Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 131, NWS Des Moines, IA

December 15, 20214 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Dec 15, 2021, 6:47 PM CST for 4 counties in Iowa. It was in force for 43 min. 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
Dec 15, 2021, 6:47 PM CST (00:47 UTC)
Expired
Dec 15, 2021, 7:30 PM CST
In force
43 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Damage threat
Considerable
Hail
0.75 in
Wind
70.0 mph

Counties Grundy County, IA, Hardin County, IA, Marshall County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 69 km from the middle of the area, began a volume at 00:47 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
Dec 15, 7:15 PM CSTTSTM WND DMG2 N Gilman, IASNAPPED POWER POLES. TIME ESTIMATED VIA RADAR.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Dec 15, 1:23 PM CSTTornado WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 0.8 hours before the alert went out and 223 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, Davenport, at 00:00Z on 2021-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 229 joules per kilogram.LCLLFCEL10008507005003002001001 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, Davenport, at 00:00Z on 2021-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 433 square meters per square second.1939587897117Sfc1 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
229 J/kg
Mixed-layer CIN
-358 J/kg
Mixed-layer LCL
1061 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
433 m²/s²
0-3 km storm-relative helicity
496 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

428 
WUUS53 KDMX 160047
SVRDMX
IAC075-083-127-169-160130-
/O.NEW.KDMX.SV.W.0131.211216T0047Z-211216T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
647 PM CST Wed Dec 15 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Eastern Story County in central Iowa...
  Marshall County in central Iowa...
  Eastern Hardin County in central Iowa...
  Southwestern Grundy County in central Iowa...

* Until 730 PM CST.

* At 646 PM CST, severe thunderstorms were located along a line
  extending from near Aplington to 8 miles southeast of State Center,
  moving east at 55 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Severe thunderstorms will be near...
  Marshalltown around 700 PM CST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted, act quickly and move to a
place of safety inside a sturdy structure such as a basement or small
interior room.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across portions of central Iowa. SEEK SHELTER NOW inside 
a sturdy structure and stay away from windows! A Tornado Watch 
remains in effect until 800 PM CST for central and north central 
Iowa.

&&

LAT...LON 4186 9334 4244 9322 4256 9315 4256 9313
      4187 9276 4186 9277
TIME...MOT...LOC 0046Z 252DEG 48KT 4259 9296 4193 9305 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Cogil
1 follow-up statement
184 
WWUS53 KDMX 160130
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
730 PM CST Wed Dec 15 2021

IAC075-083-127-169-160139-
/O.EXP.KDMX.SV.W.0131.000000T0000Z-211216T0130Z/
Story IA-Marshall IA-Hardin IA-Grundy IA-
730 PM CST Wed Dec 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN STORY...MARSHALL...
EASTERN HARDIN AND SOUTHWESTERN GRUNDY COUNTIES WILL EXPIRE AT 730 PM
CST...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 800 PM CST for central and
north central Iowa.

LAT...LON 4186 9334 4244 9322 4256 9315 4256 9313
      4187 9276 4186 9277
TIME...MOT...LOC 0129Z 252DEG 48KT 4276 9224 4210 9233 

$$

Cogil

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 15, 6:13 PM CSTSevere Thunderstorm WarningDMXAppanoose, Clarke, Decatur, Lucas, Marion, Monroe and 2 more62 min
Dec 15, 6:19 PM CSTTornado WarningDMXHancock, Kossuth, Winnebago41 min
Dec 15, 6:24 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXClarke, Dallas, Jasper, Lucas, Madison, Mahaska and 5 more66 min
Dec 15, 6:30 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXBlack Hawk, Bremer, Butler, Cerro Gordo, Franklin, Grundy and 6 more75 min
Dec 15, 6:37 PM CSTTornado WarningDMXButler, Cerro Gordo, Franklin20 min
Dec 15, 7:09 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXAppanoose, Davis, Jasper, Lucas, Mahaska, Marion and 5 more66 min
Dec 15, 7:44 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXBlack Hawk, Bremer, Butler, Grundy, Tama27 min
Dec 15, 11:52 PM CSTWind AdvisoryDMXAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more6 hr

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.