Thunderstorms that moved across east central Wisconsin produced heavy rain and isolated large hail.
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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.
Thunderstorms that moved across east central Wisconsin produced heavy rain and isolated large hail.
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 May 15, 7:23 PM CST, 1 hour 7 minutes earlier.
Area Forecast Discussion...UPDATED National Weather Service Green Bay WI 823 PM CDT Mon May 15 2017 New Information added to update section .UPDATE... Issued at 806 PM CDT Mon May 15 2017 Showers continue to develop across about the northern third of the forecast area in response to mid-level shortwave crossing the region. The redevelopment has expanded south some in the past half hour. The atmosphere across the area remains rather stable. Meanwhile, a cluster of intense storms just crossed the Mississippi River into southwest Wisconsin. It's tracking east along/just north of the main front, and leaving the front shoved farther south in its wake. The past few runs of the HRRR/RAP are handling this convection better, though they still do not appear to have fully latched onto it. The short-range guidance continues to suggest redevelopment in the wake of the SW WI activity will be displaced to the north, though the focus now seems to be east- central and southeast Minnesota, with the main push of the strongest part of that convection to the ESE. That makes more sense (compared to earlier models showing the main push farther to the north) given the track of the initial convection and it's affect on the front. Continue to feel the brunt of the strongest storms later tonight will be south of the area, though storms certainly are likely to affect at least the southern part of the forecast area. Will re-align PoP grids based on the latest radar trends and send an update in about an hour. && UPDATE Issued at 533 PM CDT Mon May 15 2017 The main forecast issue is convective trends for the evening and overnight hours. Weakening band of convection driven by ascent ahead of mid-level shortwave was shifting east across the area late this afternoon. The air mass across the area is rather stable, so the convection was weakening. Only a few lightning strikes remained across the forecast area. Subsidence behind the departing shortwave is likely to limit additional development this evening. By far the most vigorous new convection in the region was down in northern Iowa. That was not modeled at all well by the HRRR and RAP, but was pretty well reflected in the 2 Hi- Res WRFs. They expand the convection, track it east into SW Wisconsin, then turn it ESE toward southern Lake Michigan by midnight. That seems to fit well with current radar trends. Of most interest is the fact that both HiRes WRFs develop a second band of strong convection along an axis from west-central to east- central Wisconsin after midnight. Despite their good performance thus far today, am somewhat skeptical the additional development will occur that far north. The synoptic frontal boundary is down near the Illinois border, and it's likely to get shoved even farther south by the first round of storms. So additional development driven/fed by strengthening 850 mb flow seems more likely to occur farther south as well. No changes to the forecast after midnight yet, but may eventually need to adjust PoPs and Wx if it becomes apparent the late night convection will focus farther south. && .SHORT TERM...Tonight and Tuesday Issued at 237 PM CDT Mon May 15 2017 First band of showers and thunderstorms across far northern Wisconsin had shifted northward into Upper Michigan with only a few remaining showers across the area. Meanwhile, a second band of showers and thunderstorms across western Wisconsin was now beginning to move into central Wisconsin associated with mid level disturbance. This band of showers and thunderstorms will move across the area for the reminder of the afternoon into the middle evening hours. Best most unstable capes (MU) remain south and west of the area as of mid afternoon, and should remain there through this evening as warm front remains well south of the area. Strong 0-6km shear moving across the region later this afternoon and evening, thus the risk of severe weather remains low for the rest of the afternoon and evening. Once this round of showers and storms exit the region this evening, there should be a brief lull before more storms develop around midnight into early Tuesday morning. Low level jet is expected to increase and warm front should start pushing northward later tonight. Elevated convection is expected to break out in response to the low level jet. Some of the storms could be strong or severe with damaging winds and large hail. Showers and thunderstorms will be ongoing Tuesday morning across northern Wisconsin as warm front pushes northward into northern Wisconsin. Across central and east-central Wisconsin, it will be the warmest day of the year along with the summer like humidity with dewpoints in the 60s. .LONG TERM...Tuesday Night Through Monday Issued at 237 PM CDT Mon May 15 2017 Active pattern continues for much of the week and into the weekend, with a possible brief break late this week. Focus of convection at the onset Tuesday evening will be over north central and parts of central Wisconsin near the frontal boundary. Forecast sounding suggests the mid level cap region gradually erodes from west to east as a frontal boundary sags into the state. The NAM erodes this cap much faster at least for the western half of the forecast area. Progs continue to focus on a second area of widespread convection Wednesday into Wednesday night with the arrival of a strong short wave trough and a frontal system. The air mass becomes more unstable in the afternoon along with increasing low level shear with the frontal system to increase the potential of strong to severe storms. Some possible limiting aspects include too many clouds and ongoing convection Wednesday morning, but model trends have in general tracked the surface low more west and placing much of east central Wisconsin in the southwest surface flow and region of a more unstable air mass. An 850 mb low is also track a bit further west placing the deformation of heavier rainfall area over the northwest third or quarter of the state, including part of far North Central Wisconsin. This shortwave trough is trending with a slower departure to warrant continued rain chances for Thursday. A weak upper ridge drifts over the area the rest of the week for a quieter period of a weather. The GFS continues to be 12 to 24 hours faster compared to the ECMWF with the next frontal system. This system departs the area late Sunday for a dry start early next week. && .AVIATION...for 00Z TAF Issuance Issued at 533 PM CDT Mon May 15 2017 The main aviation forecast issue will be determining to what extent convection results in lower ceilings later tonight into Tuesday. Unfortunately, that is a low-confidence aspect of the forecast as the behavior of the convection itself is still quite uncertain. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && UPDATE.........Skowronski SHORT TERM.....Eckberg LONG TERM......TDH AVIATION.......Skowronski
Hazardous Weather Outlook National Weather Service Green Bay WI 245 PM CDT Mon May 15 2017 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-161945- 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- 245 PM CDT Mon May 15 2017 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Rest of the Afternoon and Tonight A band of showers and thunderstorms are expected to work into central and parts of north-central Wisconsin during the rest of the afternoon and then into northeast Wisconsin toward evening. The risk of severe weather is low with these storms. Later tonight, additional thunderstorms are expected to develop along a warm front around midnight into early Tuesday morning. Some of the storms may produce damaging winds, large hail and locally heavy rainfall, especially south of a Marshfield to Manitowoc line. .DAYS TWO THROUGH SEVEN...Tuesday through Monday Periods of thunderstorms are expected Tuesday through Wednesday night, and also next weekend. A few strong storms are possible over central and north-central Wisconsin on Tuesday and Tuesday night, then for all locations Wednesday and Wednesday night, but it is too early to determine the severe weather threat at this time. Heavy rainfall is also possible over far north-central Wisconsin on Wednesday and Wednesday night. .SPOTTER INFORMATION STATEMENT... Formal spotter activation is not anticipated for the remainder of the afternoon and this evening, but may be needed after midnight south of a Marshfield to Manitowoc line. Spotters are requested to report heavy rainfall over an inch, hail or wind gusts over 35 mph. LMZ521-522-541>543-161945- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 245 PM CDT Mon May 15 2017 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight Thunderstorms are likely tonight. Hail and heavy rainfall will be possible with any thunderstorms. .DAYS TWO THROUGH SEVEN...Tuesday through Monday A chance of thunderstorms will occur at times Tuesday through Wednesday night, and also into the weekend. Winds and waves hazardous to small craft could occur Tuesday night through Thursday. Eckberg/TDH
The Green Bay radar (KGRB), 56 km away, was scanning. The volume nearest the first event began at 02:31 UTC.
1 hail. Local standard time, as filed.
A thunderstorms produced penny size hail as it passed through the Manitowoc area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2017Every state in 2017This day in weather historyWarnings in Wisconsin, May 2017
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: 702948.