Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 28, NWS Chicago, IL

August 9, 2021Lee County, Illinois

NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 5:11 PM CDT for Lee County, Illinois. It was in force for 49 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, 5:11 PM CDT (22:11 UTC)
Expired: Aug 9, 2021, 6:00 PM CDT
In force: 49 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Lee County, IL

The radar

The Chicago radar (KLOT), 103 km from the middle of the area, began a volume at 22:12 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

Davenport, (KDVN), launched 12:00Z, 10.2 hours before the alert went out and 97 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.

055 
WFUS53 KLOT 092211
TORLOT
ILC103-092300-
/O.NEW.KLOT.TO.W.0028.210809T2211Z-210809T2300Z/

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

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  Southern Lee County in north central Illinois...

* Until 600 PM CDT.
    
* At 510 PM CDT, a thunderstorm capable of producing a tornadoe was 
  located near Amboy with another near Walnut, moving east at 10 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.

* These dangerous storms will be near...
  Amboy and Woodhaven Lakes around 515 PM CDT.

Other locations in the path of these tornadic storms include
Sublette.

Including the following interstate...
 I-39 between mile markers 78 and 86.
 
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 4164 8963 4173 8938 4175 8900 4163 8901
      4163 8917 4158 8917 4159 8963
TIME...MOT...LOC 2210Z 271DEG 8KT 4169 8933 4162 8957 

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

$$

Carlaw

2 follow-up statements

240 
WWUS53 KLOT 092240
SVSLOT

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

ILC103-092300-
/O.CON.KLOT.TO.W.0028.000000T0000Z-210809T2300Z/
Lee IL-
540 PM CDT Mon Aug 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM CDT FOR
SOUTHEASTERN LEE COUNTY...
    
At 539 PM CDT, two severe thunderstorms capable of producing 
tornadoes were located along a line extending from 6 miles northeast 
of Sublette to near Woodhaven Lakes, 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.

These tornadic storms will remain over mainly rural areas of
southeastern Lee County, including the following locations... Compton
and West Brooklyn.

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 4172 8927 4175 8900 4163 8901 4163 8917
      4158 8917 4159 8946 4163 8945
TIME...MOT...LOC 2239Z 262DEG 22KT 4169 8913 4162 8937 

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

$$

LENNING

346 
WWUS53 KLOT 092303
SVSLOT

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

ILC103-092311-
/O.EXP.KLOT.TO.W.0028.000000T0000Z-210809T2300Z/
Lee IL-
603 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR SOUTHEASTERN LEE COUNTY HAS EXPIRED...
    
The storms which prompted the warning have 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.

Remember, a Tornado Warning remains in effect for far southeast Lee 
County until 645 PM CDT.

LAT...LON 4172 8927 4175 8900 4163 8901 4163 8917
      4158 8917 4159 8946 4163 8945
TIME...MOT...LOC 2301Z 271DEG 8KT 4169 8907 4162 8931 

$$

LENNING

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, 5:15 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.