Alert archive / South Dakota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 52, NWS Sioux Falls, SD

July 8, 2021Clay County, Union County, South Dakota; Plymouth County, Sioux County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 8, 2021, 11:50 PM CDT for Clay County, Union County, South Dakota; Plymouth County, Sioux County, Iowa. It was in force for 40 min. 2 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: Jul 8, 2021, 11:50 PM CDT (04:50 UTC)
Expired: Jul 9, 2021, 12:30 AM CDT
In force: 40 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Plymouth County, IA, Sioux County, IA, Clay County, SD, Union County, SD

The radar

The Sioux Falls radar (KFSD), 94 km from the middle of the area, began a volume at 04:54 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

Time	Report	Where	Remark
Jul 9, 12:29 AM CDT	HAIL 1	5 S Le Mars, IA	QUARTER SIZED HAIL AND HEAVY RAIN.
Jul 9, 12:31 AM CDT	HAIL 1	5 E Merrill, IA	QUARTER SIZED HAIL, HEAVY RAIN, AND NOT MUCH WIND.

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.

Issued	Product	Office	Lasted
Jul 8, 9:33 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.8 hours before the alert went out and 160 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 155 J/kg
Mixed-layer CIN: -474 J/kg
Mixed-layer LCL: 1131 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 200 m²/s²
0-3 km storm-relative helicity: 406 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

842 
WUUS53 KFSD 090450
SVRFSD
IAC149-167-SDC027-127-090530-
/O.NEW.KFSD.SV.W.0052.210709T0450Z-210709T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
1150 PM CDT Thu Jul 8 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  South central Sioux County in northwestern Iowa...
  Plymouth County in northwestern Iowa...
  Southeastern Clay County in southeastern South Dakota...
  Central Union County in southeastern South Dakota...

* Until 1230 AM CDT.

* At 1150 PM CDT, a severe thunderstorm was located near Akron, or 13
  miles east of Vermillion, moving east at 40 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* This severe thunderstorm will be near...
  Akron around 1200 AM CDT.
  Craig around 1215 AM CDT.
  Merrill around 1220 AM CDT.
  Struble around 1225 AM CDT.
  Le Mars around 1230 AM CDT.

Other locations impacted by this severe thunderstorm include Oyens,
Chatsworth, Brunsville and Westfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4270 9680 4271 9681 4271 9684 4272 9686
      4292 9687 4291 9605 4256 9608
TIME...MOT...LOC 0450Z 273DEG 36KT 4284 9666 

HAIL...1.25IN
WIND...60MPH
 
$$

APT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 10:53 PM CDT	Severe Thunderstorm Warning	FSD	Bon Homme, Hutchinson, Turner, Yankton	52 min
Jul 8, 10:56 PM CDT	Severe Thunderstorm Warning	FSD	Yankton	19 min
Jul 8, 11:11 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Yankton	34 min
Jul 8, 11:21 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Hutchinson, Lincoln, Turner, Yankton	39 min
Jul 8, 11:59 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Lincoln, Turner, Union	46 min
Jul 9, 12:44 AM CDT	Severe Thunderstorm Warning	FSD	Clay, Union	46 min
Jul 9, 12:46 AM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Union	44 min
Jul 9, 1:22 AM CDT	Severe Thunderstorm Warning	FSD	Aurora, Davison, Jerauld, Sanborn	38 min
Jul 9, 2:15 AM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Union	45 min
Jul 9, 2:34 AM CDT	Severe Thunderstorm Warning	FSD	Hanson, Lake, McCook, Miner	41 min
Jul 8, 11:45 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	45 min
Jul 9, 12:29 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	46 min

Nearby

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