Tornadoes · United States · Wisconsin · 1986

F2 tornado, Jefferson County, Wisconsin, September 28, 1986

This F2 tornado ran 9.0 miles across Jefferson County on September 28, 1986, touching down at 5:23 PM CDT and reaching 100 yards wide. It killed nobody and injured 1, and did $500,000 to $5 million of property damage.

The rating scale

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

  1. F040 to 72 mph

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

  2. F173 to 112 mph

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

  3. F2113 to 157 mphthis tornado

    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. F3158 to 206 mph

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

  5. F4207 to 260 mph

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

  6. F5261 to 318 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
F2
Date
September 28, 1986
Touchdown
5:23 PM CDT (22:23 UTC)
Path length
9.0 miles (14.5 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
1
Property damage
$500,000 to $5 million
County
Jefferson County
Touchdown point
42.870, -88.730
Lift-off point
42.920, -88.600
Record number
696

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.

Issued (UTC)ExpiredProductOffice
22:10 UTC23:00 UTCSevere Thunderstorm WarningMKX
22:44 UTC23:30 UTCTornado WarningMKX

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 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

10.4 hours before the tornado, 182 km from the path. September 28, 1986.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 1986-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 583 joules per kilogram, CIN -45, lifted condensation level 883 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, Green Bay/Straub, WI at 12:00Z on 1986-09-28The 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 -1 square meters per square second, 0 to 6 km bulk shear 54 knots.1939587897Sfc1 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
583 J/kg
Mixed-layer CIN
-45 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
883 m above ground
0-6 km bulk shear
54 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.6
0-3 km lapse rate
3.8 K/km

Open this sounding in Storm Lab

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

1.6 hours after it, 182 km from the path. September 29, 1986.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 1986-09-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1557 joules per kilogram, CIN -4, lifted condensation level 753 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, Green Bay/Straub, WI at 00:00Z on 1986-09-29The 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 85 square meters per square second, 0 to 6 km bulk shear 50 knots.1939587897Sfc1 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
1557 J/kg
Mixed-layer CIN
-4 J/kg
Surface CAPE
1763 J/kg
Mixed-layer LCL
753 m above ground
0-6 km bulk shear
50 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
250 m²/s²
Significant tornado parameter
1.4
Supercell composite
6.5
0-3 km lapse rate
6.5 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1986 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

The other tornadoes of September 28, 1986

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 285:34 PM CDTF4Polk, IA20.0250$500,000 to $5 million
September 286:15 PM CDTF0Winnebago, IL0.210
September 287:05 PM CDTF1Clay, IA0.113$5,000 to $50,000
September 287:35 PM CDTF0Webster, IA0.113
September 289:45 PM CDTF2Floyd, IA0.2232$50,000 to $500,000
September 2812:45 AM EDTF0Wayne, MI0.210$50 to $500

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.