textproduct: Marquette

KEY MESSAGES

- Areas of dense fog, drizzle, and freezing drizzle are likely across the central and western U.P. this morning. Dense fog, drizzle and freezing drizzle will be possible again tonight.

- Warmer than normal temperatures continuing into early next 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 336 AM EST Thu Mar 5 2026

Early this morning satellite water vapor imagery and model analysis showed zonal upper level flow over the eastern half of the U.S. with a trough digging through the Intermountain West. Widespread dense fog had developed over the north central and western U.P. with the combination of moist air moving over the snowpack and upslope flow. Likewise fog was developing over Lake Superior as the moist air moved over the colder waters and ice cover. Somewhat drier air advecting into the eastern U.P. was limiting fog development there. Dense Fog Advisories have been issued for the central and western U.P. through this morning. The moist air was also helping to keep roads wet and any untreated and elevated surfaces could be icy. Temperatures were in the upper 20s and lower 30s.

The upper level trough will move through the western U.S. today with southwest flow aloft strengthening over the area and ridging developing over the Great Lakes and New England. As the trough moves east this weekend it will remain positively tilted with the southern end of the trough cutting off over the southwestern U.S. and Baja Peninsula. This trough will bring widespread precipitation to the area Friday night into the first half of Saturday. Thereafter the flow becomes zonal again, likely remaining that way through the week.

The main challenge today will be the evolution of the fog over the area. As temperatures warm after sunrise and somewhat drier air continues to be advected into the area on easterly flow the fog should begin to lift from east to west. Current thinking is that the fog lifts over the central mid-morning and noon in the west. However, the Keweenaw could very well remain socked in with fog through the entire day (and beyond into Friday morning). Temperatures will warm into the 30s in the east and Keweenaw, with mid 40s in the west.

The flow turns southerly tonight in response to the approaching trough. This will help bring more relatively warm and moist air north into the U.P. This time the better chance for dense fog will be over the central and eastern U.P. as fog and deeper moisture may be advected off of Lake Michigan. Also added drizzle and freezing drizzle to this area with the deeper moisture and weak isentropic low level lift.

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 and steep mid-level lapse rates of ~8 C/km which should result in upright convection, leading to heavier showers and a few thunderstorm Friday evening and overnight. With plenty of snow cover over the northern half of the U.P. any heavier 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 remaining 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 0.25" to 1.25" by 12z Saturday, wettest in 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 /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 630 AM EST Thu Mar 5 2026

FZFG/BR and LIFR cigs impact the TAF sites this morning. Vis improvement at SAW and IWD is expected by early this afternoon followed by a brief period of SCT skies. Confidence in full VFR recovery at IWD was too low to include yet with this 12Z TAF issuance, but likely would occur after 18Z. CMX will struggle to improve beyond IFR today as FG/BR and low cigs persist there. These conditions redevelop at IWD/SAW tonight with increasing moisture. Freezing drizzle is possible (20% chance) at IWD/CMX this morning and then tonight at SAW. Winds remain light below 10 kts through the period primarily out of the east today then southeast tonight. Heavier rain holds off until after the 12Z TAF period ends, leading to low confidence in significant improvement at the end of the 12Z TAF period or through the rest of Friday.

MARINE

Issued at 336 AM EST Thu Mar 5 2026

Easterly flow will continue through today with winds to 25 kt this morning diminishing to around 20 kt this afternoon. Low level moisture will continue to result in areas of dense fog over the water, especially the western half of the lake. 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... Dense Fog Advisory until noon EST /11 AM CST/ today for MIZ001>003-009-084.

Dense Fog Advisory until 10 AM EST /9 AM CST/ this morning for MIZ004-005-010-011.

Lake Superior... Dense Fog Advisory until 1 PM EST /noon CST/ this afternoon for LSZ162-240>249-263>265.

Lake Michigan... None.