SWODY1
SPC AC 141945
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0245 PM CDT TUE JUN 14 2011
VALID 142000Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS THROUGH TONIGHT FROM CENTRAL OK
TO THE MID MS AND TN VALLEY REGIONS...
LITTLE CHANGE IN THE SCENARIO FROM THE PREVIOUS OUTLOOK AS THE CAP
IS EXPECTED TO HOLD OVER THE MO AREA UNTIL 22-00Z WHEN LARGE SCALE
ASCENT WITH APPROACHING TROUGH AND HEATING WILL DISSIPATE THE CINH.
HIGH BASED STORMS HAVE DEVELOPED ACROSS ERN CO COINCIDENT WITH UPPER
TROUGH. DOWNSTREAM INTO SWRN KS LAPSE RATES REMAIN VERY STEEP AND
COUPLED WITH MUCAPES UP TO 1000 J/KG AND DCAPE IN EXCESS OF 1200
J/KG...THERE IS A CONCERN THAT STORMS COULD DEVELOP A COLD POOL WITH
ASSOCIATED ENHANCED WIND DAMAGE THREAT. GIVEN THE LIMITED MOISTURE
AND THE LACK OF FAVORABLE SHEAR IN POST-FRONTAL AIR MASS WILL
MAINTAIN A LOW WIND PROB.
..HALES.. 06/14/2011
.PREV DISCUSSION... /ISSUED 1130 AM CDT TUE JUN 14 2011/
...NRN/CENTRAL MO AREA THROUGH TONIGHT...
OUTFLOW WITH MORNING CONVECTION HAS CONFINED THE EFFECTIVE WARM
FRONT TO AN AXIS FROM SRN MO TO NE KS. THIS BOUNDARY SHOULD RETREAT
NWD/NEWD INTO CENTRAL/NRN MO THIS AFTERNOON AS THE MORNING STORMS
WEAKEN AND MOVE AWAY. MEANWHILE...THE SURFACE COLD FRONT WILL
PROGRESS EWD ACROSS ERN KS IN ADVANCE OF A MIDLEVEL TROUGH EJECTING
EWD FROM THE CENTRAL HIGH PLAINS.
REGIONAL 12Z SOUNDINGS REVEALED A STRONG CAP IN THE WARM
SECTOR...BUT ASCENT ALONG THE SURFACE BOUNDARIES AND IN ASSOCIATION
WITH THE APPROACHING MIDLEVEL TROUGH/HEIGHT FALLS WILL SUPPORT LATE
AFTERNOON/EVENING THUNDERSTORM DEVELOPMENT. THE MORE CONCENTRATED
AREA OF STORMS IS EXPECTED ALONG THE WARM FRONT IN MO...JUST E OF
THE SURFACE LOW. HERE...MLCAPE SHOULD INCREASE TO 2500-3500 J/KG BY
LATE AFTERNOON...COINCIDENT WITH EFFECTIVE BULK SHEAR AOA 40 KT AND
STEEP MIDLEVEL LAPSE RATES. THIS ENVIRONMENT WILL FAVOR SUPERCELL
DEVELOPMENT WITH THE POTENTIAL FOR VERY LARGE HAIL DURING THE
EVENING. THE THREAT FOR TORNADOES WILL BE MOST PRONOUNCED NEAR THE
WARM FRONT WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED...IN THE FIRST
FEW HOURS AFTER STORM INITIATION WHEN STORMS WILL BE MORE DISCRETE.
BY LATE EVENING AND OVERNIGHT...STORM MERGERS COULD RESULT IN
UPSCALE GROWTH INTO ONE OR MORE MCS/S WITH THE POTENTIAL FOR
DAMAGING WINDS EWD/SEWD ALONG THE WARM FRONT.
...I-44 CORRIDOR IN OK THIS AFTERNOON/EVENING...
STRONG SURFACE HEATING IS EXPECTED TODAY IN ADVANCE OF THE SURFACE
COLD FRONT...WHICH WILL APPROACH THE I-44 CORRIDOR LATE THIS
EVENING. THE SURFACE HEATING WILL WEAKEN THE STRONG CAP IN PLACE
BASED ON 12Z SOUNDINGS...AND THUNDERSTORM DEVELOPMENT IS EXPECTED IN
THE ZONE OF ASCENT ALONG THE FRONT THIS EVENING...AUGMENTED BY
MIDLEVEL ASCENT WITH THE APPROACHING MIDLEVEL TROUGH. A DEEP MIXED
BOUNDARY LAYER AND STEEP LAPSE RATES WILL FAVOR DAMAGING WIND
PRODUCTION WITH THE STRONGER STORMS IN A BROKEN BAND ON THE FRONT
THIS EVENING...ALONG WITH SOME THREAT FOR LARGE HAIL IN THE REGION
OF STRONGER INSTABILITY TOWARD NE OK/SE KS.
...TN VALLEY REGION THIS AFTERNOON/EVENING...
THE ONGOING CONVECTION OVER WRN KY AND APPROACHING MIDDLE TN COULD
INTENSIFY SOME THIS AFTERNOON AS THE BOUNDARY LAYER TO THE S WARMS
AND DESTABILIZES. NWLY FLOW/SHEAR ALOFT AND THE PRESENCE OF THE
NW-SE ORIENTED FRONT COULD PROVIDE A CORRIDOR FOR MAINTENANCE OF THE
STORM CLUSTERS INTO NRN AL THIS AFTERNOON. MLCAPE NEAR 1500 J/KG
AND 20-35 KT NWLY MIDLEVEL FLOW COULD SUPPORT A RISK FOR A FEW
DAMAGING GUSTS THROUGH THE AFTERNOON.
...ERN CO/WRN KS/TX PANHANDLE THIS AFTERNOON...
THOUGH THIS AREA IS POST-FRONTAL...RESIDUAL BOUNDARY LAYER DEWPOINTS
IN THE 50S AND COOLER PROFILES MAY ALLOW ISOLATED THUNDERSTORM
DEVELOPMENT IN ADVANCE OF THE MIDLEVEL TROUGH WHICH WILL CROSS THIS
AREA DURING THE AFTERNOON. PRIOR TO LOW-LEVEL DRYING WITH DOWNSLOPE
FLOW...INSTABILITY AND VERTICAL SHEAR MAY REMAIN SUFFICIENT FOR A
MARGINAL HAIL/WIND RISK.
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