Alert archive / Illinois / Dense Fog Advisories in 2021

Dense Fog Advisory 15, NWS Lincoln, IL

October 7, 202135 counties in Illinois

NWS Lincoln, IL issued this dense fog advisory at Oct 7, 2021, 8:41 PM CDT for 35 counties in Illinois. It took effect at Oct 8, 2021, 12:00 AM CDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued: Oct 7, 2021, 8:41 PM CDT (01:41 UTC)
In effect from: Oct 8, 2021, 12:00 AM CDT
Expired: Oct 8, 2021, 10:00 AM CDT
In force: 10 hr
Issued by: NWS Lincoln, IL

All 35 counties

Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fulton County, IL, Jasper County, IL, Knox County, IL, Lawrence County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Richland County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 42 km from the middle of the area, began a volume at 01:41 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 00:00Z, 1.7 hours before the alert went out and 46 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: 172 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 1166 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 7 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 dense fog advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Lincoln, IL wrote its last area forecast discussion before this dense fog advisory went out at Oct 7, 6:36 PM CDT, 2 hours 5 minutes earlier.

Area forecast discussion, Oct 7, 6:36 PM CDT, 2 hours 5 minutes before

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Hazardous weather outlook, Oct 7, 3:09 PM CDT, 5 hours 32 minutes before

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In the hours before

Local storm report, Oct 7, 3:26 PM CDT, 5 hours 15 minutes before

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Local storm report, Oct 7, 3:33 PM CDT, 5 hours 8 minutes before

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Local storm report, Oct 7, 4:52 PM CDT, 3 hours 49 minutes before

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Local storm report, Oct 7, 5:20 PM CDT, 3 hours 21 minutes before

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Local storm report, Oct 7, 6:22 PM CDT, 2 hours 19 minutes before

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Nearby

Dense Fog Advisories in Illinois, 2021 Every dense fog advisory in 2021

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.