Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 151, NWS Sioux Falls, SD

August 30, 2021Ida County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 30, 2021, 9:49 PM CDT for Ida County, Iowa. It was in force for 26 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: Aug 30, 2021, 9:49 PM CDT (02:49 UTC)
Expired: Aug 30, 2021, 10:15 PM CDT
In force: 26 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Ida County, IA

The radar

The Omaha radar (KOAX), 135 km from the middle of the area, began a volume at 02:53 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
Aug 30, 9:54 PM CDT	HAIL 0.75	2 Se Ida Grove, IA	HEAVY RAIN AND MOSTLY PEA SIZED HAIL, BUT A FEW STONES AS BIG AS PENNIES.
Aug 30, 10:02 PM CDT	HAIL 1.75	6 S Arthur, IA	GOLF BALL SIZED HAIL SHREDDED AND POUNDED CROPS IN THE FIELD.
Aug 30, 10:06 PM CDT	HAIL 1.75	8 S Arthur, IA	CROPS BADLY DAMAGED BY HAIL ESTIMATED AS LARGE AS GOLF BALLS.

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, 2.8 hours before the alert went out and 135 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: 1443 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 1305 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 143 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 3.5

Open this sounding in Storm Lab

The text

As transmitted.

941 
WUUS53 KFSD 310249
SVRFSD
IAC093-310315-
/O.NEW.KFSD.SV.W.0151.210831T0249Z-210831T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
949 PM CDT Mon Aug 30 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Ida County in west central Iowa...

* Until 1015 PM CDT.

* At 949 PM CDT, a severe thunderstorm was located over Ida Grove,
  moving southeast at 25 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...
  Arthur around 1000 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4223 9568 4232 9567 4249 9547 4249 9539
      4247 9538 4247 9532 4230 9532 4221 9533
      4221 9566
TIME...MOT...LOC 0249Z 301DEG 22KT 4234 9545 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

BP

1 follow-up statement

573 
WWUS53 KFSD 310312
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1012 PM CDT Mon Aug 30 2021

IAC093-310322-
/O.EXP.KFSD.SV.W.0151.000000T0000Z-210831T0315Z/
Ida IA-
1012 PM CDT Mon Aug 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR IDA COUNTY WILL EXPIRE AT 1015
PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Sioux Falls.

LAT...LON 4223 9568 4232 9567 4249 9547 4249 9539
      4247 9538 4247 9532 4230 9532 4221 9533
      4221 9566
TIME...MOT...LOC 0312Z 301DEG 22KT 4227 9529 

$$

BP

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 7:29 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Sioux	46 min
Aug 30, 10:05 PM CDT	Severe Thunderstorm Warning	FSD	Ida	10 min

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.