Marine Weather and Tide Forecast for South Haven, MI

DISCUSSION
Issued at 337 PM EST Sun Dec 14 2025

- Lake effect into early Eve then light snow in north Tomorrow

So bottom line upfront. Have allowed the Winter weather advisory to expire. However, periods of snow showers in a narrow band of lake effect continues. This persistent band is along the coast and looking at most MDOT webcams, while it is snowing, it is less impactful with light accumulations. The flow continues to shift and the main bands could affect the Muskegon to Holland region over the next few hours.
These bands will continue to diminish into the evening as flow cuts off and weak thermal ridge builds into the midwest.

Downsloping flow begins the work week with a weak trough moving through the Upper Great Lakes tomorrow. This weak clipper could bring light snowfall north of the I 96 corridor and mainly along and north of the US 10 corridor. Any accumulations will be light.

- Warmer, rainy and windy Thursday

The big story for the week will be the warmup and potential rain midweek. A large surface low with good mid level forcing will move through Southern Canada and draw warm southwesterly flow into Michigan Tuesday evening into Thursday.
The warm air advection by Tuesday evening should be around +7C at 850mb. To put that in perspective, it was around -25C this morning. Lows this morning were preliminary 0F, normal is 25F and record is -1F. So by Wednesday morning, the low forecast is 30F.
That warm air will continue to advect into the region through Wednesday and into Thursday. Lows projected Wednesday morning to be 10 degrees above normal and 7 degrees above normal Thursday.

Models remain consistent in bringing a large upper level system through the region Thursday. There is some question on position and that will determine how much QPF we receive. Rain is still expected. with showers likely Thursday. Slightly anomalous PWATS give credence to around 0.5 inch to .75 inch of QPF range so far.
Strong low level jet remains possible along with this system so strong southwesterly winds will remain possible Thursday.

What this transition period does to the snowpack remains to be seen. However, given the rain and persistent warm air advection, we should expect to loose much of the snowpack.

- Snow with mixed precipitation events into the weekend

The large upper level low will quickly move eastward Thursday evening. Strong northwesterly flow with -15C at 850mb should advect into the region by Friday morning. This should allow for some lake effect with perhaps an inch or two of snow Thursday night into Friday. Given the robust system, a rain/snow mix at times is probable. So a wintry mix through this timeframe is plausible. Temps drop back down to near normal on Friday before potentially getting back into the upper 30s on Saturday.



AVIATION /18Z TAFS THROUGH 18Z MONDAY/
Issued at 1202 PM EST Sun Dec 14 2025

Ceilings will be chaotic this afternoon and evening with cigs bouncing on either side of 3kft thanks to lake effect stratocu moving inland. Leaning on the NAMNEST, a few hours of intermittent MVFR snow showers are likely at MKG before diminishing mid to late afternoon. Light snow showers are possible mainly at MKG and flurries at the other terminals. MKG and GRR have the best chance of falling back into a few hours of MVFR overnight before climbing to VFR by Monday morning. Other terminals do have a 20-30 percent chance of falling back to MVFR tonight which will be monitored. Monday morning then sees wind gusts increase to 20-25 knots, after 09z at MKG and after 14z inland.

MARINE
Issued at 337 PM EST Sun Dec 14 2025

The longer duration Small Craft advisory continues into Monday morning. While there will be a lull this evening, the winds will pick up late tonight with gales expected tomorrow of 35 to 40 kts at times Monday morning. Waves remain expected to peak around 10 feet Monday morning.



GRR WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Small Craft Advisory until 4 AM EST Monday for LMZ844>849.
Gale Warning from 4 AM to 3 PM EST Monday for LMZ844>849.