Marine Weather and Tide Forecast for Pentwater, MI

DISCUSSION
Issued at 339 AM EDT Thu May 22 2025

- Rain continues today into tonight

A vertically stacked low just off to our east this morning will only slowly nudge eastward today and tonight as a northwest flow shortwave approaches from the north. In general, we remain in upper troughing through Friday. Our forecast has rain lingering today and ending for the most part for tonight and Friday. That may be optimistic given the upper flow pattern, but we feel drying northerly winds will aid in scouring out moisture for precipitation.
After this morning the moisture if confined to the low levels which will probably bring the widespread precipitation to an end.
The HRRR shows a dwindling of the precipitation as well after this morning. We will likely hang on to clouds though in some capacity both today and tonight, if not into Friday as well.

- Additional chances for precipitation next week

We are expecting a mainly dry forecast from Friday night through the holiday weekend. Surface ridging will be in place much of the holiday weekend which should keep us dry. There is a mid level shortwave that works through Saturday night into Sunday, but models are not bullish on precipitation due to the surface ridging that is present.

As we head into next week an upper low deepens overhead with a surface low moving into the Eastern Great Lakes from the Ohio Valley. Our model blends are picking up on chances for rain Tuesday into Wednesday with the upper low overhead.

- Cool into this weekend, then a slow warming trend

Ensemble data shows a steady warming of temperatures as we work through the 7 day period. We will for sure be the coolest in the next couple of days as the thermal trough is overhead at 850mb.
850mb temperatures dip negative tonight and Friday which should equate to highs holding in the 50s (normals are low 70s). The warming trend looks reasonable beyond the next couple of days.
That said, the upper low that develops next week may keep us cooler than what guidance is showing at this point. Given the expected clouds and precipitation next Tuesday we wonder of upper 60s will be realized. We may need to nudge these temperatures down with time.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
Issued at 749 AM EDT Thu May 22 2025

IFR and MVFR conditions remain at 12Z across South Central Lower Michigan, affecting LAN, JXN, BTL and AZO. GRR and MKG have improved to VFR. We expect a continued improvement as we work through the day with most observations becoming VFR in all of Southwest Lower Michigan by 21Z to 22Z. Light rain will remain possible towards LAN and JXN, but it should become more scattered this afternoon before ending.

Winds from the northwest at 10-20 knots can be expected today with gusts towards 25 knots.

MARINE
Issued at 339 AM EDT Thu May 22 2025

Maintained the current Small Craft Advisory and Beach Hazards Statement as is. Both remain in effect through 200am tonight. We will be monitoring the possibility of needing to extend the headlines south of Grand Haven into Friday as the WaveWatch3 is hinting at near 4 footers continuing into the overnight and into the day on Friday. Trends will dictate what we do in terms of the the possible extension in time as right now it is marginally into the 3-5 foot range during that time. As for today into tonight, north winds of 15 to 25 knots with gusts to around 30 knots looks like a solid forecast.

GRR WATCHES/WARNINGS/ADVISORIES
MI...Beach Hazards Statement through late tonight for MIZ037-043-050- 056-064-071.
MARINE...Small Craft Advisory until 2 AM EDT Friday for LMZ844>849.