Alert archive / Illinois / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 705

August 3, 200438 counties in Illinois; 24 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at Aug 3, 2004, 11:30 PM CDT for 38 counties in Illinois; 24 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 3, 2004, 11:30 PM CDT (04:30 UTC)
Expired
Aug 4, 2004, 5:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 62 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Iroquois County, IL, Jersey County, IL, Kankakee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Adair County, MO, Audrain County, MO, Boone County, MO, Callaway County, MO, Chariton County, MO, Clark County, MO, Cooper County, MO, Howard County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Linn County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pettis County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Saline County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO

The radar

The St Louis radar (KLSX), 142 km from the middle of the area, began a volume at 04:31 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

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

IssuedProductOfficeCountiesLasted
Aug 3, 11:36 PM CDTSevere Thunderstorm WarningLOTIroquois, Kankakee54 min
Aug 4, 1:14 AM CDTSevere Thunderstorm WarningLOTLivingston31 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

Davenport, (KDVN), launched 00:00Z, 4.5 hours before the alert went out and 194 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, Davenport, at 00:00Z on 2004-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2771 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, Davenport, at 00:00Z on 2004-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
2771 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
1163 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
163 m²/s²
Significant tornado parameter
1.6
Supercell composite
16.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 3, 7:38 PM CDTMesoscale DiscussionSPCBureau, Cook, DeKalb, DuPage, Ford, Grundy and 14 more67 min
Aug 3, 7:55 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DuPage, Ford and 21 more5 hr
Aug 3, 8:19 PM CDTMesoscale DiscussionSPCCarroll, Henry, Jo Daviess, Knox, Mercer, Rock Island and 2 more56 min
Aug 3, 9:45 PM CDTSevere Thunderstorm WatchSPCFulton, Hancock, Henderson, Henry, Knox, McDonough and 3 more5 hr
Aug 3, 9:52 PM CDTMesoscale DiscussionSPCCook, DuPage, Grundy, Kane, Kendall, Lake and 3 more53 min
Aug 3, 10:38 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 3 more67 min
Aug 4, 1:42 AM CDTMesoscale DiscussionSPCFulton, Henderson, Jersey, Livingston, McDonough, Mason and 5 more2 hr
Aug 4, 3:52 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Champaign, Christian and 32 more53 min
Aug 4, 3:39 PM CDTMesoscale DiscussionSPCHardin, Massac, Pope96 min
Aug 3, 11:34 PM CDTMesoscale DiscussionSPCClark, Putnam, Schuyler, Scotland86 min

Nearby

Severe Thunderstorm Watches in Illinois, 2004Severe Thunderstorm Watches in Missouri, 2004Every 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.