Alert archive / Iowa / Flash Flood Watches in 2008

Flash Flood Watch 19, NWS Des Moines, IA

September 12, 200822 counties in Iowa

NWS Des Moines, IA issued this flash flood watch at Sep 12, 2008, 3:48 AM CDT for 22 counties in Iowa. It took effect at Sep 12, 2008, 1:00 PM CDT. It was in force for 23 hr.

The area

The counties it named.

The facts

Issued: Sep 12, 2008, 3:48 AM CDT (08:48 UTC)
In effect from: Sep 12, 2008, 1:00 PM CDT
Expired: Sep 13, 2008, 11:34 AM CDT
In force: 23 hr
Issued by: NWS Des Moines, IA
Flood severity: None

All 22 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Clarke County, IA, Davis County, IA, Decatur 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, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 64 km from the middle of the area, began a volume at 08:49 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

Topeka, KS (KTOP), launched 00:00Z, 8.8 hours before the alert went out and 309 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: 229 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 524 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 87 m²/s²
0-3 km storm-relative helicity: 64 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 Sep 12, 12:10 AM CDT, 3 hours 38 minutes earlier.

Area forecast discussion, Sep 12, 12:10 AM CDT, 3 hours 38 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 12, 2:14 PM CDT	River Flood Warning	DMX	Appanoose, Wayne	30 hr
Sep 12, 6:56 PM CDT	Areal Flood Advisory	DMX	Adams, Appanoose, Clarke, Decatur, Lucas, Mahaska and 7 more	5 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.