Alert archive / Iowa / Flood Watches in 2021

Flood Watch 2, NWS Des Moines, IA

August 26, 202119 counties in Iowa

NWS Des Moines, IA issued this flood watch at Aug 26, 2021, 3:03 PM CDT for 19 counties in Iowa. It took effect at Aug 26, 2021, 10:00 PM CDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Aug 26, 2021, 3:03 PM CDT (20:03 UTC)
In effect from
Aug 26, 2021, 10:00 PM CDT
Expired
Aug 27, 2021, 7:00 AM CDT
In force
9 hr
Issued by
NWS Des Moines, IA
Flood severity
None

Counties Black Hawk County, IA, Bremer County, IA, Butler County, IA, Calhoun 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, Palo Alto County, IA, Pocahontas County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 121 km from the middle of the area, began a volume at 20:06 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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 8.1 hours before the alert went out and 226 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 12:00Z on 2021-08-26Temperature 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 12:00Z on 2021-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 square meters per square second.1939587897Sfc1 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
1566 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
146 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

590 
WGUS63 KDMX 262003
FFADMX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Des Moines IA
303 PM CDT Thu Aug 26 2021

.A boundary lifting into northern Iowa later this evening and 
overnight tonight combined with increasing thunderstorms capable of 
repeated locally heavy rainfall from late evening into the overnight 
hours may lead to some flash flooding.  Though the area is very dry, 
urban locations and small creeks will be susceptible to flooding if 
heavy rainfall occurs. There is some uncertainty as to the exact 
location of the heaviest band of rainfall.

IAZ005>007-015>017-023>028-034>039-270415-
/O.NEW.KDMX.FA.A.0002.210827T0300Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-Pocahontas-
Humboldt-Wright-Franklin-Butler-Bremer-Calhoun-Webster-Hamilton-
Hardin-Grundy-Black Hawk-
Including the cities of Manson, Forest City, Parkersburg, Eagle 
Grove, Grundy Center, Clarksville, Clear Lake, Emmetsburg, Rolfe, 
Aplington, Shell Rock, Gilmore City, Waverly, Rockwell City, Lake 
City, Dike, Lake Mills, Northwood, Algona, Dumont, Reinbeck, 
Pocahontas, Pomeroy, Laurens, Waterloo, Clarion, Webster City, 
Greene, Allison, Cedar Falls, Fort Dodge, Ackley, Eldora, Conrad, 
Wellsburg, Humboldt, Iowa Falls, Hampton, Mason City, Fonda, Garner, 
Britt, Manly, Kanawha, and Belmond
303 PM CDT Thu Aug 26 2021

...FLOOD WATCH IN EFFECT FROM 10 PM CDT THIS EVENING THROUGH 7 AM 
FRIDAY MORNING...

The National Weather Service in Des Moines has issued a

* Flood Watch for portions of central Iowa, north central Iowa, 
  northeast Iowa, northwest Iowa and west central Iowa, including 
  the following areas, in central Iowa, Grundy, Hamilton, Hardin and 
  Webster. In north central Iowa, Butler, Cerro Gordo, Franklin, 
  Hancock, Humboldt, Kossuth, Winnebago, Worth and Wright. In 
  northeast Iowa, Black Hawk and Bremer. In northwest Iowa, Palo 
  Alto and Pocahontas. In west central Iowa, Calhoun.

* From 10 PM CDT this evening through Friday morning.

* Though the area remains dry, locally heavy rainfall of 3 to 5 
  inches with locally higher amounts greater than 6 inches may lead 
  to isolated flash flooding mainly in urban areas, low water 
  crossings or small streams.

* Rainfall rates of 1 to 2 inches per hour may lead to urban 
  flooding and ponding or running water in city streets causing some 
  travel issues.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

REV
4 follow-up statements
646 
WGUS63 KDMX 270126
FFADMX

Flood Watch
National Weather Service Des Moines IA
826 PM CDT Thu Aug 26 2021

IAZ005>007-015>017-023>028-034>039-270930-
/O.CON.KDMX.FA.A.0002.210827T0300Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-Pocahontas-
Humboldt-Wright-Franklin-Butler-Bremer-Calhoun-Webster-Hamilton-
Hardin-Grundy-Black Hawk-
Including the cities of Manson, Forest City, Parkersburg, Eagle 
Grove, Grundy Center, Clarksville, Clear Lake, Emmetsburg, Rolfe, 
Aplington, Shell Rock, Gilmore City, Waverly, Rockwell City, Lake 
City, Dike, Lake Mills, Northwood, Algona, Dumont, Reinbeck, 
Pocahontas, Pomeroy, Laurens, Waterloo, Clarion, Webster City, 
Greene, Allison, Cedar Falls, Fort Dodge, Ackley, Eldora, Conrad, 
Wellsburg, Humboldt, Iowa Falls, Hampton, Mason City, Fonda, Garner, 
Britt, Manly, Kanawha, and Belmond
826 PM CDT Thu Aug 26 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL 7 AM CDT FRIDAY...

The Flood Watch continues for

* Portions of central Iowa, north central Iowa, northeast Iowa, 
  northwest Iowa and west central Iowa, including the following 
  areas, in central Iowa, Grundy, Hamilton, Hardin and Webster. In 
  north central Iowa, Butler, Cerro Gordo, Franklin, Hancock, 
  Humboldt, Kossuth, Winnebago, Worth and Wright. In northeast Iowa, 
  Black Hawk and Bremer. In northwest Iowa, Palo Alto and 
  Pocahontas. In west central Iowa, Calhoun.

* Until 7 AM CDT Friday.

* Though the area remains dry, locally heavy rainfall of 3 to 5 
  inches with locally higher amounts greater than 6 inches may lead 
  to isolated flash flooding mainly in urban areas, low water 
  crossings or small streams.

* Rainfall rates of 1 to 2 inches per hour may lead to urban 
  flooding and ponding or running water in city streets causing some 
  travel issues.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

AB/KP
029 
WGUS63 KDMX 270433
FFADMX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Des Moines IA
1133 PM CDT Thu Aug 26 2021

IAZ004-271200-
/O.EXA.KDMX.FA.A.0002.000000T0000Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emmet-
Including the cities of Estherville
1133 PM CDT Thu Aug 26 2021

...FLOOD WATCH IN EFFECT UNTIL 7 AM CDT FRIDAY...

The National Weather Service in Des Moines has expanded the

* Flood Watch to include a portion of northwest Iowa, including the 
  following area, Emmet.

* Until 7 AM CDT Friday.

* Though the area remains dry, locally heavy rainfall of 3 to 5 
  inches with locally higher amounts greater than 6 inches may lead 
  to isolated flash flooding mainly in urban areas, low water 
  crossings or small streams.

* Rainfall rates of 1 to 2 inches per hour may lead to urban 
  flooding and ponding or running water in city streets causing some 
  travel issues.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

IAZ005>007-015>017-023>028-034>039-271200-
/O.CON.KDMX.FA.A.0002.000000T0000Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-Pocahontas-
Humboldt-Wright-Franklin-Butler-Bremer-Calhoun-Webster-Hamilton-
Hardin-Grundy-Black Hawk-
Including the cities of Manson, Forest City, Parkersburg, Eagle 
Grove, Grundy Center, Clarksville, Clear Lake, Emmetsburg, Rolfe, 
Aplington, Shell Rock, Gilmore City, Waverly, Rockwell City, Lake 
City, Dike, Lake Mills, Northwood, Algona, Dumont, Reinbeck, 
Pocahontas, Pomeroy, Laurens, Waterloo, Clarion, Webster City, 
Greene, Allison, Cedar Falls, Fort Dodge, Ackley, Eldora, Conrad, 
Wellsburg, Humboldt, Iowa Falls, Hampton, Mason City, Fonda, Garner, 
Britt, Manly, Kanawha, and Belmond
1133 PM CDT Thu Aug 26 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL 7 AM CDT FRIDAY...

The Flood Watch continues for

* Portions of central Iowa, north central Iowa, northeast Iowa, 
  northwest Iowa and west central Iowa, including the following 
  areas, in central Iowa, Grundy, Hamilton, Hardin and Webster. In 
  north central Iowa, Butler, Cerro Gordo, Franklin, Hancock, 
  Humboldt, Kossuth, Winnebago, Worth and Wright. In northeast Iowa, 
  Black Hawk and Bremer. In northwest Iowa, Palo Alto and 
  Pocahontas. In west central Iowa, Calhoun.

* Until 7 AM CDT Friday.

* Though the area remains dry, locally heavy rainfall of 3 to 5 
  inches with locally higher amounts greater than 6 inches may lead 
  to isolated flash flooding mainly in urban areas, low water 
  crossings or small streams.

* Rainfall rates of 1 to 2 inches per hour may lead to urban 
  flooding and ponding or running water in city streets causing some 
  travel issues.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

Podrazik
300 
WGUS63 KDMX 270813
FFADMX

Flood Watch
National Weather Service Des Moines IA
313 AM CDT Fri Aug 27 2021

IAZ004>007-015>017-023>028-034>039-271200-
/O.CON.KDMX.FA.A.0002.000000T0000Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Calhoun-Webster-
Hamilton-Hardin-Grundy-Black Hawk-
Including the cities of Manson, Forest City, Parkersburg, Eagle 
Grove, Grundy Center, Clarksville, Clear Lake, Emmetsburg, Rolfe, 
Aplington, Shell Rock, Gilmore City, Waverly, Rockwell City, Lake 
City, Dike, Lake Mills, Northwood, Algona, Estherville, Dumont, 
Reinbeck, Pocahontas, Pomeroy, Laurens, Waterloo, Clarion, Webster 
City, Greene, Allison, Cedar Falls, Fort Dodge, Ackley, Eldora, 
Conrad, Wellsburg, Humboldt, Iowa Falls, Hampton, Mason City, Fonda, 
Garner, Britt, Manly, Kanawha, and Belmond
313 AM CDT Fri Aug 27 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL 7 AM CDT THIS MORNING...

The Flood Watch continues for

* Portions of central Iowa, north central Iowa, northeast Iowa, 
  northwest Iowa and west central Iowa, including the following 
  areas, in central Iowa, Grundy, Hamilton, Hardin and Webster. In 
  north central Iowa, Butler, Cerro Gordo, Franklin, Hancock, 
  Humboldt, Kossuth, Winnebago, Worth and Wright. In northeast Iowa, 
  Black Hawk and Bremer. In northwest Iowa, Emmet, Palo Alto and 
  Pocahontas. In west central Iowa, Calhoun.

* Until 7 AM CDT this morning.

* Storms with heavy rainfall will continue over portions over 
  northern Iowa into the early morning hours, which will support a 
  threat of flash flooding in the area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

Martin
633 
WGUS63 KDMX 271154
FFADMX

Flood Watch
National Weather Service Des Moines IA
654 AM CDT Fri Aug 27 2021

IAZ004>007-015>017-023>028-034>039-271300-
/O.EXP.KDMX.FA.A.0002.000000T0000Z-210827T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Calhoun-Webster-
Hamilton-Hardin-Grundy-Black Hawk-
Including the cities of Manson, Forest City, Parkersburg, Eagle 
Grove, Grundy Center, Clarksville, Clear Lake, Emmetsburg, Rolfe, 
Aplington, Shell Rock, Gilmore City, Waverly, Rockwell City, Lake 
City, Dike, Lake Mills, Northwood, Algona, Estherville, Dumont, 
Reinbeck, Pocahontas, Pomeroy, Laurens, Waterloo, Clarion, Webster 
City, Greene, Allison, Cedar Falls, Fort Dodge, Ackley, Eldora, 
Conrad, Wellsburg, Humboldt, Iowa Falls, Hampton, Mason City, Fonda, 
Garner, Britt, Manly, Kanawha, and Belmond
654 AM CDT Fri Aug 27 2021

...FLOOD WATCH WILL EXPIRE AT 7 AM CDT THIS MORNING...

The Flood Watch for portions of central Iowa, north central Iowa, 
northeast Iowa, northwest Iowa and west central Iowa, including the 
following areas, in central Iowa, Grundy, Hamilton, Hardin and 
Webster. In north central Iowa, Butler, Cerro Gordo, Franklin, 
Hancock, Humboldt, Kossuth, Winnebago, Worth and Wright. In 
northeast Iowa, Black Hawk and Bremer. In northwest Iowa, Emmet, 
Palo Alto and Pocahontas. In west central Iowa, Calhoun will expire 
at 7 AM CDT this morning.

Scattered showers and storms will continue over northern Iowa during 
the morning hours, but the threat of excessive rainfall and flash 
flooding has diminished at this time.

$$

Martin

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 3:30 AM CDTHeat AdvisoryDMXAdair, Adams, Appanoose, Audubon, Cass, Clarke and 16 more17 hr
Aug 26, 8:03 AM CDTSpecial Weather StatementDMXAudubon, Calhoun, Carroll, Pocahontas, Sac42 min
Aug 26, 8:18 AM CDTSevere Thunderstorm WarningDMXCalhoun, Carroll, Crawford, Greene, Sac42 min
Aug 26, 8:55 AM CDTSpecial Weather StatementDMXAdair, Audubon, Dallas, Guthrie65 min
Aug 26, 9:18 AM CDTSpecial Weather StatementDMXBoone, Hamilton, Webster57 min
Aug 26, 10:02 AM CDTSpecial Weather StatementDMXDallas, Jasper, Madison, Polk, Warren43 min
Aug 26, 12:29 PM CDTSpecial Weather StatementDMXBoone, Story46 min
Aug 26, 1:46 PM CDTSpecial Weather StatementDMXDavis, Wapello44 min
Aug 26, 2:16 PM CDTSevere Thunderstorm WarningDMXAppanoose, Davis, Wapello44 min

Nearby

Flood Watches in Iowa, 2021Every flood watch in 2021

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.