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112 

WWUS20 KWNS 042345

SEL1

SPC WW 042345

IAZ000-050500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 541

NWS STORM PREDICTION CENTER NORMAN OK

645 PM CDT FRI OCT 4 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  WESTERN AND CENTRAL IOWA



* EFFECTIVE THIS FRIDAY NIGHT FROM 645 PM UNTIL MIDNIGHT CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL TORNADOES WITH A FEW INTENSE TORNADOES POSSIBLE

  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



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE

MILES EAST AND WEST OF A LINE FROM 65 MILES SOUTH SOUTHWEST OF

DES MOINES IOWA TO 40 MILES WEST NORTHWEST OF MASON CITY IOWA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



&&



OTHER WATCH INFORMATION...CONTINUE...WW 539...WW 540...



DISCUSSION...DISCRETE SUPERCELLS OVER FAR SWRN AND NWRN PARTS OF IA

ARE EXPECTED TO SPREAD NEWD THIS EVENING...WITH POTENTIAL FOR NEW

STORMS TO DEVELOP ALONG/AHEAD OF AN EWD ADVANCING COLD FRONT

APPROACHING THE MO RIVER.  FAVORABLE INSTABILITY WITH CAPE RANGING

FROM 2500 J/KG IN SRN IA TO NEAR 1000 J/KG IN NRN IA COUPLED WITH

WINDS THAT VEER STRONGLY WITH HEIGHT /REF DMX VAD WIND PROFILE/ WILL

PROMOTE CONTINUATION OF A SUPERCELL/TORNADO THREAT SPREADING TOWARD

CENTRAL IA TONIGHT.



AVIATION...TORNADOES AND 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 23030.





...WEISS

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