textproduct: Marquette

KEY MESSAGES

- Potentially historic blizzard is expected early this morning through Monday night. This will create treacherous and potentially life-threatening travel conditions and could result in tree damage and power outages!

- Snow amounts of 1-3 feet are expected (locally up to 4 feet north- central and eastern U.P.) with wind speeds of 35-60 mph. Strongest winds are expected late this afternoon into Monday in the Keweenaw Peninsula and along the lakeshores of Lake Superior.

- Widespread northeast gales over Lake Superior today become northerly storm force gusts of 50-60 knots tonight into Monday. There is a 30% chance for gusts exceeding 64 knots in the east on Monday. Heavy freezing spray will also occur over ice-free areas.

- Large waves on the Great Lakes increase the risk of breaking up previously-stable ice as well as the risk for beach erosion and lakeshore flooding for all Lake Superior lakeshores tonight and Monday.

DISCUSSION

Issued at 258 AM EDT Sun Mar 15 2026

The primary focus with this forecast is the potentially historic, record-breaking blizzard that will impact the Upper Great Lakes today through Monday night. The prolonged nature of very strong winds and quickly accumulating, blowing, and drifting snow will result in treacherous and potentially life-threatening travel conditions and the risk of power outages today and Monday. Travel should be restricted to emergencies only through Monday, and even emergency vehicles will struggle to navigate the roads at times!

Current conditions at 06Z show a calm before the storm for most of the UP. METAR reports show that the storm is arriving, as stations near the state line (LNL, IMT, MNM, and EGV) show deteriorating visibility with the onset of -SN, ranging from 0.75 mile at IMT to 2.5 miles at LNL. KMQT radar shows widespread light reflectivities, indicating that the surface dry layer (dew point depressions ranging from a few degrees to as much as 10+ degrees at some RAWS sites) is currently winning out, but will not forever. Aloft, broad troughing at the jet and 500mb level still remains just to the lee side of the Rockies, but troughing is becoming more apparent approaching the Midwest at 700mb and surface low pressure is at 989mb and holding over Kansas.

By this evening, the 500mb shortwave will eject out of the Plains, forcing the surface low to the Chicago area, maintaining similar pressure or deepening slightly. The low then tracks slowly northeastward somewhere over the northern half of lower Michigan tonight, though this is when ensemble spread begins as the Euro suite shows low centers from Drummond Island all the way to the Milwaukee nearshores, a disappointing amount of spread for hour 36 of the run. The shortwave then takes on a negative tilt near western Lake Michigan early Monday and pivots north-northeast with strong vorticity advection over the east half of the CWA and Lower MI. This alongside favorable jet dynamics strengthen the low to near 980 mb Monday morning. While frustration remains in the spread in the low track, the big picture changes to the forecast due to these uncertainties are minimal and the message remains the same. A dual- moisture stream accompanies this system, with NAEFS moisture transport plots noting the atmospheric river from the Pacific northwest and stronger lower level moisture transport from the Gulf with a strengthening LLJ. Strong lift is present in the combination of jet entrance regions, isentropic ascent, robust WAA, and 700 mb f- gen into this morning.

The HREF shows the result of the copious amounts of lift and moisture: 70+% chances of snowfall rates exceeding 1"/hr and 20-50% chances of 2-3 inches per hour over the UP this afternoon. Snow then continues through Monday before tapering down Monday night into Tuesday as the surface low lifts to Quebec. 850 mb temps near -10C cool further as additional CAA builds overhead, bringing 850 mb temps down to the -20s C by Monday night. Because of ample synoptic, lake enhanced, and orographic forcing, and model sounding DGZ depths near or greater than 10 kft for long periods of time, guidance is suggesting widespread 1 to 3 ft of snow through the event with localized amounts up to 4 ft in the north-central and eastern U.P. The heaviest snowfall rates will occur today, particularly the eastern two thirds of the U.P. Snowfall rates of 0.5 to 1.5 inch per hour are favored through Monday evening, heaviest over the north central. Despite the rates being relatively lower (still elevated in an absolute sense) during the latter half of the event, blizzard conditions are still expected as northerly winds increase even further for Sunday night and Monday.

East-northeast winds begin increasing today, peaking near 40 mph for most inland locations and 50+ mph in the terrain of the Keweenaw and by the lakeshores by evening. Tonight into Monday will see these winds increase further from the northeast to north, when 60+ mph gusts are expected in the Keweenaw and by Lake Superior with 40-50 mph being possible elsewhere. The 12z EPS suggests 20-50% chances for winds exceeding 74 mph (hurricane-force!) along the lakeshore from Big Bay to Whitefish Point Monday and 10-30% chances for interior eastern areas. Should these winds occur, tree damage and power outages should be expected. With these winds in addition to the well-documented heavy snowfall, visibility will be driven to 1/4 mile to whiteout conditions for much of the next couple days. Blizzard Warnings remain on track for the entire CWA. Northerly to northwesterly winds are expected to lighten Monday night, but still remain elevated to near 40 mph near Lake Superior east of Marquette County into Tuesday morning. Strong winds over Lake Superior build wave heights of up to 20-30 ft, highest over the central third of the lake. Lakeshore Flood Warnings and a Lakeshore Flood Advisory remain tonight and Monday as a result. These strong winds will also result in snow drifts of several feet tall, adding to difficult travel and snow load on structures.

Few changes to the forecast and no changes to headlines were made with this forecast update. The biggest changes are in the west, where CAM guidance with better parameterization of orographic and mesoscale contributions to snowfall have lead to increased snow totals in the terrain of the west, most notably at Ironwood, with the storm total snow now expected to be around the 2 foot mark, give or take a half foot as the west will be the most sensitive to impacts from the low pressure track spread in the ensembles mentioned earlier. CAMs have also driven the upper percentiles of forecast snow totals into mind-boggling ranges, which are almost certain to not be realized as the strong winds are likely to depress snow ratios by fracturing dendrites into shapes that are more compact, thus leading to a denser snowfall for the same QPF.

Lake effect snow looks to continue into Tuesday over the northwest winds snowbelts, diminishing from west to east as high pressure ridging moves in from the west and WAA aloft weakens delta-Ts. Additional amounts Tuesday should remain on the light side, an inch or less.

With and immediately following the storm, polar air will keep below normal temperatures across the region, with highs Monday and Tuesday only getting into the teens to lower 20s and lows Monday and Tuesday nights dropping down into the single digits in the interior to lower teens near the Great Lakes. Wind chills will also fall to near -10F during the overnight hours Monday and Tuesday nights.

Enjoyers of spring rejoice: there is hope late in the week! The weather pattern for the back half favors a track of either one or two clipper lows (depending on your favorite ensemble member) tracking through northern Ontario. These lows should be weaker and not bring as extreme of precipitation and winds, though they will foster warm southerly flow that will bring high temperatures to the upper 30s and low 40s for the back half of the week. Precipitation is currently expected to be rain or snow (or a clean mix of both), though spread in the details of those solutions is high at this point.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 710 AM EDT Sun Mar 15 2026

Snow is currently observed lifting into the region, associated with a strengthening system that is anticipated to bring a very strong, potentially historic storm to the region. Conditions will deteriorate this morning, with all sites falling to LIFR, potentially airport minimums from snowfall rates of 1 to 3 inches per hour. By evening, these heavier snowfall rates may lighten at KIWD/KCMX, but increasing winds will result in continued LIFR conditions. Winds continue to climb overnight potentially reaching 50kts at KCMX/KSAW and near 40kts at KIWD. Between gusts, low level wind shear is expected at KSAW as well.

All told, snowfall will total 1 to 3 feet through Monday night, highest at SAW. Northeasterly to northerly winds will continue gusting to 40-50 knots at KCMX/KSAW into Monday, with 30-35 knots possible at KIWD, resulting in extreme blowing and drifting of snow and whiteout conditions.

MARINE

Issued at 258 AM EDT Sun Mar 15 2026

A strong to historic storm moves from southwest to northeast through the Upper Great Lakes today through Monday. This will result in increasing winds today, reaching gales this morning and then storm- force tonight. Guidance continues to hold a low (~30%) chance for hurricane-force winds on Monday over the east half of the lake. In addition to the strong winds driving significant wave heights of 20+ feet (some to near 30 feet between Stannard Rock and the shores of Marquette and Alger Counties), cold air descending overhead will create heavy freezing spray. As the low exits towards Quebec, winds diminish Monday night, falling below storms around midnight and below gales lakewide Tuesday morning.

For the rest of the week, the weather pattern favors one or two weaker clippers moving north of Lake Superior between early Wednesday and late Friday. The pattern also favors warm, southerly flow, reducing the risk of heavy freezing spray. While gales cannot be entirely ruled out, chances of gales for any given period in the latter half of the week are only 10-20%.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Blizzard Warning until 2 AM EDT Tuesday for MIZ001-003>005.

Lakeshore Flood Warning from 8 PM this evening to 11 PM EDT Monday for MIZ001-003.

Blizzard Warning until 8 PM EDT /7 PM CDT/ Monday for MIZ002- 009>012-084.

Lakeshore Flood Warning from 11 PM this evening to 5 PM EDT Monday for MIZ002.

Lakeshore Flood Warning from 8 PM this evening to 2 AM EDT Tuesday for MIZ005.

Blizzard Warning until 8 AM EDT Tuesday for MIZ006-007-013-014- 085.

Lakeshore Flood Warning from 8 PM this evening to 8 AM EDT Tuesday for MIZ006.

Lakeshore Flood Warning from 5 AM Monday to 2 AM EDT Tuesday for MIZ007.

Lakeshore Flood Advisory from 10 PM this evening to 4 PM CDT Monday for MIZ009.

Lake Superior... Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ162- 240>242-263.

Heavy Freezing Spray Warning until 2 AM EDT /1 AM CDT/ Tuesday for LSZ162.

Storm Warning from 8 PM EDT /7 PM CDT/ this evening to 11 AM EDT /10 AM CDT/ Monday for LSZ162.

Heavy Freezing Spray Warning from 2 PM EDT /1 PM CDT/ this afternoon to 2 PM EDT /1 PM CDT/ Tuesday for LSZ240>248- 263>265.

Storm Warning from 8 PM EDT /7 PM CDT/ this evening to 2 PM EDT /1 PM CDT/ Monday for LSZ240>242-263.

Gale Warning from 11 AM this morning to 8 PM EDT this evening for LSZ243>251-264>267.

Storm Warning from 8 PM this evening to 2 AM EDT Tuesday for LSZ243>251-264>267.

Heavy Freezing Spray Warning from 8 PM this evening to 5 PM EDT Tuesday for LSZ249>251-266-267.

Lake Michigan... Gale Warning until 8 PM EDT this evening for LMZ248-250.

Storm Warning from 8 PM this evening to 4 PM EDT Monday for LMZ248-250.

Heavy Freezing Spray Warning from 2 AM Monday to 2 AM EDT Tuesday for LMZ248-250.