Alert archive / Illinois / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 394
The Storm Prediction Center issued this severe thunderstorm watch at May 29, 2011, 8:53 AM CDT for 4 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- May 29, 2011, 8:53 AM CDT (13:53 UTC)
- Expired
- May 29, 2011, 2:35 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 70 kt
All 62 counties
Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Jo Daviess 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, Marshall County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN, Clark County, MO, Scotland County, MO
The radar
The Quad Cities radar (KDVN), 44 km from the middle of the area, began a volume at 13:54 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 95%
- One or more gusts of 65 knots or more
- 70%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
24 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 29, 9:18 AM CDT | Severe Thunderstorm Warning | DVN | Des Moines, Henry, Jefferson, Johnson, Lee, Louisa and 3 more | 57 min |
| May 29, 9:32 AM CDT | Severe Thunderstorm Warning | DVN | Cedar, Johnson, Jones, Linn | 58 min |
| May 29, 9:55 AM CDT | Severe Thunderstorm Warning | DVN | Hancock | 65 min |
| May 29, 9:58 AM CDT | Severe Thunderstorm Warning | DVN | Henderson, Mercer, Rock Island, Warren | 62 min |
| May 29, 10:12 AM CDT | Flash Flood Warning | DVN | Bureau, Henry, Mercer | 4 hr |
| May 29, 10:14 AM CDT | Severe Thunderstorm Warning | ILX | Knox, Stark | 61 min |
| May 29, 10:15 AM CDT | Severe Thunderstorm Warning | DVN | Henderson, Warren | 60 min |
| May 29, 10:19 AM CDT | Flash Flood Warning | ILX | Knox | 6 hr |
| May 29, 10:26 AM CDT | Severe Thunderstorm Warning | DVN | Clinton, Jackson, Scott | 64 min |
| May 29, 10:33 AM CDT | Severe Thunderstorm Warning | DVN | Bureau, Henry, Mercer, Rock Island, Whiteside | 57 min |
| May 29, 10:42 AM CDT | Severe Thunderstorm Warning | ILX | Fulton, Knox, Peoria, Stark, Tazewell | 33 min |
| May 29, 10:54 AM CDT | Severe Thunderstorm Warning | DVN | Carroll, Rock Island, Whiteside | 66 min |
| May 29, 11:03 AM CDT | Severe Thunderstorm Warning | DVN | Hancock, McDonough, Warren | 34 min |
| May 29, 11:08 AM CDT | Severe Thunderstorm Warning | ILX | Fulton, Knox, Marshall, Peoria, Stark, Tazewell and 1 more | 52 min |
| May 29, 11:13 AM CDT | Severe Thunderstorm Warning | LOT | DeKalb, LaSalle, Lee, Livingston | 62 min |
| May 29, 11:17 AM CDT | Severe Thunderstorm Warning | DVN | Bureau, Putnam | 43 min |
| May 29, 11:23 AM CDT | Severe Thunderstorm Warning | LOT | Cook, DeKalb, DuPage, Kane, Kendall, Lake and 1 more | 67 min |
| May 29, 11:31 AM CDT | Flash Flood Warning | LOT | DeKalb, LaSalle, Lee | 6 hr |
| May 29, 11:58 AM CDT | Severe Thunderstorm Warning | LOT | DeKalb, DuPage, Ford, Grundy, Kane, Kankakee and 6 more | 77 min |
| May 29, 12:32 PM CDT | Tornado Warning | LOT | Grundy, Kankakee, Livingston, Will | 43 min |
| May 29, 12:38 PM CDT | Flash Flood Warning | LOT | Boone, Cook, DeKalb, DuPage, Kane, Lake and 4 more | 5 hr |
| May 29, 12:43 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage, Ford, Grundy, Iroquois, Kane and 5 more | 77 min |
| May 29, 1:16 PM CDT | Tornado Warning | LOT | Kankakee | 44 min |
| May 29, 1:34 PM CDT | Severe Thunderstorm Warning | LOT | Benton, Jasper | 41 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, 1.9 hours before the alert went out and 38 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 995 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 291 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 29, 8:39 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 26 more | 66 min |
| May 29, 11:59 AM CDT | Mesoscale Discussion | SPC | Cook, DeKalb, DuPage, Ford, Grundy, Iroquois and 9 more | 61 min |
| May 29, 12:29 PM CDT | Tornado Watch | SPC | Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more | 7 hr |
| May 29, 3:17 PM CDT | Mesoscale Discussion | SPC | Allen, DeKalb, LaGrange, Noble, Steuben | 88 min |
| May 29, 1:41 AM CDT | Mesoscale Discussion | SPC | Appanoose, Davis, Decatur, Jefferson, Monroe, Page and 5 more | 2 hr |
| May 29, 4:36 PM CDT | Mesoscale Discussion | SPC | Fremont, Mills, Page | 24 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2011Severe Thunderstorm Watches in Iowa, 2011Severe Thunderstorm Watches in Indiana, 2011Every severe thunderstorm watch in 2011
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.