Day 2 Convective Outlook From NWS SPC

DAY 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 STORMS/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.
...UPPER OHIO VALLEY...
STORMS ARE LIKELY ALONG THE ADVANCING COLD FRONT THROUGH THE
AFTERNOON ACROSS THE OHIO VALLEY. AFTERNOON HEATING COUPLED WITH
SURFACE DEWPOINTS IN THE 50S F MAY RESULT IN MLCAPE AS HIGH AS 500
J/KG. COUPLED WITH MODEST VERTICAL SHEAR/LARGELY UNIDIRECTIONAL
FLOW...A FEW OF THE STRONGER MULTICELL STORMS MAY BE CAPABLE OF
STRONG WIND GUSTS/HAIL BEFORE SUNSET.
..GUYER.. 04/08/2008