Alert archive / Illinois / Severe Thunderstorm Warnings in 2017
Severe Thunderstorm Warning 99, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Jun 29, 2017, 5:58 PM CDT for Iroquois County, Illinois. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jun 29, 2017, 5:58 PM CDT (22:58 UTC)
- Expired
- Jun 29, 2017, 6:27 PM CDT
- In force
- 29 min
- Issued by
- NWS Chicago, IL
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
County Iroquois County, IL
The radar
The Chicago radar (KLOT), 98 km from the middle of the area, began a volume at 22:57 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.
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 11.0 hours before the alert went out and 93 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
- 1213 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 97 m²/s²
- 0-3 km storm-relative helicity
- -70 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 29, 3:33 PM CDT, 2 hours 25 minutes earlier.
Area forecast discussion, Jun 29, 3:33 PM CDT, 2 hours 25 minutes before
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</html>Hazardous weather outlook, Jun 29, 3:52 PM CDT, 2 hours 6 minutes before
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Local storm report, Jun 29, 4:26 PM CDT, 1 hour 32 minutes before
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</html>The office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 28, 7:10 PM CDT | Severe Thunderstorm Warning | LOT | Boone, Winnebago | 65 min |
| Jun 28, 7:40 PM CDT | Tornado Warning | LOT | Winnebago | 20 min |
| Jun 28, 7:55 PM CDT | Severe Thunderstorm Warning | LOT | Boone, DeKalb, Kane, McHenry, Ogle, Winnebago | 65 min |
| Jun 28, 8:03 PM CDT | Flash Flood Watch | LOT | Boone, DeKalb, DuPage, Kane, Lake, Lee and 3 more | 8 hr |
| Jun 28, 8:07 PM CDT | Special Marine Warning | LOT | 3 hr | |
| Jun 28, 8:19 PM CDT | Tornado Warning | LOT | Boone, DeKalb | 26 min |
| Jun 28, 8:24 PM CDT | Flash Flood Warning | LOT | Boone, Winnebago | 6 hr |
| Jun 28, 8:35 PM CDT | Severe Thunderstorm Warning | LOT | Lake | 50 min |
| Jun 28, 8:38 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DeKalb, DuPage, Kane, McHenry | 52 min |
| Jun 28, 9:09 PM CDT | Flash Flood Warning | LOT | Lake, McHenry | 6 hr |
| Jun 28, 10:47 PM CDT | River Flood Advisory | LOT | Boone | 3 days |
| Jun 28, 11:36 PM CDT | Special Weather Statement | LOT | DuPage | 24 min |
| Jun 28, 11:56 PM CDT | Severe Thunderstorm Warning | LOT | Cook, DuPage | 34 min |
| Jun 28, 11:58 PM CDT | Special Marine Warning | LOT | 92 min | |
| Jun 29, 2:28 AM CDT | Areal Flood Warning | LOT | Boone, Winnebago | 15 hr |
| Jun 29, 4:39 AM CDT | River Flood Warning | LOT | Boone | 30 hr |
| Jun 29, 4:39 AM CDT | River Flood Warning | LOT | Winnebago | 41 hr |
| Jun 29, 6:05 AM CDT | River Flood Warning | LOT | Ogle | 39 hr |
| Jun 29, 9:25 AM CDT | River Flood Advisory | LOT | Winnebago | 59 hr |
| Jun 29, 9:25 AM CDT | River Flood Advisory | LOT | Winnebago | 36 hr |
| Jun 29, 9:25 AM CDT | River Flood Advisory | LOT | Lee | 71 hr |
| Jun 29, 9:32 AM CDT | River Flood Watch | LOT | Winnebago | 4 days |
| Jun 29, 10:02 AM CDT | River Flood Advisory | LOT | Kane, Kendall | 36 hr |
| Jun 29, 10:02 AM CDT | River Flood Advisory | LOT | Cook | 36 hr |
| Jun 29, 6:03 PM CDT | Special Weather Statement | LOT | Ford | 27 min |
| Jun 29, 6:09 PM CDT | Severe Thunderstorm Warning | LOT | Ford | 14 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 2017Every severe thunderstorm warning 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.