Sunday, April 19, 2009

Tornado Watch - Mississippi-Alabama


   URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 173
NWS STORM PREDICTION CENTER NORMAN OK
220 PM CDT SUN APR 19 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

WESTERN ALABAMA
SOUTHEAST MISSISSIPPI

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 220 PM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF
TUSCALOOSA ALABAMA TO 15 MILES EAST SOUTHEAST OF GULFPORT
MISSISSIPPI. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 171...WW 172...

DISCUSSION...SCATTERED THUNDERSTORMS HAVE BEEN SLOWLY INCREASING
OVER SOUTHEAST MS...AHEAD OF PRE-FRONTAL CONVERGENCE AXIS. VERTICAL
SHEAR REMAINS VERY STRONG IN THIS REGION WITH LOCAL VAD PROFILES
SUGGESTING 300-400 M2/S2 EFFECTIVE HELICITY. A NARROW AXIS OF
INSTABILITY ALONG AND EAST OF TROUGH MAY ALLOW ISOLATED CELLS TO
INTENSIFY AND BECOME SUPERCELLULAR THIS AFTERNOON AND EARLY EVENING.
ISOLATED TORNADOES WILL BE POSSIBLE...ALONG WITH DAMAGING WINDS AND
HAIL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 24035.


...HART

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