

502 

WWUS20 KWNS 232217

SEL9

SPC WW 232217

IAZ000-MOZ000-NEZ000-240600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 679

NWS STORM PREDICTION CENTER NORMAN OK

515 PM CDT SAT JUL 23 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN IOWA

       NORTHERN MISSOURI

       FAR SOUTHEAST NEBRASKA



EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 515 PM

UNTIL 100 AM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 120

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH

NORTHWEST OF KNOXVILLE IOWA TO 15 MILES SOUTH SOUTHWEST OF LAMONI

IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 678...



DISCUSSION...TSTMS EXPECTED TO CONTINUE FORMING ALONG NRN EDGE OF

STEEP LOW LVL LAPSE RATES PLUME THAT LIES BENEATH BELT OF SLIGHTLY

ENHANCED MID LVL FLOW AND CORRIDOR OF HIGH PW ALONG NRN FRINGE OF

SUBTROPICAL HIGH.  SETUP APPEARS CONDUCIVE TO PRODUCTION OF WET

MICROBURSTS WITH DMGG WIND...AND POSSIBLY MARGINALLY SVR HAIL /REF

MCD 1711/.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 26025.





...CORFIDI

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