Alert archive / Illinois / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 761

August 18, 20044 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 18, 2004, 5:35 PM CDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 18, 2004, 5:35 PM CDT (22:35 UTC)
Expired: Aug 18, 2004, 11:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 66 counties

Des Moines County, IA, Adams County, IL, Brown County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Knox County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Sangamon County, IL, Schuyler County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Woodford County, IL, Bartholomew County, IN, Brown County, IN, Clark County, IN, Clay County, IN, Decatur County, IN, Fountain County, IN, Greene County, IN, Hancock County, IN, Hendricks County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Sullivan County, IN, Vermillion County, IN, Vigo County, IN, Washington County, IN, Oldham County, KY, Trimble County, KY

The radar

The Lincoln radar (KILX), 41 km from the middle of the area, began a volume at 22:36 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

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

Issued	Product	Office	Counties	Lasted
Aug 18, 5:47 PM CDT	Severe Thunderstorm Warning	ILX	Clark, Edgar	58 min
Aug 18, 5:55 PM CDT	Tornado Warning	DVN	Des Moines	50 min
Aug 18, 6:03 PM CDT	Severe Thunderstorm Warning	DVN	Warren	57 min
Aug 18, 6:05 PM CDT	Tornado Warning	DVN	Henderson	40 min
Aug 18, 6:08 PM CDT	Severe Thunderstorm Warning	IND	Vigo	52 min
Aug 18, 6:14 PM CDT	Severe Thunderstorm Warning	ILX	Coles	61 min
Aug 18, 6:22 PM CDT	Severe Thunderstorm Warning	ILX	Knox	53 min
Aug 18, 6:38 PM CDT	Severe Thunderstorm Warning	DVN	Des Moines	37 min
Aug 18, 6:44 PM CDT	Tornado Warning	DVN	Henderson, Warren	61 min
Aug 18, 7:04 PM CDT	Severe Thunderstorm Warning	IND	Monroe, Owen	56 min
Aug 18, 7:11 PM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Henry	49 min
Aug 18, 7:12 PM CDT	Tornado Warning	ILX	Fulton	63 min
Aug 18, 7:23 PM CDT	Tornado Warning	IND	Monroe	52 min
Aug 18, 7:28 PM CDT	Severe Thunderstorm Warning	ILX	Knox	62 min
Aug 18, 7:44 PM CDT	Severe Thunderstorm Warning	DVN	Henderson, Warren	76 min
Aug 18, 7:51 PM CDT	Severe Thunderstorm Warning	IND	Owen	54 min
Aug 18, 8:03 PM CDT	Severe Thunderstorm Warning	ILX	Peoria, Tazewell	57 min
Aug 18, 8:16 PM CDT	Severe Thunderstorm Warning	ILX	Fulton	59 min
Aug 18, 8:55 PM CDT	Severe Thunderstorm Warning	ILX	Peoria, Tazewell	65 min
Aug 18, 8:57 PM CDT	Severe Thunderstorm Warning	IND	Monroe	48 min
Aug 18, 8:58 PM CDT	Severe Thunderstorm Warning	ILX	Peoria, Tazewell	62 min
Aug 18, 9:57 PM CDT	Severe Thunderstorm Warning	IND	Jackson, Jennings	48 min

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, 10.6 hours before the alert went out and 22 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 648 J/kg
Mixed-layer CIN: -86 J/kg
Mixed-layer LCL: 738 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 17, 7:48 PM CDT	Mesoscale Discussion	SPC	Ford, Grundy, Iroquois, Kankakee, Livingston, Will	117 min
Aug 18, 1:39 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Champaign, Christian, Clark and 28 more	96 min
Aug 18, 4:17 PM CDT	Mesoscale Discussion	SPC	Hancock, Henderson, Mercer, Rock Island, Warren	118 min
Aug 18, 5:17 PM CDT	Mesoscale Discussion	SPC	Adams, Bond, Brown, Cass, Champaign, Christian and 48 more	88 min
Aug 18, 12:27 PM CDT	Mesoscale Discussion	SPC	Allamakee, Howard, Winneshiek	63 min
Aug 18, 1:10 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Bremer, Chickasaw, Clayton, Fayette, Floyd and 2 more	7 hr
Aug 18, 3:46 PM CDT	Mesoscale Discussion	SPC	Allamakee, Bremer, Butler, Chickasaw, Clayton, Fayette and 3 more	59 min
Aug 18, 4:50 PM CDT	Severe Thunderstorm Watch	SPC	Appanoose, Davis, Decatur, Henry, Jefferson, Lee and 7 more	6 hr
Aug 18, 5:52 PM CDT	Mesoscale Discussion	SPC	Clayton, Fayette	113 min

Nearby

Severe Thunderstorm Watches in Illinois, 2004 Severe Thunderstorm Watches in Indiana, 2004 Severe Thunderstorm Watches in Kentucky, 2004 Every severe thunderstorm 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.