Alert archive / Missouri / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 455
The Storm Prediction Center issued this severe thunderstorm watch at Jun 9, 2011, 4:43 PM CDT for 4 counties in Illinois; 9 counties in Missouri. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 9, 2011, 4:43 PM CDT (21:43 UTC)
- Expired
- Jun 9, 2011, 9:48 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Adams County, IL, Brown County, IL, Calhoun County, IL, Pike County, IL, Audrain County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Pike County, MO, Ralls County, MO, Shelby County, MO
The radar
The St Louis radar (KLSX), 149 km from the middle of the area, began a volume at 21:44 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
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
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 9, 5:09 PM CDT | Severe Thunderstorm Warning | LSX | Adams, Pike | 51 min |
| Jun 9, 5:54 PM CDT | Severe Thunderstorm Warning | LSX | Adams, Pike | 51 min |
| Jun 9, 6:26 PM CDT | Severe Thunderstorm Warning | LSX | Pike | 30 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, 9.7 hours before the alert went out and 237 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
- 121 J/kg
- Mixed-layer CIN
- -128 J/kg
- Mixed-layer LCL
- 1420 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- -114 m²/s²
- 0-3 km storm-relative helicity
- -95 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 |
|---|---|---|---|---|
| Jun 8, 8:43 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 19 more | 92 min |
| Jun 8, 11:45 PM CDT | Mesoscale Discussion | SPC | Bureau, Cook, DeKalb, DuPage, Grundy, Kane and 6 more | 90 min |
| Jun 9, 1:44 AM CDT | Mesoscale Discussion | SPC | Bureau, Carroll, DeKalb, Henderson, Henry, Jo Daviess and 12 more | 2 hr |
| Jun 9, 5:46 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cass, Champaign, Cook and 34 more | 59 min |
| Jun 9, 4:29 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Christian, Fulton, Greene and 12 more | 61 min |
| Jun 9, 5:31 PM CDT | Mesoscale Discussion | SPC | Champaign, Clark, Coles, Crawford, Cumberland, Douglas and 9 more | 89 min |
| Jun 9, 9:50 AM CDT | Mesoscale Discussion | SPC | Adair, Atchison, Gentry, Harrison, Holt, Mercer and 6 more | 55 min |
| Jun 9, 2:13 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Buchanan, Cass, Clay, Clinton and 6 more | 92 min |
| Jun 9, 3:05 PM CDT | Tornado Watch | SPC | Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 29 more | 7 hr |
Nearby
Severe Thunderstorm Watches in Missouri, 2011Severe Thunderstorm Watches in Illinois, 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.