Tornadoes · United States · Illinois · 2019

EF1 tornado, (Ugn) Waukegan Airport to Beach Park, Illinois, September 3, 2019

From (Ugn) Waukegan Airport to Beach Park, this EF1 tornado ran 3.1 miles across Lake County on September 3, 2019, touching down at 6:39 PM CDT and reaching 200 yards wide. It killed nobody and injured 1.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mphthis tornado

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF1
Date
September 3, 2019
Touchdown
6:39 PM CDT (23:39 UTC)
Lifted
6:43 PM CDT (23:43 UTC)
On the ground
4 minutes
Path length
3.1 miles (5.0 km)
Path width
200 yards (183 m)
Deaths
0
Injuries
1
County
Lake County
Touchdown point
42.411, -87.862
Lift-off point
42.403, -87.803
Record number
1909031739-01

What the Weather Service recorded

A thunderstorm moved across far northeast Illinois during the evening of September 3rd producing a tornado.

A tornado touched downed just west of Twyford Road and moved east southeast through parts of Waukegan. Damage from the tornado was minor to commercial buildings and residences, including windows blown out, minor roof damage, fence destruction and damage to a gas station canopy. A vehicle was flipped over just east of the intersection of York House Road and Lewis Avenue where one minor injury occurred. Numerous trees were blown down or suffered heavy branch damage. The tornado was at its widest and strongest in the latter half of its path. Estimated peak winds for this tornado were 90 mph. A one mile stretch between the last damage point and the Lake Michigan shore was unable to be surveyed due a nature area in the Illinois Beach Nature Preserve. A waterspout was reported just off shore and so by interpolation, the path for this tornado was continued to the Lake Michigan shore.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:56 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Green Bay/Straub, WI (KGRB), 12:00Z

11.7 hours before the tornado, 231 km from the path. September 3, 2019.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2019-09-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 61 joules per kilogram, CIN -169, lifted condensation level 870 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2019-09-03The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 443 square meters per square second, 0 to 6 km bulk shear 62 knots.19395878Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
61 J/kg
Mixed-layer CIN
-169 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
870 m above ground
0-6 km bulk shear
62 kt
0-1 km bulk shear
53 kt
0-1 km storm-relative helicity
443 m²/s²
0-3 km storm-relative helicity
346 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
4.2 K/km

Open this sounding in Storm Lab

Green Bay/Straub, WI (KGRB), 00:00Z

0.3 hours after it, 231 km from the path. September 4, 2019.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 2019-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -84293, lifted condensation level 1638 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Green Bay/Straub, WI at 00:00Z on 2019-09-04The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 59 square meters per square second, 0 to 6 km bulk shear 53 knots.19395878Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-84293 J/kg
Surface CAPE
41 J/kg
Mixed-layer LCL
1638 m above ground
0-6 km bulk shear
53 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

The radar

The Milwaukee radar (KMKX), 86 km away, was scanning. The volume nearest the touchdown began at 23:38 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
23:40 UTCTSTM WND DMG1 S Beach ParkLake, IL*** 1 INJ *** PATH OF WIND DAMAGE IN FAR NORTH WAUKEGAN STARTED AT THIS POINT AND WENT TO THE LAKE FRONT. COMMERCIAL BUILDINGS WITH MINOR DAMAGE, CAR TIPPED/ROLLED ONTO ITS TOP, TREE DAMAGE INTO LYONS WOODS FOREST PRESER

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2019 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.