Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 37, NWS Chicago, IL

August 9, 2021Will County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 10:06 PM CDT for Will County, Illinois. It was in force for 54 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 9, 2021, 10:06 PM CDT (03:06 UTC)
Expired: Aug 9, 2021, 11:00 PM CDT
In force: 54 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Will County, IL

The radar

The Chicago radar (KLOT), 37 km from the middle of the area, began a volume at 03:09 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 9, 2:43 PM CDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 3.1 hours before the alert went out and 157 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: 4598 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 775 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 179 m²/s²
0-3 km storm-relative helicity: 284 m²/s²
Significant tornado parameter: 3.9
Supercell composite: 24.2

Open this sounding in Storm Lab

The text

As transmitted.

524 
WFUS53 KLOT 100306
TORLOT
ILC197-100400-
/O.NEW.KLOT.TO.W.0037.210810T0306Z-210810T0400Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
1006 PM CDT Mon Aug 9 2021

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  East central Will County in northeastern Illinois...

* Until 1100 PM CDT.
    
* At 1006 PM CDT, a severe thunderstorm capable of producing a
  tornado was located near Manhattan, or near Peotone, moving east at
  25 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.

* Locations impacted include...
  Monee, University Park, Park Forest, Crete, Beecher and Steger.

This includes...  Governors State University.
 
Including the following interstate...
 I-57 between mile markers 328 and 337.
 
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.

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

&&

LAT...LON 4133 8791 4141 8792 4147 8771 4147 8757
      4145 8756 4136 8756
TIME...MOT...LOC 0306Z 258DEG 20KT 4137 8790 

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

$$

Carlaw

4 follow-up statements

280 
WWUS53 KLOT 100325
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1025 PM CDT Mon Aug 9 2021

ILC197-100400-
/O.CON.KLOT.TO.W.0037.000000T0000Z-210810T0400Z/
Will IL-
1025 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT FOR EAST
CENTRAL WILL COUNTY...
    
At 1025 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Monee, or near Park Forest, moving east at 25 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.

Locations impacted include...
Park Forest, Steger, Crete, University Park and Monee. 

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.

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

&&

LAT...LON 4137 8782 4145 8779 4147 8771 4147 8757
      4145 8756 4141 8756
TIME...MOT...LOC 0325Z 251DEG 20KT 4142 8776 

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

$$

Carlaw

393 
WWUS53 KLOT 100337
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1037 PM CDT Mon Aug 9 2021

ILC197-100400-
/O.CON.KLOT.TO.W.0037.000000T0000Z-210810T0400Z/
Will IL-
1037 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT FOR EAST
CENTRAL WILL COUNTY...
    
At 1037 PM CDT, a severe thunderstorm capable of producing a tornado
was located over University Park, or over Park Forest, moving east at
20 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.

Locations impacted include...
Park Forest, Steger, Crete and University Park. 

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.

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

&&

LAT...LON 4141 8772 4147 8772 4147 8757 4145 8756
      4143 8756
TIME...MOT...LOC 0337Z 255DEG 19KT 4144 8769 

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

$$

Carlaw

494 
WWUS53 KLOT 100347
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1047 PM CDT Mon Aug 9 2021

ILC197-100400-
/O.CON.KLOT.TO.W.0037.000000T0000Z-210810T0400Z/
Will IL-
1047 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT FOR EASTERN
WILL COUNTY...
    
At 1046 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Crete, or over Steger, moving east at 25 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.

Locations impacted include...
Steger and Crete. 

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.

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

&&

LAT...LON 4142 8765 4147 8765 4147 8757 4145 8756
      4143 8756
TIME...MOT...LOC 0346Z 257DEG 21KT 4145 8761 

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

$$

Carlaw

439 
WWUS53 KLOT 100354
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
1054 PM CDT Mon Aug 9 2021

ILC197-100404-
/O.EXP.KLOT.TO.W.0037.000000T0000Z-210810T0400Z/
Will IL-
1054 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR EASTERN WILL COUNTY WILL EXPIRE AT 1100 PM
CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until midnight CDT for northeastern
Illinois.

LAT...LON 4142 8765 4147 8765 4147 8757 4145 8756
      4143 8756
TIME...MOT...LOC 0354Z 258DEG 20KT 4146 8755 

$$

Carlaw

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 7:18 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	42 min
Aug 9, 8:21 PM CDT	Special Marine Warning	LOT		114 min
Aug 9, 9:19 PM CDT	Special Weather Statement	LOT	Grundy	26 min
Aug 9, 9:30 PM CDT	Tornado Warning	LOT	Kankakee, Will	45 min
Aug 9, 10:12 PM CDT	Special Marine Warning	LOT		2 hr
Aug 10, 3:07 PM CDT	Heat Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	28 hr
Aug 10, 5:21 PM CDT	Special Weather Statement	LOT	Lee, Ogle, Winnebago	54 min
Aug 10, 5:39 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle, Winnebago	81 min
Aug 10, 6:10 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, LaSalle, Lee	65 min
Aug 10, 6:16 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, McHenry	74 min
Aug 10, 6:34 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, DuPage, Kane, Lake, McHenry	86 min
Aug 10, 6:38 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kane, Kendall	82 min
Aug 10, 6:55 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, DuPage, Will	95 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.