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305 

WWUS20 KWNS 150610

SEL7

SPC WW 150610

ARZ000-ILZ000-MOZ000-151300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 477

NWS STORM PREDICTION CENTER NORMAN OK

110 AM CDT WED JUN 15 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN ARKANSAS

       SOUTHWEST ILLINOIS

       CENTRAL AND SOUTHERN MISSOURI



EFFECTIVE THIS WEDNESDAY MORNING FROM 110 AM UNTIL 800 AM CDT.



HAIL TO 2 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 35 MILES EAST

SOUTHEAST OF RUSSELLVILLE ARKANSAS TO 55 MILES NORTH NORTHWEST OF

FARMINGTON MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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...TSTMS HAVE RECENTLY INCREASED IN COVERAGE AND INTENSITY

AHEAD OF COLD FRONT FROM NW OF TBN TO E OF FSM WITH ACTIVITY LIKELY

BEING FORCED BY DCVA IN ADVANCE OF MIDLEVEL TROUGH.  AMBIENT WARM

SECTOR AIR MASS IS RATHER MOIST AND MODERATELY TO STRONGLY UNSTABLE

WITH MLCAPE VALUES OF 2000-3000 J/KG.  WHEN COUPLED WITH 40+ KT OF

DEEP WLY SHEAR...SETUP WILL BE FAVORABLE FOR THE UPSCALE GROWTH OF

STORMS INTO A FORWARD-PROPAGATING MCS CAPABLE OF DAMAGING WINDS AND

LARGE HAIL.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 27035.





...MEAD

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