

000 

WWUS20 KWNS 172059

SEL8

SPC WW 172059

NEZ000-SDZ000-180400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 408

NWS STORM PREDICTION CENTER NORMAN OK

300 PM MDT SUN JUN 17 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN NEBRASKA

       SOUTHWEST SOUTH DAKOTA



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 300 PM UNTIL

1000 PM MDT.



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 75 MILES NORTH

NORTHWEST OF VALENTINE NEBRASKA TO 35 MILES EAST OF SIDNEY

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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...



DISCUSSION...DEEP MIXING DUE TO HOT SURFACE CONDITIONS IS SUPPORTING

MARGINAL TO MODERATE MLCAPE AND INCREASING THUNDERSTORMS OVER WRN

PORTIONS OF WW  LATE THIS AFTERNOON.  SHEAR WILL REMAIN ADEQUATE FOR

ORGANIZED STORMS...INCLUDING SUPERCELLS.  LARGE HAIL AND DAMAGING

WINDS WILL BE PRIMARY SEVERE THREATS AS THIS ACTIVITY SHIFTS ENEWD

THROUGH THE EVENING.



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 25025.





...EVANS

