Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 41, NWS Chicago, IL

July 24, 2021Cook County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 24, 2021, 4:26 PM CDT for Cook County, Illinois. It was in force for 49 min. 3 reports 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 24, 2021, 4:26 PM CDT (21:26 UTC)
Expired: Jul 24, 2021, 5:15 PM CDT
In force: 49 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Cook County, IL

The radar

The Chicago radar (KLOT), 48 km from the middle of the area, began a volume at 21:29 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 24, 4:34 PM CDT	TSTM WND DMG	1 Sse Norridge, IL	VIDEO SHARED ON SOCIAL MEDIA OF A LARGE TREE SNAPPED IN NORRIDGE. TIME ESTIMATED FROM RADAR.
Jul 24, 4:39 PM CDT	TSTM WND DMG	1 Nne Portage Park - Ch, IL	PHOTO SHARED ON SOCIAL MEDIA OF A LARGE TREE BRANCH DOWNED NEAR THE I-90 AND I-94 SPLIT ON THE NORTHWEST SIDE OF CHICAGO. TIME ESTIMATED FROM RADAR.
Jul 24, 4:49 PM CDT	TSTM WND DMG	1 Sw Lincoln Park - Chi, IL	LARGE TREE LIMBS DOWNED ONTO A CAR IN LINCOLN PARK. TIME ESTIMATED FROM RADAR.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 24, 3:32 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.4 hours before the alert went out and 210 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: 553 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 964 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 65 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

088 
WUUS53 KLOT 242126
SVRLOT
ILC031-242215-
/O.NEW.KLOT.SV.W.0041.210724T2126Z-210724T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Chicago/Romeoville
426 PM CDT Sat Jul 24 2021

The National Weather Service in Chicago has issued a

* Severe Thunderstorm Warning for...
  Central Cook County in northeastern Illinois...

* Until 515 PM CDT.

* At 425 PM CDT, a severe thunderstorm was located over near Ohare 
  Airport, moving southeast at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Chicago, Cicero, Evanston, Skokie, Oak Lawn, Berwyn, Oak Park, Park
  Ridge, Niles, West Town, Englewood, Chicago Lawn, Austin, West
  Ridge, Lincoln Park, Bridgeport, Chicago Loop, South Lawndale, Lake
  View and Irving Park.


This includes...Brookfield Zoo, Lincoln Park Zoo, Loyola University, 
Triton College, University of Chicago, Hawthorne Park, Northeastern 
Illinois University, Soldier Field, University of Illinois Chicago, 
Guaranteed Rate Field...IL Institute of Technology, Wrigley Field, 
The Loop, Museum of Science and Industry, Museum Campus, and 
Northerly Island.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4204 8767 4198 8765 4196 8763 4196 8764
      4190 8762 4189 8761 4188 8762 4187 8762
      4187 8761 4185 8761 4178 8757 4178 8756
      4177 8756 4173 8778 4192 8792 4196 8792
      4206 8770
TIME...MOT...LOC 2125Z 313DEG 27KT 4199 8790 

HAIL...<.75IN
WIND...60MPH
 
$$

Kluber

3 follow-up statements

714 
WWUS53 KLOT 242147
SVSLOT

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

ILC031-242215-
/O.CON.KLOT.SV.W.0041.000000T0000Z-210724T2215Z/
Cook IL-
447 PM CDT Sat Jul 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR NORTHEASTERN COOK COUNTY...

At 446 PM CDT, severe thunderstorms were located along a line 
extending from near Uptown and Lakeview to near Brookfield, moving 
southeast at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Chicago, Cicero, Evanston, Skokie, Oak Lawn, Berwyn, Oak Park, West
Town, Englewood, Chicago Lawn, Austin, West Ridge, Lincoln Park,
Bridgeport, Chicago Loop, South Lawndale, Lake View, Irving Park,
Midway Airport and South Shore.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4204 8767 4198 8765 4196 8763 4196 8764
      4190 8762 4189 8761 4188 8762 4187 8762
      4187 8761 4185 8761 4178 8757 4178 8756
      4177 8756 4173 8778 4192 8792 4203 8769
TIME...MOT...LOC 2146Z 318DEG 26KT 4198 8760 4183 8785 

HAIL...<.75IN
WIND...60MPH
 
OEMC zones...SEVERE THUNDERSTORM WARNING.  
1...2...3...4...5...6...7...8...9...and 11.
 
$$

Kluber

804 
WWUS53 KLOT 242205
SVSLOT

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

ILC031-242215-
/O.CON.KLOT.SV.W.0041.000000T0000Z-210724T2215Z/
Cook IL-
505 PM CDT Sat Jul 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR EAST CENTRAL COOK COUNTY...

At 505 PM CDT, severe thunderstorms were located along a line
extending from Hyde Park to Burbank, moving southeast at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
South side of Chicago, Cicero, Oak Lawn, Berwyn, Englewood, Chicago 
Lawn, Midway Airport, Bridgeport, South Lawndale, South Shore, 
Burbank, Brookfield, Summit, Northerly Island, New City, Brighton 
Park, Ashburn, Auburn Gresham, Hyde Park and Bridgeview.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4186 8761 4185 8761 4178 8757 4178 8756
      4177 8756 4173 8778 4182 8785 4186 8764
TIME...MOT...LOC 2205Z 316DEG 26KT 4182 8759 4175 8778 

HAIL...<.75IN
WIND...60MPH
 
OEMC zones...SEVERE THUNDERSTORM WARNING.  
5...6...7...8...9...and 11.
 
$$

Kluber

027 
WWUS53 KLOT 242216
SVSLOT

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

ILC031-242226-
/O.EXP.KLOT.SV.W.0041.000000T0000Z-210724T2215Z/
Cook IL-
516 PM CDT Sat Jul 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL COOK COUNTY HAS
EXPIRED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been allowed to expire.

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

Remember, a Severe Thunderstorm Warning still remains in effect for 
southern Cook County, including the far south side of Chicago, until 
600 PM CDT.

LAT...LON 4186 8761 4185 8761 4178 8757 4178 8756
      4177 8756 4173 8778 4182 8785 4186 8764
TIME...MOT...LOC 2216Z 313DEG 27KT 4176 8753 4169 8772 

$$

Kluber

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 3:34 PM CDT	Special Weather Statement	LOT	Lake	41 min
Jul 24, 3:54 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	51 min
Jul 24, 3:58 PM CDT	Special Marine Warning	LOT		92 min
Jul 24, 5:00 PM CDT	Special Marine Warning	LOT		60 min
Jul 24, 5:01 PM CDT	Severe Thunderstorm Warning	LOT	Cook	59 min
Jul 24, 5:31 PM CDT	Special Weather Statement	LOT	Will	29 min
Jul 24, 5:36 PM CDT	Severe Thunderstorm Warning	LOT	Will	16 min
Jul 24, 5:50 PM CDT	Special Weather Statement	LOT	Will	55 min
Jul 24, 6:07 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee, Will	53 min
Jul 24, 6:36 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee	39 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2021 Every severe thunderstorm warning 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.