Alert archive / Iowa / Flash Flood Watches in 2018
Flash Flood Watch 10, NWS Des Moines, IA
NWS Des Moines, IA issued this flash flood watch at Sep 4, 2018, 3:33 AM CDT for 28 counties in Iowa. It took effect at Sep 4, 2018, 1:00 PM CDT. It was in force for 18 hr.
The area
The counties it named.
The facts
- Issued
- Sep 4, 2018, 3:33 AM CDT (08:33 UTC)
- In effect from
- Sep 4, 2018, 1:00 PM CDT
- Expired
- Sep 5, 2018, 7:00 AM CDT
- In force
- 18 hr
- Issued by
- NWS Des Moines, IA
- Flood severity
- None
All 28 counties
Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Calhoun County, IA, Cerro Gordo County, IA, Dallas County, IA, Emmet County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Jasper County, IA, Kossuth County, IA, Marshall County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Sac 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), 89 km from the middle of the area, began a volume at 08:35 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
Minneapolis, MN (KMPX), launched 00:00Z, 8.6 hours before the alert went out and 258 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.
- Mixed-layer CAPE
- 55 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 600 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 5 m²/s²
- 0-3 km storm-relative helicity
- 7 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 4, 12:05 AM CDT, 3 hours 28 minutes earlier.
Area forecast discussion, Sep 4, 12:05 AM CDT, 3 hours 28 minutes before
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</html>Hazardous weather outlook, Sep 3, 3:32 PM CDT, 12 hours 1 minute before
Hazardous Weather Outlook National Weather Service Des Moines IA 332 PM CDT Mon Sep 3 2018 IAZ004>007-015>017-023>025-033>035-044-045-057-042045- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Sac-Calhoun-Webster-Crawford-Carroll- Audubon- 332 PM CDT Mon Sep 3 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight Periods of thunderstorms with heavy rain will occur through tonight. Severe storms are not expected but heavy rainfall may cause within bank rises of streams and rivers and localized flash flooding. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday While occasional strong thunderstorms may be possible at times, the main concern will be for periods of very heavy rainfall. Portions of central and northern Iowa are the likeliest to see the heaviest rainfall amounts Tuesday evening and overnight with amounts well in excess of 2 inches likely for some. With very heavy rainfall expected, river flooding and flash flood threats will increase significantly during those time periods. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected though severe weather and rainfall reports are appreciated. IAZ026>028-036>039-046>050-058>062-070>075-081>086-092>097-042045- Franklin-Butler-Bremer-Hamilton-Hardin-Grundy-Black Hawk-Greene- Boone-Story-Marshall-Tama-Guthrie-Dallas-Polk-Jasper-Poweshiek- Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas- Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis- 332 PM CDT Mon Sep 3 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight A flash flood watch is in effect for the area, please visit www.weather.gov/desmoines for more details. Periods of thunderstorms with heavy rainfall will occur through tonight. Due to heavy rainfall the past few nights, many local streams and rivers are rising towards or above bankfull and could go into flood. In addition, soils are saturated and runoff from more rain could cause flash flooding. Flash flooding and other flooding headlines, including river floods, may be necessary. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday While occasional strong thunderstorms may be possible at times, the main concern will be for periods of very heavy rainfall. Portions of central and northern Iowa are the likeliest to see the heaviest rainfall amounts Tuesday evening and overnight with amounts well in excess of 2 inches likely for some. With very heavy rainfall expected, river flooding and flash flood threats will increase significantly during those time periods. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected though severe weather and rainfall reports are appreciated. CURTIS
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 3, 7:32 PM CDT | Special Weather Statement | DMX | Black Hawk, Bremer, Grundy | 88 min |
| Sep 3, 7:43 PM CDT | Flash Flood Warning | DMX | Black Hawk | 3 hr |
| Sep 4, 9:34 AM CDT | River Flood Watch | DMX | Cerro Gordo, Floyd, Worth | 13 hr |
| Sep 4, 9:34 AM CDT | River Flood Watch | DMX | Black Hawk, Bremer, Butler | 25 hr |
| Sep 4, 2:21 PM CDT | Severe Thunderstorm Warning | DMX | Palo Alto, Pocahontas | 14 min |
| Sep 4, 3:46 PM CDT | Tornado Warning | DMX | Kossuth | 29 min |
| Sep 4, 4:45 PM CDT | Tornado Warning | DMX | Hancock, Winnebago | 30 min |
| Sep 4, 5:09 PM CDT | Flash Flood Warning | DMX | Hancock, Kossuth, Winnebago | 6 hr |
Nearby
Flash Flood Watches in Iowa, 2018Every flash flood watch 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.