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WWUS20 KWNS 200556

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 416

NWS STORM PREDICTION CENTER NORMAN OK

1255 AM CDT WED JUN 20 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTH CENTRAL AND NORTHWEST NEBRASKA

       SOUTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY MORNING FROM 1255 AM UNTIL 600 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 85 MILES WEST OF

MULLEN NEBRASKA TO 60 MILES EAST SOUTHEAST OF CHAMBERLAIN SOUTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 414. WATCH NUMBER 414 WILL NOT

BE IN EFFECT AFTER 1255 AM CDT. CONTINUE...WW 412...WW 413...WW

415...



DISCUSSION...THE TREND OF INCREASING COVERAGE OF ELEVATED STORMS IS

EXPECTED TO CONTINUE FOR THE NEXT FEW HOURS ACROSS NEB/SD AS ASCENT

STRENGTHENS ABOVE THE FRONTAL SURFACE...IN ADVANCE OF A SHORTWAVE

TROUGH MOVING EWD OVER WY.  ELEVATED INSTABILITY AND CLOUD LAYER

SHEAR WILL BE SUFFICIENT FOR ORGANIZED CLUSTERS/SEGMENTS...AS WELL

AS SOME RISK FOR SUPERCELLS.  BOTH LARGE HAIL AND DAMAGING WINDS

WILL REMAIN POSSIBLE THROUGH THE EARLY MORNING HOURS.



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 25030.





...THOMPSON

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