

986 

WWUS20 KWNS 070050

SEL4

SPC WW 070050

IAZ000-MNZ000-WIZ000-070600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 644

NWS STORM PREDICTION CENTER NORMAN OK

750 PM CDT MON SEP 6 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST IOWA

       SOUTHEAST MINNESOTA

       SOUTHWEST WISCONSIN



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 750 PM UNTIL

100 AM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH

NORTHEAST OF LA CROSSE WISCONSIN TO 50 MILES EAST OF WATERLOO

IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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...A BROKEN LINE OF FAST MOVING THUNDERSTORMS IS SLOWLY

INTENSIFYING OVER EAST-CENTRAL IA.  THESE STORMS ARE IN ADVANCE OF A

SURFACE COLD FRONT...AND IN REGION OF MARGINAL BUT SUFFICIENT

INSTABILITY.  STRONG WIND FIELDS ALOFT WILL PROMOTE A RISK OF

LOCALLY DAMAGING WINDS AND HAIL AS STORMS TRACK ACROSS WATCH AREA.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 23045.





...HART

