Alert archive / Iowa / Flash Flood Warnings in 2019

Flash Flood Warning 21, NWS Des Moines, IA

August 20, 20194 counties in Iowa

NWS Des Moines, IA issued this flash flood warning at Aug 20, 2019, 5:06 AM CDT for 4 counties in Iowa. It was in force for 5 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 20, 2019, 5:06 AM CDT (10:06 UTC)
Expired
Aug 20, 2019, 10:27 AM CDT
In force
5 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

Counties Hamilton County, IA, Humboldt County, IA, Webster County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 104 km from the middle of the area, began a volume at 10:06 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.

What was reported inside it

TimeReportWhereRemark
Aug 20, 6:35 AM CDTHEAVY RAIN 4.5Eagle Grove, IAVIA SOCIAL MEDIA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 10.1 hours before the alert went out and 243 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2019-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2019-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1590 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

753 
WGUS53 KDMX 201006
FFWDMX
IAC079-091-187-197-201600-
/O.NEW.KDMX.FF.W.0021.190820T1006Z-190820T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Des Moines IA
506 AM CDT Tue Aug 20 2019

The National Weather Service in Des Moines  has issued a

* Flash Flood Warning for...
  Northeastern Webster County in central Iowa...
  Southern Wright County in north central Iowa...
  Eastern Humboldt County in north central Iowa...
  North central Hamilton County in central Iowa...

* Until 1100 AM CDT.

* At 504 AM CDT, Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Up to 
  three inches of rain have already fallen based on home weather 
  stations and radar estimates across the area. Flash flooding is 
  expected to begin shortly.

* Some locations that will experience flooding include...
  Webster City, Clarion, Dakota City, Humboldt, Eagle Grove, Big Wall
  Lake, Goldfield, Dows, Renwick, Blairsburg, Thor, Woolstock, Hardy,
  Galt, Clarion Municipal Airport, Eagle Grove Municipal Airport and
  Sportsman Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 4266 9350 4243 9369 4270 9422 4289 9405

$$

Hagenhoff
2 follow-up statements
726 
WGUS73 KDMX 201306
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
806 AM CDT Tue Aug 20 2019

IAC079-091-187-197-201600-
/O.CON.KDMX.FF.W.0021.000000T0000Z-190820T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Webster IA-Wright IA-Humboldt IA-Hamilton IA-
806 AM CDT Tue Aug 20 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 AM CDT FOR
NORTHEASTERN WEBSTER...SOUTHERN WRIGHT...EASTERN HUMBOLDT AND NORTH
CENTRAL HAMILTON COUNTIES...

At 802 AM CDT, Doppler radar indicated additional showers and 
thunderstorms with locally heavy rain entering the warned area. As 
much as 4 to 5 inches of rain has already fallen, with a total of 
4.5 inches thus far reported in Eagle Grove. Flash flooding is 
likely occurring in some areas, or is expected to begin.

Some locations that will experience flooding include...
Webster City, Clarion, Dakota City, Humboldt, Eagle Grove, Big Wall
Lake, Goldfield, Dows, Renwick, Blairsburg, Thor, Woolstock, Hardy,
Galt, Clarion Municipal Airport, Eagle Grove Municipal Airport and
Sportsman Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 4266 9350 4243 9369 4270 9422 4289 9405

$$

Zogg
801 
WGUS73 KDMX 201527
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
1027 AM CDT Tue Aug 20 2019

IAC079-091-187-197-201535-
/O.CAN.KDMX.FF.W.0021.000000T0000Z-190820T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Webster IA-Wright IA-Humboldt IA-Hamilton IA-
1027 AM CDT Tue Aug 20 2019

...THE FLASH FLOOD WARNING FOR NORTHEASTERN WEBSTER...SOUTHERN
WRIGHT...EASTERN HUMBOLDT AND NORTH CENTRAL HAMILTON COUNTIES IS
CANCELLED...

The heavy rain has ended. No reports of flash flooding have been 
received. Flooding is no longer expected to pose a threat. Please 
continue to heed any remaining road closures.

LAT...LON 4266 9350 4243 9369 4270 9422 4289 9405

$$

Zogg

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 2:35 AM CDTSevere Thunderstorm WarningDMXHumboldt, Kossuth, Wright40 min
Aug 20, 2:38 AM CDTSevere Thunderstorm WarningDMXCalhoun, Carroll, Sac52 min
Aug 20, 2:49 AM CDTSevere Thunderstorm WarningDMXAudubon, Carroll, Crawford41 min
Aug 20, 3:10 AM CDTSevere Thunderstorm WarningDMXEmmet, Kossuth, Palo Alto35 min
Aug 20, 3:44 AM CDTSevere Thunderstorm WarningDMXCarroll, Crawford, Sac46 min
Aug 20, 3:48 AM CDTSevere Thunderstorm WarningDMXHancock, Humboldt, Kossuth, Wright42 min
Aug 20, 4:10 AM CDTSevere Thunderstorm WarningDMXCalhoun, Carroll, Greene50 min
Aug 20, 4:20 AM CDTSevere Thunderstorm WarningDMXFranklin, Hamilton, Hardin40 min
Aug 20, 4:33 AM CDTSevere Thunderstorm WarningDMXFranklin, Hamilton, Hardin, Wright42 min
Aug 20, 4:35 AM CDTSevere Thunderstorm WarningDMXAdair, Boone, Dallas, Greene, Guthrie, Madison40 min
Aug 20, 5:02 AM CDTSevere Thunderstorm WarningDMXFranklin, Grundy, Hamilton, Hardin43 min
Aug 20, 5:29 AM CDTTornado WarningDMXMadison, Warren31 min
Aug 20, 5:32 AM CDTSevere Thunderstorm WarningDMXJasper, Polk, Warren33 min
Aug 20, 5:38 AM CDTSevere Thunderstorm WarningDMXClarke, Madison, Union, Warren28 min
Aug 20, 5:48 AM CDTSevere Thunderstorm WarningDMXJasper, Polk15 min
Aug 20, 5:55 AM CDTSevere Thunderstorm WarningDMXClarke, Jasper, Lucas, Mahaska, Marion, Monroe and 4 more65 min
Aug 20, 5:59 AM CDTTornado WarningDMXLucas, Marion, Warren16 min
Aug 20, 6:34 AM CDTSevere Thunderstorm WarningDMXAppanoose, Davis, Lucas, Mahaska, Monroe, Wapello and 1 more56 min

Nearby

Flash Flood Warnings in Iowa, 2019Every flash flood warning in 2019

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.