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639 

WWUS20 KWNS 302042

SEL9

SPC WW 302042

ARZ000-MSZ000-TNZ000-310200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 639

NWS STORM PREDICTION CENTER NORMAN OK

345 PM CDT THU JUL 30 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       FAR EASTERN ARKANSAS

       CENTRAL AND NORTHERN MISSISSIPPI

       A SMALL PART OF SOUTHWEST TENNESSEE



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 345 PM UNTIL

900 PM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES SOUTHEAST OF

JACKSON MISSISSIPPI TO 50 MILES EAST NORTHEAST OF MEMPHIS

TENNESSEE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



DISCUSSION...LINE OF STORMS HAS INCREASED IN FORWARD MOTION AND

OVERALL LINEAR ORGANIZATION MOVING INTO W-CENTRAL MS LATE THIS

AFTERNOON...WITH ADDITIONAL SUPERCELL/BOW ECHO DEVELOPMENT EXPECTED

TO CONTINUE NEAR SURFACE LOW INTO ERN AR/NRN MS.  ACTIVITY SHOULD

MOVE QUICKLY NEWD ACROSS WW INTO THE EARLY TO MID EVENING WITH

PRIMARY THREAT OF DAMAGING WINDS.  HOWEVER...AND ISOLATED TORNADO

CAN NOT BE RULED OUT ACROSS NRN PORTION OF WW NEAR THE SURFACE LOW

WHERE SHEAR WILL BE LOCALLY ENHANCED.



AVIATION...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 28040.





...EVANS

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