Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 17, NWS Quad Cities, IA

June 20, 20214 counties in Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 2021, 7:08 PM CDT for 4 counties in Iowa. It was in force for 52 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: Jun 20, 2021, 7:08 PM CDT (00:08 UTC)
Expired: Jun 20, 2021, 8:00 PM CDT
In force: 52 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Delaware County, IA, Dubuque County, IA, Jones County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 108 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.

What was reported inside it

Time	Report	Where	Remark
Jun 20, 7:08 PM CDT	HAIL 0.25	3 Ne Manchester Airport, IA	ALSO 40-45 MPH WIND GUST.
Jun 20, 7:20 PM CDT	TSTM WND DMG	Manchester, IA	BRANCHES DOWN REQUIRING CLEANUP BY THE CITY.
Jun 20, 8:02 PM CDT	TSTM WND GST 55	Cascade, IA

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

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 111 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.

203 
WUUS53 KDVN 210008 RRA
SVRDVN
IAC055-061-105-113-210100-
/O.NEW.KDVN.SV.W.0017.210621T0008Z-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...
  Southwestern Dubuque County in northeastern Iowa...
  Northwestern Jones County in east central Iowa...
  Delaware County in northeastern Iowa...
  Northeastern Linn County in east central Iowa...

* Until 800 PM CDT.

* At 708 PM CDT, a severe thunderstorm was located over Manchester,
  moving southeast 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.

* This severe thunderstorm will be near...
  Delhi and Delaware around 715 PM CDT.
  Earlville around 720 PM CDT.

Other locations in the path of this severe thunderstorm include
Hopkinton, Monticello, Worthington and Cascade.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4251 9086 4212 9111 4230 9161 4231 9160
      4244 9160 4264 9147 4265 9115
TIME...MOT...LOC 0008Z 297DEG 30KT 4246 9142 

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

RP Kinney

4 follow-up statements

613 
WWUS53 KDVN 210020
SVSDVN

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

IAC055-061-105-113-210100-
/O.CON.KDVN.SV.W.0017.000000T0000Z-210621T0100Z/
Dubuque IA-Jones IA-Delaware IA-Linn IA-
720 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR SOUTHWESTERN DUBUQUE...NORTHWESTERN JONES...DELAWARE AND
NORTHEASTERN LINN COUNTIES...

At 720 PM CDT, a severe thunderstorm was located over Delhi, or 9
miles southeast of Manchester, moving southeast 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...
  Hopkinton, Monticello, Worthington and Cascade.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4251 9086 4212 9111 4230 9161 4231 9160
      4244 9160 4260 9142 4265 9115
TIME...MOT...LOC 0020Z 297DEG 30KT 4241 9130 

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

RP Kinney

634 
WWUS53 KDVN 210032
SVSDVN

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

IAC055-061-105-113-210100-
/O.CON.KDVN.SV.W.0017.000000T0000Z-210621T0100Z/
Dubuque IA-Jones IA-Delaware IA-Linn IA-
732 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR SOUTHWESTERN DUBUQUE...NORTHWESTERN JONES...DELAWARE AND
NORTHEASTERN LINN COUNTIES...

At 731 PM CDT, a severe thunderstorm was located over Hopkinton, or
14 miles southeast of Manchester, moving southeast 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.

This severe storm will be near...
  Monticello and Worthington around 740 PM CDT.
  Cascade around 750 PM CDT.

Other locations impacted by this severe thunderstorm include
Robinson, Jones County Fairgrounds, Pictured Rocks Wildlife Area,
Buffalo Creek Park, New Wine Park, Lattnerville, Buck Creek, Camp
Courageous, Baileys Ford Park and Petersburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4251 9086 4212 9111 4230 9161 4231 9160
      4244 9160 4251 9138 4259 9113
TIME...MOT...LOC 0031Z 300DEG 29KT 4235 9123 

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

RP Kinney

655 
WWUS53 KDVN 210043
SVSDVN

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

IAC055-061-105-113-210100-
/O.CON.KDVN.SV.W.0017.000000T0000Z-210621T0100Z/
Dubuque IA-Jones IA-Delaware IA-Linn IA-
743 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR SOUTHWESTERN DUBUQUE...NORTHWESTERN JONES...SOUTHERN DELAWARE AND
NORTHEASTERN LINN COUNTIES...

At 743 PM CDT, a severe thunderstorm was located near Worthington, or
16 miles northeast of Anamosa, moving east at 35 mph.

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

This severe storm will be near...
  Cascade around 755 PM CDT.

Other locations impacted by this severe thunderstorm include Buck
Creek, Camp Courageous, Robinson, Scotch Grove, Jones County
Fairgrounds, Pictured Rocks Wildlife Area, Buffalo Creek Park, Turtle
Creek Park and Monticello Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4244 9091 4212 9111 4230 9161 4231 9160
      4244 9160 4242 9131 4252 9108
TIME...MOT...LOC 0043Z 291DEG 32KT 4232 9113 

TORNADO...POSSIBLE
HAIL...0.75IN
WIND...70MPH
 
$$

RP Kinney

254 
WWUS53 KDVN 210101
SVSDVN

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

IAC055-061-105-113-210109-
/O.EXP.KDVN.SV.W.0017.000000T0000Z-210621T0100Z/
Dubuque IA-Jones IA-Delaware IA-Linn IA-
801 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN DUBUQUE...
NORTHWESTERN JONES...SOUTHERN DELAWARE AND NORTHEASTERN LINN COUNTIES
WILL EXPIRE AT 800 PM CDT...
        
The storm which prompted the warning will continue to move southeast 
and has been replaced with a tornado warning. 

Remember, a Tornado Warning still remains in effect forparts of 
Jackson, Dubuque, and northeast Jones County!

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



LAT...LON 4244 9091 4212 9111 4230 9161 4231 9160
      4244 9160 4242 9131 4252 9108
TIME...MOT...LOC 0059Z 297DEG 30KT 4226 9097 

$$

RP Kinney

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, 7:37 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.