Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 20, NWS Quad Cities, IA

June 20, 2021Keokuk County, Washington County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 20, 2021, 8:18 PM CDT for Keokuk County, Washington County, Iowa. It was in force for 42 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, 8:18 PM CDT (01:18 UTC)
Expired: Jun 20, 2021, 9:00 PM CDT
In force: 42 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Keokuk County, IA, Washington County, IA

The radar

The Quad Cities radar (KDVN), 100 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, 8:47 PM CDT	HAIL 1.25	2 W West Chester, IA	METEOROLOGIST CHASING STORMS REPORT. LOTS OF QUARTER SIZE HAIL AND A FEW HALF DOLLAR SIZE. DELAYED REPORT FROM JUNE 20, 2021.
Jun 20, 8:49 PM CDT	HAIL 0.25	Washington, IA
Jun 20, 8:59 PM CDT	TSTM WND DMG	Washington, IA	FEW DOWNED LIMBS, ROOF OFF BASEBALL CLUBHOUSE (OUTBUILDING), UNSPECIFIED DAMAGE AT THE FAIRGROUNDS, POWER OUT IN SPOTS AROUND TOWN.

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, 1.3 hours before the alert went out and 107 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.

463 
WUUS53 KDVN 210118
SVRDVN
IAC107-183-210200-
/O.NEW.KDVN.SV.W.0020.210621T0118Z-210621T0200Z/

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

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Southeastern Keokuk County in southeastern Iowa...
  Washington County in southeastern Iowa...

* Until 900 PM CDT.

* At 818 PM CDT, a severe thunderstorm was located near Harper, or
  near Sigourney, 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...
  Washington, Ainsworth and Crawfordsville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4141 9148 4125 9148 4116 9150 4116 9168
      4122 9216 4142 9217
TIME...MOT...LOC 0118Z 275DEG 28KT 4133 9208 

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

Speck

2 follow-up statements

188 
WWUS53 KDVN 210139
SVSDVN

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

IAC107-183-210200-
/O.CON.KDVN.SV.W.0020.000000T0000Z-210621T0200Z/
Keokuk IA-Washington IA-
839 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR EAST CENTRAL KEOKUK AND WASHINGTON COUNTIES...

At 839 PM CDT, a severe thunderstorm was located 9 miles west of
Washington, moving east at 30 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Washington, Brighton, Ainsworth, Crawfordsville, Coppock, Keota, West
Chester, Noble, Washington Airport, Marr Park, Haskins, Talleyrand,
Washington County Fairgrounds and Rubio.

LAT...LON 4141 9148 4125 9148 4116 9150 4116 9168
      4120 9197 4141 9197
TIME...MOT...LOC 0139Z 275DEG 28KT 4132 9186 

TORNADO...POSSIBLE
HAIL...1.50IN
WIND...60MPH
 
$$

Speck

826 
WWUS53 KDVN 210150 RRA
SVSDVN

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

IAC107-183-210200-
/O.EXP.KDVN.SV.W.0020.000000T0000Z-210621T0200Z/
Keokuk IA-Washington IA-
850 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL KEOKUK AND
WASHINGTON COUNTIES WILL EXPIRE AT 900 PM CDT...
                
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 will be allowed to expire.

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

LAT...LON 4141 9148 4125 9148 4116 9150 4116 9168
      4120 9197 4141 9197
TIME...MOT...LOC 0150Z 275DEG 28KT 4131 9176 

$$

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