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019 

WWUS20 KWNS 222036

SEL1

SPC WW 222036

IAZ000-MIZ000-MNZ000-WIZ000-230300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 431

NWS STORM PREDICTION CENTER NORMAN OK

335 PM CDT MON JUL 22 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHEAST IOWA

  WESTERN UPPER PENINSULA MICHIGAN

  SOUTHEAST MINNESOTA

  WISCONSIN



* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 335 PM UNTIL

  1000 PM CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A FEW TORNADOES POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHWEST OF

MARQUETTE MICHIGAN TO 10 MILES EAST OF WATERLOO IOWA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 429...WW 430...



DISCUSSION...COLD FRONT WILL SWEEP EAST ACROSS THE UPPER MS VALLEY

THROUGH LATE THIS EVENING. AIRMASS AHEAD OF THE FRONT HAS BECOME

MODERATELY TO STRONGLY UNSTABLE AND SHOULD FUEL ROBUST TSTM UPDRAFTS

IN THE PRESENCE OF INCREASING DEEP-LAYER SHEAR. GREATEST SUPERCELL

HAIL AND ISOLATED TORNADO POTENTIAL WILL PROBABLY EXIST IN THE

RELATIVELY SHORT TERM ACROSS WI WHERE QUASI-DISCRETE CELLS ARE

DEVELOPING AMIDST 30-35 EFFECTIVE SHEAR. WITH TIME...LIFT AND LINEAR

FORCING ALONG THE ADVANCING FRONT MAY SUPPORT THE EVOLUTION INTO A

SEGMENTED SQUALL LINE WITH DAMAGING WINDS SPREADING EAST ACROSS THE

WATCH INTO THE EVENING.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 27030.





...CARBIN

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