Alert archive / Illinois / Tornado Warnings in 2021

Tornado Warning 23, NWS Chicago, IL

July 12, 2021Iroquois County, Illinois

NWS Chicago, IL issued this tornado warning at Jul 12, 2021, 2:39 PM CDT for Iroquois County, Illinois. It was in force for 36 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: Jul 12, 2021, 2:39 PM CDT (19:39 UTC)
Expired: Jul 12, 2021, 3:15 PM CDT
In force: 36 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), 83 km from the middle of the area, began a volume at 19:40 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
Jul 12, 2:47 PM CDT	TSTM WND DMG	Ashkum, IL	SEVERAL BRANCHES DOWNED ALONG U.S. HIGHWAY 45.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 7.7 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: 653 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 548 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

409 
WFUS53 KLOT 121939
TORLOT
ILC075-122015-
/O.NEW.KLOT.TO.W.0023.210712T1939Z-210712T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
239 PM CDT Mon Jul 12 2021

The National Weather Service in Chicago has issued a

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

* Until 315 PM CDT.
    
* At 239 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Ashkum, or near Gilman, 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.

* This dangerous storm will be near...
  Ashkum around 250 PM CDT.

Including the following interstate...
 I-57 between mile markers 290 and 294.
 
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 4084 8802 4088 8802 4094 8785 4083 8785
TIME...MOT...LOC 1939Z 261DEG 10KT 4085 8798 

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

$$

Kluber

3 follow-up statements

006 
WWUS53 KLOT 121948
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
248 PM CDT Mon Jul 12 2021

ILC075-122015-
/O.CON.KLOT.TO.W.0023.000000T0000Z-210712T2015Z/
Iroquois IL-
248 PM CDT Mon Jul 12 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 315 PM CDT FOR NORTH
CENTRAL IROQUOIS COUNTY...
    
At 248 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Ashkum, moving northeast at 15 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
north central Iroquois County.

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 4085 8798 4089 8799 4094 8785 4085 8785
TIME...MOT...LOC 1948Z 235DEG 12KT 4088 8795 

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

$$

Kluber

464 
WWUS53 KLOT 122001
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
301 PM CDT Mon Jul 12 2021

ILC075-122015-
/O.CON.KLOT.TO.W.0023.000000T0000Z-210712T2015Z/
Iroquois IL-
301 PM CDT Mon Jul 12 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 315 PM CDT FOR
NORTHWESTERN IROQUOIS COUNTY...
    
At 259 PM CDT, a severe thunderstorm capable of producing a tornado 
was located 2 miles east of Ashkum, moving east-northeast 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.

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

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 4085 8794 4090 8794 4094 8785 4085 8785
TIME...MOT...LOC 1959Z 258DEG 6KT 4088 8793 

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

$$

Kluber

148 
WWUS53 KLOT 122013
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
313 PM CDT Mon Jul 12 2021

ILC075-122022-
/O.EXP.KLOT.TO.W.0023.000000T0000Z-210712T2015Z/
Iroquois IL-
313 PM CDT Mon Jul 12 2021

...THE TORNADO WARNING FOR NORTHWESTERN IROQUOIS COUNTY WILL EXPIRE
AT 315 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.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 4085 8794 4090 8794 4094 8785 4085 8785
TIME...MOT...LOC 2012Z 261DEG 10KT 4088 8789 

$$

Kluber

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 2:11 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois	49 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.