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WWUS20 KWNS 181951

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SPC WW 181951

IAZ000-NEZ000-190300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 343

NWS STORM PREDICTION CENTER NORMAN OK

250 PM CDT FRI JUN 18 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       LARGE PART OF SOUTHWEST AND CENTRAL IOWA

       SMALL PART OF EASTERN NEBRASKA



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 250 PM UNTIL

1000 PM CDT.



TORNADOES...HAIL TO 3.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTH NORTHEAST OF

OTTUMWA IOWA TO 20 MILES NORTH NORTHWEST OF OMAHA NEBRASKA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 342...



DISCUSSION...E/W BOUNDARY FROM MORNING MCS IS DRIFTING NWD THRU SWRN

IA/SERN NEB WITH NEARLY STALLED COLD FRONT JUST TO THE NW OF OMA

WILL BE FOCI FOR RAPID DEVELOPMENT OF SEVERE THUNDERSTORMS THRU

LATER THIS AFTERNOON.  WITH MLCAPES AOA 3000 J/KG AND VEERING SHEAR

PROFILE IN PLACE ACROSS SWRN IA...SUPERCELLS INCLUDING VERY LARGE

HAIL AND POSSIBLE TORNADOES ARE EXPECTED.  STORMS WILL INITIATE

VICINITY SURFACE BOUNDARIES AND DEVELOP UPSCALE INTO A SEVERE MCS

ACROSS SRN IA BY THIS EVENING.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 3.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

600. MEAN STORM MOTION VECTOR 25025.





...HALES

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