SPC AC 260611
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0111 AM CDT THU APR 26 2007
VALID 271200Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ERN CAROLINAS THROUGH
THE MID ATLANTIC...
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF WRN AND NWRN TX
INTO SWRN OK...
...SYNOPSIS...
UPPER TROUGH INITIALLY OVER THE GREAT LAKES...OH AND TN VALLEYS WILL
MOVE EAST THROUGH THE MID ATLANTIC AND CAROLINAS. SEVERAL VORTICITY
MAXIMA WILL ROTATE THROUGH THIS FEATURE. COLD FRONT WILL EXTEND
INITIALLY FROM THE GREAT LAKES SWD INTO THE WRN FL PANHANDLE THEN
WWD THROUGH THE NRN GULF AND S TX. NRN PORTIONS OF FRONT WILL MOVE
EAST AND OFF THE MID ATLANTIC SEABOARD FRIDAY EVENING...WHILE SWRN
PORTION REMAINS QUASISTATIONARY OVER THE NRN GULF OR LIFTS SLOWLY
NWD THROUGH S TX.
FARTHER W A SECONDARY SHORTWAVE TROUGH IS FORECAST TO DROP SEWD
THROUGH THE CNTRL OR SRN PLAINS. MODELS CONTINUE TO DIFFER ON THE
TRACK OF THIS FEATURE WITH THE ECMWF AND GFS BEING FARTHER NORTH
THAN THE NAM. A COLD FRONT WILL ACCOMPANY THE SHORTWAVE TROUGH SEWD
INTO THE CNTRL AND SRN PLAINS.
...ERN CAROLINAS THROUGH MID ATLANTIC...
STORMS MAY BE ONGOING EARLY FRIDAY OVER PORTIONS OF THE WRN OR CNTRL
CAROLINAS NWD INTO THE MID ATLANTIC REGION ALONG AND JUST AHEAD OF
COLD FRONT. MID TO UPPER 60S BOUNDARY LAYER DEWPOINTS SHOULD ADVECT
NWD THROUGH PRE-FRONTAL WARM SECTOR FROM THE ERN CAROLINAS INTO ERN
VA AS SLY LOW LEVEL FLOW INCREASE DOWNSTREAM FROM EWD ADVANCING
UPPER TROUGH. THOUGH 700-500 MB LAPSE RATES WILL NOT BE PARTICULARLY
STEEP...POTENTIAL FOR SURFACE HEATING DOWNSTREAM FROM ONGOING
ACTIVITY WILL LIKELY CONTRIBUTE TO DESTABILIZATION. THIS WILL RESULT
IN POTENTIAL FOR STORMS TO INTENSIFY OR NEW STORMS TO DEVELOP WITHIN
PRE-FRONTAL CONFLUENCE ZONE. VERTICAL SHEAR OVER WARM SECTOR IS
EXPECTED TO BE LARGELY UNIDIRECTIONAL WITH 0-6 KM FROM 30 TO 40 KT.
PRIMARY THREAT SHOULD BE DAMAGING WIND ASSOCIATED WITH BOWING
SEGMENTS. SOME SUPERCELL STRUCTURES WILL ALSO BE POSSIBLE AND THIS
MAY ENHANCE THE THREAT FOR HAIL WITH THE STRONGER STORMS.
...NWRN TX THROUGH SWRN OK...
PRIMARY UNCERTAINTY IN THIS REGION IS TRACK OF SHORTWAVE TROUGH. IF
MORE NRN TRACK OF THE ECMWF VERIFIES...SEVERE THREAT WILL BE MORE
LIMITED SINCE THE STRONGER ASCENT AND BEST POTENTIAL FOR INITIATION
WILL REMAIN N OF HIGHER INSTABILITY. THE ATMOSPHERE WILL LIKELY
DESTABILIZE AS A SLY LOW LEVEL JET ACROSS WRN TX ADVECTS MODIFIED CP
AIR NWD BENEATH STEEP LAPSE RATES OVER THE SRN HIGH PLAINS.
ATMOSPHERE WILL LIKELY BE CAPPED TO SURFACE BASED STORMS UNTIL
POSSIBLY LATER IN THE AFTERNOON. HOWEVER...A HAIL THREAT MAY EXIST
WITH ANY ELEVATED ACTIVITY DURING THE MORNING FROM SWRN KS THROUGH
WRN OK INTO THE TX PANHANDLE. AS THE BOUNDARY LAYER WARMS AND CAP
WEAKENS DURING THE AFTERNOON...SURFACE BASED STORMS MAY DEVELOP
FARTHER S ACROSS PARTS OF WRN AND NWRN TX ALONG THE COLD FRONT.
VERTICAL SHEAR WILL BE SUFFICIENT FOR HIGH BASED SUPERCELLS. PRIMARY
THREATS WILL BE ISOLATED DAMAGING WIND AND HAIL.
..DIAL.. 04/26/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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