Alert archive / Iowa / Areal Flood Warnings in 2018

Areal Flood Warning 13, NWS Des Moines, IA

September 2, 2018Black Hawk County, Bremer County, Butler County, Iowa

NWS Des Moines, IA issued this areal flood warning at Sep 2, 2018, 7:32 PM CDT for Black Hawk County, Bremer County, Butler County, Iowa. It was in force for 24 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: Sep 2, 2018, 7:32 PM CDT (00:32 UTC)
Expired: Sep 3, 2018, 7:30 PM CDT
In force: 24 hr
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Flood severity: None

Counties Black Hawk County, IA, Bremer County, IA, Butler County, IA

The radar

The Des Moines radar (KDMX), 146 km from the middle of the area, began a volume at 00:35 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 00:00Z, 0.5 hours before the alert went out and 199 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: 1197 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 1295 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 108 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 3.6

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 Des Moines, IA wrote its last area forecast discussion before this areal flood warning went out at Sep 2, 6:41 PM CDT, 51 minutes earlier.

Area forecast discussion, Sep 2, 6:41 PM CDT, 51 minutes before

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Hazardous weather outlook, Sep 2, 1:59 PM CDT, 5 hours 33 minutes before

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In the hours before

Local storm report, Sep 2, 2:32 PM CDT, 5 hours before

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Special weather statement, Sep 2, 5:16 PM CDT, 2 hours 16 minutes before

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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 3, 4:29 PM CDT	Special Weather Statement	DMX	Jasper, Warren	61 min
Sep 3, 5:07 PM CDT	River Flood Warning	DMX	Tama	7 days
Sep 3, 5:07 PM CDT	River Flood Warning	DMX	Black Hawk	6 days
Sep 3, 5:07 PM CDT	River Flood Warning	DMX	Black Hawk	5 days
Sep 3, 6:31 PM CDT	Special Weather Statement	DMX	Poweshiek	44 min
Sep 3, 6:58 PM CDT	Tornado Warning	DMX	Poweshiek	32 min

Nearby

Areal Flood Warnings in Iowa, 2018 Every areal flood warning in 2018

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.