

303 

WWUS20 KWNS 271829

SEL3

SPC WW 271829

ILZ000-INZ000-LMZ000-280100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 963

NWS STORM PREDICTION CENTER NORMAN OK

1230 PM CST SAT DEC 27 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEAST ILLINOIS

       NORTHWEST INDIANA

       LAKE MICHIGAN



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL

700 PM CST.



TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS

TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 20 MILES NORTHWEST OF

MARSEILLES ILLINOIS TO 15 MILES SOUTH OF VALPARAISO INDIANA.  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 960...WW 961...WW 962...



DISCUSSION...NARROW LINE OF LOW-TOPPED STORMS CONTINUES TO RACE NEWD

ACROSS CENTRAL IL AND WILL LIKELY MOVE ACROSS AT LEAST THE SRN HALF

OF THE CHICAGO METRO AND INTO FAR NWRN IND OVER THE NEXT COUPLE

HOURS.  WIND DAMAGE WILL BE PRIMARY SEVERE THREAT FROM THE

STRONGLY-FORCED LINE...ALTHOUGH EXTREME LOW LEVEL SHEAR AND STRONG

PRESSURE FALLS AT THE SURFACE MAY SUPPORT A RISK OF ISOLATED

TORNADOES.



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

SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND

GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 300.

MEAN STORM MOTION VECTOR 23050.





...EVANS



303 

WWUS20 KWNS 271829

SEL3

SPC WW 271829

ILZ000-INZ000-LMZ000-280100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 963

NWS STORM PREDICTION CENTER NORMAN OK

1230 PM CST SAT DEC 27 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEAST ILLINOIS

       NORTHWEST INDIANA

       LAKE MICHIGAN



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL

700 PM CST.



TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS

TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 20 MILES NORTHWEST OF

MARSEILLES ILLINOIS TO 15 MILES SOUTH OF VALPARAISO INDIANA.  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 960...WW 961...WW 962...



DISCUSSION...NARROW LINE OF LOW-TOPPED STORMS CONTINUES TO RACE NEWD

ACROSS CENTRAL IL AND WILL LIKELY MOVE ACROSS AT LEAST THE SRN HALF

OF THE CHICAGO METRO AND INTO FAR NWRN IND OVER THE NEXT COUPLE

HOURS.  WIND DAMAGE WILL BE PRIMARY SEVERE THREAT FROM THE

STRONGLY-FORCED LINE...ALTHOUGH EXTREME LOW LEVEL SHEAR AND STRONG

PRESSURE FALLS AT THE SURFACE MAY SUPPORT A RISK OF ISOLATED

TORNADOES.



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

SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND

GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 300.

MEAN STORM MOTION VECTOR 23050.





...EVANS

