

461 

WWUS20 KWNS 231303

SEL6

SPC WW 231303

IAZ000-MNZ000-NEZ000-SDZ000-232100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 496

NWS STORM PREDICTION CENTER NORMAN OK

805 AM CDT TUE JUN 23 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST IOWA

       SOUTHWEST MINNESOTA

       NORTHEAST NEBRASKA

       SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 805 AM UNTIL

400 PM CDT.



HAIL TO 2 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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES NORTHWEST OF

BROOKINGS SOUTH DAKOTA TO 35 MILES EAST SOUTHEAST OF NORFOLK

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 494...WW 495...



DISCUSSION...LONG-LIVED MCS EXPECTED TO CONTINUE GENERALLY

ENE...WITH SOME DEVELOPMENT POSSIBLE ON S EDGE TOWARD AXIS OF VERY

STRONG SFC-BASED INSTABILITY OVER NE NEB/NW IA.  MODEST...DEEP WSWLY

SHEAR...AND CONTINUED ESELY NEAR-SFC FLOW...SHOULD SUPPORT MCS

MAINTENANCE...WITH A THREAT FOR DMGG WIND GUSTS AND OCCASIONAL LARGE

HAIL.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 25030.





...CORFIDI

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