SPC Day 2 (Wednesday) OutlookDAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER
NORMAN OK
1253 AM CDT TUE APR 08 2008
VALID 091200Z - 101200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS NORTH CENTRAL TX AND SOUTHERN OK...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHERN PLAINS/ARKLATEX/OZARKS...
...MUCH OF TX/OK INTO THE ARKLATEX/OZARKS...
POTENTIAL WILL EXIST FOR WIDESPREAD SEVERE STORMS ACROSS THE SOUTHERN PLAINS WEDNESDAY/WEDNESDAY NIGHT. 00Z NAM/GFS/ECMWF AND 21Z SREF GUIDANCE SUGGEST A MID/UPPER TROUGH WILL SHIFT EASTWARD OVER THE SOUTHERN ROCKIES INTO THE SOUTHERN HIGH PLAINS DURING THE DAY...TAKING ON A NEUTRAL TO NEGATIVE TILT BY THE END OF THE PERIOD. AT THE SURFACE...CYCLOGENESIS WILL OCCUR ACROSS THE SOUTHERN HIGH PLAINS...WITH BOUNDARY LAYER MOISTURE /60S F DEWPOINTS/ RETURNING WEST-NORTHWESTWARD ACROSS TX. STALLING FRONTAL BOUNDARY ACROSS THE ARKLATEX AND NORTH/CENTRAL TX ON DAY 1 IS EXPECTED TO RETREAT NORTHWARD ACROSS NORTH TX DURING THE DAY...AND INTO OK DURING THE EVENING/OVERNIGHT.
THE MOST LIKELY SCENARIO FOR SURFACE BASED RMS/SUPERCELLS DURING THE AFTERNOON/EARLY EVENING WILL BE ACROSS PORTIONS OF SOUTHWEST/WEST CENTRAL INTO NORTH CENTRAL TX AHEAD OF THE DEVELOPING SURFACE LOW/DRYLINE AND NEAR THE WARM FRONT INTERSECTION. AS THE UPPER TROUGH CONTINUES TO SHIFT EASTWARD...50 KT MID LEVEL SOUTHWESTERLY FLOW ATOP SOUTH-SOUTHEASTERLY WINDS IN THE BOUNDARY LAYER WILL YIELD STRONG VERTICAL SHEAR FOR SUPERCELLS. AMPLE HEATING/INCREASINGLY STEEP MID LEVEL LAPSE RATES IN CONJUNCTION WITH 60S F DEWPOINTS ACROSS TX WILL LEAD TO MODERATE TO STRONG INSTABILITY BY AFTERNOON...WITH MLCAPE OF 2000-3000 J/KG. THE SUPERCELLS WILL BE CAPABLE OF VERY LARGE HAIL AND TORNADOES /A FEW POTENTIALLY STRONG/...WITH AN APPRECIABLE SEVERE RISK CONTINUING WELL INTO THE NIGHT. IN ADDITION TO THE OTHER RISKS...A DAMAGING WIND THREAT MAY INCREASE DURING THE LATE EVENING/OVERNIGHT ACROSS NORTH/CENTRAL TX IN ASSOCIATION WITH THE EASTWARD SURGING DRYLINE/PACIFIC FRONT.
FARTHER NORTH ACROSS NORTHWEST TX/WESTERN OK INTO SOUTHERN KS...A LEAD IMPULSE MAY LEAD TO SCATTERED ELEVATED THUNDERSTORMS BY LATE MORNING/AFTERNOON WITHIN THE ELEVATED BAROCLINIC ZONE. A HIGHLY SHEARED ENVIRONMENT AND SUFFICIENT INSTABILITY WOULD RESULT IN AT LEAST SOME LARGE HAIL POTENTIAL. ALTHOUGH POSSIBLY IMPACTED BY ONGOING CONVECTION ACROSS TX...THE WARM FRONT WILL CONTINUE LIFTING NORTHWARD FROM NORTH TX INTO OK DURING THE EVENING/OVERNIGHT. AT LEAST A LARGE HAIL THREAT WILL CONTINUE MUCH OF THE NIGHT ACROSS OK INTO ADJACENT PORTIONS OF KS/MO/AR. HOWEVER...A SURFACED BASED SEVERE THREAT /INCLUDING TORNADOES AND DAMAGING WINDS/ CANNOT BE RULED OUT ACROSS CENTRAL/SOUTHERN OK DURING THE NIGHT.
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