textproduct: Marquette

KEY MESSAGES

- High impact winter weather is expected over the next several days. Chances of 12 inches or more of snow are around 100% percent across the north-northwest wind snow belts of the western UP by Thanksgiving, with some spots potentially receiving 2 to 3+ feet.

- Blizzard Warnings are in effect for lakeshore adjacent counties of the west and central U.P. where heavy snowfall rates combined with wind gusts greater than 40 mph will drastically reduce visibility.

- Gales up to 45 kts are expected (70-90%) on Lake Superior this evening through Thanksgiving, with Storm-Force gust to 50 kts possible (40 to 60% chance). Wave heights of 15-20 ft are expected.

- Minor lakeshore flooding and beach erosion is possible along the Lake Superior shoreline late tonight through Thanksgiving.

DISCUSSION

Issued at 352 PM EST Tue Nov 25 2025

Afternoon GOES satellite imagery reveals a slightly negatively tilted shortwave trough digging through far eastern SD, allowing for warm, moist midlevel flow to bring fog and light rain across Upper Michigan. At the surface, a ~1006 mb low is developing along the southern MN/central WI border. This low is set to further deepen as low as 990mb while tracking northeast along the southern UP border tonight through Wednesday, bringing widespread impactful winter weather in the form of heavy snow and high winds.

As the low draws near tonight, increased forcing for ascent, strong dynamical cooling, and cold air advection aloft will force a change over from rain to snow across the western UP. The strong mid to low level f-gen response will induce a rapid increase in snowfall rates during the overnight hours through much of Wednesday morning, where CAM guidance suggests a high probability (>75%) of 1 in/hr snowfall rates. Aiding snowfall rates will be lake enhancement off of a relatively warm Lake Superior (averaging ~6.5 degrees C) and local orographic enhancement along the Keweenaw Spine, Michigamme Highlands, and areas of the Porkies/Gogebic Range. These areas may exceed snowfall rates of 1-2" per hour Wednesday, making travel increasingly difficult as roadways will struggle to stay cleared despite plowing efforts. Regardless if snowfall rates don't end up being as heavy as forecast, strong N to NW winds in excess of 40-50 mph (highest along Lake Superior) will create blizzard conditions and blowing and drifting snow, especially as snow becomes fluffier as SLRs increase through Wednesday morning and afternoon between 10- 15:1. This is reflected in the 12z HREF where joint probability for snowfall rates >0.5", visibility <0.25 mi, and wind gusts >35 mi increase 60-90%. For these reasons, have opted to upgrade the ongoing Winter Storm Warnings for the western UP (except S Houghton and Iron Counties) to Blizzard Warnings beginning at 00z tonight.

Through Wednesday, rain will continue to transition to snow across the central and eventually eastern UP. Very strong N to NW winds combined with strong synoptically forced snow and lake enhancement from warm Superior water will combine to create blizzard conditions for Marquette and Alger counties, especially near the lakeshore. Have included these two counties in the Blizzard Warning beginning tomorrow morning. Conditions across the central UP, however, will vary greatly. With the surface low being nearly directly overhead the south-central UP tomorrow morning, there will be a brief lull in precip followed by a quick uptick in northerly winds and increasing snow through the afternoon.

Snowfall totals for the *first* round of snow only through tomorrow evening are quite impressive. Areas near Ironwood and the Porkies should receive anywhere from 12-24" with locally higher amounts to 30", while the Keweenaw and Houghton/Baraga counties total between 10-20". This morning's EFI of 1 and shift of tails of 2 owes high confidence in heavy snowfall totals across the western UP. What's less certain is the adjacent lakeshore areas of Marquette county. Given the strong N to NW winds and warm lake temp much above freezing, the nearshore make struggle to accumulate much more than a few inches while the higher terrain of to the west reaches 6-12". As the surface low pulls to the north and east late in the day, synoptically forced snow will transition to more of a N to NW lake effect regime into Thursday. 850 mb temperatures cool between -10 and -14C, yielding delta-Ts near 16 to 20C and allowing lake effect snowbands to climb as high as 8-10 kt feet. This transition to NW lake effect snow will mark the *second* round of snow through Thursday and linger into the weekend. Fluffier 15-20+:1 SLR lake effect snow coupled with model 6hrly QPF between 0.1-0.25 yields another round of 5-12" of snow through Thursday across the northern tier of the UP. Additionally, with strong winds holding on through the day, lake effect snow should penetrate far enough inland to accumulate all the way down to the Lake Michigan shorelines. Additionally, CAMs suggest a Lake Nipigon connecting dominant band structure in the east-central UP that may provide locally higher snowfall amounts in Alger County.

With lake effect snow beginning to taper down Friday, 2-day snowfall totals may end up between 12-32 inches (highest west, less near the lakeshores) across much of the area. This actually makes a run for the greatest 2 day total in Ironwood (35" ended 01-06-1997).

Travel over the next 48 hours may be difficult to near impossible, especially for the western UP. It is highly advised to reconsider travel plans. If you must, it is imperative to winterize your vehicle, bring extra winter gear, etc, in your vehicle. Additionally, prepare any home winterization strategies now!

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1239 AM EST Wed Nov 26 2025

A winter storm will move through the U.P throughout the TAF period. Overall expect minimums to LIFR conditions to dominate the TAF period. Recent guidance has slowed the system down some which will impact the timing of the changeover from rain to snow (delaying it for SAW).

Rain has already changed to snow at IWD and it beginning to transition from rain to snow at CMX. The combination of moderate to heavy snow and wind will create blizzard conditions by Wednesday morning, continuing through much of the day. Similar conditions will spread into SAW during the early afternoon as rain changes to snow and winds become gusty. Wind gusts up to 40 kt can be expected with up to 50 kt possible at CMX.

As the storm pushes to the east late Wednesday snow will transition to lake effect snow showers. Somewhat drier air should allow CIGs and VIS to improve to IFR, however, periods of VLIFR in moderate to heavy lake effect snow showers could continue well into the night.

MARINE

Issued at 352 PM EST Tue Nov 25 2025

A strong early winter low pressure system is set to bring high winds and waves to Lake Superior tonight through Thursday. N to NE winds 20-30 kts have already begun to ramp up this evening, and will increase quickly to 35-45 kts tonight through tomorrow morning while backing to the N and NW. Storm force gusts to 50 kts cannot be ruled out around and east of the Keweenaw (40-60% chance). While winds look to weaken over the western lake Wednesday night, the high-end gales (with potentially a few storm force gusts) looks to continue into Thanksgiving. As the troughing pattern weakens Thanksgiving through late this week, expect the winds to lighten up with time, with the gales finally ending late Thursday night. Throughout the gale event, some light freezing spray will be possible across the waters from late Wednesday through Thursday evening. In addition, expect waves of 12 to 18 feet across the waters, with some areas near the tip of the Keweenaw, near Stannard Rock, and from Marquette to Grand Marais, MI potentially seeing wave heights or 20+ ft. Winds continue to weaken through Friday, eventually becoming 20 kts or less by Friday night. The light winds look to continue until Sunday when a shortwave lifts back into the western Great Lakes region.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Blizzard Warning until 7 AM EST /6 AM CST/ Thursday for MIZ001>004-009.

Lakeshore Flood Advisory from 4 AM early this morning to 1 PM EST Thursday for MIZ001.

Lakeshore Flood Advisory until 7 PM EST /6 PM CST/ this evening for MIZ002-009.

Lakeshore Flood Advisory from 7 AM this morning to 1 AM EST Thursday for MIZ003.

Blizzard Warning from 7 AM this morning to 10 AM EST Thursday for MIZ005.

Lakeshore Flood Advisory from 7 AM this morning to 1 PM EST Thursday for MIZ005.

Blizzard Warning from 1 PM this afternoon to 7 PM EST Thursday for MIZ006.

Lakeshore Flood Advisory from 1 PM this afternoon to 1 AM EST Friday for MIZ006.

Winter Storm Warning from 1 PM this afternoon to 7 PM EST Thursday for MIZ007-013-014-085.

Lakeshore Flood Advisory from 1 AM Thursday to 1 AM EST Friday for MIZ007.

Winter Storm Warning until 7 AM EST /6 AM CST/ Thursday for MIZ010-084.

Winter Weather Advisory from 9 AM to 6 PM CST Wednesday for MIZ011-012.

Lake Superior... Gale Warning from 4 PM this afternoon to 1 AM EST Friday for LSZ251-267.

Gale Warning until 7 AM EST /6 AM CST/ Thursday for LSZ162- 240>242.

Gale Warning until 1 PM EST Thursday for LSZ243-246-263.

Gale Warning until 7 PM EST Thursday for LSZ244-245-264-265.

Gale Warning until 1 PM EST Thursday for LSZ247-248.

Gale Warning from 10 AM this morning to 1 AM EST Friday for LSZ249.

Gale Warning from 1 PM this afternoon to 1 AM EST Friday for LSZ250.

Gale Warning until 1 AM EST Friday for LSZ266.

Lake Michigan... Gale Warning from 4 PM this afternoon to 1 AM EST Friday for LMZ221-248-250.