Alert archive / Iowa / Frost Advisories in 2021

Frost Advisory 7, NWS Des Moines, IA

October 21, 202113 counties in Iowa

NWS Des Moines, IA issued this frost advisory at Oct 21, 2021, 2:49 AM CDT for 13 counties in Iowa. It took effect at Oct 22, 2021, 1:00 AM CDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Oct 21, 2021, 2:49 AM CDT (07:49 UTC)
In effect from
Oct 22, 2021, 1:00 AM CDT
Expired
Oct 22, 2021, 9:00 AM CDT
In force
8 hr
Issued by
NWS Des Moines, IA

Counties Adams County, IA, Dallas County, IA, Jasper County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Warren County, IA

The radar

The Des Moines radar (KDMX), 42 km from the middle of the area, began a volume at 07:52 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

Omaha, NE (KOAX), launched 00:00Z, 7.8 hours before the alert went out and 230 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, Omaha, NE at 00:00Z on 2021-10-21Temperature 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, Omaha, NE at 00:00Z on 2021-10-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 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
823 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

946 
WWUS73 KDMX 210749
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
249 AM CDT Thu Oct 21 2021

IAZ004>007-015>017-023>028-033>039-044>049-057-058-070-071-211600-
/O.NEW.KDMX.FZ.W.0005.211022T0600Z-211022T1400Z/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Audubon-Guthrie-Cass-Adair-
Including the cities of Estherville, Algona, Forest City, 
Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha,
Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, 
Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, 
Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison,
Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, 
Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, 
Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, 
Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, 
Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, 
Marshalltown, Audubon, Exira, Guthrie Center, Panora, Bayard, 
Casey, Atlantic, Greenfield, Stuart, Adair, and Fontanelle
249 AM CDT Thu Oct 21 2021

...FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM CDT FRIDAY...

* WHAT...Sub-freezing temperatures as low as 30 expected.

* WHERE...Northern and Central Iowa.

* WHEN...From 1 AM to 9 AM CDT Friday.

* IMPACTS...Frost and freeze conditions will kill crops, other
  sensitive vegetation and possibly damage unprotected outdoor
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

IAZ050-059>062-072>075-081-082-092-093-211600-
/O.NEW.KDMX.FR.Y.0007.211022T0600Z-211022T1400Z/
Tama-Dallas-Polk-Jasper-Poweshiek-Madison-Warren-Marion-Mahaska-
Adams-Union-Taylor-Ringgold-
Including the cities of Tama, Toledo, Traer, Dysart, Gladbrook, 
Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Winterset, 
Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, 
Oskaloosa, Corning, Creston, Bedford, Lenox, New Market, 
and Mount Ayr
249 AM CDT Thu Oct 21 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM CDT FRIDAY...

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

* WHERE...Central and Southwestern Iowa.

* WHEN...From 1 AM to 9 AM CDT Friday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if left
  uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/desmoines

Hagenhoff
4 follow-up statements
248 
WWUS73 KDMX 212203
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
503 PM CDT Thu Oct 21 2021

IAZ004>007-015>017-023>028-033>039-044>049-057-058-070-071-220615-
/O.CON.KDMX.FZ.W.0005.211022T0600Z-211022T1400Z/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Audubon-Guthrie-Cass-Adair-
Including the cities of Estherville, Algona, Forest City, 
Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha,
Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, 
Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, 
Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison,
Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, 
Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, 
Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, 
Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, 
Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, 
Marshalltown, Audubon, Exira, Guthrie Center, Panora, Bayard, 
Casey, Atlantic, Greenfield, Stuart, Adair, and Fontanelle
503 PM CDT Thu Oct 21 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 1 AM TO 9 AM CDT
FRIDAY...

* WHAT...Sub-freezing temperatures as low as 29 expected.

* WHERE...Parts of Northern and Central Iowa.

* WHEN...From 1 AM to 9 AM CDT Friday.

* IMPACTS...Frost and freeze conditions will kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

IAZ050-059>062-072>075-081-082-092-093-220615-
/O.CON.KDMX.FR.Y.0007.211022T0600Z-211022T1400Z/
Tama-Dallas-Polk-Jasper-Poweshiek-Madison-Warren-Marion-Mahaska-
Adams-Union-Taylor-Ringgold-
Including the cities of Tama, Toledo, Traer, Dysart, Gladbrook, 
Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Winterset, 
Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, 
Oskaloosa, Corning, Creston, Bedford, Lenox, New Market, 
and Mount Ayr
503 PM CDT Thu Oct 21 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM CDT
FRIDAY...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Parts of Central and Southwestern Iowa.

* WHEN...From 1 AM to 9 AM CDT Friday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/desmoines

AB/RD
385 
WWUS73 KDMX 220349
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
1049 PM CDT Thu Oct 21 2021

IAZ004>007-015>017-023>028-033>039-044>049-057-058-070-071-221200-
/O.CON.KDMX.FZ.W.0005.211022T0600Z-211022T1400Z/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Audubon-Guthrie-Cass-Adair-
Including the cities of Estherville, Algona, Forest City, 
Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha,
Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, 
Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, 
Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison,
Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, 
Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, 
Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, 
Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, 
Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, 
Marshalltown, Audubon, Exira, Guthrie Center, Panora, Bayard, 
Casey, Atlantic, Greenfield, Stuart, Adair, and Fontanelle
1049 PM CDT Thu Oct 21 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM CDT FRIDAY...

* WHAT...Sub-freezing temperatures as low as 29 expected.

* WHERE...Portions of Northern and Central Iowa.

* WHEN...Until 9 AM CDT Friday.

* IMPACTS...Frost and freeze conditions will kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

IAZ050-059>062-072>075-081-082-092-093-221200-
/O.CON.KDMX.FR.Y.0007.211022T0600Z-211022T1400Z/
Tama-Dallas-Polk-Jasper-Poweshiek-Madison-Warren-Marion-Mahaska-
Adams-Union-Taylor-Ringgold-
Including the cities of Tama, Toledo, Traer, Dysart, Gladbrook, 
Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Winterset, 
Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, 
Oskaloosa, Corning, Creston, Bedford, Lenox, New Market, 
and Mount Ayr
1049 PM CDT Thu Oct 21 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM CDT FRIDAY...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Portions of Central and Southwestern Iowa.

* WHEN...Until 9 AM CDT Friday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/desmoines

AB/RD
999 
WWUS73 KDMX 220836
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
336 AM CDT Fri Oct 22 2021

IAZ004>007-015>017-023>028-033>039-044>049-057-058-070-071-221400-
/O.CON.KDMX.FZ.W.0005.000000T0000Z-211022T1400Z/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Audubon-Guthrie-Cass-Adair-
Including the cities of Estherville, Algona, Forest City, 
Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha,
Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, 
Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, 
Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison,
Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, 
Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, 
Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, 
Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, 
Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, 
Marshalltown, Audubon, Exira, Guthrie Center, Panora, Bayard, 
Casey, Atlantic, Greenfield, Stuart, Adair, and Fontanelle
336 AM CDT Fri Oct 22 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM CDT THIS MORNING...

* WHAT...Sub-freezing temperatures as low as 29 expected.

* WHERE...Portions of Northern and Central Iowa.

* WHEN...Until 9 AM CDT today.

* IMPACTS...Frost and freeze conditions will kill crops, other
  sensitive vegetation and possibly damage unprotected outdoor
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

IAZ050-059>062-072>075-081-082-092-093-221400-
/O.CON.KDMX.FR.Y.0007.000000T0000Z-211022T1400Z/
Tama-Dallas-Polk-Jasper-Poweshiek-Madison-Warren-Marion-Mahaska-
Adams-Union-Taylor-Ringgold-
Including the cities of Tama, Toledo, Traer, Dysart, Gladbrook, 
Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Winterset, 
Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, 
Oskaloosa, Corning, Creston, Bedford, Lenox, New Market, 
and Mount Ayr
336 AM CDT Fri Oct 22 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM CDT THIS MORNING...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Portions of Central and Southwestern Iowa.

* WHEN...Until 9 AM CDT today.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/desmoines

Hagenhoff
296 
WWUS73 KDMX 221359
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
859 AM CDT Fri Oct 22 2021

IAZ004>007-015>017-023>028-033>039-044>049-057-058-070-071-221500-
/O.EXP.KDMX.FZ.W.0005.000000T0000Z-211022T1400Z/
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Audubon-Guthrie-Cass-Adair-
Including the cities of Estherville, Algona, Forest City, 
Lake Mills, Northwood, Manly, Emmetsburg, Garner, Britt, Kanawha,
Mason City, Clear Lake, Pocahontas, Laurens, Rolfe, Fonda, 
Gilmore City, Humboldt, Eagle Grove, Clarion, Belmond, Hampton, 
Parkersburg, Clarksville, Shell Rock, Greene, Aplington, Allison,
Dumont, Waverly, Sac City, Lake View, Odebolt, Wall Lake, 
Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, 
Fort Dodge, Webster City, Iowa Falls, Eldora, Ackley, 
Grundy Center, Reinbeck, Conrad, Dike, Wellsburg, Waterloo, 
Cedar Falls, Denison, Carroll, Jefferson, Boone, Ames, 
Marshalltown, Audubon, Exira, Guthrie Center, Panora, Bayard, 
Casey, Atlantic, Greenfield, Stuart, Adair, and Fontanelle
859 AM CDT Fri Oct 22 2021

...FREEZE WARNING WILL EXPIRE AT 9 AM CDT THIS MORNING...

Temperatures are warming to above freezing this morning.

$$

IAZ050-059>062-072>075-081-082-092-093-221500-
/O.EXP.KDMX.FR.Y.0007.000000T0000Z-211022T1400Z/
Tama-Dallas-Polk-Jasper-Poweshiek-Madison-Warren-Marion-Mahaska-
Adams-Union-Taylor-Ringgold-
Including the cities of Tama, Toledo, Traer, Dysart, Gladbrook, 
Perry, Waukee, Adel, Des Moines, Newton, Grinnell, Winterset, 
Earlham, Indianola, Norwalk, Carlisle, Pella, Knoxville, 
Oskaloosa, Corning, Creston, Bedford, Lenox, New Market, 
and Mount Ayr
859 AM CDT Fri Oct 22 2021

...FROST ADVISORY WILL EXPIRE AT 9 AM CDT THIS MORNING...

With the sun rising and temperatures warming into the middle and
upper 30s, the threat of frost no longer exist. 

$$

For more information from the National Weather Service visit
https://weather.gov/desmoines

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 21, 2:49 AM CDTFreeze WarningDMXAdair, Audubon, Black Hawk, Boone, Bremer, Butler and 24 more30 hr

Nearby

Frost Advisories in Iowa, 2021Every frost advisory 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.