Alert archive / Illinois / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 519
The Storm Prediction Center issued this severe thunderstorm watch at Jun 19, 2011, 11:42 PM CDT for 19 counties in Illinois; 16 counties in Iowa; Clark County, Scotland County, Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 19, 2011, 11:42 PM CDT (04:42 UTC)
- Expired
- Jun 20, 2011, 6:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 37 counties
Benton County, IA, Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Iowa County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Bureau County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Knox County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Woodford County, IL, Clark County, MO, Scotland County, MO
The radar
The Quad Cities radar (KDVN), 43 km from the middle of the area, began a volume at 04:43 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
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 70%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 1:00 AM CDT | Flash Flood Warning | DVN | Van Buren | 9 hr |
| Jun 20, 1:45 AM CDT | Severe Thunderstorm Warning | DVN | Henry, Jefferson, Lee, Van Buren | 75 min |
| Jun 20, 2:00 AM CDT | Severe Thunderstorm Warning | DVN | Henderson, Mercer, Warren | 34 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, 4.7 hours before the alert went out and 49 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
- 2723 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 881 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 29 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 6.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 4:08 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Cass, Champaign, Christian and 43 more | 67 min |
| Jun 20, 1:04 PM CDT | Mesoscale Discussion | SPC | Champaign, Christian, Clark, Coles, Crawford, Cumberland and 14 more | 56 min |
| Jun 19, 9:16 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 31 more | 59 min |
| Jun 19, 9:49 PM CDT | Tornado Watch | SPC | Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more | 6 hr |
| Jun 20, 1:40 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 24 more | 35 min |
| Jun 20, 3:27 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more | 33 min |
| Jun 20, 3:46 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Audubon, Black Hawk, Boone, Calhoun, Carroll and 26 more | 5 hr |
| Jun 20, 7:29 AM CDT | Mesoscale Discussion | SPC | Black Hawk, Grundy, Hamilton, Hardin, Jasper, Mahaska and 6 more | 61 min |
| Jun 20, 3:08 PM CDT | Tornado Watch | SPC | Audubon, Carroll, Cass, Crawford, Fremont, Harrison and 6 more | 7 hr |
| Jun 20, 5:55 PM CDT | Mesoscale Discussion | SPC | Adair, Audubon, Boone, Calhoun, Carroll, Dallas and 15 more | 65 min |
| Jun 20, 6:17 PM CDT | Mesoscale Discussion | SPC | Fremont, Harrison, Mills, Monona, Plymouth, Woodbury | 58 min |
| Jun 20, 6:53 PM CDT | Tornado Watch | SPC | Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 41 more | 6 hr |
Nearby
Severe Thunderstorm Watches in Illinois, 2011Severe Thunderstorm Watches in Iowa, 2011Severe Thunderstorm Watches in Missouri, 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.