Alert archive / Nebraska / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 173, NWS Sioux Falls, SD

December 15, 2021Union County, South Dakota; Dakota County, Dixon County, Nebraska; Plymouth County, Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Dec 15, 2021, 4:26 PM CST for Union County, South Dakota; Dakota County, Dixon County, Nebraska; Plymouth County, Woodbury County, Iowa. It was in force for 34 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, 4:26 PM CST (22:26 UTC)
Expired
Dec 15, 2021, 5:00 PM CST
In force
34 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Possible
Damage threat
Considerable
Hail
0.75 in
Wind
70.0 mph

Counties Plymouth County, IA, Woodbury County, IA, Dakota County, NE, Dixon County, NE, Union County, SD

The radar

The Sioux Falls radar (KFSD), 117 km from the middle of the area, began a volume at 22:26 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, 4:31 PM CSTTSTM WND DMG2 E Lawton, IAPOWER LINES DOWN ACROSS HWY 20. TIME ESTIMATED FROM RADAR.
Dec 15, 4:31 PM CSTTSTM WND DMG2 Ene Lawton, IAPOLE SHED ROOF OFF WITH DEBRIS BLOWN INTO FIELD. TIME ESTIMATED FROM RADAR.
Dec 15, 4:33 PM CSTTORNADO3 Ene Lawton, IAREPORT OF POWER FLASHES FROM POWER LINES.

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, 10.4 hours before the alert went out and 138 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.

929 
WUUS53 KFSD 152226
SVRFSD
IAC149-193-NEC043-051-SDC127-152300-
/O.NEW.KFSD.SV.W.0173.211215T2226Z-211215T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
426 PM CST Wed Dec 15 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Western Woodbury County in west central Iowa...
  Southwestern Plymouth County in northwestern Iowa...
  Northeastern Dakota County in northeastern Nebraska...
  Northeastern Dixon County in northeastern Nebraska...
  Southern Union County in southeastern South Dakota...

* Until 500 PM CST.

* At 424 PM CST, severe thunderstorms were located along a line
  extending from Ponca State Park to near Lawton to near Hornick,
  moving north at 50 mph.

  HAZARD...70 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Elk Point around 430 PM CST.
  Moville and Hinton around 440 PM CST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for northwestern
and west central Iowa...northeastern Nebraska...and southeastern
South Dakota.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across parts of Nebraska as well as an isolated tornado 
near Salix. SEEK SHELTER NOW inside a sturdy structure and stay away 
from windows! A Tornado Watch remains in effect until 800 PM CST for 
northwestern and west central Iowa...northeastern Nebraska...and 
southeastern South Dakota.

&&

LAT...LON 4274 9680 4270 9606 4222 9602 4234 9629
      4259 9680
TIME...MOT...LOC 2224Z 199DEG 42KT 4262 9669 4246 9626 4229 9610 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Weisser

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 2:56 AM CSTDense Fog AdvisoryFSDBeadle, Bon Homme, Brookings, Clay, Davison, Hanson and 12 more6 hr
Dec 15, 9:01 AM CSTDense Fog AdvisoryFSDBeadle, Brookings, Davison, Hanson, Kingsbury, Lake and 4 more119 min
Dec 15, 3:23 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDUnion67 min
Dec 15, 4:00 PM CSTTornado WarningFSDUnion45 min
Dec 15, 3:59 PM CSTTornado WarningFSDDakota, Dixon31 min
Dec 15, 4:05 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDBuena Vista, Cherokee, Ida, Plymouth, Woodbury55 min
Dec 15, 4:17 PM CSTTornado WarningFSDPlymouth, Woodbury28 min
Dec 15, 4:31 PM CSTTornado WarningFSDIda, Plymouth, Woodbury29 min
Dec 15, 4:32 PM CSTTornado WarningFSDPlymouth, Woodbury28 min
Dec 15, 4:42 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay, Ida, O'Brien, Plymouth and 1 more33 min
Dec 15, 4:51 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDO'Brien, Sioux39 min
Dec 15, 4:56 PM CSTSevere Thunderstorm Warning Destructive damage threatFSDBuena Vista, Cherokee, Clay, Ida46 min
Dec 15, 5:08 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay37 min
Dec 15, 5:15 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay, O'Brien30 min
Dec 15, 5:29 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDDickinson46 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2021Severe Thunderstorm Warnings in Iowa, 2021Severe Thunderstorm Warnings in South Dakota, 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.