Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 25, NWS Sioux Falls, SD

June 16, 20214 counties in Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 16, 2021, 8:38 PM CDT for 4 counties in Iowa. It was in force for 37 min. 6 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: Jun 16, 2021, 8:38 PM CDT (01:38 UTC)
Expired: Jun 16, 2021, 9:15 PM CDT
In force: 37 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Buena Vista County, IA, Cherokee County, IA, Clay County, IA, O'Brien County, IA

The radar

The Sioux Falls radar (KFSD), 147 km from the middle of the area, began a volume at 01:43 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
Jun 16, 8:43 PM CDT	TSTM WND GST 70	7 S Peterson, IA	WIND GUSTS ESTIMATED AT 60 TO 70 MPH MOVED AN OLD FRIDGE ACROSS THE OUTDOOR DECK.
Jun 16, 8:43 PM CDT	HAIL 1.75	7 S Peterson, IA	HAIL RANGED FROM QUARTER TO GOLF BALL SIZED.
Jun 16, 9:00 PM CDT	HAIL 1	Alta, IA	WIND GUSTS ALSO UP TO ABOUT 50 MPH.
Jun 16, 9:02 PM CDT	HAIL 0.88	3 S Alta, IA	LOTS OF DIME TO NICKEL SIZED HAIL. ABOUT 5 MINUTES OF WIND GUSTS TO AROUND 50 MPH.
Jun 16, 9:05 PM CDT	HAIL 1	4 Sse Alta, IA	MOSTLY DIME, BUT A FEW QUARTER SIZED HAIL STONES. ALSO ABOUT 40 TO 50 MPH WIND GUSTS.
Jun 16, 9:09 PM CDT	HAIL 0.5	1 W Storm Lake, IA	REPORT FROM MPING.

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, 1.6 hours before the alert went out and 178 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: 2997 J/kg
Mixed-layer CIN: -144 J/kg
Mixed-layer LCL: 1946 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 120 m²/s²
0-3 km storm-relative helicity: 435 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 27.9

Open this sounding in Storm Lab

The text

As transmitted.

693 
WUUS53 KFSD 170138
SVRFSD
IAC021-035-041-141-170215-
/O.NEW.KFSD.SV.W.0025.210617T0138Z-210617T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
838 PM CDT Wed Jun 16 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Eastern Cherokee County in northwestern Iowa...
  Buena Vista County in northwestern Iowa...
  Southwestern Clay County in northwestern Iowa...
  Southeastern O'Brien County in northwestern Iowa...

* Until 915 PM CDT.

* At 838 PM CDT, a severe thunderstorm was located near Linn Grove,
  or 14 miles north of Storm Lake, moving southeast at 50 mph.

  HAZARD...60 mph wind gusts and quarter 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...
  Alta and Truesdale around 850 PM CDT.
  Storm Lake and Lakeside around 855 PM CDT.
  Newell around 900 PM CDT.

Other locations impacted by this severe thunderstorm include Calumet
and Rembrandt.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4256 9556 4297 9560 4298 9512 4256 9492
TIME...MOT...LOC 0138Z 336DEG 44KT 4284 9529 

HAIL...1.00IN
WIND...60MPH
 
$$

APT

1 follow-up statement

411 
WWUS53 KFSD 170155
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
855 PM CDT Wed Jun 16 2021

IAC041-141-170203-
/O.CAN.KFSD.SV.W.0025.000000T0000Z-210617T0215Z/
Clay IA-O'Brien IA-
855 PM CDT Wed Jun 16 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN CLAY AND
SOUTHEASTERN O'BRIEN COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4256 9492 4256 9556 4291 9559 4291 9509
TIME...MOT...LOC 0153Z 344DEG 44KT 4271 9524 

$$

IAC021-035-170215-
/O.CON.KFSD.SV.W.0025.000000T0000Z-210617T0215Z/
Cherokee IA-Buena Vista IA-
855 PM CDT Wed Jun 16 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM CDT
FOR EASTERN CHEROKEE AND BUENA VISTA COUNTIES...

At 853 PM CDT, a severe thunderstorm was located near Truesdale, or
near Storm Lake, moving south at 50 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Spotter reported. At 8:43 pm, golf ball sized hail and wind 
         gusts to 60 mph were reported northeast of Aurelia, Iowa. 
         Have also received reports of weak rotation with this storm.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

This severe storm will be near...
  Storm Lake and Lakeside around 900 PM CDT.

Other locations impacted by this severe thunderstorm include
Rembrandt.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4256 9492 4256 9556 4291 9559 4291 9509
TIME...MOT...LOC 0153Z 344DEG 44KT 4271 9524 

HAIL...1.75IN
WIND...60MPH
 
$$

APT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 16, 9:00 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee, Ida	45 min
Jun 16, 9:47 PM CDT	Severe Thunderstorm Warning	FSD	Ida	28 min
Jun 16, 10:04 PM CDT	Severe Thunderstorm Warning	FSD	Ida	9 min
Jun 17, 3:00 AM CDT	Heat Advisory	FSD	Buena Vista, Cherokee, Ida, Woodbury	16 hr

Nearby

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.