A long duration mixed precipitation event resulted in highly variable snowfall amounts across western and central Wisconsin at the onset of April. Near freezing surface temperatures at precipitation onset on April 1st resulted in mostly rain falling across the area, eventually switching to snow in colder spots primarily along the ridge tops.
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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.
A long duration mixed precipitation event resulted in highly variable snowfall amounts across western and central Wisconsin at the onset of April. Near freezing surface temperatures at precipitation onset on April 1st resulted in mostly rain falling across the area, eventually switching to snow in colder spots primarily along the ridge tops. The combination of these near freezing surface temperatures with narrow bands of precipitation resulted in highly variable snowfall accumulations. Near the City of La Crosse (La Crosse County), the overall maximum snowfall accumulation of 15.8 was reported along the ridgetops while the overall minimum of 1.2 was reported 4 miles away on French Island (La Crosse County) within the Mississippi River Valley.
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 Apr 1, 10:02 PM CST, 6 hours 13 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service La Crosse WI 1102 PM CDT Mon Apr 1 2024 .KEY MESSAGES... - Rain and snow continue into the evening before tapering off. Snow to the north of Interstate 90 may have minor accumulations (less than 1/2 inch). - A rapidly evolving storm system is now forecast to impact the area Tuesday and Wednesday with accumulating snow in central and eastern Wisconsin. Some wet heavy snow accumulations are now forecast in central Wisconsin /3-6"/, with lighter amounts westward. Some lower chances (25%) exist for more than 6" of snow. - Strong winds of 20 to 30 mph with gusts of 40 to 50 mph Wednesday are now likely (60-70% chances). && .DISCUSSION... Issued at 329 PM CDT Mon Apr 1 2024 Snow Band and Showers Slowly Weaken Tonight, Minor Snow Accumulations Mainly on Grass Current radar shows an area of heavier precipitation along and just north of I-90. This is associated with a frontogenesis band allowing for increased lift in this area. This band of frontogenesis is expected to gradually weaken through the rest of the afternoon and evening. Heavy rain and snow showers are currently being reported under this band. Minor accumulations, mainly on grassy surfaces, are expected, however, if this band slows down and stays over an area for a prolonged period of time, accumulations on roads may be possible. An area of uncertainty regarding any accumulation are the temperatures. Current temperatures are in the low to mid 30s where the heaviest precipitation is ongoing. These temperatures will limit any road accumulations and keep accumulations mainly on grassy surfaces. Another item of note is that there is an area of instability in northeast Iowa and far southwestern Wisconsin where thunderstorms could occur with MUCAPE of <300 J/Kg. This area of instability will shift southeasterly during the afternoon, reducing the chance of thunderstorms. These storms could produce small hail. Snow and Wind Forecast Trends All Increasing for Tuesday into Wednesday The region is the focus of two strong weather systems merging over the Great Lakes. GOES water vapor imagery showing a well formed shortwave trough over southwest New Mexico ejecting northeastward toward the Plains at this time...and fueling the Moderate risk of severe storms in Oklahoma. Another shortwave trough from the northwest is clearly visible in the GOES water vapor imagery driving southeast through Saskatchewan. These two system merge over the Great Lakes and fuel strong cyclogenesis of a surface low tracking from northern IL north into the Michigan. Consensus forecast model trends have rapidly shifted the surface low west to eastern Lake Michigan /vs Ohio/ over the last 24 hours. This is causing a much stronger low center, further west, and a delayed exit overall to the east for any weather. The 01.12Z ECMWF ensemble low centers still have some members tracking just off the western Lake MI shore line, so some western track migration could still occur. This is a very challenging system with snow ratios, accumulation rate in the 30s, and westward extent of the frontogenetic band(s) northwest of the deepening low all baking a complex pie. The prolonged nature to the snowfall also reduces impact overall. Most ensemble guidance suggests 48 hour probabilities of 6"+ are in the 30% range with a 10:1 ratio and no melting. Thus, have increased the snow amounts in central Wisconsin into the 3 to 5 inch range with amounts decreasing to an inch along an Eau Claire to Winona to Waterloo line. However, the highest accumulation in any 6 hour period is 2" later Tuesday night and Wednesday morning. This slow rate of snow accumulation will struggle to produce higher end impacts. However, this storm is complex and weather outcomes still can change in the next 24 hours. Signals continue on a deeper mixed layer to ~1.5 km on Wednesday as cold advection kicks in and taps a stronger low-level wind field. The 01.00Z EC ensemble yields 70-80% chance of wind gusts over 45 mph along an Eau Claire to Waterloo corridor, which has good support in the latest deterministic model runs showing 35-45kt winds Wednesday at 925 mb. Wind Advisories will be needed, with the chance for High Wind Warning around 20%. The combination of potential hazards seems to target the Tuesday night period and Wednesday. While confidence in reaching Winter Storm Warning is around 25% at this time for central Wisconsin due to the complicating accumulation factors and longer duration and low-moderate snow rates, the wind gusts Wednesday and any change to a more favorable cyclone track (further west) could increase that probability. It would appear an Advisory may be the most likely for Tuesday night and Wednesday, but this is still considered a fluid forecast of lower confidence. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1050 PM CDT Mon Apr 1 2024 Flight restrictions are forecast through the TAF period. MVFR/IFR ceilings are a mainstay through the forecast with gusty northeast winds. Winds slowly turn to the north Tuesday morning. Some locations may experience occasional drizzle/sprinkles/flurries overnight before precipitation chances increase again tomorrow morning, especially east of the Mississippi River where a rain/snow mix is likely. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && DISCUSSION...Baumgardt/Cecava AVIATION...KAA
Hazardous Weather Outlook National Weather Service La Crosse WI 421 AM CDT Tue Apr 2 2024 WIZ017-029-034-042>044-053-055-031330- Taylor-Clark-Jackson-Monroe-Juneau-Adams-Vernon-Richland- 421 AM CDT Tue Apr 2 2024 This Hazardous Weather Outlook is for portions of southwest through central Wisconsin. .DAY ONE...Today and Tonight Snowfall accumulations of 2 to 6 inches expected in central Wisconsin this afternoon into Wednesday morning. Narrow bands of higher snowfall amounts are possible. Increased wind gusts of 35 to 45 mph tonight may result in patchy blowing snow and difficult travel. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Ongoing snowfall will impact the Wednesday morning commute. Wind gusts of 35 to 45 mph are expected Wednesday into Wednesday night. Periods of light snow possible into Thursday. .SPOTTER INFORMATION STATEMENT... Snowfall reports appreciated. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled. IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ032-033-041- 054-061-031330- Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette- Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston- Buffalo-Trempealeau-La Crosse-Crawford-Grant- 421 AM CDT Tue Apr 2 2024 This Hazardous Weather Outlook is for portions of north central Iowa...northeast Iowa...southeast Minnesota...southwest Wisconsin and west central Wisconsin. .DAY ONE...Today and Tonight Light snow tonight into Wednesday morning will provide 1 to 3 inches of accumulation. Strong wind gusts of 35 to 45 mph tonight. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Strong wind gusts of 40 to 50 mph expected Wednesday into Wednesday night. .SPOTTER INFORMATION STATEMENT... Snowfall reports appreciated. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled.
The national radar mosaic for the moment the first event began.
8 winter weather, 2 winter storm. Local standard time, as filed.
Volunteer observers reported 1 to 5 of snow accumulation in Trempealeau County.
Volunteer observers reported 2 to 5 of snow accumulation in Crawford County with a maximum of 5.0 near Bell Center and Prairie Du Chien.
Volunteer observers reported 1 to 4 of snow accumulation in Grant County with a maximum of 6.5 in Platteville.
Volunteer observers reported 2 to 14 of snow accumulation in La Crosse County with a maximum of 15.8 in La Crosse.
Volunteer observers reported 3 to 9 of snow accumulation in Vernon County with a maximum of 11.5 in La Farge.
Volunteer observers reported 4 to 6 of snow accumulation in Monroe County with a maximum of 6.0 in Warrens.
Volunteer observers reported 2 to 5 of snow accumulation in Clark County with a maximum of 7.0 in Thorp.
Volunteer observers reported a maximum snow accumulation of 6.7 in Medford.
Volunteer observers reported 3.0 to 6.0 in Adams County with a maximum of 8.5 in Grand Marsh.
A volunteer observer reported 3.6 of snow accumulation in Grand Marsh.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2024Every state in 2024This day in weather historyWarnings in Wisconsin, April 2024
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: 1170877, 1170861, 1170862, 1170863, 1170871, 1170870, 1170857, 1170860, 1170235, 1170236.