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154 

WWUS20 KWNS 152216

SEL7

SPC WW 152216

NEZ000-SDZ000-160600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 397

NWS STORM PREDICTION CENTER NORMAN OK

515 PM CDT FRI JUN 15 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN NEBRASKA

       CENTRAL SOUTH DAKOTA



EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 515 PM

UNTIL 100 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 55

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH

NORTHWEST OF MOBRIDGE SOUTH DAKOTA TO 60 MILES SOUTH SOUTHWEST OF

VALENTINE NEBRASKA.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 395...WW 396...



DISCUSSION...STORMS DEVELOPING WITHIN LEE-SIDE/THERMAL LOW AND

DEVELOPING WARN FRONT ACROSS SD SHOULD CONTINUE TO SPREAD EAST ALONG

THE NEB/SD BORDER AND ALSO INTO AREAS OF CENTRAL SD THROUGH THE

EVENING HOURS. REGION LIES WITHIN/BENEATH MID LEVEL JET STREAK THAT

IS PROVIDING DEEP SHEAR SUPPORTIVE OF STORM ORGANIZATION AND

PERSISTENCE. IN ADDITION TO LARGE HAIL WITH INITIAL CELLULAR

DEVELOPMENT...STORM MERGERS AND SOME UPSCALE GROWTH WITHIN THE

DEEP-LAYER WLY FLOW REGIME...AND INCREASE IN NOCTURNAL LLJ...COULD

CONTRIBUTE TO MCS DEVELOPMENT WITH AN INCREASING CHANCE FOR MORE

NUMEROUS SEVERE OR NEAR SEVERE WIND EVENTS WITH TIME.



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 450. MEAN STORM

MOTION VECTOR 27015.





...CARBIN

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