Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 24, NWS Chicago, IL

July 24, 2021Iroquois County, Illinois

NWS Chicago, IL issued this tornado warning at Jul 24, 2021, 8:51 PM CDT for Iroquois County, Illinois. It was in force for 24 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
Jul 24, 2021, 8:51 PM CDT (01:51 UTC)
Expired
Jul 24, 2021, 9:15 PM CDT
In force
24 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Iroquois County, IL

The radar

The Chicago radar (KLOT), 117 km from the middle of the area, began a volume at 01:51 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
Jul 24, 3:32 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.9 hours before the alert went out and 82 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 00:00Z on 2021-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2275 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 00:00Z on 2021-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 160 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
2275 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
1261 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
262 m²/s²
Significant tornado parameter
1.1
Supercell composite
13.1

Open this sounding in Storm Lab

The text

As transmitted.

329 
WFUS53 KLOT 250151
TORLOT
ILC075-250215-
/O.NEW.KLOT.TO.W.0024.210725T0151Z-210725T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
851 PM CDT Sat Jul 24 2021

The National Weather Service in Chicago has issued a

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

* Until 915 PM CDT.
    
* At 850 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Cissna Park, or 10 miles west of Milford, moving
  southeast at 30 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 tornadic thunderstorm will remain over mainly rural areas of
  southeastern Iroquois County, including the following locations...
  Claytonville and Wellington.

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 4059 8799 4068 8787 4058 8753 4049 8754
      4049 8787
TIME...MOT...LOC 0150Z 308DEG 26KT 4060 8789 

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

$$

Birk
2 follow-up statements
116 
WWUS53 KLOT 250159
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
859 PM CDT Sat Jul 24 2021

ILC075-250215-
/O.CON.KLOT.TO.W.0024.000000T0000Z-210725T0215Z/
Iroquois IL-
859 PM CDT Sat Jul 24 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 915 PM CDT FOR
SOUTHEASTERN IROQUOIS COUNTY...
    
At 859 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Cissna Park, or 8 miles southwest of Milford, moving
southeast at 30 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...
Cissna Park, Wellington and Claytonville. 

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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4056 8796 4064 8786 4056 8753 4049 8754
      4049 8787
TIME...MOT...LOC 0159Z 308DEG 26KT 4056 8782 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Birk
727 
WWUS53 KLOT 250216
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
916 PM CDT Sat Jul 24 2021

ILC075-250226-
/O.EXP.KLOT.TO.W.0024.000000T0000Z-210725T0215Z/
Iroquois IL-
916 PM CDT Sat Jul 24 2021

...THE TORNADO WARNING FOR SOUTHEASTERN IROQUOIS COUNTY HAS
EXPIRED...
        
The storm which prompted the warning has weakened below severe 
limits. Therefore, the warning has been allowed to expire.  However 
gusty winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
east central Illinois.

LAT...LON 4056 8796 4064 8786 4056 8753 4049 8754
      4049 8787
TIME...MOT...LOC 0216Z 308DEG 26KT 4049 8770 

$$

Birk

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 7:22 PM CDTSevere Thunderstorm WarningLOTIroquois53 min
Jul 24, 8:06 PM CDTSpecial Weather StatementLOTIroquois24 min
Jul 24, 8:10 PM CDTSevere Thunderstorm WarningLOTIroquois65 min
Jul 24, 8:47 PM CDTAreal Flood AdvisoryLOTIroquois4 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.