Alert archive / Illinois / Areal Flood Warnings in 2021

Areal Flood Warning 1, NWS Quad Cities, IA

April 11, 2021Des Moines County, Louisa County, Iowa; 5 counties in Illinois

NWS Quad Cities, IA issued this areal flood warning at Apr 11, 2021, 11:34 AM CDT for Des Moines County, Louisa County, Iowa; 5 counties in Illinois. It was in force for 6 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: Apr 11, 2021, 11:34 AM CDT (16:34 UTC)
Expired: Apr 11, 2021, 5:15 PM CDT
In force: 6 hr
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Flood severity: None

Counties Des Moines County, IA, Louisa County, IA, Henderson County, IL, Henry County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL

The radar

The Quad Cities radar (KDVN), 57 km from the middle of the area, began a volume at 16:35 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, 4.6 hours before the alert went out and 60 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 540 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 116 m²/s²
0-3 km storm-relative helicity: 161 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 areal flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Quad Cities, IA wrote its last area forecast discussion before this areal flood warning went out at Apr 11, 6:40 AM CDT, 4 hours 54 minutes earlier.

Area forecast discussion, Apr 11, 6:40 AM CDT, 4 hours 54 minutes before

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Hazardous weather outlook, Apr 11, 3:32 AM CDT, 8 hours 2 minutes before

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In the hours before

Local storm report, Apr 11, 9:47 AM CDT, 1 hour 47 minutes before

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Local storm report, Apr 11, 9:52 AM CDT, 1 hour 42 minutes before

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Local storm report, Apr 11, 10:03 AM CDT, 1 hour 31 minutes before

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Local storm report, Apr 11, 10:30 AM CDT, 1 hour 4 minutes before

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Local storm report, Apr 11, 10:53 AM CDT, 41 minutes before

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Local storm report, Apr 11, 11:13 AM CDT, 21 minutes before

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      <p id="message2">
        Please try again in a few minutes.
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 10, 8:12 PM CDT	River Flood Warning	DVN	Clinton, Scott	67 hr
Apr 11, 8:26 AM CDT	River Flood Warning	DVN	Des Moines, Henry, Lee	31 hr
Apr 10, 7:58 PM CDT	River Flood Warning	DVN	Henry	33 hr
Apr 10, 8:21 PM CDT	River Flood Warning	DVN	Henry, Rock Island	38 hr

Nearby

Areal Flood Warnings in Illinois, 2021 Areal Flood Warnings in Iowa, 2021 Every areal flood warning 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.