Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 27, NWS Chicago, IL

August 9, 2021DeKalb County, Ogle County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 4:39 PM CDT for DeKalb County, Ogle County, Illinois. It was in force for 51 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, 4:39 PM CDT (21:39 UTC)
Expired: Aug 9, 2021, 5:30 PM CDT
In force: 51 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties DeKalb County, IL, Ogle County, IL

The radar

The Chicago radar (KLOT), 88 km from the middle of the area, began a volume at 21:38 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, 4:52 PM CDT	TORNADO	3 Sw Kingston, IL	MULTIPLE REPORTS OF A TORNADO SOUTH OF KENTLAND AND KINGSTON.

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, 9.7 hours before the alert went out and 140 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.

886 
WFUS53 KLOT 092139
TORLOT
ILC037-141-092230-
/O.NEW.KLOT.TO.W.0027.210809T2139Z-210809T2230Z/

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

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  East central Ogle County in north central Illinois...
  Northwestern De Kalb County in north central Illinois...

* Until 530 PM CDT.
    
* At 439 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Kirkland, or 9 miles southeast of Rockford 
  Airport, moving east at 25 mph. An additional tornado warning is 
  in effect for a cell northeast of Esmond.

  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...
  Kirkland around 455 PM CDT.

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

Including the following interstate...
 I-39 between mile markers 109 and 114.
 
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 4207 8904 4215 8903 4215 8876 4201 8877
TIME...MOT...LOC 2139Z 278DEG 21KT 4210 8897 

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

$$

Carlaw

2 follow-up statements

859 
WWUS53 KLOT 092158
SVSLOT

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

ILC141-092207-
/O.CAN.KLOT.TO.W.0027.000000T0000Z-210809T2230Z/
Ogle IL-
458 PM CDT Mon Aug 9 2021

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

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

LAT...LON 4215 8876 4201 8877 4206 8894 4215 8894
TIME...MOT...LOC 2157Z 276DEG 19KT 4209 8886 

$$

ILC037-092230-
/O.CON.KLOT.TO.W.0027.000000T0000Z-210809T2230Z/
De Kalb IL-
458 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR
NORTHWESTERN DE KALB COUNTY...
    
At 457 PM CDT, a severe thunderstorm capable of producing a tornado 
was located 2 miles west of Kirkland, or 10 miles west of Genoa, 
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...
  Kingston.

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 4215 8876 4201 8877 4206 8894 4215 8894
TIME...MOT...LOC 2157Z 276DEG 19KT 4209 8886 

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

$$

Carlaw

034 
WWUS53 KLOT 092230
SVSLOT

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

ILC037-092240-
/O.EXP.KLOT.TO.W.0027.000000T0000Z-210809T2230Z/
De Kalb IL-
530 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR NORTHWESTERN DE KALB COUNTY HAS EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.

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

LAT...LON 4215 8876 4201 8877 4206 8894 4215 8894
TIME...MOT...LOC 2230Z 278DEG 21KT 4206 8861 

$$

Carlaw

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, 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
Aug 9, 6:50 PM CDT	Tornado Warning	LOT	Kane	40 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.