SPC AC 081226
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0626 AM CST SAT MAR 08 2008
VALID 081300Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN NC INTO THE MID
ATLANTIC...
...ERN NC INTO THE MID ATLANTIC...
INCREASING MOIST CONVECTION/LOW-TOPPED THUNDERSTORMS WERE ALREADY
UNDERWAY EARLY THIS MORNING ACROSS ERN NC ASSOCIATED WITH
STRENGTHENING DEEP LAYER ASCENT OVERSPREADING THE REGION. AS STRONG
MID/UPPER LEVEL TROUGH TAKES ON NEGATIVE-TILT AND EJECTS RAPIDLY
NEWD...THIS ACTIVITY SHOULD FURTHER INCREASE AND EXPAND QUICKLY NWD
INTO THE MID ATLANTIC BY THE EARLY/MID AFTERNOON. COASTAL/WEDGE
FRONT HAS ERODED SOME OVERNIGHT AND NOW EXTENDS FROM SECONDARY LOW
CENTER NEAR HKY NEWD TO JUST WEST OF RIC TOWARDS THE DE/SRN NJ
COAST. AS SURFACE LOW CONSOLIDATES/DEEPENS INTO CENTRAL PA THROUGH
THE AFTERNOON...ATLANTIC MOISTURE WILL INCREASE NWD ACROSS ERN
VA/CHESAPEAKE AND POSSIBLY THE DELMARVA AHEAD OF A STRENGTHENING
SURFACE COLD FRONT EXPECTED TO SURGE EWD AND OFF THE NC/VA COAST
AROUND 21Z.
DESPITE THE EXTREME SHEAR ALREADY IN PLACE AHEAD OF THIS SYSTEM...
SEVERITY OF ENSUING THUNDERSTORMS WILL BE MODULATED BY LIMITED
INSTABILITY/WEAK LAPSE RATES WITHIN WARM SECTOR. VWPS AND 12Z
SOUNDINGS INDICATE SFC-3 KM SRH IN EXCESS OF 300 M2/S2 AND SFC-6 KM
SHEAR AOA 50 KT ACROSS ERN NC/SERN VA...SUGGESTING ACTIVITY WILL
QUICKLY ACQUIRE ROTATION AS STORMS RACE NNEWD WITH ATTENDANT THREAT
OF ISOLATED TORNADOES. DEEP ASCENT COLLOCATED WITH STRONG SURFACE
COLD FRONT NOW PUSHING EWD ACROSS CENTRAL NC/SC MAY ALSO SUPPORT A
NARROW LINE OF MOIST CONVECTION AS IT INTERACTS WITH LOW LEVEL MOIST
AXIS OVER ERN NC/SERN VA THIS MORNING. THIS WILL PROVIDE ADDITIONAL
HAZARD OF DAMAGING WINDS AS STRONG DRYING/SUBSIDENCE ALONG FRONTAL
ZONE ENHANCES DOWNWARD TRANSPORT OF 50+ KT SWLY WINDS JUST OFF THE
SURFACE. NWD EXTENT OF THIS BROKEN LINE OF LOW-TOPPED CONVECTION
AND RESULTANT SEVERE THREAT COULD EXTEND INTO PORTIONS OF THE
DELMARVA/MID ATLANTIC COAST LATER THIS AFTERNOON.
...LONG ISLAND INTO SRN NEW ENGLAND...
INCREASING LOW LEVEL WAA AND WEAK MUCAPE WILL SUPPORT THUNDERSTORM
DEVELOPMENT ATOP COOLER/STABLE SURFACE LAYER INTO LONG ISLAND/SRN
NEW ENGLAND LATER TODAY. DESPITE POSSIBLE COASTAL/WARM FRONT
LIFTING NWD PLACING THESE AREAS IN WARM SECTOR...FORECAST SOUNDINGS
SUGGEST SURFACE INVERSION MAY PROVE TOO DIFFICULT FOR INTENSE
SURFACE DOWNDRAFTS. HOWEVER...AN ISOLATED STRONG/SEVERE GUST OR TWO
WILL REMAIN POSSIBLE INTO THIS REGION LATER TODAY/THIS EVENING AND
WILL LEAVE LOW SEVERE WIND PROBABILITIES IN PLACE.
..EVANS.. 03/08/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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