Alert archive / South Dakota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 161, NWS Sioux Falls, SD

September 17, 2021Plymouth County, Sioux County, Iowa; 5 counties in South Dakota; Dixon County, Nebraska

NWS Sioux Falls, SD issued this severe thunderstorm warning at Sep 17, 2021, 12:29 AM CDT for Plymouth County, Sioux County, Iowa; 5 counties in South Dakota; Dixon County, Nebraska. It was in force for 46 min. 5 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
Sep 17, 2021, 12:29 AM CDT (05:29 UTC)
Expired
Sep 17, 2021, 1:15 AM CDT
In force
46 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Plymouth County, IA, Sioux County, IA, Dixon County, NE, Clay County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 85 km from the middle of the area, began a volume at 05:28 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
Sep 17, 12:38 AM CDTTSTM WND GST 716 E Vermillion, SDPERSONAL WEATHER STATION (KSDBURBA2).
Sep 17, 12:39 AM CDTTSTM WND GST 633 Ssw Beresford, SDMESONET STATION 16 SD RWIS BERESFORD.
Sep 17, 12:50 AM CDTTSTM WND GST 631 Ssw Hawarden, IAMESONET STATION FW6302 HAWARDEN.
Sep 17, 1:07 AM CDTTSTM WND GST 632 Ne Maurice, IAKSXK AWOS REPORTED GUST TO 63 MPH.
Sep 17, 1:15 AM CDTTSTM WND DMGOrange City, IACORRECTS TIME OF PREVIOUS TSTM WND DMG REPORT FROM ORANGE CITY. REPORT FROM ORANGE CITY IA, SPOTTER SENT PICTURE OF LARGE TREE BRANCH DOWNED DURING THE STORM.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 5.5 hours before the alert went out and 175 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 2021-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 612 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 2021-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.1939Sfc1 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
612 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
2155 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

801 
WUUS53 KFSD 170529
SVRFSD
IAC149-167-NEC051-SDC027-083-125-127-135-170615-
/O.NEW.KFSD.SV.W.0161.210917T0529Z-210917T0615Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
1229 AM CDT Fri Sep 17 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Sioux County in northwestern Iowa...
  Western Plymouth County in northwestern Iowa...
  Northern Dixon County in northeastern Nebraska...
  Clay County in southeastern South Dakota...
  Southern Lincoln County in southeastern South Dakota...
  Southeastern Yankton County in southeastern South Dakota...
  Southeastern Turner County in southeastern South Dakota...
  Union County in southeastern South Dakota...

* Until 115 AM CDT.

* At 1228 AM CDT, severe thunderstorms were located along a line
  extending from near Centerville to 6 miles west of Union Grove
  State Park to near Hartington, moving east at 55 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Beresford and Union Grove State Park around 1235 AM CDT.
  Alcester, Maskell and Newton Hills State Park around 1245 AM CDT.
  Vermillion, Akron, Hudson and Fairview around 1250 AM CDT.
  Hawarden and Newcastle around 1255 AM CDT.
  Rock Valley, Ireton, Craig and Ponca State Park around 100 AM CDT.
  Sioux Center and Elk Point around 105 AM CDT.
  Hull, Jefferson, Maurice and Struble around 110 AM CDT.
  Orange City, Alton and Boyden around 115 AM CDT.

Other locations impacted by these severe thunderstorms include
Gayville, Chatsworth, Brunsville and Westfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4258 9702 4276 9701 4277 9704 4277 9713
      4280 9716 4281 9721 4285 9723 4286 9732
      4294 9724 4323 9712 4326 9591 4291 9605
      4257 9646
TIME...MOT...LOC 0528Z 270DEG 47KT 4315 9685 4294 9690 4270 9729 

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

$$

SG
1 follow-up statement
716 
WWUS53 KFSD 170601
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
101 AM CDT Fri Sep 17 2021

SDC125-135-170610-
/O.CAN.KFSD.SV.W.0161.000000T0000Z-210917T0615Z/
Yankton SD-Turner SD-
101 AM CDT Fri Sep 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN YANKTON AND
SOUTHEASTERN TURNER COUNTIES IS CANCELLED...

The storms which prompted the warning have  moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 4258 9698 4316 9670 4316 9595 4291 9605
      4257 9646
TIME...MOT...LOC 0600Z 270DEG 47KT 4315 9628 4294 9633 4270 9672 

$$

IAC149-167-NEC051-SDC027-083-127-170615-
/O.CON.KFSD.SV.W.0161.000000T0000Z-210917T0615Z/
Sioux IA-Plymouth IA-Dixon NE-Clay SD-Lincoln SD-Union SD-
101 AM CDT Fri Sep 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 AM CDT
FOR SOUTHERN SIOUX...WESTERN PLYMOUTH...NORTHERN DIXON...SOUTHEASTERN
CLAY...SOUTHEASTERN LINCOLN AND UNION COUNTIES...

At 100 AM CDT, severe thunderstorms were located along a line
extending from near Rock Valley to near Ireton to near Elk Point,
moving east at 55 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

These severe storms will be near...
  Sioux Center, Ireton and Craig around 105 AM CDT.
  Maurice and Struble around 110 AM CDT.
  Orange City around 115 AM CDT.
  Alton around 120 AM CDT.
  Le Mars around 135 AM CDT.

Other locations impacted by these severe thunderstorms include
Brunsville, Westfield and Chatsworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4258 9698 4316 9670 4316 9595 4291 9605
      4257 9646
TIME...MOT...LOC 0600Z 270DEG 47KT 4315 9628 4294 9633 4270 9672 

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

$$

SG

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 12:36 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDClay, Dickinson, Lyon, O'Brien, Osceola, Sioux54 min
Sep 17, 1:11 AM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee, Clay, Ida, O'Brien, Plymouth and 2 more49 min
Sep 17, 1:23 AM CDTSevere Thunderstorm WarningFSDClay, Dickinson, Lyon, O'Brien, Osceola, Sioux67 min
Sep 16, 10:20 PM CDTSevere Thunderstorm WarningFSDCharles Mix, Gregory25 min
Sep 16, 11:31 PM CDTSevere Thunderstorm WarningFSDBon Homme, Charles Mix, Hutchinson, Yankton29 min
Sep 17, 12:10 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDBrookings, Lake, McCook, Minnehaha, Moody35 min
Sep 17, 12:34 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDMinnehaha56 min

Nearby

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