Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 16, NWS Quad Cities, IA

June 20, 2021Iowa County, Keokuk County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 2021, 7:08 PM CDT for Iowa County, Keokuk County, Iowa. It was in force for 38 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, 7:08 PM CDT (00:08 UTC)
Expired: Jun 20, 2021, 7:46 PM CDT
In force: 38 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Iowa County, IA, Keokuk County, IA

The radar

The Quad Cities radar (KDVN), 129 km from the middle of the area, began a volume at 00:13 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.

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, 0.1 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: 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.

575 
WUUS53 KDVN 210008
SVRDVN
IAC095-107-210100-
/O.NEW.KDVN.SV.W.0016.210621T0008Z-210621T0100Z/

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

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Northeastern Keokuk County in southeastern Iowa...
  Southern Iowa County in east central Iowa...

* Until 800 PM CDT.

* At 708 PM CDT, a severe thunderstorm was located 9 miles west of
  Millersburg, or 9 miles east of Montezuma, moving east at 30 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...
  Millersburg around 725 PM CDT.

Other locations in the path of this severe thunderstorm include North
English, South English, Parnell and Kinross.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4151 9236 4151 9230 4167 9230 4165 9190
      4151 9193 4151 9195 4138 9195
TIME...MOT...LOC 0008Z 282DEG 26KT 4157 9234 

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

Speck

3 follow-up statements

612 
WWUS53 KDVN 210021
SVSDVN

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

IAC095-107-210100-
/O.CON.KDVN.SV.W.0016.000000T0000Z-210621T0100Z/
Keokuk IA-Iowa IA-
721 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR NORTHEASTERN KEOKUK AND SOUTHERN IOWA COUNTIES...

At 720 PM CDT, a severe thunderstorm was located near Millersburg, or
14 miles north of Sigourney, moving east at 30 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 storm will be near...
  Millersburg around 725 PM CDT.

Other locations in the path of this severe thunderstorm include North
English, South English, Parnell and Kinross.

LAT...LON 4151 9230 4166 9230 4165 9190 4151 9193
      4151 9195 4138 9195
TIME...MOT...LOC 0020Z 282DEG 26KT 4155 9222 

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

Speck

414 
WWUS53 KDVN 210034
SVSDVN

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

IAC095-107-210100-
/O.CON.KDVN.SV.W.0016.000000T0000Z-210621T0100Z/
Keokuk IA-Iowa IA-
734 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR NORTHEASTERN KEOKUK AND SOUTHERN IOWA COUNTIES...

At 734 PM CDT, a severe thunderstorm was located over North English,
or 14 miles northeast of Sigourney, moving east at 30 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 storm will be near...
  Parnell around 740 PM CDT.

Other locations in the path of this severe thunderstorm include
Kinross.

LAT...LON 4151 9219 4165 9220 4165 9190 4151 9193
      4151 9195 4144 9195
TIME...MOT...LOC 0034Z 282DEG 26KT 4153 9209 

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

Speck

303 
WWUS53 KDVN 210046
SVSDVN

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

IAC095-107-210055-
/O.CAN.KDVN.SV.W.0016.000000T0000Z-210621T0100Z/
Keokuk IA-Iowa IA-
746 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN KEOKUK AND
SOUTHERN IOWA COUNTIES IS CANCELLED...
                
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 has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
southeastern and east central Iowa.

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

LAT...LON 4151 9219 4165 9220 4165 9190 4151 9193
      4151 9195 4144 9195
TIME...MOT...LOC 0042Z 282DEG 26KT 4151 9198 

$$

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	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, 8:04 PM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Henry, Lee, Van Buren	41 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

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.