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000 

WWUS20 KWNS 221005

SEL7

SPC WW 221005

ILZ000-INZ000-MIZ000-OHZ000-LEZ000-LHZ000-221700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 67

NWS STORM PREDICTION CENTER NORMAN OK

505 AM CDT THU MAR 22 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF EASTERN ILLINOIS

       MUCH OF NORTHERN AND CENTRAL INDIANA

       MUCH OF SOUTHERN LOWER MICHIGAN

       PARTS OF NORTHWEST OHIO

       LAKE ERIE

       LAKE HURON



EFFECTIVE THIS THURSDAY MORNING FROM 505 AM UNTIL NOON 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 75

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

FLINT MICHIGAN TO 40 MILES SOUTH SOUTHEAST OF DANVILLE ILLINOIS.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 66...



DISCUSSION...LINE OF THUNDERSTORMS DEVELOPING RAPIDLY FROM SRN LM

SWWD TO CENTRAL IL IN RESPONSE TO FAST MOVING S/WV TROUGH WRN GREAT

LAKES. 60-70 KT LLJ IS RAPIDLY INCREASING MOISTURE AND INSTABILITY

NEWD ACROSS WATCH AREA.  PRIMARY CONCERN WILL BE DAMAGING WINDS

GIVEN THE VERY STRONG LOW LEVEL GRADIENT IN PLACE COUPLED WITH THE

ORGANIZED LINE OF THUNDERSTORMS MOVING RAPIDLY EWD ACROSS THE WATCH

AREA.



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 450. MEAN STORM

MOTION VECTOR 24040.





...HALES

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