Marine Weather and Tide Forecast for Grand Ledge, MI

DISCUSSION
Issued at 330 PM EDT Wed Jul 9 2025

- Showers and storm this afternoon, small chance for severe

Storms have spring as a low continues to move through Michigan dragging a cold front through southern lower this afternoon and evening. Weak supercells with damaging wind is the primary threat, with the best DCAPE through central Michigan, north of I 96. Shear remains weak though SFC based CAPE is over 2000 J/kg.
These storms will continue to form along the frontal boundary, with southwesterly flow ahead of the front, and westerly flow behind it. The front will continue to move to the east through the evening. With strong moisture through the mid levels, heavy rainfall remains a concern, and as such WPC has southern lower in an excessive rainfall outlook. Expect periods of heavy rainfall with any thunderstorm, though only minor flooding is possible.
The most likely location for any flooding would be just east of Jackson and Lansing, where 2 to 3 inches of rainfall fell overnight.
Strong storms will be possible through the afternoon and into the early evening. CAMS concur that as the boundary moves to the east by mid evening, convection will cease.

- Dry weather Tomorrow

As the cold front moves to the east overnight, skies will clear.
Patchy fog should form overnight due to moist low levels, especially in regions that received recent recent rainfalls. Calm winds will also aid in fog development. While not expected dense fog, it is possible, especially in low lying regions. Fog should lift/dissipate by mid morning. With high pressure overhead fair weather with highs in the 80s is a foregone conclusion.

- Rain chances continue to expand, Friday into Saturday

Models continue to show the high pressure weakening into Friday as a negatively short wave moves into the region daytime Friday.
This is out ahead of a deepening low that will be moving through the Great Plains. A moisture boundary through the mid levels could feed into this short wave and, given the summer sunshine could allow for some scattered showers Friday afternoon. The previously mentioned low should be engulfed by a deeper level low moving through southern Canada and should trek through the northern Great Lakes bringing widespread, beneficial rains through Saturday.
Latest QPF has upwards of a half on a inch, though given that NAEFS mean PWATS have 1 to 1.75 over the area through most of Saturday, those values could be higher. Deep layer shear remains present and given large SFC based CAPE potential, organized convection remains possible Saturday.

Front should move to the east with drier air filtering into the region in its wake. Expect warm, fair summer weather to return late Sunday into early next week.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
Issued at 138 AM EDT Thu Jul 10 2025

Skies have cleared out nicely at all of the terminals. This along with light winds is setting most of the area up for a round of fog toward daybreak this morning with the moisture that is left over from the rain at most of the sites, except KMKG. Have hit the eastern sites at KLAN and KJXN the hardest as they saw the most rain most recently. We have gone down to VLIFR there, and gradually improved conditions as you head toward KMKG where they did not have much rain.

Once the fog burns off, we will just see some cumulus clouds as any low level boundary layer moisture mixes up and eventually out.
Winds will remain under 12 knots from mainly the west and northwest.

We will see some low-mid level VFR clouds likely move in late to the western terminals. This will be associated with the next wave moving in just after the valid time of this set of forecasts.

MARINE
Issued at 330 PM EDT Wed Jul 9 2025

Winds and waves are building as northerly flow continue to strengthens behind the front. The northerly flow with beneficial fetch will continue to build through the afternoon and through the early evening as the gradient tightens.
Winds will slacken overnight as a high builds into the area.
Expect waves to subside overnight with fair winds and waves tomorrow.

GRR WATCHES/WARNINGS/ADVISORIES
MI...Beach Hazards Statement until 2 AM EDT early this morning for MIZ050-056-064-071.
MARINE...Small Craft Advisory until 2 AM EDT early this morning for LMZ844>847.