Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 83, NWS Quad Cities, IA

August 11, 2021Henderson County, McDonough County, Warren County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 11, 2021, 10:57 AM CDT for Henderson County, McDonough County, Warren County, Illinois. It was in force for 33 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: Aug 11, 2021, 10:57 AM CDT (15:57 UTC)
Expired: Aug 11, 2021, 11:30 AM CDT
In force: 33 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Henderson County, IL, McDonough County, IL, Warren County, IL

The radar

The Quad Cities radar (KDVN), 100 km from the middle of the area, began a volume at 15:58 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
Aug 11, 10:57 AM CDT	TSTM WND DMG	2 E Smithshire, IL	LARGE EVERGREEN TREE SNAPPED HALFWAY UP.

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

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 4.0 hours before the alert went out and 102 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: 2852 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 1040 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

270 
WUUS53 KDVN 111557
SVRDVN
ILC071-109-187-111630-
/O.NEW.KDVN.SV.W.0083.210811T1557Z-210811T1630Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
1057 AM CDT Wed Aug 11 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  East central Henderson County in west central Illinois...
  Southern Warren County in west central Illinois...
  Northeastern McDonough County in west central Illinois...

* Until 1130 AM CDT.

* At 1057 AM CDT, a severe thunderstorm was located over Roseville,
  or 11 miles south of Monmouth, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Little Swan Lake around 1105 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4061 9079 4084 9081 4087 9044 4062 9045
TIME...MOT...LOC 1557Z 268DEG 41KT 4074 9069 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin

4 follow-up statements

475 
WWUS53 KDVN 111604
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1104 AM CDT Wed Aug 11 2021

ILC071-109-111614-
/O.CAN.KDVN.SV.W.0083.000000T0000Z-210811T1630Z/
Henderson IL-McDonough IL-
1104 AM CDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL HENDERSON AND
NORTHEASTERN MCDONOUGH COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4066 9071 4084 9078 4087 9044 4063 9045
TIME...MOT...LOC 1604Z 268DEG 41KT 4074 9058 

$$

ILC187-111630-
/O.CON.KDVN.SV.W.0083.000000T0000Z-210811T1630Z/
Warren IL-
1104 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 AM CDT
FOR SOUTHERN WARREN COUNTY...

At 1104 AM CDT, a severe thunderstorm was located near Roseville, or
12 miles south of Monmouth, moving east at 45 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 remain over mainly rural areas of
southern Warren County, including the following locations... Warren
County Fairgrounds, Swan Creek, Ponemah, Youngstown, Greenbush,
Larchland, Berwick and Ormonde.

LAT...LON 4066 9071 4084 9078 4087 9044 4063 9045
TIME...MOT...LOC 1604Z 268DEG 41KT 4074 9058 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin

811 
WWUS53 KDVN 111610
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1110 AM CDT Wed Aug 11 2021

ILC187-111630-
/O.CON.KDVN.SV.W.0083.000000T0000Z-210811T1630Z/
Warren IL-
1110 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 AM CDT
FOR SOUTHERN WARREN COUNTY...

At 1110 AM CDT, a severe thunderstorm was located near Roseville, or
11 miles southeast of Monmouth, moving east at 45 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...
Roseville, Little Swan Lake, Greenbush, Berwick, Warren County
Fairgrounds, Swan Creek, Ponemah, Youngstown, Larchland and Ormonde.

LAT...LON 4066 9071 4084 9073 4087 9044 4063 9045
TIME...MOT...LOC 1610Z 264DEG 37KT 4077 9056 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin

981 
WWUS53 KDVN 111617
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1117 AM CDT Wed Aug 11 2021

ILC187-111630-
/O.CON.KDVN.SV.W.0083.000000T0000Z-210811T1630Z/
Warren IL-
1117 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 AM CDT
FOR SOUTHEASTERN WARREN COUNTY...

At 1117 AM CDT, a severe thunderstorm was located near Abingdon, or
13 miles south of Galesburg, moving east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Greenbush and Berwick. 

LAT...LON 4067 9054 4085 9061 4087 9044 4063 9045
TIME...MOT...LOC 1617Z 264DEG 37KT 4077 9046 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin

105 
WWUS53 KDVN 111622
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1122 AM CDT Wed Aug 11 2021

ILC187-111632-
/O.EXP.KDVN.SV.W.0083.000000T0000Z-210811T1630Z/
Warren IL-
1122 AM CDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN WARREN COUNTY
WILL EXPIRE AT 1130 AM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However small hail is still possible with this
thunderstorm.

LAT...LON 4067 9054 4085 9061 4087 9044 4063 9045
TIME...MOT...LOC 1622Z 268DEG 41KT 4077 9042 

$$

Ervin

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 5:56 AM CDT	Severe Thunderstorm Warning	DVN	Hancock	19 min
Aug 11, 6:24 AM CDT	Special Weather Statement	DVN	McDonough	36 min
Aug 11, 6:24 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, Warren	22 min
Aug 11, 6:38 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, Mercer, Warren	37 min
Aug 11, 6:59 AM CDT	Flash Flood Warning	DVN	Hancock, Henderson	3 hr
Aug 11, 7:32 AM CDT	Special Weather Statement	DVN	Rock Island	28 min
Aug 11, 7:55 AM CDT	Special Weather Statement	DVN	Bureau, Henry, Whiteside	65 min
Aug 11, 8:07 AM CDT	Severe Thunderstorm Warning	DVN	Bureau, Henry, Rock Island, Whiteside	53 min
Aug 11, 8:16 AM CDT	High Wind Warning	DVN	Henderson, Henry, Mercer, Rock Island, Warren, Whiteside	104 min
Aug 11, 8:33 AM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Bureau, Putnam, Whiteside	57 min
Aug 11, 9:46 AM CDT	Areal Flood Warning	DVN	Henderson	3 hr
Aug 11, 9:59 AM CDT	Special Weather Statement	DVN	McDonough	31 min
Aug 11, 10:45 AM CDT	Special Weather Statement	DVN	Henderson, Warren	30 min

Nearby

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.