textproduct: Marquette

KEY MESSAGES

- A compact low pressure pushing south of the UP today brings bands of moderate to heavy snowfall to the UP today, with snowfall totals today up to 1 foot and visibility at 1/4 mile or lower at times. Winter Storm Warnings remain in effect across the UP until this evening.

- A low pressure emerging from the Rockies will arrive in the region Saturday night through the beginning of the week, bringing potentially record-breaking snowfall to the UP, with snow totals of 1-3 feet possible along with blizzard conditions. Winter Storm Watches have been issued across the UP beginning late Saturday night and lasting through late Monday/early Tuesday.

- For the system today, widespread gales are ongoing, driving waves up to 14 feet off the shores of the Keweenaw Peninsula and leading to a minor lakeshore flooding threat. For the system this weekend into next week, waves of 25-30 feet are possible between Stannard Rock, and the shores of Marquette and Alger counties.

- Unseasonably cool temperatures to follow for the first half of next week, with highs in the teens and upper 20s and lows in the single digits to low 10s.

DISCUSSION

Issued at 556 AM EDT Fri Mar 13 2026

KMQT radar returns at 06Z show widespread light to moderate snowfall overspreading the UP with the heaviest band being oriented NW/SE along a line from MNM to IMT to ONTM4. The peak reflectivity values are still a little less than 30 dBZ, indicating not quite 1"/hr rates, but the IMT METAR showing 1/4 mile visibility indicates that there is still some moderate to heavy snowfall rates at times making travel difficult. Furthermore, wind gusts are trending upwards, which will make for some blowing/drifting snow hazards as well as the falling snow. RAP analysis shows a 987mb low centered north of Minneapolis, already tracking towards the southeast, which would bring it along a track south of the UP like the ensembles hinted at prior to this morning. This is supported by a neutrally tilted compact 500mb trough over Minnesota that is in the process of negatively tilting, which should allow for the pressure to continue to maintain strength or drop a little bit over the next 24 hours as it passes south of the UP. Being on the north side of the low has the UP in a prime area for isentropic ascent and FGEN banded snowfall which will contribute to some 1"+/hr snowfall rates. The 00Z HREF shows through 8 AM EST this morning 40-80% chances of 1"/hr snowfall rates. Compact pressure gradient and rapid height rises/falls will lead to gusty winds today, with wind gusts in excess of 35-40 mph along the lakeshores and 25-30 mph in the interior. The combination of gusty winds and decent snowfall rates (even after snowfall rates lighten up in the PM in a brief lake effect setup) lead to 60+% chances of visibility around 1/4 mile for much of today. While these may be "blizzard-like conditions", confidence in the coverage of both 35+ mph winds and 1/4 mile visibility for 3+ hours with no breaks is too low to issue any blizzard warnings today. However, the ongoing Winter Storm Warnings are on-track, with some minor time extensions for a few counties due to hi-res models hanging onto lake effect snowfall longer in the evening. Wind-driven waves in excess of 10 ft will lead to minor lakeshore flooding in particularly vulnerable locations near the tip of the Keweenaw and along the Garden Peninsula today.

Snowfall wraps up quickly tonight in response to high pressure building over the Great Lakes for Saturday afternoon. This will lead to near-seasonable temperatures around the freezing mark for highs and light winds, a welcome reprieve from the past two winter storms.

That reprieve is short-lived, however, as Saturday night, a trough will push through the Rockies, deepening and tilting as it does. This will translate at the surface as a mid-990s mb low pressure around CO/WY by 00Z Sunday. By 12Z Sunday, NAEFS IVT plots show a dual-moisture supply to this system with 90th+ percentile moisture transport from the Gulf as well as from the Pacific. As this low tracks through Lower Michigan (as has been consistent with the last ~24 hours of ensemble guidance), the UP will be on the north and west side of the low for the duration of the event, so little to no dry slot and plenty of deformation to continue to keep snowfall over the UP. Snow totals will be higher closer to the low, so this will impact Menominee, Delta, Schoolcraft, Alger, and Luce counties the most, though chances of over a foot of snow in 72 hours are still near 50% for even the furthest west extent of the UP. With the depth of the DGZ in GFS soundings in excess of 10kft Sunday, there will be times where snowfall rates will exceed 2-3"/hr. The deepening low contrasted with building high pressure over the Plains will also lead to strong wind gusts, with chances of wind gusts in excess of 50 mph peaking at 30-70% even in the interior UP Monday afternoon. Strong winds and heavy snow will lead to whiteout conditions and extremely difficult to impossible travel conditions on even high- priority roads late this weekend into the beginning of next weekend. Travelers should formulate backup plans and residents should be prepared for an extended duration of perhaps multiple days where roads to grocery stores/etc may be impassible. Confidence in this outcome is high - even the 10th percentile of the NBM 5.0 gives snow totals by Tuesday morning of a foot and a half to 2 feet for much of the UP. Despite massive DGZ depths, this snow total even includes a lower snow ratio due to high winds tending to fracture dendrites into more compact shapes. Winter Storm Watches have been issued beginning late Saturday night (chances of snowfall beginning prior to 06Z Sunday are 15-30% only) and lasting through Sunday and Monday before beginning to fall off late Monday night into Tuesday morning.

A period of light lake effect snow trailing this system is possible even into the daytime hours of Tuesday, though snow totals will be plenty manageable. The first half of the week will also be marked by unseasonably cold temperatures, with lows in the single digits to low 10s and highs in the teens to low 20s. This compares to the normal temperatures being highs around freezing and lows in the mid- upper teens. The next system appears to be a weak system passing roughly through northern Ontario Wednesday, which will bring chances of light to moderate snowfall, but ensemble spread is high. Hope for spring-like conditions does appear in the NBM high temperatures late in the week - interior west and central locations should (50-70% chance) see multiple days in a row with highs in the 40s.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 734 AM EDT Fri Mar 13 2026

IFR/LIFR condtions are present at all terminals this morning as a compact clipper system works just south of the UP. As this continues to kick east, a brief lull in snowfall intensity may be seen here this morning before lake effect snow on the backside of the system and gusty N to NW winds increase during the late morning to early afternoon. Present visibility and low cigs are expected to remain through much of the day. This evening, as lake effect snow begins to diminish with the departing system, expect a rise to MVFR from west to east. Gusts 25-35 kts will be common today, gradually settling by 00z.

MARINE

Issued at 556 AM EDT Fri Mar 13 2026

As a compact low pressure passes south of the Upper Peninsula today, easterly gales to around 40 knots turn northerly in the afternoon, falling to near 25 knots by this evening and below 20 knots overnight. Waves will peak around 15 ft around Stannard Rock this morning before falling to 4-7 feet tonight and below 4 ft by the early morning hours. A weak high pressure will keep relatively calm conditions on the lake for Saturday.

Attention then turns to a CO-style low that rushes through the Great Lakes late this weekend into early next week. In addition to heavy snowfall bringing long-duration low visibility, cooler temperatures will bring a heavy freezing spray threat. Compact pressure gradient and rapid pressure falls and rises will help mix down strong winds to the lake surface, driving widespread gales, 40-70% chances of 50+ kt storm force gusts over the east half, and even up to 30% chances of 64+ kt hurricane force wind gusts over the southern portion of the east half of the lake on Monday out of the north. This will drive strong waves, with peak wave heights of over 25 feet between Stannard Rock and the shorelines of Marquette and Alger Counties (including the cities of Big Bay, Marquette, Au Train, and Munising as well as Pictured Rocks National Lakeshore). As the low quickly departs the region and is replaced by high pressure, wind gusts fall below storms Monday night into Tuesday morning, below gales late Tuesday morning, and below 20 kt by Tuesday evening. Peak waves will follow suit, falling below 20 ft Tuesday morning, below 10 ft Tuesday afternoon, and below 5 ft Tuesday night.

Minor disturbances moving through the region will periodically bring winds to 20-30 kt and waves of 4-7 ft throughout the rest of the forecast period, but confidence in the details of such events is too low at this time.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Warning until 2 PM EDT /1 PM CDT/ this afternoon for MIZ001>003-010>012-084.

Lakeshore Flood Advisory until 2 PM EDT this afternoon for MIZ001-013-014.

Winter Storm Watch from late Saturday night through late Monday night for MIZ001>005-013-084.

Winter Storm Warning until 8 PM EDT /7 PM CDT/ this evening for MIZ004>007-009-013-014-085.

Winter Storm Watch from late Saturday night through Tuesday morning for MIZ006-007-014-085.

Winter Storm Watch from late Saturday night through Monday evening for MIZ009>012.

Lake Superior... Gale Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162-242-263.

Gale Warning until 2 AM EDT Saturday for LSZ243>251-264>267.

Lake Michigan... Gale Warning until 4 PM EDT this afternoon for LMZ248-250.