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479 

WWUS20 KWNS 231717

SEL3

SPC WW 231717

NEZ000-SDZ000-240000-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 53

NWS STORM PREDICTION CENTER NORMAN OK

1220 PM CDT MON MAR 23 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       LARGE PART OF CENTRAL AND EASTERN NEBRASKA

       PARTS OF SOUTHERN SOUTH DAKOTA



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 1220 PM UNTIL

700 PM 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 85 STATUTE

MILES EAST AND WEST OF A LINE FROM 30 MILES EAST NORTHEAST OF

PIERRE SOUTH DAKOTA TO 50 MILES SOUTH SOUTHEAST OF HASTINGS

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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.



DISCUSSION...VIGOROUS UPPER TROUGH AND DEEP SURFACE LOW SWRN NE WITH

STRONG LOW LEVEL JET PROVIDING A MOIST/UNSTABLE AIRMASS ACROSS WATCH

AREA. WITH ADDITIONAL HEATING...THUNDERSTORMS EXPECTED TO RAPIDLY

INCREASE IN NUMBER AND INTENSITY AHEAD OF LOW AND TROUGH WITH SHEAR

MORE THAN SUFFICIENT FOR DEVELOPMENT OF SUPERCELLS.  ALONG WITH

LARGE HAIL/DAMAGING WINDS...TORNADOES WILL BE POSSIBLE WITH ANY

SUPERCELL AS THEY MOVE RAPIDLY NEWD ACROSS THE WATCH DURING THE

AFTERNOON.



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

450. MEAN STORM MOTION VECTOR 20040.





...HALES

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