Alert archive / Illinois / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 636
The Storm Prediction Center issued this severe thunderstorm watch at Jul 12, 2011, 1:45 PM CDT for 55 counties in Illinois; 6 counties in Indiana; 28 counties in Missouri. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 12, 2011, 1:45 PM CDT (18:45 UTC)
- Expired
- Jul 12, 2011, 9:00 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 89 counties
Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Fulton County, IL, Gallatin County, IL, Greene County, IL, Hamilton County, IL, Hancock County, IL, Jackson County, IL, Jasper County, IL, Jefferson 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, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Perry County, IL, Pike County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Adair County, MO, Audrain County, MO, Boone County, MO, Callaway County, MO, Chariton County, MO, City of Saint Louis, MO, Clark County, MO, Franklin County, MO, Howard County, MO, Jefferson 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, Pike County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Saline County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 51 km from the middle of the area, began a volume at 18:47 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
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 70%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
30 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 12, 1:58 PM CDT | Severe Thunderstorm Warning | EAX | Adair, Linn, Macon, Sullivan | 47 min |
| Jul 12, 1:58 PM CDT | Severe Thunderstorm Warning | LSX | Knox, Lewis | 47 min |
| Jul 12, 2:08 PM CDT | Severe Thunderstorm Warning | LSX | Knox, Lewis, Shelby | 52 min |
| Jul 12, 2:25 PM CDT | Severe Thunderstorm Warning | LSX | Madison, Saint Clair | 26 min |
| Jul 12, 2:31 PM CDT | Flash Flood Warning | LSX | Madison, Saint Clair | 3 hr |
| Jul 12, 2:36 PM CDT | Flash Flood Warning | LSX | Knox | 2 hr |
| Jul 12, 2:54 PM CDT | Severe Thunderstorm Warning | LSX | Knox, Lewis, Marion, Shelby | 51 min |
| Jul 12, 3:38 PM CDT | Severe Thunderstorm Warning | LSX | Adams, Brown | 52 min |
| Jul 12, 3:44 PM CDT | Severe Thunderstorm Warning | LSX | Adams, Pike | 46 min |
| Jul 12, 4:06 PM CDT | Flash Flood Warning | LSX | Marion | 3 hr |
| Jul 12, 4:18 PM CDT | Severe Thunderstorm Warning | LSX | Marion | 27 min |
| Jul 12, 4:21 PM CDT | Flash Flood Warning | ILX | Clay | 6 hr |
| Jul 12, 4:21 PM CDT | Severe Thunderstorm Warning | LSX | Callaway | 39 min |
| Jul 12, 4:31 PM CDT | Severe Thunderstorm Warning | LSX | Brown, Calhoun, Greene, Jersey, Pike | 44 min |
| Jul 12, 4:44 PM CDT | Tornado Warning | LSX | Greene, Macoupin, Pike | 46 min |
| Jul 12, 4:45 PM CDT | Severe Thunderstorm Warning | LSX | Callaway, Osage | 45 min |
| Jul 12, 4:46 PM CDT | Severe Thunderstorm Warning | ILX | Scott | 44 min |
| Jul 12, 4:48 PM CDT | Severe Thunderstorm Warning | LSX | Marion | 42 min |
| Jul 12, 5:03 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Greene, Jersey, Macoupin, Madison, Montgomery and 1 more | 57 min |
| Jul 12, 5:10 PM CDT | Severe Thunderstorm Warning | LSX | Fayette, Montgomery | 30 min |
| Jul 12, 5:29 PM CDT | Flash Flood Warning | PAH | Gibson, Pike, Spencer, Warrick | 2 hr |
| Jul 12, 5:39 PM CDT | Severe Thunderstorm Warning | ILX | Lawrence | 51 min |
| Jul 12, 5:45 PM CDT | Flash Flood Warning | ILX | Lawrence, Richland | 5 hr |
| Jul 12, 5:51 PM CDT | Severe Thunderstorm Warning | LSX | Bond, Fayette, Marion | 39 min |
| Jul 12, 5:52 PM CDT | Severe Thunderstorm Warning | PAH | Posey, Vanderburgh | 23 min |
| Jul 12, 6:28 PM CDT | Flash Flood Warning | ILX | Crawford, Jasper | 5 hr |
| Jul 12, 6:37 PM CDT | Severe Thunderstorm Warning | ILX | Crawford, Lawrence | 38 min |
| Jul 12, 7:50 PM CDT | Flash Flood Warning | LSX | Randolph | 3 hr |
| Jul 12, 8:34 PM CDT | Flash Flood Warning | PAH | Jackson, Williamson | 86 min |
| Jul 12, 8:35 PM CDT | Severe Thunderstorm Warning | EAX | Carroll, Chariton, Cooper, Howard, Saline | 40 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, 6.8 hours before the alert went out and 207 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
- 1615 J/kg
- Mixed-layer CIN
- -167 J/kg
- Mixed-layer LCL
- 777 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- -4 m²/s²
- 0-3 km storm-relative helicity
- -14 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 12, 1:00 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 53 more | 2 hr |
| Jul 12, 3:48 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 38 more | 87 min |
| Jul 12, 6:43 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Christian, Clark and 41 more | 62 min |
| Jul 11, 8:22 PM CDT | Severe Thunderstorm Watch | SPC | Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more | 3 hr |
| Jul 12, 2:09 AM CDT | Mesoscale Discussion | SPC | Audubon, Buena Vista, Carroll, Cass, Cherokee, Crawford and 11 more | 66 min |
| Jul 11, 10:22 PM CDT | Mesoscale Discussion | SPC | Bath, Breathitt, Clay, Elliott, Estill, Fleming and 20 more | 83 min |
| Jul 12, 12:18 PM CDT | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bourbon, Boyle and 35 more | 87 min |
| Jul 12, 4:33 PM CDT | Mesoscale Discussion | SPC | Barton, Bates, Benton, Buchanan, Camden, Cass and 26 more | 87 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2011Severe Thunderstorm Watches in Missouri, 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.