textproduct: Marquette

KEY MESSAGES

- Patchy dense fog is possible tonight into Wednesday morning across the west and central UP.

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

- Mostly dry weather until Friday and Saturday when widespread rain chances return (60-90% chance).

DISCUSSION

Issued at 203 PM EST Tue Mar 3 2026

Early afternoon GOES satellite imagery reveals mostly cloudy skies overhead Upper Michigan with patches of clearing across the west- central. Weak shortwave action across the northern Great Lakes has been able to force some light rain/snow showers that will continue to track east out of the are this afternoon. Further north, a stalled frontal boundary may dip far enough south tonight to produce some addition like mix-precip showers in the Keweenaw and far northeastern UP, otherwise the rest of the forecast area should remain dry. Lingering low level moisture noted in bufkit soundings combined with light winds and meager upsloping will enable areas of patchy fog tonight, mainly across the west half of the UP, though confidence on the spatial extent is low. The latest HREF suggests increasing probabilities (>60% chance) for vis below 1 SM just before and moreso after midnight in the west and central, highest in the Keweenaw and high terrain of Marquette/Baraga counties. These probabilities for fog linger through the morning hours.

Zonal flow aloft remains in place through Wednesday. Meanwhile, a shortwave ejecting out of the Rockies will help veer surface to mid- level flow out of the southwest. Daytime temps will have no problem reaching 40F area wide and the NBM suggests 45-50F will be common away from the Great Lakes, however, the higher end near 50F may be contingent on cloud cover and the northward push of the aforementioned stalled frontal boundary. This weak shortwave works south of the UP through the Ohio River Valley and into the Lower Great Lakes late into Thursday morning while a strengthening Canadian high pressure shunts the wobble stalled boundary back south across Lake Superior. Some guidance hints at light precip development along the tight thermal gradient reaching the northern tier of the UP, but opting for a dry forecast for now. The tight gradient may lead to another difficult temp forecast Thursday afternoon where the northern tier might not punch 40 while the southern half could smack 50 again given a little bit of sunshine.

More impactful weather begins to take shape Friday through Saturday as a deep trough ejects out of the western CONUS, developing a potentially strong low pressure system that is set to work its way northward through Lake Superior. There is good model agreement that a bulk of the perception will fall as rain, however, there is still disagreement on the overall timing and strength of this low that may have implications for how much precip will fall. The latest NBM 25- 75th percentile shows 24hr rainfall amounts at our office in the central UP by 12z Saturday between 0.25-1.10". Add 0.25" to both ends in the s-central UP and subtract 0.25" for the ranges in the west half. Additionally, ensembles suggest ~100-300 j/kg of elevated instability present Friday night. Should elevated convection develop, pockets of higher QPF may result in ponding on roads, especially after additional snowmelt. A brief period of rain/snow mix or all snow is likely to follow behind the surface cold front on Saturday, but little to now accumulations are anticipated at this time.

Continued above average temperatures are expected Sunday into early next week with highs in the 40s to near 50 and lows in the 20s. There is a slight chance for showers but widespread precipitation isn't likely during this period. A stronger storm system could impact the region during the later half of the week but quite a bit of uncertainty remains at this point. It could mark the start of a cooler pattern, the CPC outlook days 8-14 is indicating higher chances for below normal temperatures and equal chances for above/below normal precipitation.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1233 PM EST Tue Mar 3 2026

Lingering low clouds in the wake of a weak disturbance is leading to MVFR to high-end IFR conditions at all sites this early afternoon, though satellite observations are showing more clearing than expected over the western UP, northwestern WI, and western Lake Superior, so some low-level SCT cloud cover prevails at IWD through the afternoon hours. Expect cloud cover to increase tonight and for all sites to become MVFR to IFR overnight. For the morning hours of Wednesday, the combination of cooling to the dew point and moist air over the snow pack is leading to increasing potential for FG development to varying degrees at all sites. IWD currently has around a 20% chance of FG, though the uncertainty is a little too high to include in the TAF for this issuance, but could be handled with TEMPOs in future issuances. CMX/SAW are 40-50+% to see at least MVFR FG, with chances of IFR at 20-40% and LIFR at around 20%. While the models are currently forecasting improvements around 16-17Z, the pattern of warm, moist air over snowpack does tend to lead to lower vis than forecast, though in this case, winds increasing to 5-10 kt with gusts of 10-15kt early Wednesday PM would tend towards decreasing FG coverage and intensity.

MARINE

Issued at 203 PM EST Tue Mar 3 2026

Light winds below 20kt are expected through Wednesday with weak troughing over Lake Superior. Ongoing southwest winds shift northerly tonight as a weak frontal boundary drops south over the lake, before shifting southerly again on Wednesday. As low pressure deepens along the eastern slopes of the central Rockies easterly flow will develop and strengthen to 25kt Wednesday night 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 (30-40% chance) on Saturday night into Sunday as the pressure gradient strengthens in response to a low pressure tracking through Ontario.

MQT WATCHES/WARNINGS/ADVISORIES

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