Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 39, NWS Chicago, IL

October 3, 2021Iroquois County, Illinois

NWS Chicago, IL issued this tornado warning at Oct 3, 2021, 3:28 PM CDT for Iroquois County, Illinois. It was in force for 17 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
Oct 3, 2021, 3:28 PM CDT (20:28 UTC)
Expired
Oct 3, 2021, 3:45 PM CDT
In force
17 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Tornado
Observed
Hail
0.0 in

County Iroquois County, IL

The radar

The Chicago radar (KLOT), 76 km from the middle of the area, began a volume at 20:31 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 nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 8.5 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2021-10-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 819 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, Lincoln, IL at 12:00Z on 2021-10-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
819 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
631 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

049 
WFUS53 KLOT 032028
TORLOT
ILC075-032045-
/O.NEW.KLOT.TO.W.0039.211003T2028Z-211003T2045Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
328 PM CDT Sun Oct 3 2021

The National Weather Service in Chicago has issued a

* Tornado Warning for...
  Northwestern Iroquois County in east central Illinois...

* Until 345 PM CDT.

* At 328 PM CDT, a confirmed tornado was located near Ashkum, or near
  Clifton, moving south at 5 mph.

  HAZARD...Damaging tornado.

  SOURCE...Weather spotters confirmed tornado.

  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 tornadic thunderstorm will remain over mainly rural areas of
  northwestern Iroquois County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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 4094 8808 4094 8801 4089 8801 4089 8808
TIME...MOT...LOC 2028Z 359DEG 5KT 4092 8805 

TORNADO...OBSERVED
MAX HAIL SIZE...0.00 IN
$$

Birk
1 follow-up statement
396 
WWUS53 KLOT 032043
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
343 PM CDT Sun Oct 3 2021

ILC075-032053-
/O.EXP.KLOT.TO.W.0039.000000T0000Z-211003T2045Z/
Iroquois IL-
343 PM CDT Sun Oct 3 2021

...THE TORNADO WARNING FOR NORTHWESTERN IROQUOIS COUNTY WILL EXPIRE
AT 345 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 4094 8808 4094 8801 4089 8801 4089 8808
TIME...MOT...LOC 2043Z 359DEG 5KT 4090 8805 

$$

Birk

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 2, 7:47 PM CDTAreal Flood AdvisoryLOTLivingston4 hr
Oct 3, 3:26 PM CDTAreal Flood AdvisoryLOTCook, Will5 hr

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.