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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 51

NWS STORM PREDICTION CENTER NORMAN OK

215 PM CST WED FEB 29 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       FAR SOUTHEAST ARKANSAS

       NORTHEAST LOUISIANA

       NORTHERN AND CENTRAL MISSISSIPPI



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 215 PM UNTIL

900 PM CST.



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 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 110 MILES WEST OF

JACKSON MISSISSIPPI TO 20 MILES SOUTH SOUTHEAST OF COLUMBUS

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 48...WW 49...WW 50...



DISCUSSION...THE GLANCING INFLUENCE OF A MIDLEVEL IMPULSE

TRANSLATING ACROSS THE MID-MS VALLEY WILL COMBINE WITH A MOIST AND

MODERATELY UNSTABLE AIR MASS /I.E. MLCAPE VALUES OF AROUND 1000 J

PER KG/ TO SUPPORT AN INCREASE IN TSTMS ALONG AND AHEAD OF COLD

FRONT THIS AFTERNOON INTO TONIGHT.  SUPPLEMENTAL 18Z JAN SOUNDING

INDICATED THE PRESENCE OF WARM MIDLEVEL TEMPERATURES AND A RESULTING

CAPPING LAYER...SUGGESTING THAT THE MORE ROBUST UPDRAFTS WILL LIKELY

REMAIN N OF THE I-20 CORRIDOR.  WHILE LOW-LEVEL WIND FIELD WILL

CONTINUE TO VEER AND GRADUALLY WEAKEN...STRONG...WSWLY DEEP-LAYER

SHEAR WILL PERSIST...SUPPORTING ORGANIZED STORM MODES CAPABLE OF

MAINLY DAMAGING WINDS AND SEVERE HAIL.



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 25040.





...MEAD

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