Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 4, NWS Chicago, IL

June 20, 2021Cook County, DuPage County, Will County, Illinois

NWS Chicago, IL issued this tornado warning at Jun 20, 2021, 11:05 PM CDT for Cook County, DuPage County, Will County, Illinois. It was in force for 40 min. 4 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, 11:05 PM CDT (04:05 UTC)
Expired: Jun 20, 2021, 11:45 PM CDT
In force: 40 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Cook County, IL, DuPage County, IL, Will County, IL

The radar

The Chicago radar (KLOT), 11 km from the middle of the area, began a volume at 04:06 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, 11:05 PM CDT	TORNADO	2 Ssw Naperville, IL	* 11 INJ * AN NWS STORM SURVEY DETERMINED THAT AN EF-3 TORNADO WITH PEAK WINDS OF 140 MPH, PATH LENGTH OF 16.1 MILES, AND MAXIMUM WIDTH OF 600 YARDS IMPACTED NAPERVILLE, WOODRIDGE, DARIEN, BURR RIDGE, AND WILLOW SPRINGS DURING THE EVENING OF JUNE 20, 2021.
Jun 20, 11:10 PM CDT	TSTM WND DMG	1 E Bolingbrook, IL	PUBLIC REPORT OF TREE DAMAGE IN BOLINGBROOK.
Jun 20, 11:12 PM CDT	TSTM WND DMG	Woodridge, IL	MULTIPLE SPOTTER REPORTS OF DAMAGE TO TREES, STRUCTURES, AND POWER LINES NEAR 75TH AND JANES IN WOODRIDGE. DEBRIS ON I-355. PROBABLE TORNADO. TIME ESTIMATED BY RADAR.
Jun 20, 11:16 PM CDT	TSTM WND DMG	1 Wsw Darien, IL	PHOTO SHARED VIA SOCIAL MEDIA OF TORNADO DAMAGE TO A RESIDENCE IN DARIEN. PROBABLE TORNADO. TIME ESTIMATED BY 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, 9:40 PM CDT	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 4.1 hours before the alert went out and 178 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: 1632 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 1351 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 159 m²/s²
0-3 km storm-relative helicity: 421 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 13.7

Open this sounding in Storm Lab

The text

As transmitted.

334 
WFUS53 KLOT 210405
TORLOT
ILC031-043-197-210445-
/O.NEW.KLOT.TO.W.0004.210621T0405Z-210621T0445Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
1105 PM CDT Sun Jun 20 2021

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  Northwestern Will County in northeastern Illinois...
  Southern DuPage County in northeastern Illinois...
  South central Cook County in northeastern Illinois...

* Until 1145 PM CDT.
    
* At 1105 PM CDT, a severe thunderstorm capable of producing a
  tornado was located over Naperville, moving east at 50 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Woodridge around 1110 PM CDT.
  Lockport, Homer Glen, Westmont, Darien, Willowbrook and Clarendon 
  Hills around 1115 PM CDT.
  Hinsdale, Lemont, Burr Ridge, Western Springs, Countryside, Willow 
  Springs and Indian Head Park around 1120 PM CDT.
  Orland Park, Palos Hills, Justice, Summit, Bridgeview, Hickory 
  Hills, Palos Heights, Worth and Hodgkins around 1125 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Tinley Park, Oak Lawn, Midway Airport, Burbank, Oak Forest, Alsip,
Ashburn, Midlothian, Chicago Ridge, Crestwood, Chicago Lawn and
Evergreen Park.

This includes...  Argonne National Laboratory, SeatGeek Stadium,
Benedictine University, Hollywood Casino Amphitheatre, Moraine Valley
Community College, and North Central College.
 
Including the following interstates...
 I-55 between mile markers 263 and 282.
 I-80 between mile markers 144 and 150.
 I-355 between mile markers 5 and 18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4167 8819 4178 8819 4180 8769 4151 8778
TIME...MOT...LOC 0405Z 279DEG 43KT 4173 8814 

TORNADO...RADAR INDICATED
HAIL...<.75IN

OEMC zones...TORNADO WARNING. 8 and 10.
 
$$

FRIEDLEIN

5 follow-up statements

728 
WWUS53 KLOT 210410
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1110 PM CDT Sun Jun 20 2021

ILC031-043-197-210445-
/O.CON.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Will IL-DuPage IL-Cook IL-
1110 PM CDT Sun Jun 20 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT FOR
NORTHWESTERN WILL...SOUTHERN DUPAGE AND SOUTH CENTRAL COOK
COUNTIES...
        
At 1109 PM CDT, a confirmed tornado was located near the Woodridge 
and Bolingbrook border, moving east at 50 mph. This is confirmed via 
debris signature on radar.

HAZARD...Damaging tornado.

SOURCE...Radar confirmed tornado.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This tornado will be near...
  Homer Glen, Darien, Willowbrook and Clarendon Hills around 1115 PM 
  CDT.
  Hinsdale, Burr Ridge, Countryside, Willow Springs and Indian Head 
  Park around 1120 PM CDT.
  Orland Park, Palos Hills, Justice, Summit, Bridgeview, Chicago 
  Ridge, Hickory Hills, Palos Heights, Worth and Hodgkins around 
  1125 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Tinley Park, Oak Lawn, Midway Airport, Burbank, Oak Forest, Alsip,
Ashburn, Midlothian, Crestwood, Chicago Lawn and Evergreen Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 4167 8819 4178 8819 4180 8769 4151 8778
TIME...MOT...LOC 0409Z 279DEG 43KT 4172 8806 

TORNADO...OBSERVED
HAIL...<.75IN

OEMC zones...TORNADO WARNING. 8 and 10.
 
$$

FRIEDLEIN

083 
WWUS53 KLOT 210416
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1116 PM CDT Sun Jun 20 2021

ILC031-043-197-210445-
/O.CON.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Will IL-DuPage IL-Cook IL-
1116 PM CDT Sun Jun 20 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT FOR
NORTHWESTERN WILL...SOUTHEASTERN DUPAGE AND SOUTH CENTRAL COOK
COUNTIES...
        
At 1115 PM CDT, a confirmed large and extremely dangerous tornado 
was located over Darien, or over far east Woodridge, moving east at 
45 mph. Radar confirms debris with this tornado moving over 
populated areas.

This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!

HAZARD...Damaging tornado.

SOURCE...Radar confirmed tornado.

IMPACT...You are in a life-threatening situation. Flying debris may 
         be deadly to those caught without shelter. Mobile homes 
         will be destroyed. Considerable damage to homes, 
         businesses, and vehicles is likely and complete destruction 
         is possible.

The tornado will be near...
  Burr Ridge, Western Springs and Indian Head Park around 1120 PM 
  CDT.
  Palos Hills, Justice, Summit, Bridgeview, Hickory Hills, 
  Countryside, Willow Springs and Hodgkins around 1125 PM CDT.
  Oak Lawn, Midway Airport, Burbank, Alsip, Chicago Ridge, Palos 
  Heights, Crestwood and Worth around 1130 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Chicago Lawn, Oak Forest, Ashburn, Evergreen Park and Midlothian.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a large, extremely dangerous and potentially deadly
tornado is on the ground. To protect your life, TAKE COVER NOW! Move
to a basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 4166 8817 4178 8811 4180 8769 4151 8778
TIME...MOT...LOC 0415Z 275DEG 41KT 4175 8799 

TORNADO...OBSERVED
TORNADO DAMAGE THREAT...CONSIDERABLE
HAIL...<.75IN

OEMC zones...TORNADO WARNING. 8 and 10.
 
$$

FRIEDLEIN

442 
WWUS53 KLOT 210424
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1124 PM CDT Sun Jun 20 2021

ILC031-043-197-210445-
/O.CON.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Will IL-DuPage IL-Cook IL-
1124 PM CDT Sun Jun 20 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT FOR NORTH
CENTRAL WILL...SOUTHEASTERN DUPAGE AND SOUTH CENTRAL COOK COUNTIES...
        
At 1123 PM CDT, a confirmed large and extremely dangerous tornado 
was located over Willow Springs, or over Justice, moving east at 50 
mph. This storm has a history of producing damage across southern 
DuPage County, and radar has indicated debris lofted thousands of 
feet in the air.

This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!

HAZARD...Damaging tornado.

SOURCE...Radar confirmed tornado.

IMPACT...You are in a life-threatening situation. Flying debris may 
         be deadly to those caught without shelter. Mobile homes 
         will be destroyed. Considerable damage to homes, 
         businesses, and vehicles is likely and complete destruction 
         is possible.

The tornado will be near...
  Oak Lawn, Midway Airport, Alsip, Midlothian and Crestwood around 
  1130 PM CDT.
  Chicago Lawn, Ashburn and Evergreen Park around 1135 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a large, extremely dangerous and potentially deadly
tornado is on the ground. To protect your life, TAKE COVER NOW! Move
to a basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 4161 8805 4179 8798 4180 8769 4151 8778
TIME...MOT...LOC 0423Z 268DEG 44KT 4174 8787 

TORNADO...OBSERVED
TORNADO DAMAGE THREAT...CONSIDERABLE
HAIL...<.75IN

OEMC zones...TORNADO WARNING. 8 and 10.
 
$$

FRIEDLEIN

652 
WWUS53 KLOT 210433
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1133 PM CDT Sun Jun 20 2021

ILC043-197-210442-
/O.CAN.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Will IL-DuPage IL-
1133 PM CDT Sun Jun 20 2021

...THE TORNADO WARNING FOR NORTH CENTRAL WILL AND SOUTHEASTERN DUPAGE
COUNTIES IS CANCELLED...
    
The tornadic 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 200 AM CDT for
northeastern Illinois.

LAT...LON 4151 8778 4151 8779 4156 8779 4156 8791
      4161 8791 4178 8789 4180 8769
TIME...MOT...LOC 0432Z 278DEG 41KT 4173 8777 

$$

ILC031-210445-
/O.CON.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Cook IL-
1133 PM CDT Sun Jun 20 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT FOR SOUTH
CENTRAL COOK COUNTY...
        
At 1132 PM CDT, a storm capable of producing a tornado was located 
near Burbank, moving east at 45 mph. The rotation in this storm has 
shown weakening over the past 10 minutes, and if this trend 
continues, a downstream warning will not be needed and this warning 
will be allowed to expire.

HAZARD...Damaging tornado.

SOURCE...Radar confirmed tornado.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This tornado will be near...
  Chicago Lawn, Ashburn, Evergreen Park and Midlothian around 1135 
  PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4151 8778 4151 8779 4156 8779 4156 8791
      4161 8791 4178 8789 4180 8769
TIME...MOT...LOC 0432Z 278DEG 41KT 4173 8777 

TORNADO...OBSERVED
HAIL...<.75IN

OEMC zones...TORNADO WARNING. 8 and 10.
 
$$

FRIEDLEIN

874 
WWUS53 KLOT 210443
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1143 PM CDT Sun Jun 20 2021

ILC031-210452-
/O.EXP.KLOT.TO.W.0004.000000T0000Z-210621T0445Z/
Cook IL-
1143 PM CDT Sun Jun 20 2021

...THE TORNADO WARNING FOR SOUTH CENTRAL COOK COUNTY WILL EXPIRE AT
1145 PM CDT...
        
The storm which prompted the warning has weakened in rotation, and 
has exited the warned area. Therefore, the warning will be allowed 
to expire. However gusty winds are still possible with these 
thunderstorms.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
northeastern Illinois.

LAT...LON 4151 8778 4151 8779 4156 8779 4156 8791
      4161 8791 4178 8789 4180 8769
TIME...MOT...LOC 0442Z 279DEG 43KT 4171 8763 

$$

FRIEDLEIN

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 20, 8:39 PM CDT	Severe Thunderstorm Warning	LOT	Winnebago	21 min
Jun 20, 9:02 PM CDT	Severe Thunderstorm Warning	LOT	Ogle	58 min
Jun 20, 10:12 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb	33 min
Jun 20, 10:22 PM CDT	Severe Thunderstorm Warning	LOT	Kane	53 min
Jun 20, 10:40 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	50 min
Jun 20, 10:43 PM CDT	Tornado Warning	LOT	DuPage, Kane	32 min
Jun 20, 10:46 PM CDT	Tornado Warning	LOT	Cook, DuPage	20 min
Jun 20, 10:48 PM CDT	Special Marine Warning	LOT		117 min
Jun 20, 10:50 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Grundy, Kane, Kendall, LaSalle	55 min
Jun 20, 10:56 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Will	79 min
Jun 20, 11:08 PM CDT	Areal Flood Advisory	LOT	Cook, DuPage, Kane, Kendall, Lake, McHenry and 1 more	4 hr
Jun 20, 11:15 PM CDT	Tornado Warning	LOT	Cook, DuPage	30 min
Jun 20, 11:30 PM CDT	Severe Thunderstorm Warning	LOT	Cook	30 min
Jun 20, 11:41 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee, Will	79 min
Jun 21, 12:00 AM CDT	Tornado Warning	LOT	Will	34 min
Jun 21, 3:22 PM CDT	Small Craft Advisory	LOT		7 hr

Nearby

Tornado Warnings in Illinois, 2021 Every tornado warning in 2021 Tornadoes 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.