Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 21, NWS Quad Cities, IA

June 20, 2021Carroll County, Jo Daviess County, Illinois; Clinton County, Jackson County, Jones County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 2021, 8:19 PM CDT for Carroll County, Jo Daviess County, Illinois; Clinton County, Jackson County, Jones County, Iowa. It was in force for 41 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: Jun 20, 2021, 8:19 PM CDT (01:19 UTC)
Expired: Jun 20, 2021, 9:00 PM CDT
In force: 41 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 70.0 mph

Counties Clinton County, IA, Jackson County, IA, Jones County, IA, Carroll County, IL, Jo Daviess County, IL

The radar

The Quad Cities radar (KDVN), 55 km from the middle of the area, began a volume at 01:20 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, 9:05 PM CDT	TSTM WND DMG	Savanna, IL	DOWNED TREE LIMB AND POWERLINE. TIME ESTIMATED FROM RADAR.

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, 8:10 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jun 20, 4:01 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.3 hours before the alert went out and 55 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.

115 
WUUS53 KDVN 210119
SVRDVN
ILC015-085-IAC045-097-105-210200-
/O.NEW.KDVN.SV.W.0021.210621T0119Z-210621T0200Z/

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

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  South central Jo Daviess County in northwestern Illinois...
  Northwestern Carroll County in northwestern Illinois...
  Jackson County in east central Iowa...
  East central Jones County in east central Iowa...
  Northeastern Clinton County in east central Iowa...

* Until 900 PM CDT.

* At 818 PM CDT, a severe thunderstorm was located over Fulton, or 8
  miles north of Maquoketa, moving east at 45 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Andrew around 830 PM CDT.
  Springbrook around 835 PM CDT.

Other locations in the path of this severe thunderstorm include
Spragueville, Preston, Green Island, Miles, Savanna and Sabula.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4206 9104 4226 9090 4223 9008 4192 9018
TIME...MOT...LOC 0118Z 279DEG 37KT 4218 9072 

HAIL...<.75IN
WIND...70MPH
 
$$

Ervin

3 follow-up statements

656 
WWUS53 KDVN 210129
SVSDVN

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

IAC105-210139-
/O.CAN.KDVN.SV.W.0021.000000T0000Z-210621T0200Z/
Jones IA-
829 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL JONES COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
east central Iowa. A Severe Thunderstorm Watch also remains in effect
until 100 AM CDT for northwestern Illinois.

LAT...LON 4223 9008 4192 9018 4204 9090 4207 9090
      4225 9066
TIME...MOT...LOC 0129Z 279DEG 37KT 4216 9057 

$$

ILC015-085-IAC045-097-210200-
/O.CON.KDVN.SV.W.0021.000000T0000Z-210621T0200Z/
Jo Daviess IL-Carroll IL-Jackson IA-Clinton IA-
829 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR SOUTH CENTRAL JO DAVIESS...NORTHWESTERN CARROLL...JACKSON AND
NORTHEASTERN CLINTON COUNTIES...

At 829 PM CDT, a severe thunderstorm was located over Andrew, or 8
miles northeast of Maquoketa, moving east at 45 mph.

HAZARD...70 mph wind gusts.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Springbrook around 835 PM CDT.

Other locations in the path of this severe thunderstorm include
Spragueville, Preston, Green Island, Miles, Savanna and Sabula.

LAT...LON 4223 9008 4192 9018 4204 9090 4207 9090
      4225 9066
TIME...MOT...LOC 0129Z 279DEG 37KT 4216 9057 

HAIL...<.75IN
WIND...70MPH
 
$$

Ervin

444 
WWUS53 KDVN 210142
SVSDVN

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

ILC015-085-IAC045-097-210200-
/O.CON.KDVN.SV.W.0021.000000T0000Z-210621T0200Z/
Jo Daviess IL-Carroll IL-Jackson IA-Clinton IA-
842 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR SOUTH CENTRAL JO DAVIESS...NORTHWESTERN CARROLL...SOUTHEASTERN
JACKSON AND NORTHEASTERN CLINTON COUNTIES...

At 842 PM CDT, a severe thunderstorm was located near Green Island,
or 15 miles east of Maquoketa, moving east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Green Island around 845 PM CDT.

Other locations in the path of this severe thunderstorm include
Miles, Savanna and Sabula.

LAT...LON 4223 9008 4192 9018 4203 9078 4215 9063
      4225 9053
TIME...MOT...LOC 0142Z 279DEG 37KT 4214 9039 

HAIL...<.75IN
WIND...60MPH
 
$$

Ervin

237 
WWUS53 KDVN 210157
SVSDVN

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

IAC045-097-ILC015-085-210206-
/O.EXP.KDVN.SV.W.0021.000000T0000Z-210621T0200Z/
Jo Daviess IL-Carroll IL-Jackson IA-Clinton IA-
857 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL JO DAVIESS...
NORTHWESTERN CARROLL...SOUTHEASTERN JACKSON AND NORTHEASTERN CLINTON
COUNTIES WILL EXPIRE AT 900 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
east central Iowa. A Severe Thunderstorm Watch also remains in effect
until 100 AM CDT for northwestern Illinois.

Remember, a Severe Thunderstorm Warning still remains in effect for
eastern Jackson, Jo Daviess, and Carroll through 10 PM.

LAT...LON 4223 9008 4192 9018 4203 9078 4215 9063
      4225 9053
TIME...MOT...LOC 0156Z 279DEG 37KT 4212 9020 

$$

Ervin

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 8:04 PM CDT	Severe Thunderstorm Warning	DVN	Hancock	41 min
Jun 20, 8:37 PM CDT	Tornado Warning	DVN	Hancock, Henderson	39 min
Jun 20, 8:53 PM CDT	Severe Thunderstorm Warning	DVN	Carroll, Jo Daviess, Stephenson	67 min
Jun 20, 9:18 PM CDT	Special Weather Statement	DVN	Henderson	42 min
Jun 20, 9:29 PM CDT	Special Weather Statement	DVN	Henderson	46 min
Jun 20, 9:36 PM CDT	Special Weather Statement	DVN	Whiteside	39 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
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, 8:27 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, 8:47 PM CDT	Special Weather Statement	DVN	Jones, Linn	43 min
Jun 20, 8:59 PM CDT	Special Weather Statement	DVN	Louisa	31 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.