SWODY1
SPC AC 290528
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1128 PM CST FRI NOV 28 2008
VALID 291200Z - 301200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A SEASONABLY STRONG UPPER RIDGE HAS DEVELOPED ACROSS THE EASTERN
PACIFIC INTO THE PACIFIC COAST STATES...WITH A VERY STRONG MID/UPPER
JET STREAK NOW IN THE PROCESS OF ROUNDING ITS CREST... ACROSS THE
CANADIAN AND NORTHERN U.S. ROCKIES. MODELS SUGGEST THAT THE LATTER
FEATURE WILL CONTINUE TO NOSE SOUTHEASTWARD THROUGH THIS FORECAST
PERIOD...WITH A SERIES OF EMBEDDED IMPULSES CONTRIBUTING TO AN
AMPLIFYING UPPER TROUGH ACROSS MUCH OF THE MISSISSIPPI VALLEY. AS
THE PERIOD PROGRESSES...MODELS INDICATE INCREASED PHASING OF THIS
TROUGH WITH A LINGERING SOUTHERN BRANCH TROUGH...ACROSS THE GULF
COAST/GULF OF MEXICO REGION...AND WITH A SHORT WAVE TROUGH ROTATING
AROUND THE SOUTHWESTERN PERIPHERY OF THE EASTERN CANADIAN POLAR
VORTEX.
PRECEDING THE EVOLUTION OF THE PRIMARY SURFACE CYCLONE...WHICH MAY
BEGIN TO CONSOLIDATE OVER THE LOWER OHIO VALLEY LATE IN THIS PERIOD
INTO EARLY SUNDAY...MODELS INDICATE WEAK SURFACE WAVE DEVELOPMENT
ALONG A FRONT ACROSS THE CENTRAL/EASTERN GULF STATES...AS ANOTHER
COLD FRONT ADVANCES SOUTHWARD TO THE LEE OF THE SOUTHERN
APPALACHIANS. THIS IS EXPECTED TO CONFINE MOIST POTENTIALLY
UNSTABLE BOUNDARY LAYER AIR TO SOUTHERN PORTIONS OF THE EASTERN GULF
STATES...WHERE RELATIVELY WARM LAYERS ALOFT WILL LIKELY LIMIT
INSTABILITY AND CONVECTIVE POTENTIAL.
...CENTRAL/EASTERN GULF STATES...
WHILE WEAK LOWER/MID TROPOSPHERIC LAPSE RATES MAY ONLY ALLOW FOR
WEAK PRE-FRONTAL CONDITIONAL INSTABILITY...THIS SHOULD BE BASED NEAR
THE SURFACE IN THE VICINITY OF THE FRONTAL WAVE...WHERE THE PRESENCE
OF STRONG SHEAR WILL SUPPORT AT LEAST LOW SEVERE PROBABILITIES. THE
WAVE IS EXPECTED TO MIGRATE FROM PARTS OF CENTRAL MISSISSIPPI INTO
WEST CENTRAL GEORGIA DURING THE DAY...BEFORE AN ASSOCIATED MID-LEVEL
SHORT WAVE IMPULSE... EMANATING FROM THE SOUTHERN STREAM...LIFTS
NORTHEAST OF THE LOWER OHIO/TENNESSEE VALLEYS. WHILE THE
ENVIRONMENT MAY NOT BE SUPPORTIVE OF MUCH BEYOND AN ISOLATED SEVERE
STORM OR TWO...SIZABLE LOW-LEVEL HODOGRAPHS BENEATH 40 KT
SOUTHWESTERLY 850 MB FLOW MAY PROMOTE SUPERCELLS WITH LOW-LEVEL
MESOCYCLONES CAPABLE OF PRODUCING A TORNADO OR LOCALIZED DAMAGING
WIND GUSTS.
THEREAFTER...FORCING ASSOCIATED WITH UPSTREAM PATTERN AMPLIFICATION
MAY SUPPORT INCREASING FRONTAL AND PRE-FRONTAL STORM DEVELOPMENT
ACROSS THE NORTHERN GULF OF MEXICO. THIS MAY INCLUDE ISOLATED
SUPERCELLS FORMING AHEAD OF A MAIN FRONTAL BAND...ONE OR TWO OF
WHICH COULD POSE A RISK FOR AN ISOLATED TORNADO OR DAMAGING WIND
GUST ACROSS THE FLORIDA PANHANDLE DURING THE EVENING/ OVERNIGHT
HOURS...BEFORE WEAKENING AS THEY MOVE FARTHER INLAND.
..KERR/SMITH.. 11/29/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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