textproduct: Marquette

KEY MESSAGES

- Areas of fog, drizzle, and freezing drizzle are likely across UP tonight into Thursday morning.

- Warmer than normal temperatures continuing through the week. Highs in the upper 30s to low 50s. Lows near or just above freezing late in the week.

- Active weather set to bring widespread rain, including a few thunderstorms, Friday into Saturday, followed by light snow across the west half Saturday.

DISCUSSION

Issued at 125 PM EST Wed Mar 4 2026

Early afternoon GOES satellite imagery and regional observations reveal a stalled frontal boundary draped across northern Lake Superior. Meanwhile, a shortwave working out of the Rockies into the Upper MS Valley is supporting southwest flow into the northern Great Lakes. The juxtaposition of these two features is resulting in clearing skies across much of the area save for the Keweenaw and far west. Areas of the south-central has already punched 50F while Houghton to Copper Harbor remain below 40. Tonight, building Canadian high pressure shunts the stalled boundary back south across the UP, ushering in cloud cover and ample low level moisture. As moisture returns, areas of fog, drizzle, freezing fog, and freezing drizzle will be possible tonight through Thursday morning. Confidence on the spatial coverage of freezing drizzle is low, however, have opted to add some low (<25%) chance PoPs for the Keweenaw where guidance hints at a glaze of freezing drizzle most likely. Upstream obs in northern MN and Thunder Bay, ON reporting freezing drizzle have increased confidence in this scenario somewhat. Elsewhere, latest 12z HREF shows medium to high confidence (60-90% chance) in areas of fog developing tonight, mostly across the upslope locations of the west and north-central UP. This may impact your morning commute, so take it slow and be sure to turn on your fog lights if necessary. As winds veer more south-easterly through the morning, expect fog to dissipate. Quiet weather persists through Thursday as shortwave action remains well to the south of the UP. Temps come in cooler Thursday afternoon with highs in the low to mid 40s, mid to upper 30s east and Keweenaw.

Active weather returns Friday into Saturday as a deep trough lifts from the Rockies into the Great Lakes, sending a surface low pressure that tracks from Kansas/Nebraska northward to Lake Superior by Saturday morning. Northward moisture transport (near the peak of NAEFS PWAT climatology) and strong isentropic ascent will force widespread rain showers. Models continue to show elevated instability which could be enough for heavier showers and possibly a rumble of thunder. With plenty of snow cover over the northern half of the U.P. any heavier convective showers could result in ponding of water on roadways. Still, there continues to be differences in the overall strength of the low center, with the operational GFS notably more aggressive, deepening the low center to 992 mb as it crosses the lake. The differences in deterministic and ensemble solutions remain evident in the latest NBM 25th to 75th 24hr QPF forecast, which ranges from roughly 0.5" to 1.25" by 12z Saturday, slightly less in the west and slightly more across the south-central and east. As the low departs northeast into Ontario/Quebec through Saturday, the system's cold front sweeps through, resulting in breezy conditions and light snow accumulations across the west half.

A return a zonal flow aloft keeps above normal temperatures in the 40s and 50s Sunday into early next week. Ensembles continue to highlight negative mid to upper level height anomalies heading into the midweek, potentially pointing to an active period with increasing chances for precipitation (all types).

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 635 PM EST Wed Mar 4 2026

VFR conditions prevail at SAW and IWD this evening with low lake clouds causing lingering MVFR conditions through the evening at CMX. The impactful weather will arrive around 03-06Z tonight when a boundary brings rich moisture to the low levels and the combination of radiational cooling to the dew point and upslope flow will lead to FG formation and low ceiling formation. All 3 sites show 40+% chances for virtually all hours of the overnight period of seeing LIFR ceilings/vis, with virtually the entire suite of deterministic guidance suggesting a period of airport minimum visibility at SAW and several models showing similar conditions at IWD and CMX (though not a consensus). Uncertainty exists in the cessation of FG and ceilings, with some models suggesting the intrusion of drier air sooner than others, but broadly speaking, SCT out to VFR is expected at IWD and SAW in the early afternoon with lingering IFR at CMX.

MARINE

Issued at 125 PM EST Wed Mar 4 2026

Light southerly winds shift northeast this afternoon as a frontal boundary sags south over the lake. Low pressure deepens along the eastern slopes of the central Rockies will bring a tightening pressure gradient, helping winds strengthen to 25kt tonight into Thursday. Low pressure tracking through the Upper Great Lakes on Friday into Saturday will bring increasing southerly winds to 30kt, shifting northerly on Saturday with a few gales to 35 kt possible. Widespread southwesterly gales are possible (50-75% chance) on Saturday night into Sunday as the pressure gradient strengthens in response to a low pressure tracking through Ontario. Wind fall to 25kt Sunday night with the next chance for stronger winds coming midweek as another low pressure tracks into the Great Lakes.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... None.