

300 

WWUS20 KWNS 151911

SEL3

SPC WW 151911

ARZ000-MOZ000-MSZ000-TNZ000-160200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 143

NWS STORM PREDICTION CENTER NORMAN OK

210 PM CDT FRI APR 15 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEAST ARKANSAS

       MISSOURI BOOTHEEL

       NORTHERN MISSISSIPPI

       WESTERN TENNESSEE



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 210 PM UNTIL 900

PM CDT.



TORNADOES...HAIL TO 2 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 90 STATUTE

MILES EAST AND WEST OF A LINE FROM 50 MILES NORTHEAST OF

DYERSBURG TENNESSEE TO 40 MILES SOUTH SOUTHEAST OF OXFORD

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 140...WW 141...WW 142...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON ALONG COLD FRONT AS DEEP ASCENT IN EXIT

REGION OF MID AND UPPER-LEVEL JET STREAKS MOVES INTO THE REGION.

THE COMBINATION OF STRONG DAYTIME HEATING...BOUNDARY LAYER DEWPOINTS

OF 55-60 F AND COOLING MIDLEVEL TEMPERATURES WILL SUPPORT FURTHER

AIR MASS DESTABILIZATION WITH MLCAPE VALUES APPROACHING 1000-1500

J/KG.  WHEN COUPLED WITH VERTICALLY-VEERING WIND

PROFILES...ENVIRONMENT WILL BE SUPPORTIVE OF SUPERCELLS AND BOWING

STRUCTURES WILL A RISK FOR TORNADOES...LARGE HAIL AND DAMAGING

WINDS.



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

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

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

400. MEAN STORM MOTION VECTOR 24030.





...MEAD

