During the early part of May, between 1 and 3 inches of rain fell across western Wisconsin. Runoff from this rain produced some flooding along the Kickapoo and Yellow Rivers.
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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 ARX wrote it up.
During the early part of May, between 1 and 3 inches of rain fell across western Wisconsin. Runoff from this rain produced some flooding along the Kickapoo and Yellow Rivers.
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 La Crosse, WI wrote its last area forecast discussion before the first event at May 2, 5:25 AM CST, 4 hours 20 minutes earlier.
Area Forecast Discussion National Weather Service La Crosse WI 625 AM CDT Wed May 2 2018 .SHORT TERM...(Today and tonight) Issued at 348 AM CDT Wed May 2 2018 At 3 AM, a surface low was located northwest of Green Bay. This system brought the showers and storms to our area on Tuesday evening and early this morning. These lingering showers will exit the area by sunrise. Rain cooled area in the wake of this convection will keep the area stable this morning, so not expecting too much redevelopment until mid to late afternoon as another wave moves northeast along the frontal boundary. The 02.00z models are differing on how much surface based and elevated CAPE will build south of Interstate 90. The RAP only has 500 to 1000 J/kg. Meanwhile, the GFS has higher dew points (mid- 60s), so it has CAPES are in the 2-3K J/kg. The NAM and ECMWF are more in the 1-2K range. With better shear (0-6 km greater than 40 knots - much of it in the 0-3 km layer), the amount of instability in very important factor for determining our severe weather threat. Looking at the dew points upstream, thinking that the NAM and ECMWF seem a bit more realistic with their CAPES. Like this evening, the soundings suggest that the convection across northeast Iowa and southwest Wisconsin will be mainly elevated, so isolated hail looks to be the primary threat late this afternoon and early evening. The showers and scattered storms will continue into the early overnight and then depart the area by morning. .LONG TERM...(Thursday through Tuesday) Issued at 348 AM CDT Wed May 2 2018 On Thursday afternoon and Thursday night, a southern stream short wave trough will move northeast through the area. The models continue to differ on where the heaviest rain with this system will fall. The 00z runs continue to be much further north than the 12z runs. There is considerable difference in the dew points across the region. The NAM has dew points mainly in the 50s. Meanwhile, the GFS has dew points in the lower and mid 60s south of Interstate 94. The ECMWF is between these 2 models. These dew points are in important because they have a huge impact on the amount of CAPE available. The NAM and ECMWF both have CAPES less than 1K J/kg. Meanwhile, the GFS has CAPES of 1.5-2.5 J/kg. With all these models having deep shear, these CAPES will have to be something to monitor. However, with the cloud cover ahead of this system and rain cooled air from the convection tonight would think that the lower CAPE scenarios in the NAM and ECMWF seem a bit more realistic. With precipitable water values up to 1.5 inches, some heavy rainfall could occur along and south of the Interstate 90 corridor. From late Saturday afternoon into Saturday night, a northern stream short wave will move southeast through the region. Unlike the system earlier this week, there will be less of a Gulf of Mexico connection, so rainfall amounts will be generally less than a quarter of an inch. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 625 AM CDT Wed May 2 2018 Took much longer than expected, but stratus has finally developed in the vicinity of Rochester (along with a little fog). That stratus is expected to hang tight for a few hours this morning with LIFR conditions for RST but MVFR conditions likely expanding east toward LSE for a few hours as well. However, confidence on thicker stratus reaching LSE isn't exactly the highest now that the sun is coming up, so there is some chance that LSE actually ends up avoiding much of the lower stratus. Something to watch closely the next hour or two. Otherwise, looking like a return to VFR for both locations by late morning with just some thicker mid level clouds working overhead. Later tonight, we could see some showers branch north toward LSE for a few hours after mainly 06Z, though conditions would remain VFR should that occur. Winds will shift northwest this morning around 10 knots, becoming light overnight. && .HYDROLOGY... Issued at 348 AM CDT Wed May 2 2018 Flood warnings continue along stretches of the Mississippi River. Additional rounds of rainfall are possible from today through Thursday night. Additional rainfall south of Interstate 90 looks to be in the 1 to 2 inch range. With soils still dry across northeast Iowa and southwest Wisconsin, much of this rain will likely go into the soils. Therefore, not expecting widespread flooding from this rain, but additional rises on area rivers are possible. This will be especially along the case along the Kickapoo River. Please see water.weather.gov for the specific river forecast information. && .CLIMATE... Issued at 348 AM CDT Wed May 2 2018 With a high temperature of 79F at La Crosse Regional Airport, this was the warmest start to a May since 2001 (also 79F). A total of 0.92 inches of rain fell. This was the wettest start to a May since 1993 (1.17 inches - tied for the wettest May 1st). This was the 5th wettest start to a May. The only Mays which had a wetter starts were 1911, 1935, and 1993 which all had 1.17 inches of rain and 1973 (1 inch). Rochester had a high temperature of 71F which was their warmest start since 2012 (also 71F). A total of 0.59 inches of rain fell. This was the wettest start to a May since 2013 (1.02 inches). && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && SHORT TERM...Boyne LONG TERM...Boyne AVIATION...Lawrence HYDROLOGY...Boyne CLIMATE...Boyne
Hazardous Weather Outlook National Weather Service La Crosse WI 403 AM CDT Wed May 2 2018 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029- 032>034-041>044-053>055-061-031200- Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette- Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston- Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau- Adams-Vernon-Crawford-Richland-Grant- 403 AM CDT Wed May 2 2018 This Hazardous Weather Outlook is for portions of southeast Minnesota, northeast Iowa, and southwest into central Wisconsin. .DAY ONE...Today and Tonight Thunderstorms will be possible along and south of Interstate 90 from late this afternoon into the evening. A few of these storms may produce isolated large hail across parts of northeast Iowa and southwest Wisconsin. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Thunderstorms will be possible Thursday afternoon into Thursday night, and again Saturday night. At this time, there is a small risk of severe storms south of Interstate 90 on Thursday afternoon and evening. Water levels will continue to rise along the Mississippi River through the weekend, with minor flooding expected in some areas. Please visit water.weather.gov for the latest river forecast information. .SPOTTER INFORMATION STATEMENT... Rainfall reports are appreciated. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled. Boyne
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
602 AM CDT WED MAY 2 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 AM HEAVY RAIN 1 SE DE SOTO 43.42N 91.18W
05/02/2018 M2.50 INCH CRAWFORD WI TRAINED SPOTTER
&&
LAWRENCEThe national radar mosaic for the moment the first event began.
7 flood. Local standard time, as filed.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Readstown. The river crested over three feet above the flood stage at 14.2 feet on the 4th.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Viola. The river crested over two feet above the flood stage at 16.55 feet on the 5th.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Gays Mills. The river crested over two feet above the flood stage at 15.63 feet on the 5th.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Ontario. The river crested less than a foot above the flood stage at 16.63 feet on the 4th.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Soldiers Grove. The river crested less than a foot above the flood stage at 13.83 feet on the 4th.
Runoff from heavy rain pushed the Kickapoo River out of its banks in Steuben. The river crested over a foot above the flood stage at 13.48 feet on the 5th.
Runoff from heavy rain pushed the Yellow River out of its banks in Necedah. The river crested less than a foot above the flood stage at 15.45 feet on the 7th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2018Every state in 2018This day in weather historyWarnings in Wisconsin, May 2018
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: 757006, 757005, 757009, 757004, 757008, 757010, 757011.