Alert archive / Illinois / Areal Flood Advisories in 2021

Areal Flood Advisory 25, NWS Lincoln, IL

August 9, 2021Logan County, Menard County, Sangamon County, Illinois

NWS Lincoln, IL issued this areal flood advisory at Aug 9, 2021, 7:07 AM CDT for Logan County, Menard County, Sangamon County, Illinois. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Aug 9, 2021, 7:07 AM CDT (12:07 UTC)
Expired: Aug 9, 2021, 9:44 AM CDT
In force: 3 hr
Issued by: NWS Lincoln, IL
Area: Storm-based polygon

Counties Logan County, IL, Menard County, IL, Sangamon County, IL

The radar

The Lincoln radar (KILX), 31 km from the middle of the area, began a volume at 12:09 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 12:00Z, 0.1 hours before the alert went out and 198 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: 1676 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 705 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood 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 areal flood advisory went out at Aug 9, 5:22 AM CDT, 1 hour 45 minutes earlier.

Area forecast discussion, Aug 9, 5:22 AM CDT, 1 hour 45 minutes before

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Hazardous weather outlook, Aug 9, 5:28 AM CDT, 1 hour 39 minutes before

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In the hours before

Local storm report, Aug 9, 3:05 AM CDT, 4 hours 2 minutes before

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Local storm report, Aug 9, 5:07 AM CDT, 2 hours before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 8, 7:20 PM CDT	Areal Flood Advisory	ILX	McLean	115 min
Aug 9, 2:26 AM CDT	Areal Flood Advisory	ILX	Clay	3 hr
Aug 9, 6:28 AM CDT	Areal Flood Advisory	ILX	Christian, Macon, Moultrie, Shelby	3 hr
Aug 9, 10:50 AM CDT	Areal Flood Advisory	ILX	Clay, Crawford, Effingham, Jasper	2 hr
Aug 9, 1:54 PM CDT	Heat Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	29 hr
Aug 9, 3:07 PM CDT	River Flood Warning	ILX	Clay, Richland	6 days

Nearby

Areal Flood Advisories in Illinois, 2021 Every areal flood 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.