SPC AC 280039
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0739 PM CDT FRI APR 27 2007
VALID 280100Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS EVENING OVER PARTS OF
SOUTHEAST VA AND NORTHEAST NC...
...EASTERN VA/NC...
BROAD UPPER TROUGH REMAINS OVER THE EASTERN STATES THIS
EVENING...WITH PRIMARY SURFACE COLD FRONT EXTENDING FROM EXTREME
SOUTHERN DE INTO CENTRAL NC. SCATTERED THUNDERSTORMS HAVE
RE-DEVELOPED ALONG THE FRONT DURING THE PAST COUPLE OF HOURS...WHERE
DEWPOINTS REMAIN IN THE MID 60S AND RELATIVELY STRONG LOW LEVEL
CONVERGENCE IS NOTED. THIS ACTIVITY MAY PERSIST FOR ANOTHER FEW
HOURS AS IT ADVANCES EASTWARD TOWARDS THE COAST. 00Z WAL SOUNDING
SHOWS OVER 40 KNOTS OF EFFECTIVE SHEAR...SUPPORTING A RISK OF
ORGANIZED MULTICELL OR SUPERCELL STORMS CAPABLE OF LARGE HAIL AND
DAMAGING WINDS.
...SOUTHWEST MO...
SMALL CLUSTER OF INTENSE THUNDERSTORMS HAS TRACKED FROM EASTERN KS
INTO SOUTHWEST MO THIS EVENING...AHEAD OF COMPACT UPPER SHORTWAVE
TROUGH. THESE STORMS HAVE PRODUCED NUMEROUS FUNNEL CLOUDS AND A
COUPLE OF TORNADOES...ALONG WITH LARGE HAIL. ACTIVITY IS MOVING
INTO A PROGRESSIVELY MORE STABLE ENVIRONMENT THAT WAS AFFECTED BY
EARLIER CONVECTION. THE SEVERE THREAT IS EXPECTED TO DIMINISH
RATHER RAPIDLY THROUGH 03Z IN THIS AREA.
...SOUTHWEST OK/NORTHWEST TX...
SURFACE OUTFLOW BOUNDARY FROM EARLIER CONVECTION EXTENDS ACROSS
SOUTHERN OK INTO NORTHWEST TX. ONSET OF DIURNAL COOLING AND
CONSIDERABLE CLOUDINESS ALONG THIS BOUNDARY ARE SUGGESTING THAT THE
POTENTIAL FOR CONVECTIVE INITIATION IS WANING. NEVERTHELESS...00Z
SOUNDINGS AND RECENT MODEL GUIDANCE CONTINUE TO INDICATE A LOW
PROBABILITY OF THUNDERSTORMS THIS EVENING ALONG THE BOUNDARY. IF
CONVECTION CAN FORM...STEEP MID LEVEL LAPSE RATES AND FAVORABLE
VERTICAL SHEAR PROFILES WOULD SUPPORT A RISK OF HIGH-BASED
SUPERCELLS CAPABLE OF LARGE HAIL.
..HART.. 04/28/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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