Marine Weather and Tide Forecast for Muskegon, MI

DISCUSSION
Issued at 213 PM EDT Wed May 14 2025

- Scattered Showers and Storms into this Evening

This afternoon Mixed Layer CAPE values of 500-1000 J/kg and high precipitable values around 1.4 inches will be present. Shear however is lacking, therefore only expecting general thunderstorms with heavy downpours as seen my the moist sounding profiles. Best coverage could be along the lake breeze as it will aid in a source of lift this afternoon with isolated to scattered coverage elsewhere. Thunderstorms should taper off after sunset as the inversion builds in with light and variable winds overnight. The moisture trapped below the inversion could develop into areas of fog into Thursday morning.

- Round of Strong to Severe Storms Thursday Evening

During the day, Thursday is expected to be dry as warm air aloft prevents any thunderstorm. Dew points will continue to be in the 60s as we remain in our moist environment with precipitable water values around 1.5 inches. Warm air advection ahead of the 925-850mb front will help erode our CAP allowing for thunderstorms to tap into 2000 J/kg + of CAPE and 30-40 knots of shear Thursday evening. There is ample directional shear in the low levels creating plenty of spin in the environment which is favorable for storms to rotate. Mid level lapse rates will also be favorable for hail development. With these variables large hail (30 percent chance of 2 inch diameter hail or larger), damaging winds, and tornadoes.

The main window for severe storms will be between 8pm Thursday to 2am Friday from west (US 31) to east (US 127). There is some uncertainty with the southern extent due to some drier air in the mid levels, either way if storms develop they have a high probability of becoming severe. With storms occuring overnight, make sure you have a way to receive warnings and that you have a plan to take shelter.

- Additional Chances for Showers and Gusty Winds

Friday should be breezy with a good amount of sunshine, though ensemble members are far from settled whether this will be a day with gusts around 30 mph or 40-45 mph. A shortwave trough rounding the base of the low and a proximate cold front may touch off a quick round of showers late Fri evening, perhaps thunderstorms in Southern Michigan given the potential for instability rebuilding to 500-1000 J/kg.

Saturday does have the potential to be another breezy day, though the magnitude of peak gusts is still questionable among the ensembles, dependent on the pressure gradient between the low over the northern Great Lakes and the high over the SE US. Lingering showers are possible through the morning hours before drying out during the afternoon.

Canadian sfc high builds in early next week with potential for scattered frost Sunday night and Monday night.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
Issued at 131 PM EDT Wed May 14 2025

Scattered showers are ongoing across West Michigan, with isolated thunderstorms possible at all terminals. Confidence in direct impacts to a terminal is low, but IFR conditions are possible if a storm does impact a terminal. Will monitor TAFs and amend as needed.

Tonight, increasing dewpoints will lead to areas of MVFR fog, particularly at MKG, LAN, and JXN, and possibly MVFR cigs as well. The likely timeframe is 09z-13z before any fog mixes out bringing MVFR conditions through the remainder of the period.

MARINE
Issued at 213 PM EDT Wed May 14 2025

Areas of fog continue over the lake as moist air moves over the waters. Have extended the Dense Fog Advisory through 00z (8pm ET)
and cannot rule out needing further extensions into the overnight hours until winds increase Thursday morning.

Thunderstorms are likely Thursday Evening as a cold front moves across the lake. Strong to severe storms are possible, with severe storms capable of gusts in excess of 40 knots and large hail.

Southerly winds Friday veer to westerly by Saturday with winds of 15- 20 knots. Gusts to 30 knots and waves in excess of 4 feet are likely to bring conditions hazardous to small craft.

GRR WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Dense Fog Advisory until 8 PM EDT this evening for LMZ844>849.