Tornadoes · United States · Wisconsin · 2019

EF0 tornado, Green Bay to Pine Grove, Wisconsin, August 7, 2019

From Green Bay to Pine Grove, this EF0 tornado ran 6.2 miles across Brown County on August 7, 2019, touching down at 5:48 PM CDT and reaching 90 yards wide. It killed nobody, and did $50,000 of property damage.

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 7, 2019
Touchdown
5:48 PM CDT (22:48 UTC)
Lifted
5:57 PM CDT (22:57 UTC)
On the ground
9 minutes
Path length
6.2 miles (10.0 km)
Path width
90 yards (82 m)
Deaths
0
Injuries
0
Property damage
$50,000
County
Brown County
Touchdown point
44.495, -87.988
Lift-off point
44.447, -87.882
Record number
1908071648-01

What the Weather Service recorded

Severe thunderstorms formed in very unstable air ahead of a passing cold front. The worst of the damage from the storms occurred across east-central and parts of northeast Wisconsin. Thunderstorm winds downed numerous trees and some power lines, hail as large as golf balls fell, and a weak tornado touched down on the east side of Green Bay (Brown Co.). Heavy rain led to flooding in parts of east-central Wisconsin as the storms formed an east-west line that slowly moved southeast.

A tornado quickly formed southeast of the city of Green Bay and moved southeast into the town of Bellevue. Three power poles sustained damage and a business sign was heavily damaged in Green Bay. The tornado continued southeast and damaged at least 100 trees along the path (DI 27 and 28, DOD 1-3). A poorly constructed carport lost part of its metal roof at an apartment building and a nearby house lost a couple shingles (DI 2, DOD 2).

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
21:51 UTC22:30 UTCSevere Thunderstorm WarningGRB
22:06 UTC02:00 UTCLakeshore Flood AdvisoryGRB
22:23 UTC23:15 UTCSevere Thunderstorm WarningGRB
22:48 UTC23:45 UTCSevere Thunderstorm WarningGRB
00:01 UTC00:47 UTCFlood AdvisoryGRB
00:22 UTC01:00 UTCSevere Thunderstorm WarningGRB
00:42 UTC03:03 UTCFlood WarningGRB

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. The outlook in force was issued at 20:00 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

10.8 hours before the tornado, 13 km from the path. August 7, 2019.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2019-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 20 joules per kilogram, CIN -91, lifted condensation level 1433 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, Green Bay/Straub, WI at 12:00Z on 2019-08-07The 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 71 square meters per square second, 0 to 6 km bulk shear 25 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
20 J/kg
Mixed-layer CIN
-91 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1433 m above ground
0-6 km bulk shear
25 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
97 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.0 K/km

Open this sounding in Storm Lab

The radar

The Green Bay radar (KGRB), 14 km away, was scanning. The volume nearest the touchdown began at 22:46 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
21:06 UTCHAIL 1OcontoOconto, WIHAIL UP TO AN INCH IN DIAMETER IN OCONTO.
21:06 UTCHAIL 1.5OcontoOconto, WIUPDATE OF PREVIOUS REPORT - OBSERVER MEASURED HAIL AND FOUND SOME AS LARGE AS 1.5 INCHES
21:21 UTCTSTM WND DMGLittle SturgeonDoor, WITREES DOWN. TIME ESTIMATED BY RADAR.
21:35 UTCTSTM WND DMGBrusselsDoor, WITREES DOWN. TIME ESTIMATED BY RADAR.
21:35 UTCTSTM WND DMGMaplewoodDoor, WI1 TREE DOWN. TIME ESTIMATED BY RADAR.
21:42 UTCHAIL 0.5Green BayBrown, WIDIME SIZE HAIL AT INTERSECTION OF EAST MASON STREET AND ALPINE ROAD.
21:59 UTCTSTM WND DMGBear CreekOutagamie, WICOUPLE TREES DOWN IN THE TOWNSHIP OF DEER CREEK, FAR NORTHWEST OUTAGAMIE COUNTY.
22:12 UTCTSTM WND DMGNavarinoShawano, WINUMEROUS TREES DOWN, SOME ON POWER LINES, OVER THE SOUTH CENTRAL AND SOUTHEAST PART OF SHAWANO COUNTY.
22:48 UTCTORNADO1 Sse Green BayBrown, WITORNADO TOUCHED DOWN ON SOUTHEAST SIDE OF CITY OF GREEN BAY AND MOVED SOUTHEAST INTO TOWN OF BELLEVUE. EF0 DAMAGE WITH PEAK WINDS ESTIMATED NEAR 85 MPH. SEVERAL BUILDINGS SUSTAINED DAMAGE. NEARLY 100 TREES WERE AFFECTED.
22:49 UTCTSTM WND DMGGreen BayBrown, WI2 POWER LINES DOWN AND SEVERAL TREES SNAPPED NEAR HEYRMAN AND CASS STREETS. TIME ESTIMATED BY RADAR.
22:50 UTCTSTM WND DMG2 Se Green BayBrown, WIROOF OFF HARDWARE STORE AND TREES SNAPPED IN A 2-4 BLOCK RADIUS ON SOUTHEAST SIDE OF GREEN BAY.
22:50 UTCHAIL 0.752 Ene Green BayBrown, WI
22:54 UTCHAIL 0.5Green BayBrown, WIDIME SIZE HAIL AT INTERSECTION OF EAST MASON STREET AND ALPINE DRIVE.
22:55 UTCTSTM WND DMG1 N BellevueBrown, WIWIRES DOWN BELLEVUE AND ALLOUEZ AREAS
23:05 UTCTSTM WND DMG1 W LuxemburgKewaunee, WICOUPLE SMALL TREES AND SOME BRANCHES DOWN AT HWY 54 AND H. TIME ESTIMATED BY RADAR.
23:05 UTCFLOODLuxemburgKewaunee, WIFLOODING REPORTED FROM LUXEMBURG TO ALGOMA. NO OTHER DETAILS KNOWN AT THIS TIME. TIME ESTIMATED.
00:02 UTCHAIL 0.882 E AppletonOutagamie, WI
00:05 UTCHAIL 1AppletonOutagamie, WIFROM SOCIAL MEDIA
00:05 UTCHAIL 1HilbertCalumet, WIFROM SOCIAL MEDIA. TIME ESTIMATED.
00:09 UTCHAIL 12 E Green BayBrown, WIMOST HAIL WAS SMALLER, BY SOME UP TO QUARTER SIZE.
00:11 UTCHAIL 0.253 E Green BayBrown, WI
00:17 UTCHAIL 0.883 E Green BayBrown, WI
00:19 UTCFLOODGreen BayBrown, WI2 FEET OF STANDING WATER AT INTERSECTION OF MILITARY AND SHAWANO IN GREEN BAY
00:27 UTCHAIL 1AppletonOutagamie, WI
01:21 UTCTSTM WND DMGChiltonCalumet, WILARGE TREE BRANCHES DOWN ON WATER STREET IN CHILTON.

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

This ground now

The live radar over the trackEvery 2019 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

The other tornadoes of August 7, 2019

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 72:47 PM EDTEF0Union, NJ0.1100$117,000
August 73:45 PM EDTEF0Pender, NC0.120
August 74:33 PM EDTEF0Mercer, NJ0.325
August 76:40 PM EDTEF0Cumberland, NJ0.110

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.