

810 

WWUS20 KWNS 232337

SEL4

SPC WW 232337

NEZ000-240600-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 504

NWS STORM PREDICTION CENTER NORMAN OK

635 PM CDT TUE JUN 23 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       CENTRAL AND WESTERN NEBRASKA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 635 PM

UNTIL 100 AM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 85 MILES WEST SOUTHWEST OF

MULLEN NEBRASKA TO 20 MILES NORTH NORTHEAST OF BROKEN BOW

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 499...WW 500...WW

501...WW 502...WW 503...



DISCUSSION...DISCRETE STORMS FORMING ALONG AND N OF A SLOW-MOVING

FRONT WILL LIKELY DEVELOP SUPERCELL STRUCTURE GIVEN EFFECTIVE BULK

SHEAR AOA 40 KT AND MLCAPE NEAR 3000 J/KG.  ADDITIONALLY...LOW-LEVEL

MOISTURE AND SRH ARE FOCUSED IN A NARROW CORRIDOR ALONG AND N OF THE

BOUNDARY...WHERE A COUPLE OF TORNADOES WILL BE POSSIBLE THIS

EVENING.  OTHERWISE...LARGE HAIL AND DAMAGING WINDS WILL BE THE MORE

COMMON THREATS...ESPECIALLY LATER AS THE STORMS IN WY/CO POTENTIALLY

GROW UPSCALE AND SPREAD FARTHER E INTO NEB THROUGH EARLY TONIGHT.



AVIATION...TORNADOES AND 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

550. MEAN STORM MOTION VECTOR 27015.





...THOMPSON

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