Alert archive / Illinois / Tornado Watches in 2004

Tornado Watch 783

August 25, 200440 counties in Illinois; Saint Charles County, Saint Louis County, City of Saint Louis, Missouri

The Storm Prediction Center issued this tornado watch at Aug 25, 2004, 2:20 PM CDT for 40 counties in Illinois; Saint Charles County, Saint Louis County, City of Saint Louis, Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 25, 2004, 2:20 PM CDT (19:20 UTC)
Expired
Aug 25, 2004, 8:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 43 counties

Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Fulton County, IL, Greene County, IL, Jasper County, IL, Jersey County, IL, Lawrence County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Richland County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Vermilion County, IL, City of Saint Louis, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The Lincoln radar (KILX), 51 km from the middle of the area, began a volume at 19:24 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.

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 25, 2:49 PM CDTFlash Flood WarningILXSchuyler6 hr
Aug 25, 3:07 PM CDTFlash Flood WarningILXCass, Morgan, Scott6 hr
Aug 25, 3:42 PM CDTFlash Flood WarningILXMason6 hr
Aug 25, 4:07 PM CDTSevere Thunderstorm WarningILXMason38 min
Aug 25, 4:30 PM CDTFlash Flood WarningILXMenard6 hr
Aug 25, 5:23 PM CDTSevere Thunderstorm WarningLSXCalhoun, Jersey22 min
Aug 25, 5:27 PM CDTSevere Thunderstorm WarningLSXGreene33 min
Aug 25, 5:31 PM CDTSevere Thunderstorm WarningLSXMacoupin44 min
Aug 25, 5:37 PM CDTFlash Flood WarningILXLogan, Sangamon6 hr
Aug 25, 5:51 PM CDTSevere Thunderstorm WarningLSXJersey, Macoupin, Madison, Saint Clair39 min
Aug 25, 5:52 PM CDTFlash Flood WarningILXDeWitt, McLean, Macon6 hr
Aug 25, 5:55 PM CDTSevere Thunderstorm WarningILXMorgan, Sangamon65 min
Aug 25, 6:40 PM CDTFlash Flood WarningILXChristian6 hr
Aug 25, 7:10 PM CDTFlash Flood WarningILXPiatt6 hr
Aug 25, 7:34 PM CDTFlash Flood WarningILXChampaign5 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 7.3 hours before the alert went out and 92 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2004-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1166 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2004-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 179 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1166 J/kg
Mixed-layer CIN
-143 J/kg
Mixed-layer LCL
777 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
179 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WWUS20 KWNS 251920
SEL3  
SPC WW 251920
ILZ000-MOZ000-260100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 783
NWS STORM PREDICTION CENTER NORMAN OK
220 PM CDT WED AUG 25 2004

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

       CENTRAL ILLINOIS
       EAST CENTRAL MISSOURI

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 220 PM UNTIL
800 PM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS ALONG AND 65 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 60 MILES NORTH NORTHWEST OF SAINT LOUIS
MISSOURI TO 35 MILES EAST OF MATTOON ILLINOIS.

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 782...

DISCUSSION...E/W BOUNDARY ACROSS CENTRAL IL WILL BE FOCUS FOR
INTENSE THUNDERSTORM DEVELOPMENT.  WITH EXTREMELY UNSTABLE AIR MASS
AND APPROACH OF S/WV TROUGH AND ATTENDANT STRONG DEEP LAYER
SHEAR...SUPERCELLS ARE LIKELY WITH TORNADO POTENTIAL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 25025.


...HALES

402,0904 402,0873 383,0873 383,0904

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 25, 9:24 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, DeWitt, Fulton and 22 more2 hr
Aug 25, 11:59 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Greene, Hancock, Pike and 2 more91 min
Aug 25, 12:35 PM CDTTornado WatchSPCAdams, Brown, Hancock, Henderson, Mercer, Pike6 hr
Aug 25, 1:22 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cass, Champaign, DeKalb and 42 more113 min
Aug 25, 3:15 PM CDTSevere Thunderstorm WatchSPCMonroe, Saint Clair6 hr
Aug 25, 5:14 PM CDTMesoscale DiscussionSPCBond, Brown, Calhoun, Cass, Champaign, Christian and 34 more91 min
Aug 24, 8:20 PM CDTSevere Thunderstorm WatchSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 26 more7 hr
Aug 24, 11:47 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Caldwell, Carroll, Chariton and 22 more118 min
Aug 25, 2:14 AM CDTMesoscale DiscussionSPCAdair, Andrew, Buchanan, Caldwell, Chariton, Clinton and 14 more31 min
Aug 25, 8:50 AM CDTSevere Thunderstorm WatchSPCAndrew, Atchison, Buchanan, Daviess, DeKalb, Gentry and 6 more5 hr
Aug 25, 4:50 PM CDTMesoscale DiscussionSPCBates, Cass, Clay, Jackson, Platte, Vernon85 min
Aug 25, 5:15 PM CDTSevere Thunderstorm WatchSPCBates, Cass, Clay, Jackson, Platte5 hr

Nearby

Tornado Watches in Illinois, 2004Tornado Watches in Missouri, 2004Every tornado watch in 2004

Sources

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.