

370 

WWUS20 KWNS 062352

SEL6

SPC WW 062352

IAZ000-ILZ000-MOZ000-NEZ000-070500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 476

NWS STORM PREDICTION CENTER NORMAN OK

655 PM CDT TUE AUG 6 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHERN IOWA

  A SMALL PART OF WEST CENTRAL AND NORTHWEST ILLINOIS

  EXTREME NORTHEAST MISSOURI

  EAST CENTRAL NEBRASKA



* EFFECTIVE THIS TUESDAY NIGHT FROM 655 PM UNTIL MIDNIGHT CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  SEVERAL LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES SOUTH OF

COLUMBUS NEBRASKA TO 35 MILES NORTH NORTHEAST OF BURLINGTON IOWA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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.



&&



OTHER WATCH INFORMATION...CONTINUE...WW 474...WW 475...



DISCUSSION...WIDELY SCATTERED STORMS SHOULD INTENSIFY SOME IN THE

NEXT COUPLE OF HOURS FROM ERN NEB EWD ACROSS SRN IA...IN A ZONE OF

MODERATE-STRONG INSTABILITY AND SUFFICIENT DEEP-LAYER WIND SHEAR FOR

ORGANIZED/SUPERCELL STORMS.  A FEW DAMAGING WIND AND LARGE HAIL

EVENTS ARE THE MAIN CONCERNS FOR THE NEXT FEW HOURS...BEFORE THE

SURFACE LAYER BEGINS TO COOL AND SLOWLY STABILIZE.



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 550. MEAN STORM

MOTION VECTOR 31025.





...THOMPSON

