

150 

WWUS20 KWNS 211931

SEL4

SPC WW 211931

MIZ000-WIZ000-LMZ000-LSZ000-220400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 494

NWS STORM PREDICTION CENTER NORMAN OK

225 PM CDT WED AUG 21 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  UPPER MICHIGAN

  NORTHERN AND CENTRAL WISCONSIN

  LAKE MICHIGAN

  LAKE SUPERIOR



* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 225 PM

  UNTIL 1100 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 120

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

MARQUETTE MICHIGAN TO 35 MILES SOUTH SOUTHWEST OF MOSINEE

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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.



&&



DISCUSSION...TSTMS NOW FORMING ALONG NW WI/WRN UPR MI COLD FRONT

EXPECTED TO INCREASE IN COVERAGE/STRENGTH THROUGH EARLY THIS EVE AS

SFC HEATING FURTHER DESTABILIZES REGION/ELIMINATES CIN...AND AS AREA

IS GLANCED BY UPR IMPULSE CROSSING WRN ONT. AMPLE WNWLY DEEP SHEAR

WILL EXIST FOR SUSTAINED/STORMS SUPERCELLS/LEWPS CAPABLE OF SVR

HAIL/WIND GIVEN RICH LOW-LVL MOISTURE AND DEEP EML. A TORNADO OR TWO

CANNOT BE RULED OUT...ESPECIALLY IN UPR MI AND NRN WI WHERE LOW-LVL

SHEAR MAY BE LOCALLY ENHANCED NEAR INTERSECTION OF FRONT WITH

WSW-ENE BOUNDARY ASSOCIATED WITH OVERNIGHT STORMS IN ND/MN.



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 550. MEAN STORM

MOTION VECTOR 28030.





...CORFIDI

