Tornadoes · United States · Illinois · 2023

Unrated tornado, Maytown, Illinois, August 14, 2023

This Unrated tornado ran 0.3 miles across Lee County on August 14, 2023, touching down at 4:22 PM CDT and reaching 10 yards wide. It killed nobody.

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 mph

    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. Unratedthis tornado

    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
Unrated
Date
August 14, 2023
Touchdown
4:22 PM CDT (21:22 UTC)
Lifted
4:23 PM CDT (21:23 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.5 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Lee County
Touchdown point
41.623, -89.413
Lift-off point
41.622, -89.407
Record number
2308141522-01

What the Weather Service recorded

Scattered thunderstorms moved across northern Illinois during the afternoon and evening of August 14th producing a weak landspout tornado and a few funnel clouds. Heavy rain caused localized flash flooding in parts of Chicago.

A brief landspout tornado touched down in a field southwest of Amboy, causing no known damage. Video evidence showed a funnel cloud more than half way from the cloud base to the ground just southeast of the intersection of Maytown Road and Downey Road. A review of satellite imagery from two days later indicated a likely short path in a field coincident with the location depicted in the video.

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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:32 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.

Davenport, (KDVN), 12:00Z

9.4 hours before the tornado, 91 km from the path. August 14, 2023.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2023-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 64 joules per kilogram, CIN -57, lifted condensation level 666 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, Davenport, at 12:00Z on 2023-08-14The 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 108 square meters per square second, 0 to 6 km bulk shear 33 knots.1939587897117Sfc1 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
64 J/kg
Mixed-layer CIN
-57 J/kg
Surface CAPE
504 J/kg
Mixed-layer LCL
666 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
116 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

2.6 hours after it, 91 km from the path. August 15, 2023.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2023-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 121 joules per kilogram, CIN -1, lifted condensation level 1119 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, Davenport, at 00:00Z on 2023-08-15The 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 14 square meters per square second, 0 to 6 km bulk shear 19 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
121 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
922 J/kg
Mixed-layer LCL
1119 m above ground
0-6 km bulk shear
19 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
7.2 K/km

Open this sounding in Storm Lab

The surface observations

Sterling Rockfal (SQI), 26 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:25 UTC73.469.8 3 kt1010.5
19:25 UTC310° 2 kt1010.5
19:30 UTC0° 0 kt1010.5
19:35 UTC330° 5 kt1010.5
19:40 UTC340° 4 kt1010.5
19:41 UTC73.469.8 5 kt1010.5
19:45 UTC350° 5 kt1010.2
19:50 UTC0° 0 kt1010.2
19:55 UTC360° 2 kt1010.2
19:56 UTC75700° 0 kt1010.2
20:00 UTC360° 4 kt1009.8
20:04 UTC7769.820° 3 kt1009.8
20:05 UTC360° 4 kt1009.8
20:10 UTC40° 2 kt1009.8
20:15 UTC60° 4 kt1009.8
20:18 UTC73.469.880° 3 kt1009.8TS
20:20 UTC0° 0 kt1009.8
20:25 UTC60° 4 kt1009.5
20:30 UTC60° 2 kt1009.5
20:33 UTC73.469.880° 6 kt1009.5-TSRA
20:35 UTC80° 7 kt1009.1-RA
20:40 UTC60° 4 kt1009.5RA
20:50 UTC300° 8 kt1009.8RA BR
20:52 UTC69.869.8310° 15 kt211009.8+TSRA BR
20:55 UTC 1010.2+RA BR
20:56 UTC6765330° 11 kt211009.8+TSRA BR
21:00 UTC0° 0 kt1009.8-RA BR
21:05 UTC320° 11 kt1010.2-RA
21:10 UTC 1010.5RA
21:15 UTC310° 13 kt1011.2-RA
21:20 UTC340° 9 kt1011.2-RA
21:25 UTC350° 5 kt1011.2-RA
21:30 UTC350° 8 kt1011.2-RA
21:31 UTC66.266.2350° 8 kt1011.2-TSRA
21:35 UTC350° 7 kt1011.2-RA
21:40 UTC310° 7 kt1011.2-RA
21:45 UTC320° 5 kt1011.2
21:50 UTC340° 9 kt1011.2
21:55 UTC320° 8 kt1011.2
21:56 UTC6563320° 8 kt1011.2VCTS
22:05 UTC310° 7 kt1011.2
22:10 UTC64.464.4310° 9 kt1010.8
22:10 UTC310° 9 kt1010.8
22:15 UTC310° 8 kt1011.2
22:20 UTC300° 9 kt1011.2
22:30 UTC320° 10 kt1011.5
22:33 UTC66.264.4330° 11 kt1011.5VCTS
22:35 UTC330° 11 kt1011.5
22:45 UTC330° 14 kt1011.9-RA
22:55 UTC350° 11 kt1011.2+RA
22:56 UTC6464350° 9 kt191011.2TSRA
23:05 UTC310° 10 kt1011.5-RA
23:09 UTC64.464.4320° 9 kt1011.5
23:15 UTC320° 7 kt1011.5

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Quad Cities radar (KDVN), 97 km away, was scanning. The volume nearest the touchdown began at 21:24 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
21:20 UTCRAIN 2.411 N SterlingWhiteside, ILSince midnight. 1.3 inches in the past hour.
21:49 UTCFUNNEL CLOUD3 Wnw Troy GroveLa Salle, ILPossible tornado. Time estimated by radar.
21:52 UTCFUNNEL CLOUDMendotaLa Salle, ILFunnel cloud picture shared on social mediia.

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

This ground now

The live radar over the trackEvery 2023 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of August 14, 2023

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 141:25 PM CDTUnratedDubuque, IA1.220
August 146:32 PM EDTEF0Franklin, IN2.8150$70,000
August 147:50 PM EDTEF0Butler, OH1.320$3,000
August 1412:56 AM EDTEF1Avery, NC3.035$5,000

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.