Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 115, NWS Sioux Falls, SD

August 27, 2021Jackson County, Nobles County, Minnesota; 6 counties in Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 27, 2021, 1:52 AM CDT for Jackson County, Nobles County, Minnesota; 6 counties in Iowa. It was in force for 68 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 27, 2021, 1:52 AM CDT (06:52 UTC)
Expired
Aug 27, 2021, 3:00 AM CDT
In force
68 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, O'Brien County, IA, Osceola County, IA, Jackson County, MN, Nobles County, MN

The radar

The Sioux Falls radar (KFSD), 129 km from the middle of the area, began a volume at 06:50 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 26, 8:03 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 6.9 hours before the alert went out and 207 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, Minneapolis, MN at 00:00Z on 2021-08-27Temperature 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, Minneapolis, MN at 00:00Z on 2021-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 393 square meters per square second.19395878Sfc1 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
792 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
393 m²/s²
0-3 km storm-relative helicity
392 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

072 
WUUS53 KFSD 270652
SVRFSD
IAC021-035-041-059-141-143-MNC063-105-270800-
/O.NEW.KFSD.SV.W.0115.210827T0652Z-210827T0800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
152 AM CDT Fri Aug 27 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Northern Cherokee County in northwestern Iowa...
  Osceola County in northwestern Iowa...
  Dickinson County in northwestern Iowa...
  Northern Buena Vista County in northwestern Iowa...
  Clay County in northwestern Iowa...
  O'Brien County in northwestern Iowa...
  Southern Jackson County in southwestern Minnesota...
  Southeastern Nobles County in southwestern Minnesota...

* Until 300 AM CDT.

* At 152 AM CDT, severe thunderstorms were located along a line
  extending from near Ocheyedan to near Sanborn to near Paullina,
  moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Hartley and Ocheyedan around 200 AM CDT.
  Round Lake and Harris around 205 AM CDT.
  Everly around 210 AM CDT.

Other locations in the path of these severe thunderstorms include
Lake Park, Peterson, Spencer In Clay County, Okoboji, Royal,
Wahpeton, Fostoria, Linn Grove, Spirit Lake, Sioux Rapids, Orleans,
Greenville, Terril, Webb and Superior.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4350 9491 4289 9492 4290 9585 4355 9582
      4367 9485 4350 9485
TIME...MOT...LOC 0652Z 259DEG 37KT 4344 9563 4318 9560 4291 9568 

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

$$

SG
2 follow-up statements
418 
WWUS53 KFSD 270726
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
226 AM CDT Fri Aug 27 2021

IAC035-MNC105-270736-
/O.CAN.KFSD.SV.W.0115.000000T0000Z-210827T0800Z/
Cherokee IA-Nobles MN-
226 AM CDT Fri Aug 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN CHEROKEE AND
SOUTHEASTERN NOBLES COUNTIES IS CANCELLED...

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

A Severe Thunderstorm Watch remains in effect until 300 AM CDT for
northwestern Iowa.

LAT...LON 4350 9491 4289 9492 4289 9538 4291 9541
      4360 9539 4367 9485 4350 9485
TIME...MOT...LOC 0726Z 259DEG 37KT 4350 9518 4324 9515 4297 9523 

$$

IAC021-041-059-141-143-MNC063-270800-
/O.CON.KFSD.SV.W.0115.000000T0000Z-210827T0800Z/
Osceola IA-Dickinson IA-Buena Vista IA-Clay IA-O'Brien IA-Jackson MN-
226 AM CDT Fri Aug 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 AM CDT
FOR EASTERN OSCEOLA...DICKINSON...NORTHERN BUENA VISTA...CLAY...
EASTERN O'BRIEN AND SOUTHERN JACKSON COUNTIES...

At 226 AM CDT, severe thunderstorms were located along a line
extending from near Orleans to Fostoria to near Greenville, moving
east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Spirit Lake, Arnolds Park, Okoboji, Orleans, Terril, Webb and 
  Superior.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4350 9491 4289 9492 4289 9538 4291 9541
      4360 9539 4367 9485 4350 9485
TIME...MOT...LOC 0726Z 259DEG 37KT 4350 9518 4324 9515 4297 9523 

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

$$

SG
176 
WWUS53 KFSD 270751
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
251 AM CDT Fri Aug 27 2021

IAC021-041-059-141-143-MNC063-270801-
/O.EXP.KFSD.SV.W.0115.000000T0000Z-210827T0800Z/
Osceola IA-Dickinson IA-Buena Vista IA-Clay IA-O'Brien IA-Jackson MN-
251 AM CDT Fri Aug 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN OSCEOLA...DICKINSON...
NORTHERN BUENA VISTA...CLAY...EASTERN O'BRIEN AND SOUTHERN JACKSON
COUNTIES WILL EXPIRE AT 300 AM CDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 300 AM CDT for
northwestern Iowa.

LAT...LON 4350 9491 4289 9492 4289 9538 4291 9541
      4360 9539 4367 9485 4350 9485
TIME...MOT...LOC 0751Z 259DEG 37KT 4355 9484 4329 9481 4302 9489 

$$

Weisser

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 12:17 AM CDTSevere Thunderstorm WarningFSDLyon, Sioux28 min
Aug 27, 12:34 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDPlymouth, Sioux41 min
Aug 27, 1:04 AM CDTTornado WarningFSDSioux26 min
Aug 27, 1:09 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDCherokee, Lyon, O'Brien, Osceola, Plymouth, Sioux51 min
Aug 27, 1:25 AM CDTSevere Thunderstorm Warning Considerable damage threatFSDCherokee, Ida, Plymouth, Woodbury50 min
Aug 27, 2:00 AM CDTSevere Thunderstorm WarningFSDBuena Vista60 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Severe Thunderstorm Warnings in Minnesota, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.