

110 

WWUS20 KWNS 130132

SEL6

SPC WW 130132

ALZ000-LAZ000-MSZ000-CWZ000-130800-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 146

NWS STORM PREDICTION CENTER NORMAN OK

830 PM CDT SUN APR 12 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHWEST AND WEST CENTRAL ALABAMA

       SOUTHEAST LOUISIANA

       SOUTHERN AND EAST CENTRAL MISSISSIPPI

       COASTAL WATERS



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 830 PM UNTIL

300 AM 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 75 STATUTE

MILES EAST AND WEST OF A LINE FROM 60 MILES NORTH NORTHEAST OF

MERIDIAN MISSISSIPPI TO 15 MILES SOUTH SOUTHWEST OF SLIDELL

LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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...THIS TORNADO WATCH REPLACES TORNADO

WATCH NUMBER 145. WATCH NUMBER 145 WILL NOT BE IN EFFECT AFTER

830 PM CDT.



DISCUSSION...AN ORGANIZED BAND OF THUNDERSTORMS WITH EMBEDDED

BOW/SUPERCELL STRUCTURES WILL LIKELY PERSIST AND SPREAD EWD/NEWD

TOWARD WRN/SWRN AL THROUGH THE OVERNIGHT HOURS.  THE SURFACE MOIST

SECTOR AND THE WARM FRONT WILL LIFT NWD ACROSS MS/AL IN CONJUNCTION

WITH A SURFACE LOW DEVELOPING NWD FROM NW MS TOWARD WRN TN...AND AT

LEAST WEAK SURFACE-BASED INSTABILITY CAN BE EXPECTED WITH MID-UPPER

60S BOUNDARY LAYER DEWPOINTS.  THE N EDGE OF THE WARM SECTOR WILL

COINCIDE WITH A ZONE OF STRONG WAA WHICH WILL HELP MAINTAIN

THUNDERSTORM DEVELOPMENT...WHERE A 50-60 KT LLJ WILL CONTRIBUTE TO

VERY STRONG LOW-LEVEL SHEAR AND AN ASSOCIATED THREAT FOR A COUPLE OF

TORNADOES AND DAMAGING WINDS.



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

500. MEAN STORM MOTION VECTOR 24030.





...THOMPSON

