SWODY1
SPC AC 181620
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT SUN MAY 18 2008
VALID 181630Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS OF THE DELMARVA...
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS OF THE TN VALLEY...
...SYNOPSIS
COLD UPPER TROUGH CONTINUES TO DEEPEN INTO NERN U.S. AS A STRONG
WIND MAX ROTATES ACROSS THE OH VALLEY TO DELMARVA BY TONIGHT.
COMPLEX SURFACE PRESSURE PATTERN AHEAD OF TROUGH WITH SEVERAL LOWS.
LOW CENTER CENTRAL PA WITH COLD FRONT SWWD THRU WV TO NR AR. THIS
LOW GRADUALLY DEEPENS AS IT MOVES INTO SRN NEW ENGLAND THIS EVENING
AS COLD FRONT SWEEPS OFFSHORE THE MID ATLANTIC STATES OVERNIGHT.
...DELMARVA...
OTHER THAN THE LACK OF INSTABILITY...PARAMETERS ARE IN PLACE FOR
SEVERE THUNDERSTORMS E OF APPALACHIANS THIS AFTERNOON AS THE STRONG
TROUGH AND WIND FIELDS ACCOMPANY THE FRONT THROUGH THE AREA. THE
ISSUE OF INSTABILITY IS GOING TO MAKE IT DIFFICULT TO DEVELOP DEEP
CONVECTION AS LOW LEVEL MOISTURE...DEWPOINTS MID 50S OR
LOWER...REMAINS MARGINAL.
HAVE FOCUSED THE SLIGHT IN THE AREA THAT IS CURRENTLY RECEIVING THE
BEST DAYTIME HEATING...BASICALLY E OF THE BLUE RIDGE AND S OF THE DC
METRO. WITH TEMPERATURES WARMING TO NEAR 80F IN THIS REGION OF
VA/SRN MD...MLCAPES WILL CLIMB TO AROUND 500 J/KG WHICH COUPLED WITH
STEEP LOW LEVEL LAPSE RATES WILL SUPPORT A WIND DAMAGE POTENTIAL.
FURTHER N INTO SRN PA/NJ CLOUD COVER WILL LIMIT SEVERE...HOWEVER
WITH THE STRENGTH OF THE TROUGH/SHEAR PROFILES...A FEW LOW TOPPED
SEVERE STORMS ARE POSSIBLE ALONG/AHEAD OF COLD FRONT AND SURFACE LOW
THIS AFTERNOON.
LOW TOPPED THUNDERSTORMS WILL INCREASE BY MID AFTERNOON E OF THE
BLUE RIDGE FORMING INTO SHORT LINE SEGMENTS UNDER THE
STRONG...UNIDIRECTIONAL SHEAR ENVIRONMENT. PRIMARY THREAT GIVEN THE
STEEP LOW LEVEL LAPSE RATES AND MARGINAL INSTABILITY WILL BE
DAMAGING WINDS AND MARGINALLY SEVERE HAIL.
...TN VALLEY TO SRN APPALACHIANS...
HAVE MADE LITTLE CHANGES FROM PREVIOUS OUTLOOK THIS AREA AS AGAIN
INSTABILITY WILL BE LIMITED. AHEAD OF THE COLD FRONT THERE IS
CONSIDERABLE MID LEVEL CONVECTION ASSOCIATED WITH THE SRN IMPULSE
NOW SHEARING/WEAKENING AS IT IS ABSORBED IN THE LARGE CIRCULATION
OVER THE GREAT LAKES.
SEVERE THUNDERSTORMS THIS AFTERNOON WILL BE DEPENDENT ON HOW QUICKLY
THIS CLOUD COVER MOVES AWAY/DISSIPATES TO ALLOW SURFACE HEATING
AHEAD OF COLD FRONT.
WITH SATELLITE CURRENTLY SHOWING THINNING CLOUD COVER ACROSS NRN MS
INTO WRN TN SPREADING EWD...LOOKS LIKE HEATING WILL BE SUFFICIENT
FOR TEMPERATURES TO RISE THRU THE 70S AND WITH DEWPOINTS INTO THE
UPPER 50S RESULT IN AREAS OF MLCAPE UPWARDS TO 1000 J/KG AHEAD OF
THE FRONT.
THUNDERSTORMS WILL DEVELOP BY MID/LATE AFTERNOON ALONG/AHEAD OF
FRONT FROM TN VALLEY TO SRN APPALACHIANS. 40-50KT OF SHEAR AND
LOCALLY STEEP LOW LEVEL LAPSE RATES IN AREAS OF GREATEST HEATING
WILL SUPPORT A THREAT OF WIND DAMAGE AND HAIL WITH STRONGEST
UPDRAFTS.
..HALES/GRAMS.. 05/18/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment