Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 121, NWS Des Moines, IA

December 15, 20218 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Dec 15, 2021, 4:13 PM CST for 8 counties in Iowa. It was in force for 77 min. 8 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, 4:13 PM CST (22:13 UTC)
Expired
Dec 15, 2021, 5:30 PM CST
In force
77 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Tornado
Possible
Damage threat
Destructive
Hail
0.75 in
Wind
80.0 mph

Counties Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Guthrie County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA

The radar

The Des Moines radar (KDMX), 113 km from the middle of the area, began a volume at 22:16 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, 5:01 PM CSTTORNADO3 Ssw Brayton, IASTORM CHASER REPORTED FLIPPED SEMIS ON I-80 AND POWER FLASHES ASSOCIATED WITH A TORNADO.
Dec 15, 5:02 PM CSTTORNADO1 Nw Atlantic, IASTORM CHASER REPORTED TORNADO ON THE WEST SIDE OF ATLANTIC.
Dec 15, 5:04 PM CSTTORNADOExira, IACORRECTS PREVIOUS TORNADO REPORT FROM EXIRA. DAMAGE TO MULTIPLE TO BARN BUILDINGS NEAR EXIRA. DELAYED REPORT VIA SOCIAL MEDIA PHOTOS. TIME ESTIMATED VIA RADAR.
Dec 15, 5:07 PM CSTTORNADO4 Se Audubon, IADELAYED REPORT. PICTURES CAME IN VIA EMAIL EAST OF HAMLIN, IA. TIME ESTIMATED BASED ON RADAR AND OTHER REPORTS IN AUDUBON COUNTY.
Dec 15, 5:11 PM CSTTSTM WND GST 88Audubon, IAPWS RECORDED WIND GUST OF 88 MPH.
Dec 15, 5:12 PM CSTTSTM WND GST 76Adair, IAPWS RECORDED A 76 MPH WIND GUST.
Dec 15, 5:15 PM CSTTSTM WND GST 802 S Adair, IAEM REPORTS 80+ MPH WINDS, ZERO VISIBILITY SOUTH OF ADAIR.
Dec 15, 5:17 PM CSTTSTM WND GST 658 W Guthrie Center, IAEM REPORTS 1/2 INCH HAIL AND ESTIMATED 65 MPH WIND, HWY 44 AND FRONTIER ROAD IN GUTHRIE CO.

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 12:00Z, 10.2 hours before the alert went out and 121 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 2021-12-15Temperature 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 2021-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 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
2165 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
384 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

363 
WUUS53 KDMX 152213
SVRDMX
IAC001-003-009-029-077-159-173-175-152330-
/O.NEW.KDMX.SV.W.0121.211215T2213Z-211215T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
413 PM CST Wed Dec 15 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Cass County in southwestern Iowa...
  Western Union County in south central Iowa...
  Western Guthrie County in west central Iowa...
  Audubon County in west central Iowa...
  Adams County in southwestern Iowa...
  Western Ringgold County in south central Iowa...
  Taylor County in southwestern Iowa...
  Western Adair County in southwestern Iowa...

* Until 530 PM CST.

* At 412 PM CST, severe thunderstorms were located along a line
  extending from near Pisgah to near Hamburg, moving northeast at 70
  mph.

  THESE ARE DESTRUCTIVE STORMS FOR SOUTHWEST IOWA!

  HAZARD...80 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be heavily damaged. Expect 
           considerable damage to roofs, windows, and vehicles. 
           Extensive tree damage and power outages are likely.

* Locations impacted include...
  Corning and Lenox.

This includes Interstate 80 between mile markers 50 and 82.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for south central,
southwestern and west central Iowa.

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

This is an EXTREMELY DANGEROUS SITUATION with tornado like wind
speeds expected. Mobile homes and high profile vehicles are
especially susceptible to winds of this magnitude and may be
overturned. For your protection move to an interior room on the
lowest floor of a building. These storms have the potential to cause
serious injury and significant property damage.

&&

LAT...LON 4057 9491 4116 9493 4116 9516 4150 9515
      4151 9504 4160 9504 4160 9509 4186 9509
      4186 9462 4057 9426
TIME...MOT...LOC 2212Z 246DEG 63KT 4180 9600 4057 9571 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Martin
1 follow-up statement
761 
WWUS53 KDMX 152241 RRA
SVSDMX

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

IAC001-003-009-029-077-159-173-175-152330-
/O.CON.KDMX.SV.W.0121.000000T0000Z-211215T2330Z/
Cass IA-Union IA-Guthrie IA-Audubon IA-Adams IA-Ringgold IA-
Taylor IA-Adair IA-
441 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CST
FOR CASS...WESTERN UNION...WESTERN GUTHRIE...AUDUBON...ADAMS...
WESTERN RINGGOLD...TAYLOR AND WESTERN ADAIR COUNTIES...

At 440 PM CST, severe thunderstorms were located along a line
extending from near Denison to near Clarinda, moving northeast at 70
mph.

THESE ARE DESTRUCTIVE STORMS FOR SOUTHWEST IOWA!

HAZARD...80 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be heavily damaged. Expect 
         considerable damage to roofs, windows, and vehicles. 
         Extensive tree damage and power outages are likely.

Locations impacted include...
Atlantic, Audubon, Greenfield, Corning, Bedford, Lenox, Griswold,
Lake Icaria, Anita, Exira, Adair, Fontanelle, Elk Horn, Lewis, Casey,
New Market, Clearfield, Massena, Diagonal and Kimballton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for south central,
southwestern and west central Iowa.

This is an EXTREMELY DANGEROUS SITUATION with tornado like wind
speeds expected. Mobile homes and high profile vehicles are
especially susceptible to winds of this magnitude and may be
overturned. For your protection move to an interior room on the
lowest floor of a building. These storms have the potential to cause
serious injury and significant property damage.

&&

LAT...LON 4057 9491 4116 9493 4116 9516 4150 9515
      4151 9504 4160 9504 4160 9509 4186 9509
      4186 9462 4057 9426
TIME...MOT...LOC 2240Z 246DEG 63KT 4200 9541 4077 9512 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Martin

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 15, 4:16 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXCarroll, Crawford, Sac74 min
Dec 15, 4:37 PM CSTTornado Warning Tornado observedDMXCass23 min
Dec 15, 4:44 PM CSTTornado WarningDMXCrawford36 min
Dec 15, 4:53 PM CSTTornado WarningDMXAdair, Audubon, Cass, Guthrie33 min
Dec 15, 5:07 PM CSTTornado WarningDMXSac27 min
Dec 15, 5:10 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXAdair, Audubon, Boone, Dallas, Greene, Guthrie and 4 more80 min
Dec 15, 5:10 PM CSTTornado WarningDMXCarroll, Crawford35 min
Dec 15, 5:14 PM CSTTornado WarningDMXAudubon, Calhoun, Carroll, Greene, Guthrie31 min
Dec 15, 5:15 PM CSTTornado WarningDMXCalhoun, Carroll, Crawford, Sac30 min
Dec 15, 5:18 PM CSTTornado Warning Tornado observedDMXAdair, Boone, Dallas, Greene, Guthrie42 min
Dec 15, 5:19 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXBoone, Calhoun, Carroll, Emmet, Greene, Humboldt and 5 more71 min
Dec 15, 5:22 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXCarroll, Crawford, Sac23 min
Dec 15, 5:22 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXAdair, Adams, Clarke, Decatur, Madison, Ringgold and 3 more68 min
Dec 15, 5:36 PM CSTTornado WarningDMXCalhoun, Humboldt, Kossuth, Palo Alto, Pocahontas24 min
Dec 15, 5:38 PM CSTTornado Warning Tornado observedDMXBoone, Calhoun, Greene, Hamilton, Webster37 min
Dec 15, 5:45 PM CSTTornado WarningDMXCalhoun, Pocahontas, Webster30 min
Dec 15, 5:52 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXBoone, Franklin, Hamilton, Hancock, Hardin, Humboldt and 6 more53 min
Dec 15, 5:58 PM CSTTornado WarningDMXHancock, Humboldt, Kossuth, Palo Alto, Pocahontas32 min

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.