Marquette forecast discussion

Key Messages

and its trailing lake effect regime, will lead to an additional tenth to half inch of rain (3/4" or higher along the high terrain of Marquette/Baraga counties) today.

- A Gale Warning is in effect as gusty northwest winds to 45 kt are forecast for Lake Superior and 35-40 kt for northern Lake Michigan. The highest waves will be for east-central Lake Superior at 14-18 ft.

- Dry and windy conditions this weekend may bring an additional risk for fire weather, but there is uncertainty in the moisture (both in the air and in the fuels).

Discussion

Issued at 252 AM EDT Fri Oct 16 2026

Midnight KMQT radar shows widespread rainfall but with more striation patterns occurring with time to indicated mesoscale bands forming. These bands will lead to some spatial variation in the rainfall totals by the time synoptic rainfall ends this morning and we transition to a lake effect rainfall pattern. At the surface, a 1005mb low is traversing the Lower Peninsula with a strengthening pressure gradient over the Dakotas as 1040mb high pressure moves over the MT/WY/SD tripoint. Aloft, the low is supported by a positively tilted 500mb trough centered over Minnesota and the high is supported by a ridge axis most prominent over the Canadian and northern US Rockies (which sits atop a monsoon trough over San Diego). With the positive tilt of the trough and the trough itself being tilted with respect to height above the surface low, the low will deepen as it moves east into this weekend, and despite the high weakening slightly with time, the strengthening low will keep the post-low pressure gradient strong. This will drive gusty winds, in conjunction with isallobaric winds (GFS shows up to 10mb/6hr rises today) and cold advection aloft will help mix down stronger winds aloft as well. Mean peak surface wind gusts in the HREF by noon today are 35-40 mph over land and 40-45 mph at and around Lake Superior as a result. On the precipitation side of things, the aforementioned cold advection will bring 850mb temperatures down to around -4 to -8 C over a Lake Superior that is around 10-12 C, inducing up to 200 J/kg of instability over eastern Lake Superior per the NAM. As ridging aloft spills into the Plains and high pressure advances towards the region, lake effect rain (and even a 10-20% chance of the first few snowflakes of the season, no accumulation forecast) will gradually decrease in coverage and intensity, ending altogether Saturday. By 06Z Saturday, mean HREF QPF is highest (0.75"+) along an arc from the US41/US141 split, up to the Mount Arvon/Eagle Mine vicinity, and down to Palmer, with the areas surrounding this arc seeing around a half inch on average and the rest of the UP still seeing a wetting rain (about 0.1"-0.33"), though perhaps not enough to bust the drought. Still, 2 of the 3 largest ongoing wildfires are within this arc, which the rain will help keep the fire behavior down, though it will also complicate access to the fire further (muddy roads, slick exposed rock, low ceilings for aviation support, etc).

Despite rainfall ending Saturday, this weekend will still carry some weather impacts. Atop the advancing ridge will be a rapidly moving and compact trough passing through the northern portions of the Canadian Prairie provinces into Hudson Bay. While the trough and resulting surface low will be too far away to deliver further precipitation to the UP for the back end of this weekend, the low (around 986 mb over western Hudson Bay Sunday afternoon per the GFS) will squeeze the pressure gradient tighter against the high pressure, which the GFS resolves at 1035 mb over Pennsylvania Sunday afternoon. This results in Euro ensemble mean gusts over the UP of 25-35 mph out of the southwest both afternoons of Saturday and Sunday, paired with LREF chances of sub-30% RHs at up to 25%. This combination of dry and windy weather could once again result in worsening wildfire weather conditions, though confidence on the RH forecast is low as well as low confidence in fuel moistures (the main question being "was wet weather this week enough to moisten the fuels in a meaningful way?"), so the forecast continues to bear monitoring through the weekend.

More consistent ridging over central North America will bring quieter weather (continued lack of rainfall but this time with lighter winds) for the beginning of next week. Expect highs around the 60s (perhaps lower for the Keweenaw and Lake Superior shores) and lows around the freezing mark in the interior and 40s closer to the shores. The next batch of widespread rainfall appears to be with a trough that passes through the Canadian Prairie in the back half of the week, but differences in ensemble timing and intensity of the parent trough results in the peak in PoPs in the NBM being around 35% Wednesday night into Thursday.

Aviation /06Z Tafs Through 06Z Saturday/

Issued at 119 AM EDT Fri Oct 16 2026

As a low pressure over Lower Michigan tracks east, a colder airmass presses in from the west. This transitions lingering stratiform rain over to lake effect rain showers this morning with MVFR/IFR conditions. Drier air working in through the day eventually lifts and scatters out lingering lake effect cloudiness, returning all sites to VFR from west to east this afternoon.

Winds quickly strengthen this morning out of the north to 20-25 kts with gusts up to 30-40 kts, strongest at CMX. Winds taper off from west to east, settling below 10 kts this evening.

Marine

Issued at 318 AM EDT Fri Oct 16 2026

A deepening low pressure moving through the southern end of the Great Lakes Basin contrasting with high pressure to the west will drive wind gusts to 45 kt out of the northwest over Lake Superior and to 35-40 kt over northern Lake Michigan. This has resulted in Gale Warnings which continue this morning. Wave heights remain maximized over east-central Lake Superior this afternoon at 14-18 ft. Wind gusts briefly fall below 20 kt tonight, but increase out of the southwest again Saturday through Sunday. Chances of gales vary between model sources, but the Euro ensemble gives isolated pockets of 20-40% chances of gale force gusts over the west half of Lake Superior. With inconsistencies in space and between models, will elect to hold off on any watches for this weekend, and if they are needed, may need to be short-fused as more high-resolution guidance becomes available. Wave heights over the west half of Lake Superior build to 6-10 ft by Saturday afternoon and to 8-12 ft Sunday afternoon (locally higher immediately north of the Keweenaw Peninsula). As wind gusts fall below 20 kt for Sunday night, wave heights also gradually relax, falling below 4 ft for the US waters of Lake Superior early Monday morning while northern Lake Superior falls below 4 ft waves around noon Monday. Quiet marine conditions are then expected for the first half of next week, with the next disturbance arriving around Thursday, but differences in models in regards to timing and location of the next system vary significantly, so the confidence in the precise wind and wave forecast is low. Chances of gales in the back half of next week are 5-15%.

Mqt Watches/Warnings/Advisories

Upper Michigan... None. Lake Superior... Gale Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162-240.

Gale Warning until 4 PM EDT /3 PM CDT/ this afternoon for LSZ241-242-263.

Gale Warning until 5 PM EDT this afternoon for LSZ243-244-264.

Gale Warning until 9 PM EDT this evening for LSZ245>248-265.

Gale Warning until 11 PM EDT this evening for LSZ249>251-266- 267.

Lake Michigan... Gale Warning from 9 AM this morning to 10 PM EDT this evening for LMZ221-248-250.

DISCUSSION...GS AVIATION...77 MARINE...GS