

117 

WWUS20 KWNS 021430

SEL5

SPC WW 021430

ARZ000-LAZ000-MSZ000-022200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 105

NWS STORM PREDICTION CENTER NORMAN OK

925 AM CDT THU APR 2 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHEAST ARKANSAS

       PARTS OF EASTERN LOUISIANA

       CENTRAL MISSISSIPPI



EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 925 AM UNTIL

500 PM CDT.



TORNADOES...HAIL TO 2.5 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 100 STATUTE

MILES EAST AND WEST OF A LINE FROM 15 MILES NORTHWEST OF

GREENWOOD MISSISSIPPI TO 40 MILES EAST OF BATON ROUGE LOUISIANA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 102...WW 103...WW 104...



DISCUSSION...A SQUALL LINE IN LA WILL CONTINUE TO MOVE EWD ACROSS

LA/MS THROUGH THIS AFTERNOON IN ASSOCIATION WITH A LEAD SHORTWAVE

TROUGH AHEAD OF THE PRIMARY SYNOPTIC LOW OVER N TX/SRN OK.  12Z

SOUNDINGS IN ADVANCE OF THE CONVECTION REVEALED AN ENVIRONMENT OF

STEEP MID LEVEL LAPSE RATES ABOVE A MOIST BOUNDARY LAYER...WHICH

WILL SUPPORT STRONG INSTABILITY WITH DAYTIME HEATING.  DEEP LAYER

AND LOW-LEVEL VERTICAL SHEAR WILL BECOME FAVORABLE FOR BOWING

SEGMENTS WITH DAMAGING WINDS IN THE LINE...WHILE SUPERCELLS WILL BE

POSSIBLE BOTH WITHIN THE LINE AND PERHAPS E OF THE LINE THIS

AFTERNOON AS CONVECTIVE INHIBITION WEAKENS.  THE SUPERCELLS WILL BE

CAPABLE OF PRODUCING TORNADOES...PERHAPS AN ISOLATED STRONG TORNADO

OR TWO...IN ADDITION TO VERY LARGE HAIL AND DAMAGING WINDS.



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

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

500. MEAN STORM MOTION VECTOR 25040.





...THOMPSON

