textproduct: Marquette

KEY MESSAGES

- Widespread snowfall is expected tonight into Friday. Strong winds could bring near whiteout conditions, especially over the eastern U.P. and Keweenaw late tonight into early Friday morning. Poor visibility in snow/blowing snow is also expected near the Lake Superior shoreline on Friday as gusty winds become northerly. Winter Storm Warnings are in effect for all of the U.P.

- A significant winter storm will track through the Great Lakes late this weekend bringing heavy snow and strong winds. Uncertainty remains with the track of this system, however there is the potential for significant impacts to the region.

DISCUSSION

Issued at 238 PM EDT Thu Mar 12 2026

This afternoon satellite water vapor imagery and model height analysis show broad upper level troughing over much of Canada and the United States with a strong jet stream coming into the Pacific Northwest. Shortwave ridging ahead of the next disturbance over the Pacific Northwest was providing mainly sunny skies over the area today except for lake effect cloudiness in the Keweenaw and parts of the north-central U.P. A band of snow showers offshore from was Marquette County moving into Alger County most of the morning and early afternoon. Some of these snow showers were on the stronger side this morning but diurnal instability over the land had caused the snow showers to become much less organized and scattered over the last hour or so. Temperatures were in the 20s and 30s.

A strong, fast moving, clipper will move through the Upper Great Lakes tonight into Friday. This will bring hazardous winter weather back into the U.P. with the combination of heavy snow and blowing snow. Winter Storm Warnings are in effect for all of the U.P.

Most guidance has shifted south a bit with the track of the low, with solutions that previously were moving the low overhead (less snowy solution) now keeping the low just south of the U.P. Other guidance puts the heaviest precipitation even further south over northern WI and the far southern U.P. Have taken the middle of the road approach with the blended solution.

As the low approaches tonight strong FGEN and isentropic lift will overspread the U.P. with moderate to heavy snow developing over the area. REFS probs for 1+ in/hr snowfall rates are near 100% over the Keweenaw and central/eastern U.P. late tonight into the early morning hours. These rates combined with southeasterly winds gusting 30-40mph (up to 50 mph over the Keweenaw) will result in whiteout conditions at times, through not expecting the conditions to last long enough for blizzard criteria. The result will be a widespread 4- 9" snowfall overnight, with areas along the Lake Superior shoreline seeing the lower end of the snowfall due to downslope flow.

Lakeshore flooding could also be an issue along the eastern side of the Keweenaw where wave heights of 17-18ft are forecast and along northern Lake Michigan where wave heights will reach 10 ft. Issued Lakeshore Flood Advisory for the late night and Friday morning hours.

On Friday the low will quickly move to Upper Lower Michigan by afternoon and Ontario by evening. Expect light to moderate snow over the northern half of the U.P. on Friday behind the low pressure. Lake effect snow will develop in the north winds snowbelts along with upslope flow to product another 4-6" of snowfall over the north winds snowbelts. Winds will be strong along the lakeshore as well, gusting to 40 mph. This will will further reduce visibility with blowing snow, especially for the M-28 corridor. Due to the strong winds, additional snowfall close to the lakeshore on Friday will be less, closer to a few inches as convergence gets pushed inland from the lakeshore.

Lake effect will ramp down overnight Friday night with seasonal weather expected for Saturday, which should give people a chance to dig out before the next system arrives on Sunday.

All eyes turn to late Saturday night into Sunday as a strong winter storm takes shape in the lee of the Rockies. This system will track through the Great Lakes Sunday into Monday bringing a band of very heavy snowfall and possibly strong winds to the region. The EPS is stronger with the system suggesting that it could bring blizzard conditions similar to that of the late December storm, through without the heavy wet snow (which was very problematic) at the onset as this system will be colder. The GEFS, while still strong, is weaker with the system and would have less impactful wind/blowing snow. Both sets of ensemble members also have the region on the western edge, suggesting the heaviest snowfall would be over the eastern U.P. with heavier snow becoming increasingly dependent on lake effect and orographic lift as you move west through the U.P. Please continue to monitor the forecast as changes to the forecast track and details are likely as we get closer to the event.

Monday into Wednesday will see much colder air move into the area with highs only in the teens Monday, low to mid 20s Tuesday and upper 20s Wednesday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 223 PM EDT Thu Mar 12 2026

VFR conditions this afternoon persist into this evening, but expect deteriorating conditions from west to east tonight when a low tracks into northern WI. Primarily IFR/LIFR vis and MVFR/IFR cigs are expected with the snow and blowing snow tonight into Friday, however some brief periods of VLIFR vis can't be ruled out in heavier snow. Added in a TEMPO group at SAW where the highest confidence was for VLIFR. Winds become variable this afternoon before increasing out of the southeast to east. As the low tracks across northern WI, a strong low level jet arrives impacting all sites with gusts up to 25- 35 kts and LLWS late tonight. Winds remain elevated into Friday as the low tracks over northern Lower MI, becoming more northerly through the day.

MARINE

Issued at 238 PM EDT Thu Mar 12 2026

A quick moving 29.1 inch low will move through the Upper Great Lakes tonight, reaching upper Lower Michigan by Friday afternoon and Lake Huron by evening. Ahead of the low southeast gales of 40-45kt will develop tonight with waves building 12-18 feet. Winds will shift northerly on Friday morning as the low pushes east with gales to 40kt. Northerly winds subside on Friday night and shift southwest on Saturday as ridging builds over the area. Another strong but slower moving low pressure will move through the Great Lakes Sunday into Monday with gales expected and possibly storm force winds (50-70% chance). Much colder air will also arrive Sunday into Monday with heavy freezing spray expected.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Warning from 8 PM EDT /7 PM CDT/ this evening to 2 PM EDT /1 PM CDT/ Friday for MIZ001>004-009-010-084.

Lakeshore Flood Advisory from 5 AM to 2 PM EDT Friday for MIZ001.

Winter Storm Warning from 11 PM this evening to 5 PM EDT Friday for MIZ005.

Winter Storm Warning from midnight tonight to 8 PM EDT Friday for MIZ006-007-013-014-085.

Winter Storm Warning from 10 PM this evening to 1 PM CDT Friday for MIZ011-012.

Lakeshore Flood Advisory from 2 AM to 2 PM EDT Friday for MIZ013-014.

Lake Superior... Gale Warning from 10 PM EDT /9 PM CDT/ this evening to 11 AM EDT /10 AM CDT/ Friday for LSZ162.

Gale Warning from 11 PM this evening to 2 PM EDT Friday for LSZ242-263.

Gale Warning from 11 PM this evening to 2 AM EDT Saturday for LSZ243>251-264>267.

Lake Michigan... Gale Warning from midnight tonight to 4 PM EDT Friday for LMZ248-250.