Alert archive / Illinois / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 89, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Aug 19, 2009, 3:31 PM CDT for Ford County, Livingston County, Illinois. It was in force for 74 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
- Aug 19, 2009, 3:31 PM CDT (20:31 UTC)
- Expired
- Aug 19, 2009, 4:45 PM CDT
- In force
- 74 min
- Issued by
- NWS Chicago, IL
- Area
- Storm-based polygon
Counties Ford County, IL, Livingston County, IL
The radar
The Chicago radar (KLOT), 99 km from the middle of the area, began a volume at 20:34 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 19, 12:49 PM CDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 8.5 hours before the alert went out and 68 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
- 272 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 766 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
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 Aug 19, 3:16 PM CDT, 15 minutes earlier.
Area forecast discussion, Aug 19, 3:16 PM CDT, 15 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 |
|---|---|---|---|---|
| Aug 19, 4:01 PM CDT | Severe Thunderstorm Warning | LOT | Grundy, LaSalle, Livingston | 55 min |
| Aug 19, 4:24 PM CDT | Small Craft Advisory | LOT | 29 hr | |
| Aug 19, 4:35 PM CDT | Tornado Warning | LOT | Grundy | 25 min |
| Aug 19, 4:37 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Grundy, Iroquois, Kankakee, Kendall, LaSalle and 2 more | 53 min |
| Aug 19, 4:49 PM CDT | Special Marine Warning | LOT | 116 min | |
| Aug 19, 5:08 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Iroquois, Livingston | 57 min |
| Aug 19, 5:14 PM CDT | Severe Thunderstorm Warning | LOT | Cook, Kankakee, Will | 61 min |
| Aug 19, 5:19 PM CDT | Tornado Warning | LOT | Ford, Iroquois, Livingston | 29 min |
| Aug 19, 5:40 PM CDT | Areal Flood Advisory | LOT | Cook, DeKalb, DuPage, Grundy, Kane, Kendall and 4 more | 5 hr |
| Aug 19, 5:57 PM CDT | Tornado Warning | LOT | DeKalb, Kane | 33 min |
| Aug 19, 6:11 PM CDT | Tornado Warning | LOT | Iroquois | 32 min |
| Aug 19, 6:25 PM CDT | Special Marine Warning | LOT | 65 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 2009Every severe thunderstorm warning in 2009
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.