Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 35, NWS Chicago, IL

August 9, 2021Kane County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 6:50 PM CDT for Kane County, Illinois. It was in force for 40 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 9, 2021, 6:50 PM CDT (23:50 UTC)
Expired: Aug 9, 2021, 7:30 PM CDT
In force: 40 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Kane County, IL

The radar

The Chicago radar (KLOT), 40 km from the middle of the area, began a volume at 23:52 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 9, 6:58 PM CDT	TORNADO	1 Wsw Campton Hills, IL	MULTIPLE REPORTS OF A BRIEF TORNADO NEAR CAMPTON HILLS.

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
Aug 9, 2:43 PM CDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.8 hours before the alert went out and 183 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: 1676 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 705 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.7

Open this sounding in Storm Lab

The text

As transmitted.

863 
WFUS53 KLOT 092350
TORLOT
ILC089-100030-
/O.NEW.KLOT.TO.W.0035.210809T2350Z-210810T0030Z/

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

The National Weather Service in Chicago has issued a

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

* Until 730 PM CDT.
    
* At 650 PM CDT, a severe thunderstorm capable of producing a 
  tornado was located over Campton Hills, moving east at 25 mph. 
  This storm has a history of producing tornadoes. 

  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...
  St. Charles and Valley View around 705 PM CDT.
  Bartlett, Geneva, South Elgin and Wayne around 710 PM CDT.

Other locations in the path of this tornadic thunderstorm include
West Chicago and Batavia.

This includes...  Kane County Cougars Ballpark.
 
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 4186 8826 4190 8844 4199 8842 4199 8826
TIME...MOT...LOC 2350Z 277DEG 21KT 4194 8843 

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

$$

Carlaw

1 follow-up statement

521 
WWUS53 KLOT 100029
SVSLOT

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

ILC089-100038-
/O.EXP.KLOT.TO.W.0035.000000T0000Z-210810T0030Z/
Kane IL-
729 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR EAST CENTRAL KANE COUNTY WILL EXPIRE AT
730 PM CDT...
                
The storm which prompted the warning has weakened below severe 
limits. Therefore, the warning will be allowed to expire. There is 
still some rotation with storms in this area, so future tornado 
warnings are possible if these storms strengthen. 

A Tornado Watch remains in effect until 1000 PM CDT for northeastern
Illinois.

LAT...LON 4186 8826 4190 8844 4199 8842 4199 8826
TIME...MOT...LOC 0028Z 277DEG 21KT 4191 8814 

$$

Donofrio

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 6:52 AM CDT	Special Weather Statement	LOT	Winnebago	23 min
Aug 9, 11:49 AM CDT	Areal Flood Advisory	LOT	Boone, DeKalb, Kane, McHenry, Ogle, Winnebago	3 hr
Aug 9, 2:46 PM CDT	Heat Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	28 hr
Aug 9, 3:14 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Ogle, Winnebago	61 min
Aug 9, 3:25 PM CDT	Areal Flood Advisory	LOT	Boone, Winnebago	3 hr
Aug 9, 3:46 PM CDT	Tornado Warning	LOT	Boone, Winnebago	26 min
Aug 9, 4:12 PM CDT	Areal Flood Advisory	LOT	Boone, McHenry	3 hr
Aug 9, 4:34 PM CDT	Tornado Warning Tornado observed	LOT	DeKalb	41 min
Aug 9, 4:39 PM CDT	Tornado Warning	LOT	DeKalb, Ogle	51 min
Aug 9, 5:11 PM CDT	Tornado Warning	LOT	Lee	49 min
Aug 9, 5:15 PM CDT	Tornado Warning	LOT	DeKalb, Kane	60 min
Aug 9, 5:32 PM CDT	Tornado Warning Tornado observed	LOT	DeKalb, Ogle	43 min
Aug 9, 5:42 PM CDT	Tornado Warning	LOT	Kane	48 min
Aug 9, 6:00 PM CDT	Tornado Warning	LOT	DeKalb, Lee	26 min
Aug 9, 6:09 PM CDT	Tornado Warning	LOT	DeKalb, Kane	51 min
Aug 9, 6:24 PM CDT	Tornado Warning	LOT	DuPage, Kane	66 min
Aug 9, 6:45 PM CDT	Special Marine Warning	LOT		90 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.