Tornadoes · United States · Illinois · 2021

Unrated tornado, Modesto Weber Arpt, Illinois, June 24, 2021

This Unrated tornado ran 0.2 miles across Macoupin County on June 24, 2021, touching down at 8:18 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
June 24, 2021
Touchdown
8:18 PM CDT (01:18 UTC)
Lifted
8:19 PM CDT (01:19 UTC)
On the ground
1 minutes
Path length
0.2 miles (0.4 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Macoupin County
Touchdown point
39.515, -89.918
Lift-off point
39.516, -89.914
Record number
2106241918-01

What the Weather Service recorded

A trough moved southeast through the region, generating a complex of showers and storms. Numerous reports of damaging winds, a few tornadoes and flash flooding were reported with this system.

A storm chaser observed and photographed a tornado 5 miles west of Virden, IL. Based on this chaser���s observations and radar data, the tornado formed around 0118 UTC and tracked northeastward across an open field before dissipating less than a minute later at 0119 UTC. Video showed a condensation funnel reaching the ground. The starting and ending points are estimated and based on information received. Thus the tornado is rated EFU with a path length of approximately 0.23 miles and path width of 10 yards. No damage reported.

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.

Issued (UTC)ExpiredProductOffice
21:00 UTC00:42 UTCFlash Flood WatchLSX
01:11 UTC02:00 UTCSevere Thunderstorm WarningLSX
04:49 UTC09:00 UTCTornado WatchLSX

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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 01:06 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.

Lincoln, IL (KILX), 00:00Z

1.3 hours before the tornado, 133 km from the path. June 25, 2021.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2021-06-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 263 joules per kilogram, CIN -103, lifted condensation level 875 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Lincoln, IL at 00:00Z on 2021-06-25The 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 245 square meters per square second, 0 to 6 km bulk shear 34 knots.193958Sfc1 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
263 J/kg
Mixed-layer CIN
-103 J/kg
Surface CAPE
1238 J/kg
Mixed-layer LCL
875 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
245 m²/s²
0-3 km storm-relative helicity
444 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.5
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

Lincoln, IL (KILX), 12:00Z

10.7 hours after it, 133 km from the path. June 25, 2021.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2021-06-25Temperature 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 -86258, lifted condensation level 1244 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Lincoln, IL at 12:00Z on 2021-06-25The 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 113 square meters per square second, 0 to 6 km bulk shear 32 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
-86258 J/kg
Surface CAPE
2 J/kg
Mixed-layer LCL
1244 m above ground
0-6 km bulk shear
32 kt
0-1 km bulk shear
44 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

The surface observations

Jacksonville (IJX), 40 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:35 UTC74.774.70° 0 kt1013.5-TSRA
23:55 UTC74.374.3170° 3 kt1013.9+TSRA
00:15 UTC73.673.60° 0 kt1013.9+TSRA
00:35 UTC70.770.7170° 8 kt1013.5+TSRA
00:55 UTC70.570.5130° 3 kt1013.5-VCTSRA
01:15 UTC70.370.3120° 9 kt1013.2VCTS
01:35 UTC70.270.2130° 7 kt1012.9
01:55 UTC7171140° 10 kt171012.9VCTS
02:15 UTC71.271.2130° 8 kt191012.9VCTS
02:35 UTC7272150° 8 kt1012.9VCTS
02:55 UTC72.572.50° 0 kt1012.9
03:15 UTC73.273.2140° 10 kt1013.5

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

The radar

The Lincoln radar (KILX), 86 km away, was scanning. The volume nearest the touchdown began at 01:16 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
00:10 UTCHEAVY RAIN 1.26WinchesterScott, ILMESONET STATION EW0975 WINCHESTER.
01:18 UTCTORNADO4 Ne ModestoMacoupin, ILA TORNADO OF UNKNOWN STRENGTH BRIEFLY TOUCHED DOWN IN A FARM FIELD, JUST SOUTH OF THE MACOUPIN/SANGAMON COUNTY LINE AND JUST EAST OF CAMPBELL ROAD. CAPTURED ON VIDEO BY TRAINED SPOTTERS.
01:20 UTCTSTM WND DMGLowderSangamon, ILDAMAGE TO TREES, A FLAG POLE, HOUSE SHINGLES AND SIDING. HIGH WIND LASTED ABOUT 5 MINUTES. DELAYED REPORT.
01:30 UTCHEAVY RAIN 1.641 W JacksonvilleMorgan, IL1.43 INCHES FELL AFTER 5 PM.
01:45 UTCHEAVY RAIN 2.352 W RivertonSangamon, ILTOTAL FROM LAST 90 MINUTES.
02:38 UTCHEAVY RAIN 1.06Jacksonville AirportMorgan, ILDAILY TOTAL AS OF 9PM.

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

This ground now

The live radar over the trackEvery 2021 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of June 24, 2021

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 243:32 PM CDTEF0Rusk, WI0.825$20,000
June 244:24 PM CDTEF0Chippewa, WI0.225
June 249:13 PM CDTEF0Grundy, MO1.725
June 249:17 PM CDTEF0Grundy, MO5.650
June 249:18 PM CDTEF1Grundy, MO4.975
June 2411:27 PM CDTUnratedShelby, MO0.110
June 2412:01 AM CDTEF0Marion, MO0.250
June 2412:08 AM CDTEF0Marion, MO0.125

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.