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413 

WWUS20 KWNS 122203

SEL1

SPC WW 122203

IAZ000-ILZ000-MOZ000-130500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 411

NWS STORM PREDICTION CENTER NORMAN OK

500 PM CDT SAT JUL 12 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  SOUTHERN AND EASTERN IOWA

  NORTHWEST ILLINOIS

  NORTHERN MISSOURI



* EFFECTIVE THIS SATURDAY AFTERNOON FROM 500 PM UNTIL MIDNIGHT

  CDT.



* PRIMARY THREATS INCLUDE...

  A COUPLE TORNADOES POSSIBLE

  SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY

  ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE

MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHEAST OF CEDAR

RAPIDS IOWA TO 30 MILES SOUTH SOUTHEAST OF LAMONI 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.



&&



DISCUSSION...SCTD TSTMS EXPECTED TO FORM THROUGH MID-EVE IN

MOIST...VERY WARM...AND CONFLUENT WSWLY LOW-LVL FLOW AHEAD OF

ACCELERATING COLD FRONT NOW EXTENDING FROM NE IA TO SE NEB.

LARGE-SCALE ASCENT MAY BE ENHANCED BY WEAK IMPULSE TRACKING ENE

ACROSS NEB/IA AHEAD OF AMPLIFYING NRN STREAM TROUGH NOW OVER SRN MB.

COMBINATION OF STRENGTHENING LLJ...MOIST LOW-LVL

ENVIRONMENT...COOLING BOUNDARY LAYER...AND SEMI-DISCRETE STORMS

SUGGESTS POTENTIAL FOR A COUPLE TORNADOES IN ADDITION TO SVR

WIND/HAIL.



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

550. MEAN STORM MOTION VECTOR 28030.





...CORFIDI

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