Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 34, NWS Chicago, IL

August 9, 2021DuPage County, Kane County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 6:24 PM CDT for DuPage County, Kane County, Illinois. It was in force for 66 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, 6:24 PM CDT (23:24 UTC)
Expired
Aug 9, 2021, 7:30 PM CDT
In force
66 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties DuPage County, IL, Kane County, IL

The radar

The Chicago radar (KLOT), 41 km from the middle of the area, began a volume at 23:25 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.

IssuedProductOfficeLasted
Aug 9, 2:43 PM CDTTornado WatchSPC9 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.4 hours before the alert went out and 193 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2021-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1676 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2021-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 171 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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.

294 
WFUS53 KLOT 092324
TORLOT
ILC043-089-100030-
/O.NEW.KLOT.TO.W.0034.210809T2324Z-210810T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
624 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...
  Northwestern DuPage County in northeastern Illinois...

* Until 730 PM CDT.
    
* At 624 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Valley View, or near St. Charles, 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.

* This dangerous storm will be near...
  Bartlett and Wayne around 630 PM CDT.
  West Chicago and Dupage Airport around 635 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Carol Stream, Hanover Park, Bloomingdale, Winfield, Glendale Heights,
Wheaton, Glen Ellyn, Roselle, Addison, Itasca, Downers Grove and
Lombard.

This includes...  DuPage County Fairgrounds and Wheaton College.
 
Including the following interstates...
 I-290 between mile markers 5 and 8.
 I-355 between mile markers 23 and 30.

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 4199 8826 4199 8800 4183 8802 4192 8835
      4200 8834 4200 8826
TIME...MOT...LOC 2324Z 283DEG 20KT 4197 8832 

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

$$

Carlaw
3 follow-up statements
875 
WWUS53 KLOT 092342
SVSLOT

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

ILC089-092351-
/O.CAN.KLOT.TO.W.0034.000000T0000Z-210810T0030Z/
Kane IL-
642 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR EAST CENTRAL KANE COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled. An 
additional tornadic thunderstorm is ongoing northeast of Maple Park. 

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

LAT...LON 4185 8802 4192 8826 4199 8826 4199 8800
TIME...MOT...LOC 2341Z 279DEG 20KT 4195 8819 

$$

ILC043-100030-
/O.CON.KLOT.TO.W.0034.000000T0000Z-210810T0030Z/
DuPage IL-
642 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR
NORTHWESTERN DUPAGE COUNTY...
    
At 641 PM CDT, a severe thunderstorm capable of producing a tornado 
was located over Bartlett, moving east at 25 mph. Weather spotters 
have reported a rotating wall cloud with this storm which could 
produce a tornado at any time. 

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...
  Carol Stream, Hanover Park, Bloomingdale, Winfield, Glendale 
  Heights, Wheaton, Glen Ellyn, Roselle, Addison, Itasca and 
  Lombard.

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 4185 8802 4192 8826 4199 8826 4199 8800
TIME...MOT...LOC 2341Z 279DEG 20KT 4195 8819 

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

$$

Carlaw
798 
WWUS53 KLOT 100007
SVSLOT

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

ILC043-100030-
/O.CON.KLOT.TO.W.0034.000000T0000Z-210810T0030Z/
DuPage IL-
707 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR
NORTHWESTERN DUPAGE COUNTY...
    
At 706 PM CDT, a severe thunderstorm capable of producing a tornado 
was located over Itasca, or over Addison, moving east at 20 mph. 
Additional areas of rotation exist just south of Hanover Park. 

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...
Bartlett, Carol Stream, Hanover Park, Addison, Glendale Heights, St.
Charles, West Chicago, Roselle, Bloomingdale, Itasca, Wayne and
Medinah.

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 4194 8801 4192 8826 4199 8826 4199 8800
TIME...MOT...LOC 0006Z 270DEG 18KT 4197 8803 

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

$$

Carlaw
497 
WWUS53 KLOT 100028
SVSLOT

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

ILC043-100038-
/O.EXP.KLOT.TO.W.0034.000000T0000Z-210810T0030Z/
DuPage IL-
728 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR NORTHWESTERN DUPAGE COUNTY WILL EXPIRE AT
730 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 1000 PM CDT for northeastern
Illinois.

LAT...LON 4194 8801 4192 8826 4199 8826 4199 8800
TIME...MOT...LOC 0028Z 283DEG 20KT 4194 8788 

$$

Donofrio

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 6:52 AM CDTSpecial Weather StatementLOTWinnebago23 min
Aug 9, 11:49 AM CDTAreal Flood AdvisoryLOTBoone, DeKalb, Kane, McHenry, Ogle, Winnebago3 hr
Aug 9, 2:46 PM CDTHeat AdvisoryLOTBoone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more28 hr
Aug 9, 3:14 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Ogle, Winnebago61 min
Aug 9, 3:25 PM CDTAreal Flood AdvisoryLOTBoone, Winnebago3 hr
Aug 9, 3:46 PM CDTTornado WarningLOTBoone, Winnebago26 min
Aug 9, 4:12 PM CDTAreal Flood AdvisoryLOTBoone, McHenry3 hr
Aug 9, 4:34 PM CDTTornado Warning Tornado observedLOTDeKalb41 min
Aug 9, 4:39 PM CDTTornado WarningLOTDeKalb, Ogle51 min
Aug 9, 5:11 PM CDTTornado WarningLOTLee49 min
Aug 9, 5:15 PM CDTTornado WarningLOTDeKalb, Kane60 min
Aug 9, 5:32 PM CDTTornado Warning Tornado observedLOTDeKalb, Ogle43 min
Aug 9, 5:42 PM CDTTornado WarningLOTKane48 min
Aug 9, 6:00 PM CDTTornado WarningLOTDeKalb, Lee26 min
Aug 9, 6:09 PM CDTTornado WarningLOTDeKalb, Kane51 min
Aug 9, 6:45 PM CDTSpecial Marine WarningLOT90 min
Aug 9, 6:50 PM CDTTornado WarningLOTKane40 min

Nearby

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