SWODY2
SPC AC 201724
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1224 PM CDT WED AUG 20 2008
VALID 211200Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF NRN AND WRN
ND...
...SYNOPSIS...
T.S. FAY IS FORECAST TO MOVE ACROSS NRN FL THIS PERIOD PER LATEST
NHC GUIDANCE...EVENTUALLY WEAKENING TO A DEPRESSION THROUGH THE END
OF THE PERIOD. MEANWHILE...A VIGOROUS/PROGRESSIVE TROUGH IS
EXPECTED TO CROSS THE NWRN QUARTER OF THE CONUS.
AS THE UPPER TROUGH MOVES EWD...A COLD FRONT IS FORECAST TO PRESS
SEWD ACROSS THE NRN ROCKIES AND INTO THE GREAT BASIN. AN
ASSOCIATED/BROAD AREA OF SURFACE LOW PRESSURE -- INITIALLY EXTENDING
FROM THE CANADIAN PRAIRIE INTO THE NRN HIGH PLAINS -- SHOULD
EVENTUALLY CONSOLIDATE OVER MANITOBA BY THE END OF THE PERIOD. BOTH
T.S. FAY AND THIS NWRN U.S. STORM SYSTEM WILL INFLUENCE THE TWO MAIN
AREAS OF SEVERE POTENTIAL DURING THE DAY 2 PERIOD.
...ND AND VICINITY...
MARGINAL TO MODERATE AIRMASS DESTABILIZATION IS FORECAST ACROSS
PORTIONS OF THE NRN HIGH PLAINS THROUGH THE AFTERNOON --
PARTICULARLY ACROSS WRN ND AHEAD OF THE ADVANCING UPPER SYSTEM AND
ASSOCIATED COLD FRONT. THIS FRONT IS FORECAST TO OVERTAKE A
PERSISTENT AREA OF LEE-SIDE LOW PRESSURE OVER THE NRN HIGH PLAINS BY
LATE AFTERNOON/EARLY EVENING. RESULTING INCREASE IN LOW-LEVEL UVV
AND AMPLE INSTABILITY SHOULD FUEL STORM DEVELOPMENT ACROSS WRN ND
AND VICINITY BY LATE AFTERNOON...WITH AN INCREASE IN
COVERAGE/ORGANIZATION FORECAST THROUGH THE EVENING.
CONVECTIVE ORGANIZATION WILL BE AIDED BY AN INCREASE IN DEEP-LAYER
SHEAR...AS THE NOSE OF A 60-PLUS KT SWLY MID-LEVEL JET STREAK
SPREADS EWD ATOP A SLY LOW-LEVEL JET. SHEAR WILL BE SUFFICIENT FOR
SUPERCELLS ACROSS WRN ND BY EVENING...THOUGH LINEAR FORCING ALONG
THE ADVANCING FRONT SUGGESTS THAT STORM MODE MAY TREND TOWARD LINEAR
THROUGH THE EVENING. IN EITHER CASE...RELATIVELY HIGH CLOUD BASES
ARE EXPECTED WHICH SHOULD LIMIT TORNADO POTENTIAL...WITH MAIN
THREATS LIKELY TO BE HAIL AND DAMAGING WINDS.
...NERN FL/SERN GA...
LATEST NHC TRACK GUIDANCE POSITIONS THE CENTER OF T.S. FAY ALONG THE
NERN FL COAST AT THE START OF THE DAY 2 PERIOD...AND THEN A
SUBSEQUENT/SLOW WEAKENING TREND AS THE SYSTEM MOVES WNWWD ACROSS NRN
FL THROUGH THE PERIOD. DESPITE THIS...AMPLE LOW-LEVEL SHEAR SHOULD
PERSIST WITHIN THE NERN QUADRANT OF THE STORM TO SUPPORT A CONTINUED
THREAT FOR ISOLATED/BRIEF TORNADOES -- AND THUS WILL MAINTAIN 5%
SEVERE PROBABILITY ACROSS NERN FL AND INTO SERN GA THIS FORECAST.
..GOSS.. 08/20/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment