Alert archive / Illinois / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 435
The Storm Prediction Center issued this severe thunderstorm watch at Jul 23, 2017, 3:32 AM CDT for 20 counties in Illinois. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2017, 3:32 AM CDT (08:32 UTC)
- Expired
- Jul 23, 2017, 8:00 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 65 kt
Counties Christian County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Hamilton County, IL, Jasper County, IL, Jefferson County, IL, Lawrence County, IL, Macon County, IL, Moultrie County, IL, Richland County, IL, Sangamon County, IL, Shelby County, IL, Wabash County, IL, Wayne County, IL, White County, IL
The radar
The Lincoln radar (KILX), 106 km from the middle of the area, began a volume at 08:33 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 4:17 AM CDT | Severe Thunderstorm Warning | PAH | Jefferson | 43 min |
| Jul 23, 4:42 AM CDT | Severe Thunderstorm Warning | PAH | Hamilton, Jefferson, Wayne | 33 min |
| Jul 23, 4:46 AM CDT | Severe Thunderstorm Warning | ILX | Clay, Effingham, Jasper, Richland | 44 min |
| Jul 23, 5:00 AM CDT | Severe Thunderstorm Warning | PAH | Edwards, Wayne, White | 45 min |
| Jul 23, 5:16 AM CDT | Severe Thunderstorm Warning | ILX | Crawford, Jasper, Lawrence, Richland | 44 min |
| Jul 23, 5:17 AM CDT | Severe Thunderstorm Warning | PAH | Hamilton, White | 28 min |
| Jul 23, 5:25 AM CDT | Severe Thunderstorm Warning | PAH | Wabash | 35 min |
| Jul 23, 5:33 AM CDT | Severe Thunderstorm Warning | PAH | White | 42 min |
| Jul 23, 5:39 AM CDT | Tornado Warning | PAH | Wabash | 19 min |
| Jul 23, 5:58 AM CDT | Severe Thunderstorm Warning | ILX | Crawford, Jasper, Lawrence, Richland | 47 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 00:00Z, 8.5 hours before the alert went out and 100 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
- 2392 J/kg
- Mixed-layer CIN
- -34 J/kg
- Mixed-layer LCL
- 1185 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 51 m²/s²
- 0-3 km storm-relative helicity
- 233 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 22, 7:11 PM CDT | Mesoscale Discussion | SPC | Christian, Clark, Coles, Crawford, Cumberland, Douglas and 10 more | 94 min |
| Jul 22, 11:48 PM CDT | Mesoscale Discussion | SPC | Calhoun, Pike | 87 min |
| Jul 23, 12:38 AM CDT | Severe Thunderstorm Watch | SPC | Adams, Bond, Brown, Calhoun, Cass, Clinton and 13 more | 5 hr |
| Jul 23, 3:12 AM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Christian, Clay, Clinton, Edwards and 23 more | 2 hr |
| Jul 23, 5:23 AM CDT | Mesoscale Discussion | SPC | Clay, Crawford, Edwards, Effingham, Hamilton, Jasper and 5 more | 2 hr |
| Jul 23, 1:03 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Champaign, Cook, DeKalb, Douglas and 23 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Illinois, 2017Every severe thunderstorm watch in 2017
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.