textproduct: Grand Rapids

KEY MESSAGES

- Potential for a narrow high impact snow band late Mon/Mon night

- Periodic snow chances with below average temperatures this week

DISCUSSION

Issued at 305 PM EST Sun Nov 30 2025

- Potential for a narrow high impact snow band late Mon/Mon night

We will be holding on the the lingering Winter Weather Advisory for the lakeshore and Kalamazoo County through the 7 pm expiration time.

We will be issuing a Winter Storm Watch for Oceana, Muskegon, and Ottawa counties for Monday afternoon and Night for a potentially impactful narrow heavy band of snow.

Lake effect snow showers in the advisory area has remained formidable as expected with visibilities under the snow showers dropping to below a mile at times. They have been a bit heavier in the area of a noticeable sfc trough dropping down the lakeshore, and near South Haven as of 1930z. We remain under cyclonic flow aloft lingering in the wake of last night's system, and an additional short wave is heading toward the area in the next few hours.

We will see the jet core lift NE of the area, and see inversion heights drop significantly. A nice upper ridge will be heading toward the area, and a corresponding sfc ridge will move over the area tonight, bringing light winds and some partial clearing away from the lakeshore. There may be a few snow showers right along the lake, but a likely developing land breeze with the fresh snow pack and light winds combined with the lake should push the snow showers mainly offshore.

The land breeze could be the basis for some localized high impact snow showers by Monday afternoon for portions of the lakeshore. The light wind regime and land breeze over the lake is likely to produce a convergence band over the east side of the lake. These light wind scenarios will sometimes produce meso-lows, which the hi-res models are showing happening late tonight and Monday morning.

We then see this convergent band lift north along the lakeshore as a southerly component develops with the ridge building east, and with lower pressures over the warmer lake. This will bring some lake effect snow showers back in over the lakeshore by late morning, most likely somewhere between Holland and Pentwater where the lakeshore juts out into the lake a bit given a flow from the SSW. Nothing too heavy through noon.

After noon however, we will see the approach of another stronger short wave from the west. We will see a good deal of mid-upper level moisture stream in over the area. This moisture aloft will help to seed the ongoing lake effect band. This moisture, combined with plenty of remaining instability (delta t's of mid to upper teens C), and fairly strong forcing and rising inversion heights has the potential to produce a very strong narrow band of heavy snow showers beginning late Monday afternoon, and peaking during the late evening and overnight hours Monday night.

There is a very good clue of this happening with just about all of the hi-res data, and even the lower res synoptic models. One could even say there is even some good agreement that somewhere between Holland and Pentwater could see a foot plus of snow in a localized manner. Where exactly this happens, and how much falls remains uncertain with a mesoscale feature that hasn't even developed yet. This band has the potential to drop 1-3 inches/hour for a few hours at any one location if it comes to fruition.

To give this event some attention, but not be irresponsible with potential snow amounts, a Winter Storm Watch seems like the best way to go right now, and to try to hammer home there is some localized potential. As run to run consistency may continue, and solutions hone in on the exact evolution and placement of this, a warning is likely to be issued.

Elsewhere away from this band and any lake enhancement, most locations will see an inch or two at most from this wave before it ends Tuesday morning.

- Periodic snow chances with below average temperatures this week

The upper level pattern characterized by broad troughing, and the flow from the NW will continue to dominate through the next week. This will ensure that the region sees temperatures remain below average for the most part, along with unsettled weather in the form of periodic snow showers.

Right now, it looks like much of Tuesday should be quiet as ridging builds in behind the departing system for Monday/Monday night. Even lake effect should be fairly quiet with temperatures aloft modifying along with inversion heights dropping with the ridge approaching.

The next chance of snow showers will increase on Wednesday as the next short wave drops in from the NW. This will bring snow showers then into Wednesday night, before they taper off as a stronger Canadian ridge builds overhead by Thursday.

This pattern will generally repeat with systems coming in somewhere around Friday night/Saturday, and Saturday night/Sunday. The timing with these later systems is very much likely to change on any differences that happen with the previous systems.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1255 PM EST Sun Nov 30 2025

Boundary layer winds are becoming NW areawide in wake of last night's storm system, and gusts near 25 kt expected through the afternoon. This will result in lake effect snow showers... with MVFR cigs and occasional IFR vsbys... near Lake Michigan. MKG and AZO TAFs will see greatest impact through 22-00Z. Cyclonic flow will diminish tonight as weak ridge of surface high pressure drifts overhead. Expect winds to weaken with generally SCT-BKN VFR clouds tonight.

Though TAFs will not reflect any visibility restrictions late tonight, fresh snow and light winds will allow for substantial radiational cooling. The question will be whether any low level moisture contributions stemming from temps hovering near freezing today /melting snow/ will be overcome by drier air advancing in from the NW.

MARINE

Issued at 305 PM EST Sun Nov 30 2025

No changes to the ongoing Gale Warning in effect through mid evening tonight. Latest observations along the coast show Gale conditions dominating all along the lakeshore. We should be peaking right now, with winds expected to drop below Gales by the 01z expiration time. A short duration Small Craft Advisory will likely be needed until later tonight when waves should drop below 4 ft.

The only other chance of Gales in the next week looks to come on Wednesday immediate ahead and more likely just behind a frontal system moving through. Right now, it would be borderline, but at least a solid SCA event.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory until 7 PM EST this evening for MIZ037- 043-050-056-064-071-072. Winter Storm Watch from Monday afternoon through Tuesday morning for MIZ043-050-056. MARINE...Gale Warning until 8 PM EST this evening for LMZ844>849.