Alert archive / Illinois / Severe Thunderstorm Watches in 2004
Severe Thunderstorm Watch 756
The Storm Prediction Center issued this severe thunderstorm watch at Aug 17, 2004, 1:20 PM CDT for 47 counties in Illinois; 4 counties in Iowa; 13 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2004, 1:20 PM CDT (18:20 UTC)
- Expired
- Aug 17, 2004, 7:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
All 64 counties
Des Moines County, IA, Henry County, IA, Lee County, IA, Van Buren County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Will County, IL, Woodford County, IL, Audrain County, MO, Callaway County, MO, Clark County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Scotland County, MO, Shelby County, MO
The radar
The Lincoln radar (KILX), 101 km from the middle of the area, began a volume at 18:24 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
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 3:11 PM CDT | Severe Thunderstorm Warning | LSX | Knox | 94 min |
| Aug 17, 3:42 PM CDT | Severe Thunderstorm Warning | LSX | Lewis | 48 min |
| Aug 17, 4:34 PM CDT | Severe Thunderstorm Warning | LOT | LaSalle | 56 min |
| Aug 17, 4:42 PM CDT | Severe Thunderstorm Warning | LSX | Knox, Lewis, Marion, Shelby | 93 min |
| Aug 17, 4:45 PM CDT | Severe Thunderstorm Warning | LSX | Knox, Lewis, Marion, Shelby | 90 min |
| Aug 17, 5:12 PM CDT | Severe Thunderstorm Warning | LOT | Will | 48 min |
| Aug 17, 5:22 PM CDT | Severe Thunderstorm Warning | LOT | Cook | 68 min |
| Aug 17, 5:54 PM CDT | Tornado Warning | ILX | Knox, Stark | 66 min |
| Aug 17, 6:09 PM CDT | Severe Thunderstorm Warning | LOT | Grundy | 66 min |
| Aug 17, 6:23 PM CDT | Severe Thunderstorm Warning | LOT | LaSalle | 67 min |
| Aug 17, 6:51 PM CDT | Severe Thunderstorm Warning | ILX | Marshall, Peoria, Woodford | 54 min |
| Aug 17, 6:59 PM CDT | Severe Thunderstorm Warning | ILX | Stark | 61 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 12:00Z, 6.3 hours before the alert went out and 118 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.
- Mixed-layer CAPE
- 604 J/kg
- Mixed-layer CIN
- -78 J/kg
- Mixed-layer LCL
- 823 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 111 m²/s²
- 0-3 km storm-relative helicity
- 158 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 12:57 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Calhoun, Carroll, Cass and 38 more | 63 min |
| Aug 17, 3:59 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Calhoun, Cass, Champaign and 41 more | 61 min |
| Aug 17, 5:57 PM CDT | Mesoscale Discussion | SPC | Calhoun, Cass, Champaign, Christian, DeWitt, Douglas and 19 more | 93 min |
| Aug 16, 8:54 PM CDT | Mesoscale Discussion | SPC | Audubon, Boone, Calhoun, Carroll, Crawford, Dallas and 30 more | 2 hr |
| Aug 17, 5:04 PM CDT | Mesoscale Discussion | SPC | Bates, Cass, Henry, Jackson, Johnson, Lafayette and 1 more | 116 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2004Severe Thunderstorm Watches in Missouri, 2004Severe Thunderstorm Watches in Iowa, 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.