Marine Weather and Tide Forecast for Grand Ledge, MI

DISCUSSION
Issued at 259 PM EDT Sat Jun 13 2026

- Scattered Storms This Evening and Tonight

As of early afternoon, thunderstorms have developed across north central and NE Lower MI ahead of a cold front that is approximately located across far NE WI and into the central U.P.
The environment in this region features 1500-2000 J/kg of SBCAPE and 60 kts of deep layer shear. The LLJ is better oriented across northern Lower as opposed to southern Lower, where it is divergent. Still, we believe scattered storms in the form of a broken line may develop closer to the 21z-00z time frame over central Lake Michigan into west central Lower MI, moving southeast into the 00z-04z time frame.

Synoptic support is certainly present tonight as mentioned in the previous discussion. Good upper jet divergence, a solid mid level jet of 50-60 knots, a LLJ of 30-40 kts (albeit divergent, which is not ideal), and a surface cold front will all help the cause.
Thermodynamically speaking, our setup this evening is good but not excellent. On the one hand, DCAPE looks pretty good at 800-900 J/kg ahead of the cold front, but MLCIN of 100-150 J/kg after 00z may provide a bit of a stable barrier for stronger thunderstorm wind gusts from reaching the surface. Could be a close call in certain areas where healthy convection manages to develop, and peak thunderstorm wind gusts of 40-60 mph seems reasonable. The 12z CAMs have indicated somewhat of a fickle evolution to the convection this evening, with different placements and timing of potential storm development. All in all, this looks to be a more localized setup with scattered storm development and not a widespread damaging wind issue. Model soundings do support some hail development with probably sub-severe hail being observed but can't rule out some quarter size hail in isolated spots. There may be just enough 0-3 km shear and curvature to the hodograph coupled with 0-3 km CAPE just under 100 J/kg to provide support for a weak tornado to develop across southwest portions of the state, but this threat is quite low.

- Cooler Sunday with Morning Showers

The cold front will be slow to move out of the region as the upper trough doesn't move into Lower MI until midday Sunday. As such, expecting a cool and showery morning on Sunday with gradual clearing from west to east. A NW breeze will also pick up during the day with some gusts of 20-30 mph expected. Highs in the upper 60s to around 70 are expected.

- Wet Midweek Period Likely

After a dry Monday, rain and thunderstorms return to the region midweek. The first round arrives Tuesday as model guidance is indicating a fairly strong upper trough arriving and even going negative tilt. A 30-35 kt LLJ (convergent this time) aims toward our region by 18z Tuesday as a cold front becomes situated to the west of Lake Michigan at that time. Showers and some thunderstorms are fairly likely (60-80%) near and east of US 131 especially on Tuesday into Tuesday evening. I wouldn't rule out a few stronger storms possible based on the available severe weather machine learning guidance.

The break after Tuesday evening will be very brief as another system will be hot on its heels for Wednesday. What's interesting about the Wednesday system is how anomalous the MSLP is shown by the 12z ECMWF. It is showing a 990 mb low moving toward the MI/IN border Wednesday night which would be a whopping 5 standard deviations below normal for mid June. The orientation of the low level jet looks excellent with an intense 60-70 kt core moving into northern Indiana. That said, the best instability looks to stay south of the state for this event. What is more likely to occur is a fairly widespread rain with some thunderstorms. ENS 50th percentile QPF is almost an inch at GRR, so a fairly good soaking looks to be coming later Wednesday into Wednesday night.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/
Issued at 203 AM EDT Sun Jun 14 2026

A cold front is positioned across Central Lower Michigan at 06z dropping southward. A line of showers and thunderstorms precede the front over the I-96 corridor. We are not expecting much more in the way of showers and storms at KMKG, but the other 5 TAF sites will likely see showers and storms move through 12z. It may end up being that KGRR and KLAN will be the most affected.
Overall, we expect conditions to mainly stay VFR. Winds will veer from southwest to west early this morning as the front creeps south. Some showers will likely linger along the I-94 TAF sites in the 12z to 16z time frame.

Thereafter, VFR weather will continue with the showers exiting to the south and east. Gusty west to northwest winds can be expected today at 14-26 knots.

MARINE
Issued at 259 PM EDT Sat Jun 13 2026

Winds and waves continue to be hazardous to small craft today and beach hazards will continue especially from Grand Haven to the north. For Sunday, a new set of Beach Hazards Statements and SCAs will likely be needed near and south of Grand Haven with cooler NW flow moving over the lake during the day.

GRR WATCHES/WARNINGS/ADVISORIES
MI...Beach Hazards Statement until 2 AM EDT early this morning for MIZ037-043-050-056.
MARINE...Small Craft Advisory until 2 AM EDT early this morning for LMZ846>849.