Alert archive / Illinois / Tornado Watches in 2010
Tornado Watch 115
The Storm Prediction Center issued this tornado watch at Apr 30, 2010, 2:40 PM CDT for 35 counties in Illinois; 22 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 30, 2010, 2:40 PM CDT (19:40 UTC)
- Expired
- Apr 30, 2010, 9:04 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 70 kt
All 57 counties
Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, DeWitt County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Washington County, IL, Woodford County, IL, Audrain County, MO, Callaway County, MO, City of Saint Louis, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Jefferson County, MO, Lincoln County, MO, Madison County, MO, Marion County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Warren County, MO, Washington County, MO
The radar
The St Louis radar (KLSX), 99 km from the middle of the area, began a volume at 19:41 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
- 60%
- One or more EF2 to EF5 tornadoes
- 40%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 80%
- One or more hailstones of 2 inches or more
- 50%
- Six or more combined severe hail and wind reports
- 95%
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 |
|---|---|---|---|---|
| Apr 30, 5:00 PM CDT | Severe Thunderstorm Warning | LSX | Adams | 15 min |
| Apr 30, 6:55 PM CDT | Tornado Warning | LSX | Crawford, Franklin, Washington | 50 min |
| Apr 30, 7:40 PM CDT | Tornado Warning | LSX | Crawford, Franklin, Jefferson, Washington | 50 min |
| Apr 30, 7:45 PM CDT | Flash Flood Warning | LSX | Crawford | 6 hr |
| Apr 30, 7:55 PM CDT | Tornado Warning | LSX | Jefferson, Saint Francois, Washington | 50 min |
| Apr 30, 8:07 PM CDT | Tornado Warning | LSX | Reynolds | 38 min |
| Apr 30, 8:14 PM CDT | Flash Flood Warning | LSX | Franklin, Jefferson, Washington | 6 hr |
| Apr 30, 8:21 PM CDT | Tornado Warning | LSX | Monroe | 39 min |
| Apr 30, 8:39 PM CDT | Flash Flood Warning | LSX | Saint Louis, City of Saint Louis | 6 hr |
| Apr 30, 8:43 PM CDT | Tornado Warning | LSX | Iron, Reynolds | 47 min |
| Apr 30, 8:54 PM CDT | Tornado Warning | LSX | Madison, Monroe, Saint Clair | 51 min |
| Apr 30, 9:02 PM CDT | Tornado Warning | LSX | Monroe, Randolph | 29 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, 7.7 hours before the alert went out and 227 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
- 5 J/kg
- Mixed-layer CIN
- -330 J/kg
- Mixed-layer LCL
- 1205 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 332 m²/s²
- 0-3 km storm-relative helicity
- 351 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 |
|---|---|---|---|---|
| Apr 30, 9:18 AM CDT | Mesoscale Discussion | SPC | Adams, Hancock, Henderson, Mercer, Rock Island | 57 min |
| Apr 30, 12:41 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Grundy, Jo Daviess and 9 more | 64 min |
| Apr 30, 1:05 PM CDT | Tornado Watch | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 28 more | 9 hr |
| Apr 30, 2:08 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Fulton, Greene and 13 more | 67 min |
| Apr 30, 2:41 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Henderson, Henry and 17 more | 64 min |
| Apr 30, 5:37 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, Henry, Jo Daviess and 16 more | 53 min |
| Apr 29, 7:12 PM CDT | Mesoscale Discussion | SPC | Atchison, Holt | 63 min |
| Apr 29, 11:04 PM CDT | Mesoscale Discussion | SPC | Atchison, Holt | 26 min |
| Apr 29, 11:46 PM CDT | Severe Thunderstorm Watch | SPC | Andrew, Atchison, Buchanan, Holt, Nodaway | 4 hr |
| Apr 30, 2:12 AM CDT | Mesoscale Discussion | SPC | Andrew, Buchanan, Holt, Nodaway | 93 min |
| Apr 30, 10:20 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Audrain, Benton, Boone, Caldwell, Callaway and 36 more | 5 hr |
| Apr 30, 1:11 PM CDT | Mesoscale Discussion | SPC | Barry, Camden, Christian, Dade, Dallas, Douglas and 12 more | 2 hr |
| Apr 30, 1:22 PM CDT | Mesoscale Discussion | SPC | Adair, Bates, Benton, Boone, Caldwell, Carroll and 25 more | 53 min |
| Apr 30, 1:46 PM CDT | Tornado Watch | SPC | Barry, Christian, Dallas, Dent, Douglas, Greene and 14 more | 5 hr |
| Apr 30, 5:53 PM CDT | Mesoscale Discussion | SPC | Butler, Carter, Douglas, Howell, Oregon, Ozark and 6 more | 37 min |
| Apr 30, 6:24 PM CDT | Tornado Watch | SPC | Butler, Carter, Dent, Douglas, Howell, Oregon and 5 more | 3 hr |
Nearby
Tornado Watches in Illinois, 2010Tornado Watches in Missouri, 2010Every tornado watch in 2010
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.