Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 70, NWS Quad Cities, IA

August 10, 20214 counties in Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 10, 2021, 4:28 PM CDT for 4 counties in Iowa. It was in force for 36 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 10, 2021, 4:28 PM CDT (21:28 UTC)
Expired: Aug 10, 2021, 5:04 PM CDT
In force: 36 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Benton County, IA, Buchanan County, IA, Delaware County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 131 km from the middle of the area, began a volume at 21:31 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.

Issued	Product	Office	Lasted
Aug 10, 2:08 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.5 hours before the alert went out and 136 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: 3755 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 819 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -37 m²/s²
0-3 km storm-relative helicity: 4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

917 
WUUS53 KDVN 102128
SVRDVN
IAC011-019-055-113-102215-
/O.NEW.KDVN.SV.W.0070.210810T2128Z-210810T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
428 PM CDT Tue Aug 10 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Southern Buchanan County in northeastern Iowa...
  Northeastern Benton County in east central Iowa...
  Southwestern Delaware County in northeastern Iowa...
  Northwestern Linn County in east central Iowa...

* Until 515 PM CDT.

* At 428 PM CDT, severe thunderstorms were located along a line
  extending from near Brandon to near Paris, moving northeast at 25
  mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Troy Mills around 435 PM CDT.

Other locations in the path of these severe thunderstorms include
Independence and Winthrop.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4242 9145 4214 9173 4232 9207 4234 9207
      4239 9206 4251 9179
TIME...MOT...LOC 2128Z 215DEG 20KT 4239 9198 4224 9165 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Speck

1 follow-up statement

713 
WWUS53 KDVN 102204
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
504 PM CDT Tue Aug 10 2021

IAC011-019-055-113-102214-
/O.CAN.KDVN.SV.W.0070.000000T0000Z-210810T2215Z/
Buchanan IA-Benton IA-Delaware IA-Linn IA-
504 PM CDT Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN BUCHANAN...
NORTHEASTERN BENTON...SOUTHWESTERN DELAWARE AND NORTHWESTERN LINN
COUNTIES IS CANCELLED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 800 PM CDT for
northeastern and east central Iowa.

LAT...LON 4242 9145 4214 9173 4232 9207 4234 9207
      4239 9206 4251 9179
TIME...MOT...LOC 2202Z 215DEG 20KT 4255 9183 4240 9150 

$$

Speck

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 10, 2:28 PM CDT	Heat Advisory	DVN	Benton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more	29 hr
Aug 10, 2:33 PM CDT	Special Weather Statement	DVN	Buchanan	27 min
Aug 10, 2:42 PM CDT	Special Weather Statement	DVN	Benton	33 min
Aug 10, 2:55 PM CDT	Severe Thunderstorm Warning	DVN	Buchanan	50 min
Aug 10, 3:07 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque	23 min
Aug 10, 3:25 PM CDT	Severe Thunderstorm Warning	DVN	Buchanan, Delaware, Linn	50 min
Aug 10, 3:29 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque	31 min
Aug 10, 3:49 PM CDT	Severe Thunderstorm Warning	DVN	Benton, Buchanan, Iowa	41 min
Aug 10, 4:04 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jackson, Jones, Linn	56 min
Aug 10, 4:38 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Jackson, Jones, Linn	52 min
Aug 10, 5:00 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Jackson, Jones	45 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.