Alert archive / Iowa / Flash Flood Watches in 2008

Flash Flood Watch 4, NWS Des Moines, IA

May 10, 200838 counties in Iowa

NWS Des Moines, IA issued this flash flood watch at May 10, 2008, 3:47 PM CDT for 38 counties in Iowa. It took effect at May 10, 2008, 7:00 PM CDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued: May 10, 2008, 3:47 PM CDT (20:47 UTC)
In effect from: May 10, 2008, 7:00 PM CDT
Expired: May 11, 2008, 3:57 AM CDT
In force: 9 hr
Issued by: NWS Des Moines, IA
Flood severity: None

All 38 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Webster County, IA

The radar

The Des Moines radar (KDMX), 17 km from the middle of the area, began a volume at 20:49 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, 8.8 hours before the alert went out and 268 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: 1641 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 28 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 May 10, 12:45 PM CDT, 3 hours 2 minutes earlier.

Area forecast discussion, May 10, 12:45 PM CDT, 3 hours 2 minutes before

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Hazardous weather outlook, May 10, 5:51 AM CDT, 9 hours 56 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
May 10, 4:08 AM CDT	Flood Watch	DMX	Adair, Audubon, Black Hawk, Boone, Calhoun, Carroll and 20 more	12 hr
May 10, 4:22 AM CDT	Wind Advisory	DMX	Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 32 more	32 hr

Nearby

Flash Flood Watches in Iowa, 2008 Every flash flood watch in 2008

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.