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WWUS20 KWNS 040103

SEL2

SPC WW 040103

NEZ000-SDZ000-040800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 652

NWS STORM PREDICTION CENTER NORMAN OK

805 PM CDT MON AUG 3 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF NORTH AND EAST NEBRASKA

       PARTS OF SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 805 PM UNTIL

300 AM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75

STATUTE MILES EITHER SIDE OF A LINE FROM 50 MILES SOUTH SOUTHEAST

OF MULLEN NEBRASKA TO 35 MILES EAST OF MITCHELL SOUTH DAKOTA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 ARE INCREASING IN NUMBER AND INTENSITY

AHEAD OF COOL FRONT DROPPING SEWD THRU SD.  WITH 40-45 KT OF

SHEAR...STEEP LAPSE RATES AND INCREASINGLY UNSTABLE AIR MASS  WITH

EWD EXTENT...STORMS SHOULD DEVELOP INTO LINE SEGMENTS WITH

INCREASING WIND DAMAGE THREAT AS WELL AS LARGE HAIL AS THEY MOVE

SEWD.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 29035.





...HALES

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