

000 

WWUS20 KWNS 172158

SEL1

SPC WW 172158

SDZ000-180500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 411

NWS STORM PREDICTION CENTER NORMAN OK

500 PM CDT SUN JUN 17 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL SOUTH DAKOTA



EFFECTIVE THIS SUNDAY AFTERNOON FROM 500 PM UNTIL MIDNIGHT 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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTHWEST OF

ABERDEEN SOUTH DAKOTA TO 45 MILES SOUTH OF PIERRE SOUTH DAKOTA.

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 407...WW 408...WW

409...WW 410...



DISCUSSION...SEVERE THUNDERSTORMS WILL SPREAD ENEWD ACROSS WW

THROUGH THE EVENING AHEAD OF STRONG SURFACE COLD FRONT NOW MOVING

INTO THE WRN DAKOTAS.  AIR MASS WILL BE MODERATELY UNSTABLE WITH

SUFFICIENT SHEAR FOR SUPERCELLS AND ORGANIZED CLUSTERS/LINES.  LARGE

HAIL AND DAMAGING WINDS WILL BE PRIMARY SEVERE THREATS.



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.





...EVANS

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