textproduct: Marquette

KEY MESSAGES

- Potentially historic blizzard continues through tonight. This will create treacherous and potentially life-threatening travel conditions and may cause tree damage and power outages!

- Additional snow amounts of 1-2 feet are expected over the central and eastern UP with wind speeds of 40-65 mph. Strongest winds today are expected in the Keweenaw Peninsula and along the eastern Great Lakes lakeshores.

- Widespread northerly storm force gusts of 50-60 knots over Lake Superior today with a ~30% chance for gusts exceeding 64 knots in the east today. 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 240 AM EDT Mon Mar 16 2026

The focus of the forecast discussion remains on the ongoing record- breaking blizzard impacting the Upper Great Lakes through tonight. The prolonged nature of up to hurricane-force winds and quickly accumulating, blowing, and drifting snow continue to make travel conditions treacherous and potentially life-threatening as well. In addition to travel impacts, the winds have caused some power outages and as the winds increase, more are likely to result. Travel should be restricted to just emergencies today as even emergency vehicles will struggle to navigate the roads at times!

Evening KMQT radar returns show a shield of reflectivity with some zones of 30-40 dBZ mixed in, indicating snow rates in excess of 1"/hr ongoing. Snow totals have been slightly under expected so far today at WFO MQT despite the QPF being on-target or even above- forecast. This is due to snow ratios being driven down to 6:1, which is at least a factor of 3 less than the NBM and a factor of two less than other traditional snow ratio forecasting techniques. A number of reasons partially explain it, between strong upper winds fracturing dendrites into a more compact shape, snow compaction upon being blown/drifted around, and a wetter snow than expected, though the sheer magnitude of how low the snow ratios fell is surprising. RAP analysis shows a negatively tilting trough centered over MN/IA supporting a surface low of 991mb over Valparaiso, IN. Stacked ridging over the West Coast is supporting a surface high of 1037 mb over Rapid City. The resulting pressure gradient over the UP is around 1003 mb along the Lake MI shores and around 1018mb by Isle Royale, a 15 mb gradient across Upper Michigan alone, helping drive the strong winds.

The mid level wave continues to pivot its already slight negative tilt today, resulting in strong vorticity advection over the Upper Great Lakes. This deepens the surface low to near 980 mb as it tracks to northern Lake Huron by late Monday morning. The 00Z HREF shows a robust 925mb jet forming over the east half of Lake Superior, the eastern half of Upper Michigan, and northern Lake Michigan at around 50-55 kt. With solid cold advection in the wake of the low, soundings show that there should be little problem getting those winds to mix to the surface to at least 45 kt. Soundings continue to show periods where the DGZ will be extremely tall (and moist), though as the day goes on, the cold advection aloft brings the top of the moist layer out of the DGZ. Therefore, this forecast reflects a minimum of available snow ratio model guidance as even if extreme DGZ depths are realized, it will not be for all and for long, though snow ratios should at least be higher than the 6:1 ratios observed much of Sunday. Assuming a near 10:1 ratio, the HREF shows pockets of 30-60% chances of 1+"/hr snow rates this morning over the eastern half of the UP, but declining after that. As the low pulls away and 850mb temperatures cool below -20C, snow becomes gradually less synoptically forced and more terrain and lake effect forced.

As far as impacts are concerned, if the LLJ can be tapped into and the higher winds occur, tree damage and power outages should be expected. The HREF still shows widespread 50+% chances for 1/4 mile or lower visibilities with falling and blowing snow, even despite the amount of snow falling over the Keweenaw and the far west decreasing. Given the winds and visibility still expected to reach blizzard criteria, the Blizzard Warnings will continue. However, observations will be closely monitored this morning, and if the visibility and/or wind gusts are not realized, downgrades to Winter Storm Warnings or even Winter Weather Advisories may occur. Otherwise, expect significant snow drifts several feet tall, adding to difficult travel and snow load on structures. The strong winds over Lake Superior will 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 today as a result.

With and immediately following this storm, polar air will keep below normal temperatures across the region, with highs today and Tuesday only getting into the teens to lower 20s and lows this morning, tonight, and Tuesday nights dropping down into the single digits (perhaps even subzero in the interior west Tuesday morning) to lower teens near the Great Lakes. Wind chills will also fall to near -10F during the overnight hours nightly through Tuesday morning.

Lake effect snow showers will quickly decrease in intensity and coverage Tuesday as the Plains high shifts south of the Great Lakes and brings anticyclonic flow, weakening winds, drier air, and subsidence to the region. This will provide some break in the precipitation and the winds for recovery efforts to begin.

Enjoyers of spring rejoice: there is hope late in the week! The weather pattern for the back half favors a pair of clipper lows 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 (30% chance of 50 degrees in the interior west on Friday). 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 /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 119 AM EDT Mon Mar 16 2026

A powerful winter storm continues to impact Upper Michigan terminals through Monday night with IFR/LIFR conditions in moderate to heavy snow and blowing snow. Increasing winds will maintain IFR/LIFR vis with BLSN into this morning as the strengthening surface low moves closer to the region, with winds potentially reaching 45-50 kt at KCMX/KSAW and near 40kts at KIWD. Snowfall will also pick back up in intensity this morning and promote continued IFR/LIFR conditions through most of the day. Winds will start to trend down but still remain strong in the 35-40 kt range through 00z Tue, with conditions finally starting to trend up towards low end MVFR towards 06z Tue.

MARINE

Issued at 240 AM EDT Mon Mar 16 2026

A strong to historic storm moves from southwest to northeast over the Upper Great Lakes through today. Northeast to north high-end gales to 45 knots over the west and storm-force gusts to 50-60 kts will persist today. Guidance continues to hold a low (15-25%) chance for hurricane-force winds today east half of the lake, particularly along the southern shores. In addition to the strong winds driving significant wave heights of 20+ ft (some to near 30 ft between Stannard Rock and the shores of Marquette and Alger Counties), cold air descending overhead will result in heavy freezing spray. As the low exits towards Quebec, winds diminish tonight, falling below storms around midnight and below gales lakewide Tuesday morning.

For the remainder of the week, the weather pattern favors a pair of weaker clipper systems moving north of Lake Superior between Wednesday and late Friday. The pattern also favors warm, southerly flow, reducing the risk of heavy freezing spray. Gale chances are low (10-40% chance), highest probabilities in the wake of the later system.

MQT WATCHES/WARNINGS/ADVISORIES

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

Lakeshore Flood Warning until 11 PM EDT this evening for MIZ001-003.

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

Lakeshore Flood Warning until 5 PM EDT this afternoon for MIZ002.

Lakeshore Flood Warning until 2 AM EDT Tuesday for MIZ005.

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

Lakeshore Flood Warning until 8 AM EDT Tuesday for MIZ006.

Lakeshore Flood Warning until 2 AM EDT Tuesday for MIZ007.

Lakeshore Flood Advisory until 4 PM CDT this afternoon for MIZ009.

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

Storm Warning until 11 AM EDT /10 AM CDT/ this morning for LSZ162.

Heavy Freezing Spray Warning until 2 PM EDT /1 PM CDT/ Tuesday for LSZ240>248-263>265.

Storm Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ240>242-263.

Storm Warning until 2 AM EDT Tuesday for LSZ243>251-264>267.

Heavy Freezing Spray Warning until 5 PM EDT Tuesday for LSZ249>251-266-267.

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

Heavy Freezing Spray Warning until 2 AM EDT Tuesday for LMZ248- 250.