A low pressure system tracked from southern Wisconsin Friday night (3/31) towards lower Michigan Saturday morning (4/1). A swath of 8 to 19 inches of heavy snow fell across north-central Wisconsin as easterly surface winds gusted to 30 to 40 mph on the north side of the low pressure system.
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
A low pressure system tracked from southern Wisconsin Friday night (3/31) towards lower Michigan Saturday morning (4/1). A swath of 8 to 19 inches of heavy snow fell across north-central Wisconsin as easterly surface winds gusted to 30 to 40 mph on the north side of the low pressure system.
Some of the highest snowfall amounts included 18.8 inches near Argonne (Forest Co.), 18 inches in Armstrong Creek (Forest Co.), 16.3 inches in Spread Eagle (Florence Co.) as well as in Hazelhurst (Oneida Co.), 15.8 inches in Florence (Florence Co.), 15.1 inches in Saint Germain (Vilas Co.), and 11 inches near Niagara (northern Marinette Co.) as well as in Tomahawk (Lincoln Co.).
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 Mar 31, 9:33 PM CST, 2 hours 27 minutes earlier.
Area Forecast Discussion National Weather Service Green Bay WI 1033 PM CDT Fri Mar 31 2023 Updated aviation portion for 06Z TAF issuance .UPDATE... Issued at 904 PM CDT Fri Mar 31 2023 Made some tweaks to snowfall amounts, with the biggest changes occurring in north central WI, where accumulations were lowered a few inches in the RHI/TKV areas. The only headline change was to break off northern Marinette County from the southern segment of the warning, as the higher snowfall totals (9-13 inches) did not mesh well with the rest of the warning segment. According to the RHI ASOS (0.04 inch ice accumulation) and a spotter report in Antigo, freezing rain will continue to be an issue for the next few hours, so continued the forecast of local ice accumulations up to 1/10 to 2/10s of an inch in north central and far northeast WI. Thunderstorms spread north across most of the forecast area earlier this evening, but have waned in the past hour as MUCAPE and mid-level lapse rates weakened. However, another cluster of storm is poised to impact east central WI late this evening, but these should exit quickly as the dry slot arrives. && .SYNOPSIS... Issued at 254 PM CDT Fri Mar 31 2023 A strong storm system will bring a full array of weather types from thunderstorms with hail to near blizzard conditions to the area tonight. A second, potentially even more potent storm on a more northwesterly track next week will bring mainly rain, thunderstorms, and strong winds. At least some flooding will result from snowmelt and runoff of the precipitation produced by both systems. Jet energy from the Pacific will flow southeast though the western U.S., then turn east as it diverts around a blocky pattern over northeast NOAM. Major shortwaves embedded within the flow will bring a series of intense cyclones through the Great Lakes region, resulting in heavy and possibly excessive precipitation. Temperatures will undergo significant day-to-day variation due to cloud cover/precipitation and the change of air masses associated with the passage of the cyclones. && .SHORT TERM...Tonight and Saturday Issued at 254 PM CDT Fri Mar 31 2023 Fairly active weather forecast lies ahead for the short term period. The initial shortwave moved east of the area late this morning, taking with it most of the snow and rain that stretched across the area. The warm front across southern Wisconsin still kept scattered showers and even a few rumbles of thunder in place across central to east-central Wisconsin, but most of the area saw at least a few breaks in precipitation for the early afternoon. Going forward, the initial concern for the short term will be the somewhat marginal potential for any thunderstorms from central to east- central Wisconsin. Although the greatest risk for severe weather is south of the area, a strong thunderstorm or two isn't impossible. For our neck of the woods, this would be primarily a hail concern, as instability is mainly elevated and dynamics would be favorable to organize an updraft. No tornadoes are expected for our area, but if you're traveling south or southwards in the afternoon and evening towards Iowa or Illinois, stay weather aware. Behind this, cold air arrives in behind the passing low pressure system tonight, switching precipitation over to snow from northwest to southeast. As the upper low crosses central Wisconsin, deformation across the north, a coupled jet, and lingering moisture from the strong southerly flow earlier in the day will allow for some impressive snow rates overnight. Accumulations could get over an inch to an inch and a half of snow per hour for portions of the northwoods overnight. The banded structure of the snowfall combined with the lingering warm air over the Fox Valley and east-central will make for a fairly sharp cutoff in the overall snowfall as you get towards the Fox Valley. Snowfall amounts range from 8 to 14 inches in the banded area of snowfall to as low as 1 to 3 inches near the Fox Valley. In addition to the snow, winds will also pick up overnight as the upper low passes, with gusts around 35 to 45 mph possible at times by Saturday morning. Headline wise, a winter storm warning was issued for the snow and wind for a line from Marathon County east to Oconto and then north to the Upper Peninsula border. Wood and Portage were also included in the warning for winds and snow, although the overall snow amounts will be lower than further north. Finally, a winter weather advisory was issued for Waupaca, Outagamie, Brown, and Door Counties, as the southern cutoff of the aforementioned snow gradient is not entirely clear and may still be over the northern portions of these counties. Suffice to say, even if the lower amount of around 2 inches falls over these areas, wind will be sufficient to make travel conditions quite hazardous. One final mention, the snow will likely be fairly wet and heavy at onset, before becoming lighter and more fluffy as additional cold air arrives late overnight. Saturday, precipitation will depart the region fairly quickly during the morning hours, with most of the snow out of area by the early afternoon. Winds will remain elevated a bit longer, with gusts running high through the afternoon before finally diminishing again Saturday evening. .LONG TERM...Saturday Night Through Friday Issued at 254 PM CDT Fri Mar 31 2023 Clear skies (at least early in the night), diminishing winds, and a fresh deep snowcover should allow temps to drop substantially Saturday night. Went at least 5 degrees below the NBM where the heavy snow will fall tonight, and would actually not be surprised if some of those areas ended up much colder and below zero. Uncertainty regarding the timing of arrival of clouds later in the night preclude going colder with this forecast. A shortwave and some jet energy could bring some snow changing to rain to mainly the north on Sunday, but amounts will be light and do not anticipate much if any impact on travel. Another intense cyclone (deepening to 974 mb on the ECMWF) is expected to develop in the lee of the Colorado Rockies Monday and Monday night, track across the Plains Tuesday, then toward Lake Superior on Wednesday. If this track holds, the forecast area will be on the warm side of the system. A wintry mix may occur across the far north at times, but the primary concern will be the potential for heavy convective rains combined with runoff resulting in areal and river flooding. A severe threat could manifest at some point, though current timing would bring the cold/occluded front through around 12Z which would probably mitigate the severe potential. The strength and track of the cyclone look very favorable for strong winds, especially on Wednesday when the forecast area will be beneath the upper dry slot behind the cold front/occlusion. && .AVIATION...for 06Z TAF Issuance Issued at 1020 PM CDT Fri Mar 31 2023 Poor flying conditions will be in place tonight through Saturday morning. Mixed precipitation will change to snow from northwest to southeast overnight, and continue into Saturday morning over parts of northeast and east central WI. The precipitation will briefly taper early in the TAF period, as a dry slot rotates through the area. A band of heavy snow will set up over north central and far northeast WI. Strong north winds gusting to 35-45 kts will produce blowing and drifting snow in open areas late tonight into at least early afternoon. Clearing skies and diminishing snow showers should bring VFR conditions to much of the region by late morning/midday, with the exception of open areas, where reduced vsbys in blowing snow may persist. The strong winds should diminish late in the day. && .GRB WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 10 AM CDT Saturday for WIZ005-010>013- 018-019. Winter Storm Warning until 1 PM CDT Saturday for WIZ020-021-030- 031-035-036-073-074. Winter Weather Advisory until 1 PM CDT Saturday for WIZ022- 037>039. && UPDATE.........Kieckbusch SYNOPSIS.......Skowronski SHORT TERM.....Uhlmann LONG TERM......Skowronski AVIATION.......Kieckbusch
Hazardous Weather Outlook National Weather Service Green Bay WI 935 PM CDT Fri Mar 31 2023 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-020245- 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- 935 PM CDT Fri Mar 31 2023 This Hazardous Weather Outlook is for north-central and northeast Wisconsin. .DAY ONE...Tonight Scattered thunderstorms will impact mainly east central Wisconsin through about midnight. Severe weather is not expected. Hazardous travel conditions will develop from northwest to southeast tonight as rain or freezing rain changes to snow. Travel will become dangerous at times as very heavy snow and and strong north winds combine to occasionally reduce the visibility to near zero. A total snow accumulation of six to fourteen inches is expected across most of northern Wisconsin, especially north of a Wausau to Marinette line, with lower totals to the south and east. Gusty northeast winds may result in a threat of ice shoves on the western shores of Lake Winnebago, including the Oshkosh area, late this evening. .DAYS TWO THROUGH SEVEN...Saturday through Friday Hazardous travel conditions will linger Saturday morning then abate as snow diminishes and winds begin to slowly subside. Strong north to northwest winds gusting to 40 mph may bring a threat of ice shoves to the south and southeast shores of Lake Winnebago on Saturday. .SPOTTER INFORMATION STATEMENT... Spotters are requested to forward snow and ice measurements to the National Weather Service in Green Bay. Reports of hail will also be appreciated. LMZ521-522-541>543-020245- The Bay of Green Bay south of a line from Cedar River MI to Rock Island Passage-Lake Michigan from Washington Island to Sheboygan- 935 PM CDT Fri Mar 31 2023 This Hazardous Weather Outlook is for portions of northwest Lake Michigan and the waters of Green Bay. .DAY ONE...Tonight Scattered thunderstorms are possible through about midnight. Northeast to North gale force gusts are likely tonight. .DAYS TWO THROUGH SEVEN...Saturday through Friday North gale force gusts are likely to continue through most of Saturday. Kieckbusch
Special Weather Statement National Weather Service Green Bay WI 706 PM CDT Fri Mar 31 2023 WIZ022-038>040-048>050-073-074-010500- Door-Outagamie-Brown-Kewaunee-Winnebago-Calumet-Manitowoc- Southern Marinette County-Southern Oconto County- 706 PM CDT Fri Mar 31 2023 ...AREAS OF DENSE FOG WILL RESULT IN LOCALLY HAZARDOUS TRAVEL ACROSS EASTERN WISCONSIN THIS EVENING... Areas of dense fog, with visibilities of 1/4 mile or less, will continue through this evening across parts of eastern Wisconsin, including the Fox Valley, lakeshore and bayshore areas. Visibilities may briefly improve as steadier rains move through. The foggy conditions should improve by midnight. Motorists traveling across eastern Wisconsin can expect rapidly changing and poor visibilities at times. Remember to turn on your low-beam headlights and keep a safe distance between you and the car in front of you. Kieckbusch
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
944 PM CDT FRI MAR 31 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0935 PM HEAVY RAIN 1 WSW PLOVER 44.44N 89.55W
03/31/2023 M1.80 INCH PORTAGE WI CO-OP OBSERVER
STORM TOTAL PRECIPITATION SINCE FROM 5 PM
YESTERDAY TO 9:35 PM TODAY. WATER 3 TO 6
INCHES DEEP ON SEVERAL STREETS IN PLOVER.
&&The national radar mosaic for the moment the first event began.
7 winter storm. Local standard time, as filed.
The highest snowfall totals in Vilas County included 15.1 inches in Saint Germain, 13.4 inches near Eagle River, and 6.4 inches near Boulder Junction.
The highest snowfall totals in Oneida County included 16.3 inches in Hazelhurst, 15 inches in Lake Tomahawk, 13.8 inches in Rhinelander and 13.5 inches near Goodnow.
The highest snowfall totals in Forest County included 18.8 inches near Argonne, 18 inches in Armstrong Creek, and 11 inches near Crandon.
The highest snowfall totals in Florence County included 16.3 inches in Spread Eagle, 15.8 inches in Florence, and 15.3 inches in Aurora.
The highest snowfall totals in Lincoln County included 11 inches in Tomahawk and 8.7 inches near Merrill.
The highest snowfall total in Langlade County was 8 inches in Summit Lake.
The highest snowfall totals in northern Marinette County included 11 inches near Niagara and 7 inches in Athelstane as well as Caldron Falls.
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, April 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: 1081872, 1081873, 1081874, 1081875, 1081876, 1081877, 1081878.