Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 78, NWS Quad Cities, IA

August 11, 2021Des Moines County, Henry County, Lee County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 11, 2021, 6:10 AM CDT for Des Moines County, Henry County, Lee County, Iowa. It was in force for 20 min. 1 report 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 11, 2021, 6:10 AM CDT (11:10 UTC)
Expired: Aug 11, 2021, 6:30 AM CDT
In force: 20 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Des Moines County, IA, Henry County, IA, Lee County, IA

The radar

The Quad Cities radar (KDVN), 104 km from the middle of the area, began a volume at 11:13 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 11, 6:25 AM CDT	HAIL 1	1 Wnw Burlington, IA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 11.2 hours before the alert went out and 108 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: 856 J/kg
Mixed-layer CIN: -155 J/kg
Mixed-layer LCL: 940 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 160 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -1.4

Open this sounding in Storm Lab

The text

As transmitted.

664 
WUUS53 KDVN 111110
SVRDVN
IAC057-087-111-111130-
/O.NEW.KDVN.SV.W.0078.210811T1110Z-210811T1130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
610 AM CDT Wed Aug 11 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Southeastern Henry County in southeastern Iowa...
  Central Des Moines County in southeastern Iowa...
  North central Lee County in southeastern Iowa...

* Until 630 AM CDT.

* At 610 AM CDT, a severe thunderstorm was located over Lowell, or 11
  miles southeast of Mount Pleasant, moving east at 35 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will be near...
  Danville around 615 AM CDT.
  Middletown and Iowa Army Ammunition Plant around 620 AM CDT.
  Burlington, West Burlington and Gulf Port around 630 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4072 9146 4090 9152 4102 9113 4081 9109
      4081 9110 4080 9109 4078 9109
TIME...MOT...LOC 1110Z 256DEG 31KT 4084 9139 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

DC

1 follow-up statement

989 
WWUS53 KDVN 111119
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
619 AM CDT Wed Aug 11 2021

IAC057-087-111-111130-
/O.CON.KDVN.SV.W.0078.000000T0000Z-210811T1130Z/
Henry IA-Des Moines IA-Lee IA-
619 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 AM CDT
FOR SOUTHEASTERN HENRY...CENTRAL DES MOINES AND NORTH CENTRAL LEE
COUNTIES...

At 619 AM CDT, a severe thunderstorm was located over Danville, or 9
miles west of Burlington, moving east at 35 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

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

This severe storm will be near...
  West Burlington around 630 AM CDT.

Other locations in the path of this severe thunderstorm include
Burlington and Gulf Port.

LAT...LON 4072 9146 4090 9152 4102 9113 4081 9109
      4081 9110 4080 9109 4078 9109
TIME...MOT...LOC 1119Z 256DEG 31KT 4086 9129 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

DC

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 5:38 AM CDT	Special Weather Statement	DVN	Lee	37 min
Aug 11, 5:56 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Lee	19 min
Aug 11, 6:24 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines	22 min
Aug 11, 6:38 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Louisa	37 min
Aug 11, 6:59 AM CDT	Flash Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 7:04 AM CDT	Special Weather Statement	DVN	Muscatine	26 min
Aug 11, 8:16 AM CDT	High Wind Warning	DVN	Clinton, Des Moines, Louisa, Muscatine, Scott	104 min
Aug 11, 9:46 AM CDT	Areal Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 10:24 AM CDT	Special Weather Statement	DVN	Lee	21 min
Aug 11, 3:36 PM CDT	Special Weather Statement	DVN	Washington	24 min
Aug 11, 4:26 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque	49 min
Aug 11, 5:11 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jackson, Jones	49 min
Aug 11, 5:38 PM CDT	Tornado Warning	DVN	Dubuque	13 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.