Tornadoes · United States · Illinois · 2020

EF0 tornado, Hampshire, Illinois, May 23, 2020

This EF0 tornado ran 3.2 miles across Kane and DeKalb counties on May 23, 2020, touching down at 6:06 PM CDT and reaching 50 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 mphthis tornado

    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. 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
EF0
Date
May 23, 2020
Touchdown
6:06 PM CDT (23:06 UTC)
Lifted
6:16 PM CDT (23:16 UTC)
On the ground
10 minutes
Path length
3.2 miles (5.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Counties
Kane and DeKalb counties
Touchdown point
42.139, -88.630
Lift-off point
42.151, -88.570
Record number
2005231706-01

What the Weather Service recorded

Scattered severe thunderstorms moved across northern Illinois during the afternoon of May 23rd producing wind damage, localized flooding and three tornadoes. Several funnel clouds were also reported.

A tornado touched down in De Kalb County and moved across fields in Kane County and dissipated before reaching Interstate 90.

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. One was issued for the county at another hour that day.

The county was under a tornado watch, issued at 17:33 UTC and running to 01:00 UTC.

Issued (UTC)ExpiredProductOffice
17:33 UTC01:00 UTCTornado WatchLOT
23:04 UTC00:00 UTCSevere Thunderstorm WarningLOT
23:13 UTC23:24 UTCTornado WarningLOT
23:48 UTC02:45 UTCFlood AdvisoryLOT

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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:55 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

11.1 hours before the tornado, 168 km from the path. May 23, 2020.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2020-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 145 joules per kilogram, CIN -133, lifted condensation level 859 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, Davenport, at 12:00Z on 2020-05-23The 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 148 square meters per square second, 0 to 6 km bulk shear 36 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
145 J/kg
Mixed-layer CIN
-133 J/kg
Surface CAPE
1 J/kg
Mixed-layer LCL
859 m above ground
0-6 km bulk shear
36 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
198 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

0.9 hours after it, 168 km from the path. May 24, 2020.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2020-05-24Temperature 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 -16, lifted condensation level 1245 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, Davenport, at 00:00Z on 2020-05-24The 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 23 square meters per square second, 0 to 6 km bulk shear 13 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
0 J/kg
Mixed-layer CIN
-16 J/kg
Surface CAPE
230 J/kg
Mixed-layer LCL
1245 m above ground
0-6 km bulk shear
13 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The radar

The Chicago radar (KLOT), 74 km away, was scanning. The volume nearest the touchdown began at 23:06 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
20:50 UTCTSTM WND DMGSouth BeloitWinnebago, ILWINNEBAGO COUNTY DISPATCH REPORTS WIRES DOWN ACROSS SOUTH BELOIT. LOCATION ESTIMATED BASED ON REPORT TIME.
21:30 UTCTSTM WND DMG1 Sw ChanaOgle, ILBARN HEAVILY DAMAGED. POSSIBLE BRIEF TORNADO GIVEN FUNNELS IN THE REGION, BUT HAVE NOT HAD CONFIRMATION. LOCATION OF DAMAGE RELATIVE TO RADAR ROTATION AND STORM STRUCTURE INDICATES IT COULD HAVE BEEN REAR-FLANK DOWNDRAFT
21:30 UTCTORNADO1 Wsw ChanaOgle, ILEF-1 TORNADO BEGAN AT APPROXIMATELY 430 PM CDT ON MAY 23RD NEAR THE INTERSECTION OF S. ROCKY HOLLOW RD. AND E. CANFIELD RD. (41.97, -89.24). PATH LENGTH OF APPROXIMATELY 0.3 MILES AND ESTIMATED WIDTH OF 100 YARDS. PEAK W
23:12 UTCTORNADO5 Ne GenoaDe Kalb, IL40 X 20 BARN DAMAGES WITH DEBRIS BLOWN DOWNSTREAM INTO A FIELD, POWER LINES DOWN ABOUT A MILE DOWNSTREAM, LIKELY TORNADO PATH BASED ON SPOTTER REPORTS AND RADAR.
23:12 UTCTORNADO5 Ne GenoaDe Kalb, ILLIKELY BEGAN NEAR MELMS AND POLK RD. 40 X 20 BARN DAMAGED WITH DEBRIS BLOWN DOWNSTREAM INTO A FIELD, AND POWER LINES DOWN ABOUT A MILE DOWNSTREAM. TORNADO WAS LIKELY VERY SHORT LIVED.
23:12 UTCTORNADO5 Ne GenoaDe Kalb, ILTORNADO BEGAN NEAR MELMS AND POLK RD. 40 X 20 BARN DAMAGED WITH DEBRIS BLOWN DOWNSTREAM INTO A FIELD, AND POWER LINES DOWN ABOUT A MILE DOWNSTREAM. TORNADO DISSIPATED BEFORE REACHING I-90.
23:45 UTCFUNNEL CLOUDAlgonquinMchenry, ILDELAYED REPORT OF A FUNNEL CLOUD NEAR ALGONQUIN. TIME ESTIMATED BASED ON RADAR.
23:45 UTCFLASH FLOODGenoaDe Kalb, ILCREEKS OUT OF THEIR BANKS WITH 2 TO 3 FEET OF WATER OVER SOME ROADWAYS IN TOWN.
00:15 UTCHEAVY RAIN 1.93HuntleyMchenry, ILRAIN FELL IN 45 MINUTES. FOOT OF WATER ON ROUTE 47 NORTH OF OBSERVERS LOCATION.
01:30 UTCHEAVY RAIN 1.581 Nne PalatineCook, ILRAIN FELL IN 45 MINUTES.
01:33 UTCHEAVY RAIN 1.542 Wnw Bull ValleyMchenry, ILRAIN FELL IN 3 HOURS.

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

This ground now

The live radar over the trackEvery 2020 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of May 23, 2020

13 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 2312:30 PM CDTEF1Johnson, IA7.050
May 2312:57 PM CDTEF1Cedar, IA6.930
May 231:20 PM CDTEF0Clinton, IA1.220
May 231:53 PM CDTEF0Jackson, IA1.420
May 231:54 PM CDTEF0Woodford, IL3.575$20,000
May 232:24 PM CDTUnratedJackson, IA0.010
May 232:29 PM CDTEF1Whiteside, IL12.330
May 232:53 PM CDTEF0Kendall, IL6.31001
May 234:18 PM CDTUnratedJo Daviess, IL0.520
May 234:30 PM CDTEF1Ogle, IL0.3100
May 236:14 PM CDTUnratedGarza, TX0.430
May 236:52 PM CDTEF0Benson, ND0.120
May 236:07 PM MDTUnratedSherman, KS1.150

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.