Strong thunderstorms produced gusty winds as they tracked over the bay of Green Bay and the Lake Michigan nearshore waters during the afternoon hours.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GRB wrote it up.
Strong thunderstorms produced gusty winds as they tracked over the bay of Green Bay and the Lake Michigan nearshore waters during the afternoon hours.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Green Bay, WI wrote its last area forecast discussion before the first event at Aug 11, 1:05 PM CST, 45 minutes earlier.
Area Forecast Discussion National Weather Service Green Bay WI 205 PM CDT Wed Aug 11 2021 Forecast discussion for routine afternoon forecast issuance .SHORT TERM...Tonight and Thursday Issued at 204 PM CDT Wed Aug 11 2021 Most of the action is in the short term portion of the forecast. A cold front is in the progress of crossing northeast Wisconsin this afternoon, triggering a round of potential severe weather. Instability ahead of the front has steadily increased, bringing CAPE into the 2000-3000 J/kg range. Meso models have suggested ample helicity with storms and hodographs would support some tornado formation. Shear is better than yesterday in the same areas as the instability as well, all of which has prompted the extending of the enhanced category through the area and the subsequent issuance of the tornado watch shortly after noon, effective through 8PM today. All of this will also pose a strong hail and wind threat to the region as well, in addition to the possibility for tornadoes. Flooding is not to be discounted either, as rain rates under these storms is quite high at times, likely leading to ponding in urban areas and roadways through the evening. Currently do not expect severe potential to diminish until the front gets through the region. The good news is that storms will come to an end quickly behind the front, with clearing skies and lower dewpoints which will bring in less tropical conditions. Temperatures overnight will be in the upper 50s to lower 60s. Highs tomorrow will be in the middle 70s to middle 80s under sunny skies. Some reformation of storms will be possible again tomorrow, but will likely miss our area to well to the south. This will mark the beginning of a much quieter period for northeastern Wisconsin. .LONG TERM...Thursday Night Through Wednesday Issued at 204 PM CDT Wed Aug 11 2021 Much quieter conditions will come into place for the extended as high pressure builds in across the region. A much cooler and drier air mass will slide into place Thursday night into Friday, lasting well through the weekend and into next week. At this time, seems like a pretty good shot to see dry conditions through the middle of next week, before the next trough arrives from the west sometime late next week. Temperatures will drop into the middle 70s on Friday as the cool air initially drops into place, then slowly recover towards the lower to middle 80s through the middle of next week. && .AVIATION...for 18Z TAF Issuance Issued at 1244 PM CDT Wed Aug 11 2021 A persistent stratus deck of IFR clouds will remain in the region ahead of the impending thunderstorms. Thunderstorms will roll through the region west to east in the first 6 or so hours of the TAF period, creating hazardous flying conditions. TEMPO groups trace out the best periods as these cells will be fairly fast moving and could have a couple individual cells move through. Once the front clears the area within a couple hours, expect conditions to rapidly improve behind the front, with clearing skies for the rest of the period. Winds may be gusty behind the front briefly, before becoming quiet again for the early overnight hours. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM.....Uhlmann LONG TERM......Uhlmann AVIATION.......Uhlmann
Hazardous Weather Outlook National Weather Service Green Bay WI 232 PM CDT Wed Aug 11 2021 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-121945- Vilas-Oneida-Forest-Florence-Northern Marinette County-Lincoln- Langlade-Menominee-Northern Oconto County-Door-Marathon-Shawano- Wood-Portage-Waupaca-Outagamie-Brown-Kewaunee-Waushara-Winnebago- Calumet-Manitowoc-Southern Marinette County- Southern Oconto County- 232 PM CDT Wed Aug 11 2021 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Thunderstorms continue to push across central to northeastern Wisconsin this afternoon. Some of these storms are severe, with damaging winds, torrential downpours, and tornadoes reported. Large hail is possible but the least likely of the current severe threats. The overall severe threat will come to an end behind the cold front, exiting the region in the evening hours. A tornado watch is in effect through 8PM. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday There is a chance of thunderstorms late Thursday afternoon into Thursday evening, mainly across east-central Wisconsin. No severe weather is anticipated with these storms. Heat indices will be in the lower to middle 90s across parts of east central Wisconsin Wednesday afternoon. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon into early this evening. LMZ521-522-541>543-121945- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 232 PM CDT Wed Aug 11 2021 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight There is a good chance of thunderstorms this afternoon into early this evening. Some of these storms may become severe with damaging winds and isolated waterspouts possible. .DAYS TWO THROUGH SEVEN...Thursday through Wednesday There is a chance of thunderstorms late Thursday afternoon into Thursday evening. Any storms would pose a hazard to mariners. Uhlmann/Uhlmann
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
1258 PM CDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1250 PM TSTM WND DMG 3 E IRMA 45.34N 89.60W
08/11/2021 LINCOLN WI LAW ENFORCEMENT
1 SMALL TREE DOWN AT HWY J AND HWY H
&&
MIKE.CELLITTISpecial Weather Statement
National Weather Service Green Bay WI
114 PM CDT Wed Aug 11 2021
WIZ031-037-111900-
Waupaca WI-Shawano WI-
114 PM CDT Wed Aug 11 2021
...A strong thunderstorm will impact portions of northeastern Waupaca
and eastern Shawano Counties through 200 PM CDT...
At 114 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Clintonville, or 18 miles northeast of Waupaca, moving
northeast at 30 mph.
HAZARD...Winds in excess of 40 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Clintonville around 130 PM CDT.
Other locations in the path of this storm include Embarrass, Navarino
Wildlife Area and Shawano.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Tornado Watch remains in effect until 800 PM CDT for northeastern
Wisconsin.
&&
LAT...LON 4464 8901 4485 8859 4466 8843 4459 8863
4459 8874 4455 8874 4450 8888
TIME...MOT...LOC 1814Z 240DEG 27KT 4460 8892
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
RDMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
144 PM CDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0136 PM TSTM WND DMG 1 SW SHAWANO 44.77N 88.61W
08/11/2021 SHAWANO WI PUBLIC
REPORT FROM MPING: 1-INCH TREE LIMBS BROKEN;
SHINGLES BLOWN OFF.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
150 PM CDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0136 PM FLOOD 1 NNW MERRILL 45.19N 89.68W
08/11/2021 LINCOLN WI PUBLIC
REPORT FROM MPING: STREET/ROAD FLOODING;
STREET/ROAD CLOSED.
&&
RHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
152 PM CDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0149 PM FLOOD 2 SW WAUSAU 44.95N 89.66W
08/11/2021 MARATHON WI PUBLIC
REPORT FROM MPING: CROPLAND/YARD FLOODING.
&&
RHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
218 PM CDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0206 PM TORNADO ANGELICA 44.66N 88.30W
08/11/2021 SHAWANO WI TRAINED SPOTTER
BRIEF TOUCHDOWN SOUTHWEST OF ANGELICA NEAR HWY 55 AND HWY
160.
0212 PM TORNADO 2 WNW PULASKI 44.67N 88.26W
08/11/2021 SHAWANO WI COUNTY OFFICIAL
&&
HYKINThe Green Bay radar (KGRB), 47 km away, was scanning. The volume nearest the first event began at 19:48 UTC.
5 marine thunderstorm wind. Local standard time, as filed.
A thunderstorm produced strong winds over the waters of Green Bay northwest of Brussels.
A thunderstorm wind gust to 34 knots was measured at Northport Pier.
A thunderstorm produced strong winds over the waters of Green Bay east of Howard-Suamico.
A thunderstorm wind gust to 39 knots was measured at the northern mid lake buoy.
A thunderstorm produced strong winds over the nearshore waters of Lake Michigan east of Algoma.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Lake Michigan in 2021Every state in 2021This day in weather history
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 968156, 968164, 968167, 968182, 968170.