Alert archive / Illinois / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 82
The Storm Prediction Center issued this severe thunderstorm watch at Apr 7, 2020, 5:26 PM CDT for 17 counties in Illinois; Lake County, Porter County, Indiana; 12 counties in Iowa. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 7, 2020, 5:26 PM CDT (22:26 UTC)
- Expired
- Apr 7, 2020, 11:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 55 kt
All 31 counties
Cedar County, IA, Clinton County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Boone County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Lake County, IN, Porter County, IN
The radar
The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 22:26 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
- 20%
- One or more gusts of 65 knots or more
- 10%
- 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
- 60%
Warnings issued inside it
27 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 7, 5:55 PM CDT | Severe Thunderstorm Warning | DVN | Jo Daviess, Stephenson | 50 min |
| Apr 7, 6:01 PM CDT | Severe Thunderstorm Warning | DVN | Jones, Linn | 59 min |
| Apr 7, 6:14 PM CDT | Severe Thunderstorm Warning | LOT | Winnebago | 61 min |
| Apr 7, 6:41 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Jones, Linn | 49 min |
| Apr 7, 6:51 PM CDT | Severe Thunderstorm Warning | LOT | Lake, McHenry | 54 min |
| Apr 7, 6:56 PM CDT | Severe Thunderstorm Warning | DVN | Benton, Cedar, Linn | 49 min |
| Apr 7, 7:01 PM CDT | Severe Thunderstorm Warning | LOT | Boone, Winnebago | 59 min |
| Apr 7, 7:14 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Jones | 61 min |
| Apr 7, 7:18 PM CDT | Severe Thunderstorm Warning | DVN | Stephenson | 27 min |
| Apr 7, 7:27 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, Kane, McHenry, Ogle | 48 min |
| Apr 7, 7:29 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Johnson, Linn | 46 min |
| Apr 7, 7:35 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Clinton, Scott | 55 min |
| Apr 7, 8:03 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Scott | 27 min |
| Apr 7, 8:06 PM CDT | Severe Thunderstorm Warning | DVN | Cedar, Iowa, Johnson, Muscatine | 39 min |
| Apr 7, 8:17 PM CDT | Severe Thunderstorm Warning | DVN | Henry, Rock Island, Whiteside | 58 min |
| Apr 7, 8:17 PM CDT | Severe Thunderstorm Warning | LOT | Cook | 28 min |
| Apr 7, 8:17 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage | 45 min |
| Apr 7, 8:19 PM CDT | Severe Thunderstorm Warning | LOT | Lake, Porter | 41 min |
| Apr 7, 8:38 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, Kane | 25 min |
| Apr 7, 8:40 PM CDT | Severe Thunderstorm Warning | LOT | Cook | 50 min |
| Apr 7, 8:45 PM CDT | Severe Thunderstorm Warning | DVN | Iowa, Johnson, Keokuk, Washington | 30 min |
| Apr 7, 8:55 PM CDT | Severe Thunderstorm Warning | LOT | Lake, Porter | 65 min |
| Apr 7, 9:07 PM CDT | Severe Thunderstorm Warning | DVN | Rock Island | 23 min |
| Apr 7, 9:14 PM CDT | Severe Thunderstorm Warning | DVN | Johnson, Louisa, Muscatine, Washington | 31 min |
| Apr 7, 9:27 PM CDT | Severe Thunderstorm Warning | DVN | Mercer, Rock Island | 33 min |
| Apr 7, 9:40 PM CDT | Severe Thunderstorm Warning | DVN | Mercer, Rock Island | 35 min |
| Apr 7, 9:57 PM CDT | Severe Thunderstorm Warning | DVN | Henry, Mercer, Rock Island | 33 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, 10.4 hours before the alert went out and 124 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
- 630 J/kg
- Mixed-layer CIN
- -177 J/kg
- Mixed-layer LCL
- 832 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 109 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 6, 11:03 PM CDT | Mesoscale Discussion | SPC | Boone, Cook, DeKalb, DuPage, Grundy, Kane and 8 more | 2 hr |
| Apr 7, 3:06 PM CDT | Mesoscale Discussion | SPC | Boone, Cook, DeKalb, DuPage, Kane, Lake and 2 more | 114 min |
| Apr 7, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | Lake, McHenry | 5 hr |
| Apr 7, 5:07 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 20 more | 83 min |
| Apr 7, 5:59 PM CDT | Mesoscale Discussion | SPC | Cook | 91 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2020Severe Thunderstorm Watches in Iowa, 2020Severe Thunderstorm Watches in Indiana, 2020Every severe thunderstorm watch in 2020
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.