Wake low winds behind departing thunderstorms produced wind damage in Oshkosh late Friday evening (7/28). The wake low winds uprooted and snapped trees.
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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.
Wake low winds behind departing thunderstorms produced wind damage in Oshkosh late Friday evening (7/28). The wake low winds uprooted and snapped trees. A camper underneath a tree was injured when a branch fell on their tent at the EAA grounds.
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 Jul 28, 9:44 PM CST, 16 minutes earlier.
Area Forecast Discussion National Weather Service Green Bay WI 1044 PM CDT Fri Jul 28 2023 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Saturday Issued at 337 PM CDT Fri Jul 28 2023 Complex/messy mesoscale/synoptic set-up making for a complicated forecast this afternoon into tonight. Main focus will be timing best chances for storms and if any will be on the strong side. For this afternoon into tonight...weak surface boundary, instability gradient and FGEN centered around 850mb, combined with daytime heating generating MUCAPEs of 1000-2000 J/kg will continue to produce isolated to scattered showers and storms extending east-west over parts of central and east-central WI. Main threats with this activity will be heavy rain and small hail as they should mainly remain elevated. Then attention turns to this evening as a more potent shortwave tracks into WI, likely kicking off additional showers and storms. Instability gradient still expected to be in place, with the pool of very instability well to our south in southern WI. Think the strongest of the storms, along with the main threat for severe weather, will build south/east into the better instability. We will be on the northern part of this and it may clip the southern CWA. Models are mixed on if and how widespread activity north of the main complex will behave tonight, with the HRRR very aggressive with more widespread activity, but other models have little to no activity. So confidence not great on how it will play out as you work to the north. Plenty of bulk shear to work with (around 50 kts) so any storms could be well organized and have the chance to produce hail and some brief gusty winds (especially if a cold pool can get established with the complex and it clips the southern counties). Some fog is expected later tonight as temps cool, especially in central and north central WI where winds are lighter in the boundary layer. Lows will drop into the 50s to low 60s for most spots. For Saturday...some lingering showers will be possible over north central WI in the early morning, then additional showers will be possible in the later morning and afternoon as a weak secondary frontal boundary drops south across northeast WI within a northwest upper flow, along with a weak shortwave and departing upper jet. A narrow ribbon of moisture and instability be just enough to touch off a storm, but will just mention showers for now. If models continue to trend more aggressive with this activity, PoPs will need to be expanded. It will be a little cooler and noticeably less humid with highs in the mid 70s to mid 80s. .LONG TERM...Saturday Night Through Friday Issued at 337 PM CDT Fri Jul 28 2023 Summary: Generally quiet weather will prevail Sunday into Tuesday, outside of warming temperatures. There may be a period of strong thunderstorms again Wednesday PM as southerly flow returns and a low pressure system in northern Ontario crosses the Upper Great Lakes region. Deep low pressure centered over northern Quebec on Sunday and amplifying ridging over the northern High Plains keeps the central United States under mild northwest flow Sunday into Monday. This is generally expected to be a dry period for north-central and northeast Wisconsin. Temperatures aloft warm by a degree or two from Sunday into Monday, but largely support near-normal daytime high temperatures for the beginning of next week. The ridge axis aloft shifts eastward into the Missouri Valley Monday night into Tuesday as lower-level high pressure over the Upper Midwest drops into the Ohio River Valley. This creates a return flow into northeast Wisconsin by Tuesday morning. Expect an increase in daytime high temperatures for Tuesday as a result. Low pressure over northern Manitoba breaks down the central CONUS ridge Tuesday night to further increase temperatures Wednesday ahead of the next chance of possible stronger thunderstorms to work into northeast Wisconsin later Wednesday. There may be a chance of severe thunderstorms in this time period as well, but further analysis will be needed over the next few days pending similar guidance trends. Northwest flow may then return behind the cold front later Thursday as the low then centered in northeast Ontario moves further eastward. && .AVIATION...for 06Z TAF Issuance Issued at 1044 PM CDT Fri Jul 28 2023 Rain and thunder will be out of the area by the start of the 06Z TAF period. Behind this, recent rainfall may produce some fog across the area, especially across north-central WI where skies have begun to clear. Kept the fog mention for RHI in previous TAFs. Some fog may yet be added to central WI as well, but confidence was low. Then, good flying conditions are expected for the region through Saturday. VFR conditions should prevail across the area. .KOSH... Rain and storms will exit the airfield area by the beginning of the TAF period. Currently expect temperatures to be too warm overnight to allow for any fog by the morning. Saturday then bring clear skies, relatively light winds, and good flying conditions for the area. A few mid level clouds could yet develop in the afternoon, but no active weather is expected in Oshkosh. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && SHORT TERM.....Bersch LONG TERM......NLY AVIATION.......Uhlmann
Hazardous Weather Outlook National Weather Service Green Bay WI 1006 PM CDT Fri Jul 28 2023 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-300315- 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- 1006 PM CDT Fri Jul 28 2023 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight There is a chance of lingering rain and thunderstorms early tonight, mainly across east-central WI. Heavy downpours and localized flooding are be the primary threats. .DAYS TWO THROUGH SEVEN...Saturday through Friday The chance of thunderstorms will return during the Wednesday through Thursday time frame and may produce some stronger thunderstorms. .SPOTTER INFORMATION STATEMENT... Spotters are requested to report hail, wind gusts over 40 mph, and rain totals over one inch to the National Weather Service in Green Bay. LMZ521-522-541>543-300315- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 1006 PM CDT Fri Jul 28 2023 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight There is a chance of thunderstorms. Some of these storms may become strong and could pose a hazard to mariners. .DAYS TWO THROUGH SEVEN...Saturday through Friday The chance of thunderstorms will return during the Wednesday through Thursday time frame and may produce some stronger thunderstorms. Uhlmann
Preliminary Local Storm Report
National Weather Service Green Bay WI
851 PM CDT Fri Jul 28 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0843 PM Tstm Wnd Gst Wisconsin Rapids 44.40N 89.84W
07/28/2023 M46 MPH Wood WI ASOS
&&Preliminary Local Storm Report
National Weather Service Green Bay WI
919 PM CDT Fri Jul 28 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0841 PM Tstm Wnd Dmg Hickory Corners 45.00N 88.26W
07/28/2023 Oconto WI Trained Spotter
Multiple trees down.
&&Special Weather Statement
National Weather Service Green Bay WI
944 PM CDT Fri Jul 28 2023
WIZ045-048-049-290330-
Calumet WI-Winnebago WI-Waushara WI-
944 PM CDT Fri Jul 28 2023
...Strong thunderstorma will impact portions of southwestern
Calumet, Winnebago and southeastern Waushara Counties through 1030
PM CDT...
At 944 PM CDT, Doppler radar was tracking a strong thunderstorm over
Berlin, moving east at 40 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Oshkosh, Redgranite, Central Lake Winnebago, Rush Lake, Northern Lake
Winnebago, Omro, Winneconne, Eureka, Brothertown and Stockbridge.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Green Bay.
A Severe Thunderstorm Watch remains in effect until midnight CDT for
central and east central Wisconsin.
&&
LAT...LON 4390 8889 4398 8889 4398 8911 4410 8910
4413 8829 4394 8830 4394 8840 4389 8840
TIME...MOT...LOC 0244Z 269DEG 33KT 4399 8899
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
EBPreliminary Local Storm Report
National Weather Service Green Bay WI
1005 PM CDT Fri Jul 28 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0955 PM Tstm Wnd Gst Oshkosh 44.01N 88.55W
07/28/2023 M37 MPH Winnebago WI ASOS
At the airport.
&&Preliminary Local Storm Report
National Weather Service Green Bay WI
1015 PM CDT Fri Jul 28 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 PM Tstm Wnd Dmg Coloma 44.03N 89.51W
07/28/2023 Waushara WI Emergency Mngr
Multiple trees down in the city.
&&Preliminary Local Storm Report...Summary
National Weather Service Green Bay WI
1020 PM CDT Fri Jul 28 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0330 PM Hail 1 ESE Polonia 44.55N 89.38W
07/28/2023 E0.50 inch Portage WI Public
Report from mPING: Half-inch (0.50 in.).
0356 PM Hail 1 S Iola 44.49N 89.11W
07/28/2023 M1.00 inch Waupaca WI Public
Two public reports of estimated quarter to
half dollar sized hail that fell on the
south side of Iola. Time estimated based on
combination of reports and radar.
0437 PM Hail 7 N Iola 44.60N 89.11W
07/28/2023 M0.50 inch Waupaca WI Trained Spotter
0654 PM Hail Merrill 45.18N 89.68W
07/28/2023 M0.75 inch Lincoln WI Public
0725 PM Hail 2 WSW Rib Falls 44.95N 89.93W
07/28/2023 E1.00 inch Marathon WI Public
Report from mPING: Quarter (1.00 in.).
0735 PM Hail 1 SSW Marathon City 44.94N 89.84W
07/28/2023 E1.00 inch Marathon WI Public
Public report from social media of estimated
quarter sized hail.
0751 PM Hail 3 SSE Mountain 45.15N 88.45W
07/28/2023 E1.50 inch Oconto WI Public
Public report of around ping pong ball to
possibly golf ball sized hail. Time
estimated based on report and radar.
0843 PM Tstm Wnd Gst Wisconsin Rapids 44.40N 89.84W
07/28/2023 M46 MPH Wood WI ASOS
0955 PM Tstm Wnd Gst Oshkosh 44.01N 88.55W
07/28/2023 M37 MPH Winnebago WI ASOS
At the airport.
&&The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
Wake low winds snapped and uprooted trees in the Oshkosh area behind a departing thunderstorm. A camper underneath a tree was injured when a branch fell on their tent on the EAA grounds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2023Every state in 2023This day in weather historyWarnings in Wisconsin, July 2023
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 2026-09-24. Each event’s entry at NCEI: 1106981.