textproduct: Marquette

KEY MESSAGES

- Multiple winter hazards are expected from this evening into Friday morning.

- Temperatures will quickly plummet below freezing from west to east between roughly 5 pm and midnight EST, bottoming out in the single digits and teens Friday morning. The combination of falling temperatures and developing snowfall will lead to untreated roadways becoming icy and hazardous.

- The combination of accumulating snow and strong winds will lead to limited visibility this evening into the overnight hours, especially in the western and north-central UP where localized whiteout conditions will be possible at times.

- Snowfall totals will range from 3-7 inches in the west and 2-5 inches north-central by midday Friday.

- High-end Gales to Storm Force Winds (50 knots) along with Heavy Freezing Spray expected tonight. There is high confidence in another period of high-end gales Saturday into Saturday night.

DISCUSSION

Issued at 324 PM EST Thu Dec 18 2025

Midlevel flow pattern continues to be dominated by a strong Pacific jet, zonal in orientation over the western CONUS, diving south over the central CONUS and transitioning into a ridge in the east. Vigorous PV anomaly is located over the northern/central Plains, with an attendant 984 mb low analyzed over the MN Arrowhead. Copious warmth and moisture is streaming northward ahead of this feature, with mild temps locally in the upper 30s/low 40s. Dewpoints in this range over the snowpack is resulting in some areas of fog and drizzle mainly over the central and eastern UP, which should continue into the evening hours.

Main weather hazards occur starting early this evening in the west as the low continues eastward across Lake Superior, maintaining its strength in the mid-980s. Colder air will quickly wrap in on the back of this low, which could result in any lingering moisture freezing on untreated surfaces. So travel could become difficult even where snowfall doesn't occur tonight with lows by Friday morning bottoming out in the single digits and teens (though this is often hard to predict due to increasing winds drying things out as well). Temps fall below freezing from west to east between roughly 5 pm and midnight EST.

As temperatures quickly fall, snow will spread into the western UP as well, due to a combination of lake effect and the system's deformation region. Though the latter will be more of a glancing blow, there will still be a period overnight where good lift occurs within the DGZ aloft, and the lake-based convective layer will occur within the DGZ as well closer to the surface, so it should be a pretty efficient snowfall producer with rates of 0.5-1"/hr noted at times on the HREF between 00-09Z. This, combined with wind gusts of up to 30 mph inland and 45 mph along the shoreline and Keweenaw, will result in quite hazardous travel conditions tonight due to the combination of icy roadways and limited (locally near-zero at times) visibility. Consideration was given to a Winter Storm Warning upgrade despite modest snowfall totals in the 3-7 inch range, but was decided against given that the greatest impacts will be in the overnight hours.

For the north-central and northeast UP (Marquette County eastward), the low will likely be too far north for much system enhancement from the deformation zone, and they will have a midlevel dry slot to contend with, so it's expected to be more of a pure lake effect event. For this reason, aside from perhaps a quick burst of snow in the late evening when p-type flips from rain to snow, there may be a lull in the snowfall until late tonight. However, this will place the better snowfall rates (0.25-0.5"/hr) more toward the Friday morning commute, along with the strong winds (30-35 mph inland, up to 45 mph shoreline) and associated visibility concerns. Certainly expect a difficult commute Friday morning.

For southern areas, difficult travel conditions are still possible overnight with the flash freeze concern along with some lighter snow. In collaboration with neighboring CWAs, the remainder of our CWA will be added to the winter weather advisory for this potential.

We'll see a gradual improvement through the day Friday from west to east as surface ridging builds in very briefly. Another clipper is hot on its heels Friday night into Saturday, this one further north. Forecast totals for this event appear to be more in the 1-4" range, highest in the east. A few more inches of additional accumulation is likely in the east for Saturday night into Sunday with lake effect snow occuring on the back side of the system. Another chilly day Sunday is expected with temperatures looking to moderate early next week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 110 PM EST Thu Dec 18 2025

Breezy southerly flow ahead of a deep low pressure system that is set to cross west to east across Lake Superior tonight is ushering in moist conditions and scattered rain showers. Periods of IFR/LIFR fog/rain are occuring at CMX and SAW this afternoon while IWD hovers around MVFR. Tonight, a sharp swing from S to NW winds occurs with the low pressure systems eastward migration. As winds shift to the NW, a quick drop in temperatures below freezing is expected, likely resulting in a flash freeze. Wind gusts quickly increase above 25 kts, with gusts at CMX approaching 40 kts between 00 and 12z. Snow will fill in from west to east with the drop in temperature, reducing visibilities below 1sm at times with blowing snow. Localized blizzard conditions are possible at CMX. As system/lake enhanced snowfall transitions to pure lake effect snow by the morning, cigs/vis will begin to rise to IFR/MVFR, first at IWD/SAW.

MARINE

Issued at 324 PM EST Thu Dec 18 2025

North to northwest winds will quickly increase behind a 985 mb low moving eastward across the lake this evening into the overnight hours. High-end gales are a certainty, with some storm force gusts to 50 kt expected over central portions of the lake. Heavy freezing spray is also expected over the lake tonight into Friday morning. Winds gradually decrease from west to east late tonight into midday Friday as ridging briefly builds in. However, another strong system will quickly follow Friday night into Saturday, with strong westerly winds developing Saturday into Saturday night. Gale probabilities ahead of this system in southwesterly winds are around 30% Friday night, increasing to 60-80% Saturday into Saturday night. There is roughly a 20% chance for storm force gusts to 50 kt. A Gale Watch will be issued this afternoon. Freezing spray is a expected as well. Winds diminish Saturday night into Sunday from west to east.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Weather Advisory until 10 AM EST /9 AM CST/ Friday for MIZ001>004-009-084.

Lakeshore Flood Advisory from 10 PM this evening to 7 AM EST Friday for MIZ001-003.

Wind Advisory from 10 PM this evening to 7 AM EST Friday for MIZ001-003.

Winter Weather Advisory from 9 PM this evening to 1 PM EST Friday for MIZ005>007-085.

Wind Advisory from midnight tonight to 10 AM EST Friday for MIZ005-006.

Lakeshore Flood Advisory from 1 AM to noon EST Friday for MIZ005-006.

Winter Weather Advisory from 6 PM this evening to 6 AM CST Friday for MIZ010-011.

Winter Weather Advisory from 10 PM EST /9 PM CST/ this evening to 10 AM EST /9 AM CST/ Friday for MIZ012>014.

Lake Superior... Gale Warning until 4 AM EST /3 AM CST/ Friday for LSZ162.

Heavy Freezing Spray Warning from 7 PM EST /6 PM CST/ this evening to 8 AM EST /7 AM CST/ Friday for LSZ162-240>244- 263-264.

Gale Warning from 7 PM EST /6 PM CST/ this evening to 4 AM EST /3 AM CST/ Friday for LSZ240.

Gale Warning from 7 PM EST /6 PM CST/ this evening to 7 AM EST /6 AM CST/ Friday for LSZ241-242.

Storm Warning from 7 PM this evening to 4 AM EST Friday for LSZ243>245.

Heavy Freezing Spray Warning from 10 PM this evening to 10 AM EST Friday for LSZ245>251-265>267.

Gale Warning from 9 PM this evening to 8 AM EST Friday for LSZ246.

Gale Warning until 7 AM EST Friday for LSZ247.

Gale Warning until 10 AM EST Friday for LSZ248-265.

Gale Warning until noon EST Friday for LSZ249>251-267.

Storm Warning until 7 AM EST Friday for LSZ263.

Storm Warning until 4 AM EST Friday for LSZ264.

Gale Warning until 10 PM EST this evening for LSZ266.

Storm Warning from 10 PM this evening to 4 AM EST Friday for LSZ266.

Lake Michigan... Gale Warning from 1 AM to 10 AM EST Friday for LMZ221-248-250.

Heavy Freezing Spray Warning from 4 AM to 10 AM EST Friday for LMZ221-250.