION-ALLOWING GUIDANCE SUCH AS THE
12Z WRF-NMM AND RECENT EXPERIMENTAL HRRR RUNS. WHILE BUOYANCY WILL
NOT BE PARTICULARLY ROBUST /1250-1750 J PER KG/...THE KINEMATIC
ENVIRONMENT WILL CONTRIBUTE TO FOCUSED ASCENT NEAR AND IMMEDIATELY E
OF THE SURFACE LOW THIS AFTERNOON/EVENING...AND VERTICAL SHEAR
PROFILES WILL BE HIGHLY FAVORABLE FOR SUPERCELLS CAPABLE OF VERY
LARGE HAIL AND SOME TORNADOES /EFFECTIVE SRH IN EXCESS OF 250 M2 PER
S2/ IN THE WARM SECTOR. LATER TONIGHT...SEVERE HAIL/ISOLATED
DAMAGING WINDS WILL BECOME THE PRIMARY CONCERN BY LATE
EVENING/OVERNIGHT...WITH A SEVERE THREAT POTENTIALLY DEVELOPING
EASTWARD TOWARD THE UPPER-MIDDLE MS RIVER VALLEY.
FARTHER SOUTH...OWING TO A STRONG ELEVATED MIXED LAYER AND THE
AFOREMENTIONED MODEST BOUNDARY LAYER MOISTURE AS REFLECTED BY 12Z
REGIONAL OBSERVED RAOBS/SURFACE DATA...DEEP CONVECTIVE DEVELOPMENT
ALONG THE DRYLINE IS MORE UNCERTAIN WITH SOUTHWARD EXTENT ACROSS
SOUTHEAST KS/SOUTHWEST MO INTO EASTERN OK/NORTH TX. WHILE DEEP
CONVECTIVE DEVELOPMENT IS MORE UNCERTAIN AND SHOULD INHERENTLY BE
MORE ISOLATED...ANY STORM THAT DOES FORM/REMAIN SUSTAINED WILL BE
SUPERCELLULAR AND CAPABLE OF LARGE HAIL AND POSSIBLY A TORNADO. ANY
SEVERE THREAT AT THESE LATITUDES SHOULD DIMINISH WITHIN AN HOUR OR
TWO OF SUNSET.
..GUYER/COHEN.. 03/22/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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