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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 614

NWS STORM PREDICTION CENTER NORMAN OK

330 PM CDT TUE SEP 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST IOWA

       FAR NORTHWEST ILLINOIS

       WESTERN UPPER MICHIGAN

       SOUTHEAST AND NORTHEAST MINNESOTA

       WESTERN AND CENTRAL WISCONSIN

       LAKE SUPERIOR



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 330 PM UNTIL

1100 PM CDT.



HAIL TO 2.5 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 30 MILES EAST

NORTHEAST OF ELY MINNESOTA TO 35 MILES WEST OF DUBUQUE 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...TCU/TSTMS ARE BEGINNING TO FORM IN AN ARC FROM NERN MN

SWD THROUGH FAR WRN WI INTO SE MN/NE IA...ALONG AN AXIS OF WEAK

LOW-LVL CONFLUENCE AHEAD OF A WEAK DISTURBANCE IN MODERATE WLY

MID/UPR-LVL FLOW. DEEP EML SAMPLED BY 12Z SOUNDINGS UPSTREAM FROM

REGION...RELATIVELY RICH LOW-LVL MOISTURE SUGGEST GOOD POTENTIAL FOR

LARGE HAIL GIVEN 35-45 KT WLY DEEP SHEAR/LIKELIHOOD FOR SUPERCELLS.

THE STORMS MAY MERGE INTO SEVERAL SMALL CLUSTERS CONTAINING E OR

SE-MOVING BOWING SEGMENTS WITH DMGG WIND...AND POSSIBLY

BACK-BUILDING SEGMENTS...WITH A CONTINUING RISK FOR HAIL/DMGG WIND.



AVIATION...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 550. MEAN STORM

MOTION VECTOR 27030.





...CORFIDI

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