textproduct: Marquette

KEY MESSAGES

- Areas of dense fog, drizzle, and freezing drizzle are likely again tonight, this time expanding into the eastern half of the UP.

- Warmer than normal temperatures continuing into early next week. Highs in the upper 30s to 40s through Saturday, then rising into the 50s for Sunday and Monday. 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 early Saturday.

DISCUSSION

Issued at 332 PM EST Thu Mar 5 2026

GOES visible satellite imagery reveals mostly clear skies across most of the UP as of mid afternoon, save for the Keweenaw and parts of the west where low clouds and fog have been more stubborn to erode due in part to upslope easterly flow. In the upper levels, a deep trough is noted over the western CONUS on water vapor imagery, with the axis of a low amplitude downstream ridge oriented over the Mississippi River Valley. Clouds will spread back over the UP tonight as flow pivots southwesterly ahead of the digging trough over the Rockies. Low level warm and moist advection atop the existing snowpack will likely yield another night of widespread fog, this time expanding over the eastern half of the UP as well. will need to monitor observational trends through this evening for the potential for another round of dense fog headlines into Friday morning. Patchy drizzle or freezing drizzle will also remain a concern tonight into Friday morning given weak isentropic upglide and ample moisture in the low levels of the atmosphere.

Steadier and heavier precipitation during the day on Friday and persists into early Saturday as split flow develops over the western CONUS and a potent shortwave embedded in the large scale trough ejects out of the Colorado front range towards Upper Michigan. This will result in widespread rainfall across Upper Michigan Friday into Friday night as overnight lows largely hover near or just above freezing across most of the area. The bulk of the thunderstorm activity associated with this system is expected to remain south of the UP in the warm sector across Wisconsin and Lower Michigan, however mid level lapse rates around 7.5 C/km and 100-400 J/kg MUCAPE should be sufficient to support a few rumbles of thunder across the UP Friday evening into Friday night, especially south- central. While severe thunderstorms are not expected across the UP, it should be noted that the latest SPC outlook has pulled the marginal risk for severe thunderstorms into the southern half of Menominee County for Day 2.

Precipitation amounts remain one of the primary questions from Friday into Saturday, and guidance/forecast thinking has not changed much from previous cycles in that regard. The most likely scenario still calls for roughly 0.50-0.75" of rain across the UP, with high end amounts reflected by NBM 90th percentile values still getting into the 1.00-1.50" range by Saturday afternoon. Precipitation amounts could show quite a bit of spatial variability as the presence of thunderstorms could result in localized areas of heavier rain at times. Overall, WPC's marginal threat for excessive rainfall remains south of the UP through this period, but we could certainly still see some issues with ponding of water and poor drainage given the amount of snow still on the ground.

Expect rain to change over to snow across the west Saturday morning as colder air works in behind the departing system, with a rain snow mix possible across the central UP into early Saturday afternoon. Snow amounts will be limited as the highest QPF values will have already shifted east of the region, but still could pick up around an inch or so of accumulation in the west, with no accumulation expected over the central UP.

Sunday and Monday look warm and mostly dry within zonal flow as a pair of lows pass well to the north across Ontario. Look for daytime highs to climb into the 50s in many locations as overnight lows stay above freezing area-wide Sunday night. The next system of interest looks to impact the region next Tuesday night into Wednesday as another wave ejects out of the South Plains and potentially phases with a northern stream trough during the middle of next week. Ensemble guidance displays a high degree of uncertainty regarding strength, placement, timing of this feature, leading to a low confidence in precipitation type and amounts. NBM probabilities show a around 15-25% chance for greater than 4" of snow or greater than a tenth of an inch of ice, respectively, over parts of the UP in this time frame. Will continue to monitor in the coming days.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 654 PM EST Thu Mar 5 2026

Moisture-rich low levels will once again lead to foggy conditions at the terminals tonight, though more uncertainty exists in the timing and intensity of the FG compared to last night. LIFR conditions are already ongoing at CMX and IWD, though the vis is fluctuating at IWD. A sustained period of FG or low stratus will keep LIFR conditions at IWD until winds kick out of the S to SE around 05Z, leading to P6SM vis and MVFR vis ahead of gradually descending ceilings throughout the overnight period, eventually becoming IFR by 12Z. At CMX, expect fluctuations between low-end IFR and LIFR throughout the period. SAW is forecast to have a gradual descent from VFR to LIFR tonight. Chances of RA increase through the day Friday at all sites as a disturbance approaches from the west. This will lead to continued flight category restrictions as well as a localized LLWS threat at IWD and perhaps even some TSRA at IWD/SAW after 00Z.

MARINE

Issued at 332 PM EST Thu Mar 5 2026

Easterly breezes around 20 kt this afternoon will turn more southerly tonight ahead of the next system, generally remaining below 20 kt through Friday night. Low level moisture will continue to result in areas of fog over the water, potentially dense at times tonight into Friday morning. Winds shift northwesterly on Saturday with a few gales to 35 kt possible over the eastern half of the lake. 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.