Marine Weather and Tide Forecast for Stephenson, MI

SHORT TERM /THROUGH FRIDAY NIGHT/
Issued at 414 PM EDT Thu Apr 17 2025

Strong southerly winds gusting to 25 to 40 mph continued in western and central sections this afternoon, along with low dew points in the upper teens and 20s. Showers and a few embedded storms were moving into far western sections, where a 40 knot LLJ was focused ahead of an approaching cold front, and along the leading edge of weak elevated instability.

Showers and a few storms (mainly south) will overspread the region in association with a 40-50 kt LLJ, the approaching surface cold front and a warm front at 850 mb. Moderate to locally heavy downpoours can be expected, along with potential for small hail with any stronger storm. Strong forcing shifts east as the LLJ veers WSW and weakens overnight, leading to a relative lull in the precipitation late tonight into Friday morning. Even so, there appears to be enough low-level moisture and forcing along the surface cold front to maintain a small chance of light showers or drizzle. Widespread low clouds and areas of fog will also develop behind the cold front later tonight, then linger through at least Friday morning.

Showers and storms are expected to reform along the cold front as it moves through central and eastern U.P. during the afternoon. MUCAPE of 300-600 j/kg will build into Menominee County and areas near Lake Michigan, along with mid-level lapse rates around 7.5 C/KM. A powerful upper level jet (around 135 kts) will also arrive in this area during the afternoon, along with very strong deep layer shear of 60-80 kts. Although instability is marginal, there is concern for elevated storms with hail, and this is depicted in the Day 2 Convective Outlook Marginal Risk in southern Menominee County. Showers will gradually shift east Friday night as the cold front departs.

LONG TERM /SATURDAY THROUGH THURSDAY/
Issued at 414 PM EDT Thu Apr 17 2025

High pressure will bring dry conditions over the weekend, along with a moderating trend in temperatures into Sunday.

Models are bringing a deep low pressure system much farther northwest than they were yesterday, with an impressive deformation zone moving directly through the forecast area Sunday night into Monday. Low-level temperature and thickness forecasts indicate potential for snow across the western U.P.
late Sunday night into Monday. Probabilistic forecasts show a 30-50 percent chance of 2+ inches of snow, and a 20-30 percent chance of 4+ inches over the far west. Have used a blend of Consall/Consraw to lower hourly temperatures during this period, as NBM looked much too warm.

The potent system will depart Monday night, but a chance of showers will quickly return by Tuesday night and Wednesday as an occluded front lifts into the region. Dry weather returns Wednesday night into Thursday.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
Issued at 125 AM EDT Fri Apr 18 2025

Showers continue to push eastward across the western and central UP resulting in IFR conditions. Conditions will deteriorate to LIFR at all terminals by early morning, with some improvement back to IFR by this afternoon.

MARINE
Issued at 414 PM EDT Thu Apr 17 2025

Small craft advisories continue on the nearshore waters of Lake Superior east of the Keweenaw Peninsula through this evening, and on northern Lake Michigan through Friday morning.

Areas of dense marine fog are expected to develop over western Lake Superior in the wake of the cold front later this evening, and should persist into Friday morning. A Marine Dense Fog Advisory has been posted for this area.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
Dense Fog Advisory until 11 AM EDT /10 AM CDT/ this morning for LSZ162-240>242-263.

Lake Michigan...
None.