Tornadoes · United States · Wisconsin · 2014

EF0 tornado, Winchester to Larsen, Wisconsin, August 18, 2014

From Winchester to Larsen, this EF0 tornado ran 2.1 miles across Winnebago County on August 18, 2014, touching down at 4:23 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
August 18, 2014
Touchdown
4:23 PM CDT (21:23 UTC)
Lifted
4:25 PM CDT (21:25 UTC)
On the ground
2 minutes
Path length
2.1 miles (3.3 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Winnebago County
Touchdown point
44.230, -88.618
Lift-off point
44.229, -88.576
Record number
1408181523-01

What the Weather Service recorded

The combination of copious moisture, an approaching upper level system, and a warm front across Wisconsin resulted in the formation of thunderstorms along the front. The storms produced heavy rain, causing isolated flash flooding, as they trained across the same area. The storms also dropped large hail and a brief tornado developed.

A tornado developed and caused minor damage as it moved east near Shady Lane in rural northern Winnebago County. The weak tornado (EF0) caused two single wood power poles to partially lean in saturated soil (DI 24, DOD 1) and knocked over a few trees and limbs (DI 28, DOD 2 and 3). Swirl marks could be seen in a field of tall grass. The tornado was not in contact with the ground during the entire path length. Peak winds were estimated at 65 to 75 mph.

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
21:30 UTC22:00 UTCSevere Thunderstorm WarningGRB
23:21 UTC01:35 UTCFlood AdvisoryGRB
02:02 UTC06:33 UTCFlash Flood WatchGRB

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 General Thunderstorms Risk. The outlook in force was issued at 20:39 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

9.4 hours before the tornado, 48 km from the path. August 18, 2014.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2014-08-18Temperature 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 -87684, lifted condensation level 613 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, Green Bay/Straub, WI at 12:00Z on 2014-08-18The 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 47 square meters per square second, 0 to 6 km bulk shear 27 knots.1939Sfc1 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
-87684 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
613 m above ground
0-6 km bulk shear
27 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
2.8 K/km

Open this sounding in Storm Lab

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

2.6 hours after it, 48 km from the path. August 19, 2014.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 2014-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 76 joules per kilogram, CIN -111, lifted condensation level 830 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 2014-08-19The 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 -7 square meters per square second, 0 to 6 km bulk shear 18 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
76 J/kg
Mixed-layer CIN
-111 J/kg
Surface CAPE
450 J/kg
Mixed-layer LCL
830 m above ground
0-6 km bulk shear
18 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The radar

The Green Bay radar (KGRB), 49 km away, was scanning. The volume nearest the touchdown began at 21:23 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
21:25 UTCFLASH FLOODWaupacaWaupaca, WIFLOODING REPORTED IN BASEMENTS AS WELL AS MINOR STREET FLOODING IN DOWNTOWN WAUPACA.
21:25 UTCTORNADO2 Sse MedinaWinnebago, WIA WEAK TORNADO BRIEFLY TOUCHED DOWN IN FAR NORTHERN WINNEBAGO COUNTY ON AUGUST 18. A FEW TREES WERE KNOCKED DOWN, TWO POWER POLES WERE PUSHED OVER A BIT IN SATURATED GROUND, AND SWIRL PATTERNS WERE NOTED IN A FIELD OF GR
21:51 UTCHAIL 0.88MenashaWinnebago, WI
22:10 UTCHAIL 0.881 S AppletonOutagamie, WIMEASURED NEAR 41 ON COLLEGE AVE
22:12 UTCFLASH FLOODOshkoshWinnebago, WIFLOODING REPORTED IN DOWNTOWN OSHKOSH.
22:15 UTCHEAVY RAIN 2.97New LondonWaupaca, WIRAINFALL TOTAL WITH FIRST BATCH OF STORMS...ABOUT 2 HOUR STORM TOTAL.
23:56 UTCTSTM WND DMGGreen LakeGreen Lake, WIFEW TREES DOWN IN GREEN LAKE COUNTY.

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

This ground now

The live radar over the trackEvery 2014 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin 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.