Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 41, NWS Chicago, IL

December 10, 2021Will County, Illinois; Lake County, Indiana

NWS Chicago, IL issued this tornado warning at Dec 10, 2021, 10:00 PM CST for Will County, Illinois; Lake County, Indiana. It was in force for 16 min. 2 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: Dec 10, 2021, 10:00 PM CST (04:00 UTC)
Expired: Dec 10, 2021, 10:16 PM CST
In force: 16 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Will County, IL, Lake County, IN

The radar

The Chicago radar (KLOT), 60 km from the middle of the area, began a volume at 03:59 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
Dec 10, 10:00 PM CST	TSTM WND DMG	2 W Crown Point, IN	MULTIPLE POWER POLES AND TREES DOWN ALONG FATHKE ROAD IN CROWN POINT. POSSIBLE TORNADO BASED ON SUBTLE TORNADO DEBRIS SIGNATURE ON RADAR. TIME ESTIMATED BY RADAR.
Dec 10, 10:05 PM CST	TORNADO	3 Nnw Cedar Lake, IN	NWS STORM SURVEY FOUND DAMAGE CONSISTENT WITH AN EF-0 TORNADO WITH ESTIMATED PEAK WIND SPEEDS OF 85 MPH AND A PATH LENGTH OF 4.8 MILES FROM UNINCORPORATED CEDAR LAKE INTO THE NORTH SIDE OF CROWN POINT.

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

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 4.0 hours before the alert went out and 175 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: 119 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 662 m above ground
0-6 km bulk shear: 73 kt
0-1 km storm-relative helicity: 341 m²/s²
0-3 km storm-relative helicity: 357 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

585 
WFUS53 KLOT 110400
TORLOT
ILC197-INC089-110430-
/O.NEW.KLOT.TO.W.0041.211211T0400Z-211211T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
1000 PM CST Fri Dec 10 2021

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  East central Will County in northeastern Illinois...
  Central Lake County in northwestern Indiana...

* Until 1030 PM CST.
    
* At 1000 PM CST, a severe thunderstorm capable of producing a
  tornado was located near Beecher, or near Cedar Lake, moving
  northeast at 55 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...
  Cedar Lake, Dyer, St. John and Lake Dalecarlia around 1005 PM CST.
  Schererville and Crown Point around 1010 PM CST.
  Merrillville, Lakes of the Four Seasons and Winfield around 1015 
  PM CST.
  Hobart, Lake Station and New Chicago around 1020 PM CST.

Other locations in the path of this tornadic thunderstorm include
Portage.

This includes...  Indiana University Northwest, Illiana Motor
Speedway, and Lake County Fairgrounds.
 
Including the following interstates...
 Indiana I-80 between mile markers 10 and 15.
 Indiana I-90 between mile markers 18 and 21.
 Indiana I-94 near mile marker 16.
 Indiana I-65 between mile markers 244 and 261.

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 4130 8756 4142 8762 4162 8724 4162 8722
      4136 8722
TIME...MOT...LOC 0400Z 241DEG 48KT 4138 8754 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

Borchardt

2 follow-up statements

386 
WWUS53 KLOT 110405
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1005 PM CST Fri Dec 10 2021

ILC197-110414-
/O.CAN.KLOT.TO.W.0041.000000T0000Z-211211T0430Z/
Will IL-
1005 PM CST Fri Dec 10 2021

...THE TORNADO WARNING FOR EAST CENTRAL WILL COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 4131 8753 4147 8753 4162 8724 4162 8722
      4136 8722
TIME...MOT...LOC 0404Z 240DEG 48KT 4140 8746 

$$

INC089-110430-
/O.CON.KLOT.TO.W.0041.000000T0000Z-211211T0430Z/
Lake IN-
1005 PM CST Fri Dec 10 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1030 PM CST FOR CENTRAL
LAKE COUNTY...
    
At 1004 PM CST, a severe thunderstorm capable of producing a tornado
was located over Cedar Lake, moving northeast at 55 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...
  Crown Point around 1010 PM CST.
  Merrillville, Lakes of the Four Seasons and Winfield around 1015 
  PM CST.
  Lake Station and New Chicago around 1020 PM CST.

Other locations in the path of this tornadic thunderstorm include
Hobart and Portage.

This includes...  Indiana University Northwest, Illiana Motor
Speedway, and Lake County Fairgrounds.
 
Including the following interstates...
 Indiana I-80 between mile markers 10 and 15.
 Indiana I-90 between mile markers 17 and 21.
 Indiana I-94 near mile marker 16.
 Indiana I-65 between mile markers 244 and 261.

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 4131 8753 4147 8753 4162 8724 4162 8722
      4136 8722
TIME...MOT...LOC 0404Z 240DEG 48KT 4140 8746 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

Borchardt

521 
WWUS53 KLOT 110416
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1016 PM CST Fri Dec 10 2021

INC089-110426-
/O.CAN.KLOT.TO.W.0041.000000T0000Z-211211T0430Z/
Lake IN-
1016 PM CST Fri Dec 10 2021

...THE TORNADO WARNING FOR CENTRAL LAKE COUNTY IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.

LAT...LON 4131 8753 4147 8753 4162 8724 4162 8722
      4136 8722
TIME...MOT...LOC 0414Z 241DEG 48KT 4148 8727 

$$

Borchardt

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 10, 9:26 PM CST	Severe Thunderstorm Warning	LOT	Grundy, Will	28 min
Dec 10, 9:27 PM CST	Severe Thunderstorm Warning	LOT	Ford, Iroquois, Livingston	48 min
Dec 10, 9:46 PM CST	Severe Thunderstorm Warning	LOT	Kankakee, Will	44 min
Dec 10, 9:55 PM CST	Special Weather Statement	LOT	Iroquois	65 min
Dec 10, 10:18 PM CST	Special Marine Warning	LOT		27 min
Dec 11, 5:56 PM CST	Small Craft Advisory	LOT		39 hr
Dec 10, 10:04 PM CST	Tornado Warning	LOT	Jasper, Porter	26 min
Dec 10, 10:11 PM CST	Severe Thunderstorm Warning	LOT	Porter	34 min
Dec 10, 10:22 PM CST	Severe Thunderstorm Warning	LOT	Benton, Jasper, Newton	38 min

Nearby

Tornado Warnings in Illinois, 2021 Tornado Warnings in Indiana, 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.