

770 

WWUS20 KWNS 270303

SEL4

SPC WW 270303

IAZ000-ILZ000-MOZ000-270900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 564

NWS STORM PREDICTION CENTER NORMAN OK

1005 PM CDT SUN JUN 26 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EAST CENTRAL AND SOUTHEAST IOWA

       NORTHWEST ILLINOIS

       EXTREME NORTHEAST MISSOURI



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 1005 PM UNTIL

400 AM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES WEST

NORTHWEST OF DUBUQUE IOWA TO 35 MILES SOUTH SOUTHWEST OF

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

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 559...WW 560...WW

561...WW 562...WW 563...



DISCUSSION...IN THE WAKE OF AN INITIAL MCS NOW MOVING INTO IL...AN

UPSTREAM BOW ECHO ACROSS CENTRAL IA WILL CONTINUE TO MOVE EWD/ESEWD

TO THE N OF THE SURFACE FRONT AND OUTFLOW FROM THE IL MCS.  MODERATE

INSTABILITY IS STILL PRESENT ABOVE THE SURFACE...AND DAMAGING GUSTS

COULD STILL REACH THE GROUND INTO ERN IA BEFORE THE BOW WEAKENS.

LONGER TERM TRENDS FAVOR A MORE ESEWD MOVEMENT TOWARD SE IA/NE MO/W

CENTRAL IL...ON THE N EDGE OF THE STRONG INSTABILITY GRADIENT.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 29045.





...THOMPSON

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