

150 

WWUS20 KWNS 090141

SEL4

SPC WW 090141

ALZ000-ARZ000-LAZ000-MSZ000-CWZ000-090900-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 44

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CST TUE MAR 8 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       FAR SOUTHWEST ALABAMA

       SOUTHERN ARKANSAS

       LOUISIANA

       CENTRAL AND SOUTHERN MISSISSIPPI

       COASTAL WATERS



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 735 PM

UNTIL 300 AM CST.



TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS

TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTHWEST OF

NATCHITOCHES LOUISIANA TO 55 MILES NORTHEAST OF GULFPORT

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 42...WW 43...



DISCUSSION...BI-MODAL SEVERE WEATHER EPISODE ONGOING FROM THE

ARKLATEX INTO MS/AL IS EXPECTED TO CONTINUE INTO THE EARLY MORNING

HOURS WEDNESDAY ALONG AND SOUTH OF WARM FRONT LIFTING NWD THROUGH

THE REGION.  00Z OBSERVED SOUNDINGS WITHIN SYSTEM WARM SECTOR

SAMPLED A VERY MOIST BOUNDARY LAYER WHICH WHEN COUPLED WITH RATHER

STEEP MIDLEVEL LAPSE RATES WAS RESULTING IN A MODERATELY UNSTABLE

AIR MASS WITH MLCAPE VALUES OF 1000-2000 J/KG.  WHILE SOME DECREASE

IN INSTABILITY WILL OCCUR WITH THE ONSET OF NOCTURNAL COOLING...MORE

THAN SUFFICIENT INSTABILITY WILL PERSIST TO SUSTAIN ONGOING STORMS.

AREA VWPS/PROFILERS INDICATE THAT LOW-LEVEL WIND FIELD HAS VEERED

ACROSS ERN TX...HOWEVER RATHER STRONG LOW-LEVEL SHEAR IS EXPECTED TO

PERSIST FARTHER E INTO THE LOWER MS VALLEY /IN CONJUNCTION WITH 50+

KT LLJ/ WITH EFFECTIVE SRH VALUES OF 300-600 M2/S2.  AS

SUCH...ENVIRONMENT WILL REMAIN SUPPORTIVE OF EMBEDDED SUPERCELLS

CAPABLE OF TORNADOES /SOME POSSIBLY STRONG/...DAMAGING WINDS AND

HAIL.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND

GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.

MEAN STORM MOTION VECTOR 25035.





...MEAD

