Alert archive / Iowa / Flash Flood Watches in 2007

Flash Flood Watch 10, NWS Des Moines, IA

August 18, 200722 counties in Iowa

NWS Des Moines, IA issued this flash flood watch at Aug 18, 2007, 3:39 AM CDT for 22 counties in Iowa. It took effect at Aug 18, 2007, 4:00 AM CDT. It was in force for 48 hr.

The area

The counties it named.

The facts

Issued: Aug 18, 2007, 3:39 AM CDT (08:39 UTC)
In effect from: Aug 18, 2007, 4:00 AM CDT
Expired: Aug 20, 2007, 4:00 AM CDT
In force: 48 hr
Issued by: NWS Des Moines, IA
Flood severity: None

All 22 counties

Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Cerro Gordo County, IA, Emmet County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Kossuth County, IA, Marshall County, IA, Palo Alto County, IA, Pocahontas County, IA, Story County, IA, Tama County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 108 km from the middle of the area, began a volume at 08:42 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

Minneapolis, MN (KMPX), launched 00:00Z, 8.7 hours before the alert went out and 240 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: 2194 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 53 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 watch 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 flash flood watch went out at Aug 18, 3:15 AM CDT, 24 minutes earlier.

Area forecast discussion, Aug 18, 3:15 AM CDT, 24 minutes before

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Hazardous weather outlook, Aug 17, 11:08 PM CDT, 4 hours 31 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
Aug 18, 8:20 AM CDT	Flash Flood Warning	DMX	Palo Alto	6 hr

Nearby

Flash Flood Watches in Iowa, 2007 Every flash flood watch in 2007

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.