Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 128, NWS Des Moines, IA

December 15, 20218 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Dec 15, 2021, 6:13 PM CST for 8 counties in Iowa. It was in force for 62 min. 3 reports 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, 6:13 PM CST (00:13 UTC)
Expired
Dec 15, 2021, 7:15 PM CST
In force
62 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Appanoose County, IA, Clarke County, IA, Decatur County, IA, Lucas County, IA, Marion County, IA, Monroe County, IA, Warren County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 82 km from the middle of the area, began a volume at 00:18 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, 6:18 PM CSTTSTM WND DMGOsceola, IATREES DOWN ON POWER LINES IN OSCEOLA. TIME ESTIMATED FROM RADAR.
Dec 15, 6:29 PM CSTTSTM WND GST 605 Ene Osceola, IA
Dec 15, 6:48 PM CSTTSTM WND GST 643 W Chariton, IAPEAK WIND AT KCNC.

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

Omaha, NE (KOAX), launched 00:00Z, 0.2 hours before the alert went out and 235 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 2021-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Omaha, NE at 00:00Z on 2021-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -450 square meters per square second.1939587897117136Sfc1 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
4 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
1685 m above ground
0-6 km bulk shear
103 kt
0-1 km storm-relative helicity
-450 m²/s²
0-3 km storm-relative helicity
-705 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

471 
WUUS53 KDMX 160013
SVRDMX
IAC007-039-053-117-125-135-181-185-160115-
/O.NEW.KDMX.SV.W.0128.211216T0013Z-211216T0115Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Western Monroe County in south central Iowa...
  Lucas County in south central Iowa...
  Decatur County in south central Iowa...
  Southwestern Marion County in south central Iowa...
  Wayne County in south central Iowa...
  Western Appanoose County in south central Iowa...
  Clarke County in south central Iowa...
  Southern Warren County in south central Iowa...

* Until 715 PM CST.

* At 613 PM CST, severe thunderstorms were located along a line 
  extending from near New Virginia to 7 miles southeast of Lamoni, 
  moving east at 50 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* These severe thunderstorms will remain over mainly rural areas of
  western Monroe, Lucas, Decatur, southwestern Marion, Wayne, western
  Appanoose, Clarke and southern Warren Counties, including the
  following locations... Melrose, Red Haw Lake State Park,
  Pleasanton, Promise City, Clio, Williamson, Nine Eagles State Park,
  Decatur City, Humeston and Lineville.

This includes Interstate 35 between mile markers 4 and 44.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

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

&&

LAT...LON 4116 9385 4116 9380 4117 9379 4118 9295
      4059 9305 4058 9390
TIME...MOT...LOC 0013Z 269DEG 43KT 4121 9378 4057 9382 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Martin
1 follow-up statement
602 
WWUS53 KDMX 160049
SVSDMX

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

IAC007-039-053-117-125-135-181-185-160115-
/O.CON.KDMX.SV.W.0128.000000T0000Z-211216T0115Z/
Monroe IA-Lucas IA-Decatur IA-Marion IA-Wayne IA-Appanoose IA-
Clarke IA-Warren IA-
649 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CST
FOR WESTERN MONROE...LUCAS...EASTERN DECATUR...SOUTHWESTERN MARION...
WAYNE...WESTERN APPANOOSE...EASTERN CLARKE AND SOUTHEASTERN WARREN
COUNTIES...

At 649 PM CST, severe thunderstorms were located along a line
extending from Melcher-Dallas to 12 miles south of Corydon, moving
east at 50 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Chariton, Corydon, Rathbun Lake, Seymour, Russell, Allerton,
Humeston, Lineville, Lucas, Garden Grove, Woodburn, Williamson,
Derby, Melrose, Promise City, Clio, Plano, Marysville, Pleasanton and
Millerton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4116 9362 4118 9295 4059 9305 4058 9376
TIME...MOT...LOC 0049Z 269DEG 43KT 4122 9324 4058 9328 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Martin

The office that day

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

IssuedProductOfficeCountiesLasted
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, 6:47 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXGrundy, Hardin, Marshall, Story43 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.