Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 52, NWS Chicago, IL

July 29, 2021Lake County, McHenry County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 29, 2021, 1:49 AM CDT for Lake County, McHenry County, Illinois. It was in force for 71 min. 18 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 29, 2021, 1:49 AM CDT (06:49 UTC)
Expired: Jul 29, 2021, 3:00 AM CDT
In force: 71 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 70.0 mph

Counties Lake County, IL, McHenry County, IL

The radar

The Chicago radar (KLOT), 83 km from the middle of the area, began a volume at 06:51 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.

What was reported inside it

Time	Report	Where	Remark
Jul 29, 2:10 AM CDT	TSTM WND DMG	1 Nw Antioch, IL	WIRES WERE BLOWN DOWN AND A VEHICLE WAS DAMAGED ALONG FOREST DRIVE.
Jul 29, 2:10 AM CDT	TSTM WND DMG	Wonder Lake, IL	WIRES BLOWN DOWN.
Jul 29, 2:12 AM CDT	TSTM WND GST 60	Hebron, IL	ESTIMATED 60 MPH WINDS JUST SOUTH OF HEBRON.
Jul 29, 2:14 AM CDT	TSTM WND DMG	Lake Villa, IL	WIRES BLOWN DOWN ON PARK AVENUE.
Jul 29, 2:14 AM CDT	TSTM WND DMG	Mchenry, IL	WIRES BLOW DOWN.
Jul 29, 2:22 AM CDT	TSTM WND GST 60	Crystal Lake, IL	MEASURED GUST TO 60 MPH AT MCHENRY COUNTY COLLEGE.
Jul 29, 2:24 AM CDT	TSTM WND DMG	1 W Beach Park, IL	WIRES DOWN ON EVERGREEN AVENUE.
Jul 29, 2:24 AM CDT	TSTM WND DMG	1 W Winthrop Harbor, IL	WIRES DOWN ON 11TH STREET.
Jul 29, 2:24 AM CDT	TSTM WND DMG	Zion, IL	TREE LIMB BLOWN DOWN ON A HIGH VOLTAGE LINE AT 27TH STREET AND BETHEL BLVD.
Jul 29, 2:25 AM CDT	TSTM WND DMG	Lakewood, IL	PHOTO SHARED VIA SOCIAL MEDIA SHOWS 12-18 DIAMETER TREE BRANCH DOWNED. TIME ESTIMATED BY RADAR.
Jul 29, 2:28 AM CDT	TSTM WND GST 62	1 Nw Island Lake, IL	MULTIPLE LARGE LIMBS SNAPPED OFF THE TOP OF A 30 FT TALL TREE.
Jul 29, 2:29 AM CDT	TSTM WND DMG	Wauconda, IL	PHOTO SHARED ON SOCIAL MEDIA OF TREE LIMBS BLOWN DOWN.
Jul 29, 2:30 AM CDT	TSTM WND DMG	Algonquin, IL	PHOTO SHARED TO TWITTER SHOWS LARGE TREE BRANCHES DOWNED ACROSS DRIVEWAY IN THE ALGONQUIN VICINITY. TIME ESTIMATED BY RADAR.
Jul 29, 2:30 AM CDT	TSTM WND DMG	Crystal Lake, IL	MULTIPLE REPORTS OF TREES DOWNED IN AND AROUND CRYSTAL LAKE.
Jul 29, 2:32 AM CDT	TSTM WND DMG	Mundelein, IL	LARGE TREE LIMBS BLOWN DOWN NEAR SHADDLE AVENUE AND FRENCH DRIVE.
Jul 29, 2:33 AM CDT	TSTM WND DMG	1 S Lake Barrington, IL	A TREE WAS BLOWN DOWN COMPLETELY BLOCKING OLD BARRINGTON ROAD.
Jul 29, 2:35 AM CDT	TSTM WND DMG	Kildeer, IL	PHOTO SHARED VIA TWITTER SHOWS LARGE BRANCHES DOWNED, DAMAGING ITEMS ON PATIO. TIME ESTIMATED BY RADAR.
Jul 29, 2:35 AM CDT	TSTM WND DMG	Lake Zurich, IL	PHOTO SHARED VIA TWITTER SHOWS LARGE BRANCH DOWNED IN LAKE ZURICH AREA. TIME ESTIMATED VIA 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 29, 1:00 AM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 6.8 hours before the alert went out and 228 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: 4022 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 1022 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 6.8

Open this sounding in Storm Lab

The text

As transmitted.

034 
WUUS53 KLOT 290649
SVRLOT
ILC097-111-290800-
/O.NEW.KLOT.SV.W.0052.210729T0649Z-210729T0800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Chicago/Romeoville
149 AM CDT Thu Jul 29 2021

The National Weather Service in Chicago has issued a

* Severe Thunderstorm Warning for...
  Lake County in northeastern Illinois...
  Eastern McHenry County in northeastern Illinois...

* Until 300 AM CDT.

* At 147 AM CDT, severe thunderstorms were located along a line 
  extending from near Oak Creek to near Delavan, moving southeast at 
  50 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Waukegan, Arlington Heights, Palatine, Buffalo Grove, Crystal Lake,
  Wheeling, Northbrook, North Chicago, Gurnee, Mundelein, Algonquin,
  Highland Park, Lake in the Hills, Round Lake Beach, McHenry, Vernon
  Hills, Woodstock, Zion, Huntley and Grayslake.

This includes...Chain O Lakes State Park, College of Lake County, 
Great Lakes Naval Training Center, IL Beach State Park, Lake County 
IL Fairgrounds, Lake Forest College, Mchenry County College, Mchenry 
County Fairgrounds, and Moraine Hills State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4249 8780 4238 8781 4236 8782 4237 8782
      4233 8783 4231 8782 4229 8783 4221 8780
      4215 8776 4215 8843 4250 8843
TIME...MOT...LOC 0647Z 312DEG 41KT 4287 8801 4258 8858 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...70MPH
 
$$

Kluber

3 follow-up statements

272 
WWUS53 KLOT 290714
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
214 AM CDT Thu Jul 29 2021

ILC097-111-290800-
/O.CON.KLOT.SV.W.0052.000000T0000Z-210729T0800Z/
Lake IL-McHenry IL-
214 AM CDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 AM CDT
FOR LAKE AND EASTERN MCHENRY COUNTIES...

At 213 AM CDT, severe thunderstorms were located along a line
extending from near Kenosha to near Wonder Lake, moving southeast at 
45 mph. Emergency management reported 60 mph winds with these storms 
in Hebron, Illinois.

HAZARD...70 mph wind gusts.

SOURCE...Emergency management.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Waukegan, Arlington Heights, Palatine, Buffalo Grove, Crystal Lake,
Wheeling, Northbrook, North Chicago, Gurnee, Mundelein, Algonquin,
Highland Park, Lake in the Hills, Round Lake Beach, McHenry, Vernon
Hills, Woodstock, Zion, Huntley and Grayslake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4249 8780 4238 8781 4236 8782 4237 8782
      4233 8783 4231 8782 4229 8783 4221 8780
      4215 8776 4215 8843 4250 8843
TIME...MOT...LOC 0713Z 317DEG 41KT 4257 8780 4235 8840 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...70MPH
 
$$

FRIEDLEIN

760 
WWUS53 KLOT 290736
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
236 AM CDT Thu Jul 29 2021

ILC097-111-290800-
/O.CON.KLOT.SV.W.0052.000000T0000Z-210729T0800Z/
Lake IL-McHenry IL-
236 AM CDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 AM CDT
FOR SOUTHERN LAKE AND SOUTHEASTERN MCHENRY COUNTIES...

At 235 AM CDT, severe thunderstorms were located along a line
extending from near Lake Bluff to near Huntley, moving southeast at
45 mph.

HAZARD...70 mph wind gusts.

SOURCE...Emergency management. Multiple reports of wind damage 
         across McHenry and Lake counties.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Waukegan, Arlington Heights, Palatine, Buffalo Grove, Crystal Lake,
Wheeling, Northbrook, North Chicago, Mundelein, Algonquin, Highland
Park, Lake in the Hills, Vernon Hills, Huntley, Grayslake,
Libertyville, Lake Zurich, Lake Forest, Wauconda and Barrington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4233 8783 4231 8782 4229 8783 4221 8780
      4215 8776 4215 8843 4225 8843 4234 8783
TIME...MOT...LOC 0735Z 323DEG 39KT 4227 8781 4215 8839 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...70MPH
 
$$

Kluber

658 
WWUS53 KLOT 290757
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
257 AM CDT Thu Jul 29 2021

ILC097-111-290806-
/O.EXP.KLOT.SV.W.0052.000000T0000Z-210729T0800Z/
Lake IL-McHenry IL-
257 AM CDT Thu Jul 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN LAKE AND SOUTHEASTERN
MCHENRY COUNTIES WILL EXPIRE AT 300 AM CDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.


LAT...LON 4233 8783 4231 8782 4229 8783 4221 8780
      4215 8776 4215 8843 4225 8843 4234 8783
TIME...MOT...LOC 0756Z 312DEG 41KT 4212 8758 4200 8816 

$$

FRIEDLEIN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 1:16 AM CDT	Special Marine Warning	LOT		3 hr
Jul 29, 1:23 AM CDT	Severe Thunderstorm Warning	LOT	Boone, McHenry, Winnebago	82 min
Jul 29, 2:14 AM CDT	Severe Thunderstorm Warning	LOT	Cook, DeKalb, DuPage, Kane	76 min
Jul 29, 2:58 AM CDT	Severe Thunderstorm Warning	LOT	Cook, Grundy, Kendall, Will	77 min
Jul 29, 3:04 AM CDT	Special Weather Statement	LOT	DeKalb	56 min
Jul 29, 3:45 AM CDT	Severe Thunderstorm Warning	LOT	Kankakee	60 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.