Alert archive / Iowa / Frost Advisories in 2021

Frost Advisory 1, NWS Des Moines, IA

April 13, 202118 counties in Iowa

NWS Des Moines, IA issued this frost advisory at Apr 13, 2021, 2:51 PM CDT for 18 counties in Iowa. It took effect at Apr 14, 2021, 1:00 AM CDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 13, 2021, 2:51 PM CDT (19:51 UTC)
In effect from
Apr 14, 2021, 1:00 AM CDT
Expired
Apr 14, 2021, 8:00 AM CDT
In force
7 hr
Issued by
NWS Des Moines, IA

Counties Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 78 km from the middle of the area, began a volume at 19:55 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 12:00Z, 7.9 hours before the alert went out and 231 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 12:00Z on 2021-04-13Temperature 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 12:00Z on 2021-04-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -77 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
1488 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
-77 m²/s²
0-3 km storm-relative helicity
11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

279 
WWUS73 KDMX 131951
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
251 PM CDT Tue Apr 13 2021

IAZ070>075-081>086-092>097-140800-
/O.NEW.KDMX.FR.Y.0001.210414T0600Z-210414T1300Z/
Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-
Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
Including the cities of Atlantic, Greenfield, Stuart, Adair, 
Fontanelle, Winterset, Earlham, Indianola, Norwalk, Carlisle, 
Pella, Knoxville, Oskaloosa, Corning, Creston, Osceola, Chariton,
Albia, Ottumwa, Bedford, Lenox, New Market, Mount Ayr, Lamoni, 
Leon, Corydon, Seymour, Allerton, Humeston, Centerville, 
and Bloomfield
251 PM CDT Tue Apr 13 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 8 AM CDT WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as 31 will result in 
  frost formation.

* WHERE...Portions of southern Iowa.

* WHEN...From 1 AM to 8 AM CDT Wednesday.

* 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
2 follow-up statements
497 
WWUS73 KDMX 140359
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
1059 PM CDT Tue Apr 13 2021

IAZ070>075-081>086-092>097-141200-
/O.CON.KDMX.FR.Y.0001.210414T0600Z-210414T1300Z/
Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-
Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
Including the cities of Atlantic, Greenfield, Stuart, Adair, 
Fontanelle, Winterset, Earlham, Indianola, Norwalk, Carlisle, 
Pella, Knoxville, Oskaloosa, Corning, Creston, Osceola, Chariton,
Albia, Ottumwa, Bedford, Lenox, New Market, Mount Ayr, Lamoni, 
Leon, Corydon, Seymour, Allerton, Humeston, Centerville, 
and Bloomfield
1059 PM CDT Tue Apr 13 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM CDT WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as 31 will result in 
  frost formation.

* WHERE...Portions of southern Iowa.

* WHEN...From 1 AM to 8 AM CDT Wednesday.

* 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

Small
818 
WWUS73 KDMX 140738
NPWDMX

URGENT - WEATHER MESSAGE
National Weather Service Des Moines IA
238 AM CDT Wed Apr 14 2021

IAZ070>075-081>086-092>097-141300-
/O.CON.KDMX.FR.Y.0001.000000T0000Z-210414T1300Z/
Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-
Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
Including the cities of Atlantic, Greenfield, Stuart, Adair, 
Fontanelle, Winterset, Earlham, Indianola, Norwalk, Carlisle, 
Pella, Knoxville, Oskaloosa, Corning, Creston, Osceola, Chariton,
Albia, Ottumwa, Bedford, Lenox, New Market, Mount Ayr, Lamoni, 
Leon, Corydon, Seymour, Allerton, Humeston, Centerville, 
and Bloomfield
238 AM CDT Wed Apr 14 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM CDT THIS MORNING...

* WHAT...Sub-freezing temperatures as low as 31 will result in 
  frost formation.

* WHERE...Portions of southern Iowa.

* WHEN...From 1 AM to 8 AM CDT Wednesday.

* 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

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.