Alert archive / Illinois / Flash Flood Warnings in 2020

Flash Flood Warning 16, NWS Chicago, IL

June 27, 2020Lee County, Illinois

NWS Chicago, IL issued this flash flood warning at Jun 27, 2020, 9:20 PM CDT for Lee County, Illinois. It was in force for 3 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 27, 2020, 9:20 PM CDT (02:20 UTC)
Expired: Jun 28, 2020, 12:15 AM CDT
In force: 3 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Flood severity: None

County Lee County, IL

The radar

The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 02:22 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, 2.3 hours before the alert went out and 101 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 105 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 1406 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 16 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 27, 6:50 PM CDT, 2 hours 30 minutes earlier.

Area forecast discussion, Jun 27, 6:50 PM CDT, 2 hours 30 minutes before

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Hazardous weather outlook, Jun 27, 4:01 PM CDT, 5 hours 19 minutes before

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In the hours before

Local storm report, Jun 27, 8:04 PM CDT, 1 hour 16 minutes before

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Local storm report, Jun 27, 8:18 PM CDT, 1 hour 2 minutes before

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Local storm report, Jun 27, 8:32 PM CDT, 48 minutes before

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Local storm report, Jun 27, 8:42 PM CDT, 38 minutes before

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Local storm report, Jun 27, 8:46 PM CDT, 34 minutes before

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Special weather statement, Jun 27, 8:47 PM CDT, 33 minutes before

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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 27, 7:30 PM CDT	Areal Flood Warning	LOT	Ford, Iroquois, Kankakee	12 hr
Jun 27, 8:22 PM CDT	River Flood Warning	LOT	Iroquois	4 days
Jun 27, 8:43 PM CDT	Areal Flood Advisory	LOT	Lee	52 min
Jun 27, 8:47 PM CDT	Special Weather Statement	LOT	Lee	28 min
Jun 27, 9:07 PM CDT	Areal Flood Advisory	LOT	Ford, Iroquois, Livingston	3 hr
Jun 28, 12:05 AM CDT	Areal Flood Warning	LOT	Lee	3 hr
Jun 27, 8:24 PM CDT	River Flood Advisory	LOT	Newton	12 hr
Jun 28, 7:51 AM CDT	River Flood Warning	LOT	Newton	50 hr

Nearby

Flash Flood Warnings in Illinois, 2020 Every flash flood warning 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.