

000 

WWUS20 KWNS 221924

SEL7

SPC WW 221924

NEZ000-SDZ000-230300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 287

NWS STORM PREDICTION CENTER NORMAN OK

225 PM CDT TUE MAY 22 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTH CENTRAL NEBRASKA

       CENTRAL SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 225 PM UNTIL

1000 PM 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 45 MILES SOUTH OF

AINSWORTH NEBRASKA TO 40 MILES NORTHWEST OF ABERDEEN SOUTH

DAKOTA.  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...THUNDERSTORMS WILL CONTINUE DEVELOPING/INTENSIFYING

NNEWD ACROSS WW THROUGH THE EVENING.  AIR MASS IS MARGINAL TO

MODERATELY UNSTABLE WITH SUFFICIENT SHEAR FOR A FEW SUPERCELLS AND

ORGANIZED MULTICELL CLUSTERS/LINES.  LARGE HAIL AND ISOLATED

DAMAGING WINDS ARE EXPECTED WITH THE STRONGER STORMS.



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 20025.





...EVANS

