Alert archive / Illinois / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 197
The Storm Prediction Center issued this severe thunderstorm watch at Apr 28, 2012, 1:48 PM CDT for 26 counties in Illinois; 12 counties in Missouri. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2012, 1:48 PM CDT (18:48 UTC)
- Expired
- Apr 28, 2012, 9:00 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 3 in
- Strongest gust expected
- 60 kt
All 38 counties
Bond County, IL, Calhoun County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Richland County, IL, Saint Clair County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, City of Saint Louis, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Montgomery County, MO, Pike County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO, Washington County, MO
The radar
The St Louis radar (KLSX), 66 km from the middle of the area, began a volume at 18:48 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
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
31 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 1:50 PM CDT | Severe Thunderstorm Warning | LSX | Lincoln, Montgomery, Warren | 40 min |
| Apr 28, 2:26 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun | 49 min |
| Apr 28, 3:05 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Jersey, Madison | 40 min |
| Apr 28, 3:28 PM CDT | Severe Thunderstorm Warning | ILX | Clark, Crawford, Cumberland, Jasper | 32 min |
| Apr 28, 3:45 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Madison, Saint Clair | 45 min |
| Apr 28, 3:49 PM CDT | Severe Thunderstorm Warning | ILX | Crawford, Jasper | 41 min |
| Apr 28, 3:57 PM CDT | Tornado Warning | ILX | Crawford | 37 min |
| Apr 28, 3:59 PM CDT | Tornado Warning | LSX | Saint Clair | 31 min |
| Apr 28, 4:22 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 38 min |
| Apr 28, 4:28 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 47 min |
| Apr 28, 4:49 PM CDT | Severe Thunderstorm Warning | LSX | Crawford, Washington | 41 min |
| Apr 28, 4:55 PM CDT | Severe Thunderstorm Warning | LSX | Lincoln, Montgomery, Warren | 50 min |
| Apr 28, 4:56 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 49 min |
| Apr 28, 5:13 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Marion, Washington | 47 min |
| Apr 28, 5:19 PM CDT | Severe Thunderstorm Warning | LSX | Lincoln, Saint Charles, Warren | 41 min |
| Apr 28, 5:27 PM CDT | Severe Thunderstorm Warning | LSX | Crawford, Jefferson, Saint Francois, Washington | 48 min |
| Apr 28, 5:38 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 37 min |
| Apr 28, 5:50 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun | 40 min |
| Apr 28, 5:58 PM CDT | Severe Thunderstorm Warning | PAH | Jefferson | 42 min |
| Apr 28, 6:01 PM CDT | Tornado Warning | LSX | Madison, Saint Clair | 29 min |
| Apr 28, 6:10 PM CDT | Severe Thunderstorm Warning | LSX | Monroe | 34 min |
| Apr 28, 6:17 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Washington | 33 min |
| Apr 28, 6:27 PM CDT | Severe Thunderstorm Warning | LSX | Madison, Saint Clair | 48 min |
| Apr 28, 6:35 PM CDT | Severe Thunderstorm Warning | LSX | Fayette, Marion | 25 min |
| Apr 28, 6:45 PM CDT | Severe Thunderstorm Warning | ILX | Clay, Effingham | 60 min |
| Apr 28, 6:53 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 52 min |
| Apr 28, 6:58 PM CDT | Severe Thunderstorm Warning | LSX | Fayette, Marion | 32 min |
| Apr 28, 7:23 PM CDT | Severe Thunderstorm Warning | ILX | Clay | 52 min |
| Apr 28, 7:58 PM CDT | Severe Thunderstorm Warning | ILX | Richland | 41 min |
| Apr 28, 8:12 PM CDT | Severe Thunderstorm Warning | LSX | Monroe | 48 min |
| Apr 28, 8:39 PM CDT | Severe Thunderstorm Warning | LSX | Monroe | 36 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 179 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1019 m above ground
- 0-6 km bulk shear
- 63 kt
- 0-1 km storm-relative helicity
- 681 m²/s²
- 0-3 km storm-relative helicity
- 811 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 1:17 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clay, Clinton, Crawford, Cumberland and 24 more | 88 min |
| Apr 28, 2:56 PM CDT | Mesoscale Discussion | SPC | Bond, Clark, Clay, Clinton, Crawford, Cumberland and 13 more | 64 min |
| Apr 28, 5:15 PM CDT | Tornado Watch | SPC | Clinton, Edwards, Franklin, Gallatin, Hamilton, Jackson and 12 more | 5 hr |
| Apr 28, 5:59 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clark, Clay, Clinton, Crawford and 20 more | 2 hr |
| Apr 28, 6:12 PM CDT | Mesoscale Discussion | SPC | Franklin, Hamilton, Jefferson, Monroe, Perry, Randolph and 3 more | 2 hr |
| Apr 27, 7:00 PM CDT | Mesoscale Discussion | SPC | Andrew, Buchanan, Caldwell, Cass, Clay, Clinton and 6 more | 30 min |
| Apr 27, 7:18 PM CDT | Severe Thunderstorm Watch | SPC | Bates, Buchanan, Cass, Clay, Clinton, Jackson and 1 more | 95 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2012Severe Thunderstorm Watches in Missouri, 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.