Alert archive / Illinois / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 648
The Storm Prediction Center issued this severe thunderstorm watch at Sep 25, 2012, 5:05 PM CDT for 17 counties in Illinois; 6 counties in Indiana; 17 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 25, 2012, 5:05 PM CDT (22:05 UTC)
- Expired
- Sep 25, 2012, 11:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 40 counties
Bond County, IL, Clinton County, IL, Edwards County, IL, Fayette County, IL, Franklin County, IL, Hamilton County, IL, Jefferson County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Gibson County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Moniteau County, MO, Montgomery County, MO, Osage 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), 93 km from the middle of the area, began a volume at 22:08 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
30 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 25, 5:05 PM CDT | Severe Thunderstorm Warning | LSX | Clinton | 55 min |
| Sep 25, 5:07 PM CDT | Tornado Warning | LSX | Clinton | 23 min |
| Sep 25, 5:09 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Jersey, Madison | 51 min |
| Sep 25, 5:12 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair | 18 min |
| Sep 25, 5:19 PM CDT | Tornado Warning | LSX | Washington | 26 min |
| Sep 25, 5:28 PM CDT | Severe Thunderstorm Warning | LSX | Marion | 47 min |
| Sep 25, 5:34 PM CDT | Tornado Warning | LSX | Washington | 41 min |
| Sep 25, 5:43 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Washington | 62 min |
| Sep 25, 5:48 PM CDT | Severe Thunderstorm Warning | LSX | Franklin, Jefferson, Saint Louis, City of Saint Louis | 42 min |
| Sep 25, 6:08 PM CDT | Severe Thunderstorm Warning | LSX | Madison, Monroe, Saint Clair | 52 min |
| Sep 25, 6:08 PM CDT | Tornado Warning | PAH | Jefferson | 37 min |
| Sep 25, 6:14 PM CDT | Severe Thunderstorm Warning | LSX | Washington | 46 min |
| Sep 25, 6:16 PM CDT | Severe Thunderstorm Warning | LSX | Callaway, Cole, Osage | 44 min |
| Sep 25, 6:22 PM CDT | Severe Thunderstorm Warning | LSX | Jefferson, Saint Louis, City of Saint Louis | 38 min |
| Sep 25, 6:30 PM CDT | Severe Thunderstorm Warning | LSX | Marion | 26 min |
| Sep 25, 6:31 PM CDT | Severe Thunderstorm Warning | PAH | Jefferson, Wayne | 44 min |
| Sep 25, 6:43 PM CDT | Severe Thunderstorm Warning | PAH | Jefferson | 23 min |
| Sep 25, 6:45 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Madison, Marion, Washington | 45 min |
| Sep 25, 6:45 PM CDT | Severe Thunderstorm Warning | LSX | Franklin, Gasconade | 45 min |
| Sep 25, 6:50 PM CDT | Severe Thunderstorm Warning | LSX | Monroe, Saint Clair | 46 min |
| Sep 25, 6:55 PM CDT | Severe Thunderstorm Warning | LSX | Franklin, Jefferson, Saint Louis | 50 min |
| Sep 25, 7:00 PM CDT | Severe Thunderstorm Warning | PAH | Edwards, Wabash | 31 min |
| Sep 25, 7:05 PM CDT | Severe Thunderstorm Warning | LSX | Lincoln, Saint Charles, Warren | 40 min |
| Sep 25, 7:29 PM CDT | Severe Thunderstorm Warning | LSX | Marion, Washington | 46 min |
| Sep 25, 7:29 PM CDT | Severe Thunderstorm Warning | PAH | Jefferson | 31 min |
| Sep 25, 7:41 PM CDT | Severe Thunderstorm Warning | LSX | Franklin, Jefferson, Saint Louis | 49 min |
| Sep 25, 8:11 PM CDT | Severe Thunderstorm Warning | LSX | Bond, Clinton, Madison, Saint Clair | 34 min |
| Sep 25, 8:13 PM CDT | Severe Thunderstorm Warning | LSX | Madison, Saint Clair | 47 min |
| Sep 25, 8:38 PM CDT | Severe Thunderstorm Warning | LSX | Bond, Clinton, Fayette, Marion | 52 min |
| Sep 25, 8:59 PM CDT | Flash Flood Warning | LSX | Clinton, Washington | 6 hr |
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, 10.1 hours before the alert went out and 214 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
- 221 J/kg
- Mixed-layer CIN
- -192 J/kg
- Mixed-layer LCL
- 560 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 108 m²/s²
- 0-3 km storm-relative helicity
- 134 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.7
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 25, 12:51 AM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clay, Clinton, Crawford, Edwards and 33 more | 114 min |
| Sep 25, 12:59 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clay, Clinton, Edwards, Effingham and 21 more | 61 min |
| Sep 25, 6:57 PM CDT | Mesoscale Discussion | SPC | Clinton, Edwards, Franklin, Gallatin, Hamilton, Jefferson and 11 more | 93 min |
| Sep 25, 4:47 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Bates, Benton, Camden, Cedar and 16 more | 88 min |
| Sep 25, 5:46 PM CDT | Severe Thunderstorm Watch | SPC | Barton, Benton, Camden, Cedar, Dade, Dallas and 12 more | 4 hr |
Nearby
Severe Thunderstorm Watches in Illinois, 2012Severe Thunderstorm Watches in Missouri, 2012Severe Thunderstorm Watches in Indiana, 2012Every severe thunderstorm watch in 2012
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.