Alert archive / Illinois / Flash Flood Warnings in 2009
Flash Flood Warning 11, NWS Chicago, IL
NWS Chicago, IL issued this flash flood warning at Jun 8, 2009, 1:44 AM CDT for 8 counties in Illinois. It was in force for 8 hr. 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 8, 2009, 1:44 AM CDT (06:44 UTC)
- Expired
- Jun 8, 2009, 9:31 AM CDT
- In force
- 8 hr
- Issued by
- NWS Chicago, IL
- Area
- Storm-based polygon
- Flood severity
- None
Counties Boone County, IL, DeKalb County, IL, Kane County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Winnebago County, IL
The radar
The Chicago radar (KLOT), 80 km from the middle of the area, began a volume at 06:47 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
Davenport, (KDVN), launched 00:00Z, 6.7 hours before the alert went out and 140 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
- 560 J/kg
- Mixed-layer CIN
- -87 J/kg
- Mixed-layer LCL
- 962 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 310 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 9.8
What forecasters said that day
The local office's own words before this flash flood 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 flash flood warning went out at Jun 8, 12:16 AM CDT, 1 hour 28 minutes earlier.
Area forecast discussion, Jun 8, 12:16 AM CDT, 1 hour 28 minutes before
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</html>Hazardous weather outlook, Jun 7, 9:43 PM CDT, 4 hours 1 minute 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 7, 9:30 PM CDT | Marine Dense Fog Advisory | LOT | 12 hr | |
| Jun 7, 9:30 PM CDT | Small Craft Advisory | LOT | 22 hr | |
| Jun 8, 1:48 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, Kane, Lee, Ogle | 42 min |
| Jun 8, 3:57 PM CDT | Severe Thunderstorm Warning | LOT | Lake, McHenry | 56 min |
| Jun 8, 3:58 PM CDT | Special Marine Warning | LOT | 2 hr |
Nearby
Flash Flood Warnings in Illinois, 2009Every flash flood 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.