

000 

WWUS20 KWNS 050454

SEL7

SPC WW 050454

IAZ000-ILZ000-MOZ000-NEZ000-051000-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 457

NWS STORM PREDICTION CENTER NORMAN OK

1155 PM CDT WED JUN 4 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       LARGE PARTS OF IOWA

       SMALL PART OF NORTHWEST ILLINOIS

       SMALL PART OF NORTHEAST MISSOURI

       PARTS OF NORTHEAST NEBRASKA



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1155 PM

UNTIL 500 AM CDT.



TORNADOES...HAIL TO 2.5 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 75 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTHWEST OF SIOUX

CITY IOWA TO 50 MILES NORTH NORTHEAST OF BURLINGTON IOWA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU7).



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...THIS TORNADO WATCH REPLACES TORNADO

WATCH NUMBER 453. WATCH NUMBER 453 WILL NOT BE IN EFFECT AFTER

1155 PM CDT. CONTINUE...WW 454...WW 455...WW 456...



DISCUSSION...SEVERE THUNDERSTORMS CONTINUE TO DEVELOP AND MOVE EWD

IN STRONG WARM ADVECTION ZONE.  WITH 50-60 KT LLJ COUPLED WITH

MLCAPES TO 2000 J/KG...SUPERCELLS AND BOWING SEGMENTS WILL BE THE

PRIMARY MODE. ALONG WITH DAMAGING WINDS...TORNADOES WILL BE POSSIBLE

ACROSS THE WATCH AREA.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 24025.





...HALES

