Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 19, NWS Quad Cities, IA

June 20, 20214 counties in Iowa; Hancock County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 2021, 8:04 PM CDT for 4 counties in Iowa; Hancock County, Illinois. It was in force for 41 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: Jun 20, 2021, 8:04 PM CDT (01:04 UTC)
Expired: Jun 20, 2021, 8:45 PM CDT
In force: 41 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Des Moines County, IA, Henry County, IA, Lee County, IA, Van Buren County, IA, Hancock County, IL

The radar

The Quad Cities radar (KDVN), 140 km from the middle of the area, began a volume at 01:05 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
Jun 20, 4:01 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.1 hours before the alert went out and 145 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: 1058 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 1009 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 174 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 7.8

Open this sounding in Storm Lab

The text

As transmitted.

887 
WUUS53 KDVN 210104
SVRDVN
ILC067-IAC057-087-111-177-210145-
/O.NEW.KDVN.SV.W.0019.210621T0104Z-210621T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
804 PM CDT Sun Jun 20 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Northwestern Hancock County in west central Illinois...
  Southeastern Henry County in southeastern Iowa...
  Southwestern Des Moines County in southeastern Iowa...
  Southeastern Van Buren County in southeastern Iowa...
  Lee County in southeastern Iowa...

* Until 845 PM CDT.

* At 803 PM CDT, a severe thunderstorm was located over Bonaparte, or
  9 miles east of Keosauqua, moving east at 35 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.

* Locations impacted include...
  Donnellson, Pilot Grove, Franklin, St. Paul, West Point, Lowell, 
  Fort Madison, Middletown and Denmark.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4057 9166 4058 9169 4059 9171 4061 9173
      4061 9184 4078 9187 4087 9126 4050 9128
TIME...MOT...LOC 0103Z 264DEG 30KT 4070 9179 

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

Speck

2 follow-up statements

046 
WWUS53 KDVN 210117
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
817 PM CDT Sun Jun 20 2021

ILC067-IAC057-087-111-177-210145-
/O.CON.KDVN.SV.W.0019.000000T0000Z-210621T0145Z/
Hancock IL-Henry IA-Des Moines IA-Van Buren IA-Lee IA-
817 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM CDT
FOR NORTHWESTERN HANCOCK...SOUTHEASTERN HENRY...SOUTHWESTERN DES
MOINES...SOUTHEASTERN VAN BUREN AND LEE COUNTIES...

At 817 PM CDT, a severe thunderstorm was located near Donnellson, or
16 miles northwest of Fort Madison, moving east at 35 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.

Locations impacted include...
Fort Madison, Nauvoo, West Point, Danville, Donnellson, Montrose,
Bonaparte, Middletown, Franklin, St. Paul, New Boston, Pilot Grove,
Croton, Niota, Lowell, Denmark, Farmington, Houghton, Charleston and
Geode State Park.

LAT...LON 4057 9166 4058 9169 4059 9171 4061 9173
      4061 9184 4076 9178 4081 9167 4087 9126
      4050 9128
TIME...MOT...LOC 0117Z 264DEG 30KT 4071 9164 

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

Speck

656 
WWUS53 KDVN 210143
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
843 PM CDT Sun Jun 20 2021

IAC057-087-111-177-ILC067-210152-
/O.EXP.KDVN.SV.W.0019.000000T0000Z-210621T0145Z/
Hancock IL-Henry IA-Des Moines IA-Van Buren IA-Lee IA-
843 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN HANCOCK...
SOUTHEASTERN HENRY...SOUTHWESTERN DES MOINES...SOUTHEASTERN VAN BUREN
AND LEE COUNTIES WILL EXPIRE AT 845 PM CDT...
    
The severe thunderstorm which prompted the warning has been replaced 
with a tornado warning. Therefore, the severe thunderstorm warning 
will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
west central Illinois...southeastern Iowa...and northeastern
Missouri.

LAT...LON 4057 9166 4058 9169 4059 9171 4061 9173
      4061 9184 4076 9178 4081 9167 4087 9126
      4050 9128
TIME...MOT...LOC 0142Z 264DEG 30KT 4073 9138 

$$

Speck

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 7:08 PM CDT	Severe Thunderstorm Warning	DVN	Iowa, Keokuk	38 min
Jun 20, 7:08 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jones, Linn	52 min
Jun 20, 7:37 PM CDT	Severe Thunderstorm Warning	DVN	Benton, Buchanan, Linn	38 min
Jun 20, 7:48 PM CDT	Tornado Warning	DVN	Dubuque, Jackson, Jones	42 min
Jun 20, 8:18 PM CDT	Severe Thunderstorm Warning	DVN	Keokuk, Washington	42 min
Jun 20, 8:19 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Jackson, Jones	41 min
Jun 20, 8:27 PM CDT	Tornado Warning Tornado observed	DVN	Jackson	33 min
Jun 20, 8:28 PM CDT	Tornado Warning	DVN	Keokuk, Washington	32 min
Jun 20, 8:37 PM CDT	Tornado Warning	DVN	Des Moines, Lee	39 min
Jun 20, 8:47 PM CDT	Special Weather Statement	DVN	Jones, Linn	43 min
Jun 20, 8:53 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Jackson	67 min
Jun 20, 8:59 PM CDT	Special Weather Statement	DVN	Louisa	31 min
Jun 20, 9:29 PM CDT	Special Weather Statement	DVN	Lee	46 min
Jun 20, 9:36 PM CDT	Special Weather Statement	DVN	Scott	39 min
Jun 20, 9:18 PM CDT	Special Weather Statement	DVN	Henderson	42 min
Jun 20, 9:47 PM CDT	Special Weather Statement	DVN	Bureau, Henry	43 min
Jun 20, 10:03 PM CDT	Special Weather Statement	DVN	Hancock, McDonough	27 min
Jun 20, 10:23 PM CDT	Severe Thunderstorm Warning	DVN	McDonough	22 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Severe Thunderstorm Warnings in Illinois, 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.