Severe Thunderstorm Watch 621

Issued

Jul 24, 2009, 11:00 PM CDT (04:00 UTC)

Expired

Jul 25, 2009, 2:26 AM CDT

In force

3 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

Counties Champaign County, IL, Christian County, IL, Coles County, IL, Douglas County, IL, Edgar County, IL, Iroquois County, IL, Kankakee County, IL, Macon County, IL, Moultrie County, IL, Piatt County, IL, Shelby County, IL, Vermilion County, IL, Benton County, IN, Fountain County, IN, Jasper County, IN, Newton County, IN, Parke County, IN, Vermillion County, IN, Warren County, IN

The Lincoln radar (KILX), 104 km from the middle of the area, began a volume at 04:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

10%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

20%

One or more hailstones of 2 inches or more

10%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 1667Jul 24, 11:46 PM CDT

704 
WWUS20 KWNS 250400
SEL1  
SPC WW 250400
ILZ000-INZ000-250800-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 621
NWS STORM PREDICTION CENTER NORMAN OK
1100 PM CDT FRI JUL 24 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       EAST CENTRAL AND NORTHEAST ILLINOIS
       EXTREME NORTHWEST INDIANA

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 1100 PM
UNTIL 300 AM CDT.

HAIL TO 1 INCH 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 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES WEST
SOUTHWEST OF BLOOMINGTON ILLINOIS TO 45 MILES NORTHEAST OF
DANVILLE ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 620...

DISCUSSION...WELL-DEVELOPED BOW ECHO HAS ACCELERATED TOWARD THE SE
AT 45-50 KT ACROSS IL...AND WILL LIKELY MOVE INTO THE WATCH AREA
WITHIN THE NEXT 30-60 MINUTES.  THOUGH INSTABILITY WEAKENS WITH
EWD/SEWD EXTENT...THE ORGANIZED STORM STRUCTURE SUGGESTS THAT SOME
WIND DAMAGE THREAT WILL PERSIST FOR AT LEAST ANOTHER 2-3 HOURS AND
POTENTIALLY SPREAD INTO INDIANA.

AVIATION...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 500. MEAN STORM MOTION
VECTOR 31045.


...THOMPSON

Severe Thunderstorm Watches in Illinois, 2009Severe Thunderstorm Watches in Indiana, 2009Every severe thunderstorm watch in 2009

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.