textproduct: Grand Rapids

KEY MESSAGES

- Brief periods of scattered light rain/snow showers through tonight

- Quiet with moderating temperatures mid-week

- Periods of rain late Wednesday through Friday

DISCUSSION

Issued at 303 AM EDT Mon Apr 6 2026

- Brief periods of scattered light rain/snow showers through tonight

The coldest and most unsettled weather in the CONUS right now is over the Great Lakes and far NE states. The responsible feature is a long wave trough that extends over the aforementioned area. Over this area is the northern branch of the jet with multiple short wave impulses riding through it.

One of these impulses is moving through right now with a few areas of light rain over the southern portion of the state, while some rain or snow is ongoing over the northern section of the area. Either way, this is not too impactful with sfc temps almost all above freezing in the mid to upper 30s, and road sfc temps sitting in the lower 40s. This will be short lived, and move out of the area by daybreak.

The next wave will approach the area late this afternoon. Initially ahead of the wave and associated sfc front will be a few sprinkles/light rain showers. Then along and just behind the front, a fairly robust narrow line of showers will try to drop through the area. The best forcing will be further north, and the precipitation will gradually diminish as it sinks south. There is just not much moisture to work with. In addition, even though the air is cold, it is not cold enough for lake effect/enhancement to do much.

- Quiet with moderating temperatures mid-week

The upper jet will finally lift NE of the area on Tuesday as the upper ridge over the Pacific NW is pushed eastward by a strong low coming out of the Gulf of Alaska. This ridge will bring drier weather with no short waves and rising heights. Tuesday will start off a bit below average with the colder air mass coming in behind today's cold front. 850 mb temperatures around -9C will support highs likely only in the 30s.

The sfc ridge will slip east of the area by Wednesday. Return flow in the lower levels will advect quite a bit of warmer air up over the area. This warm up is shown well by the 850 mb temps as temps warm to +7C by later Wed, an increase of around 16C from just 24 hours before.

Most areas should stay dry on Wednesday. There is a small chance that the far NW section of the forecast area gets clipped by a warm front and showers along it.

- Periods of rain late Wednesday through Friday

The better threat of rain initially will come in late Wednesday night and Thursday. Thankfully this system does not look nearly as wet as the systems from last week regarding rain amounts. Some of the latest data indicates that the coverage of rain may diminish some as the low level flow will initially be drawing some moisture from the Gulf, and then becomes more from the south Appalachians which would be a bit drier. Also, the passage of the front during the coolest times of the day.

Thursday's front stalls out just south of Michigan over IN and OH late Thursday. Then we see additional short wave energy eject from the newly formed upper low off of CA ride along this boundary, and lift it back north over the area. This time, the flow more directly from the Gulf will support better rain chances, especially for the southern half of the area. Right now, the front looks to stay just south of the area, with the warm sector staying south. That would be where the better convective potential will be.

We see a fairly strong Canadian ridge then build in behind the wet system from Thu-Fri. This should dry the area out efficiently, while cooling us down once again. This will hold for late Fri through Sat, with the next system potentially approaching late next Sunday.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 146 AM EDT Mon Apr 6 2026

This forecast period starts out with all of the terminals sitting at VFR with mainly mid and high clouds overhead. There is some light rain being reported at times at KLDM with some spotty MVFR ceilings. Some light rain will be more likely at KMKG and KGRR for a couple of hours early this morning. Have gone VCSH at most of the other sites.

Some MVFR clouds are likely to move in at KGRR and KMKG for a few hours behind a weak front. These are likely only to persist for a few hours before lifting to VFR. Another band of showers is expected to move southward through the area mid-late afternoon. These are likely to start out as some rain showers. Then they will change to snow showers as a band moves through and colder air moves in. More impacts are expected to affect KMKG and KGRR before they weaken further south and east. Have gone tempo/prob30 for this line to account for it.

Winds will then shift to become from the NNE. A few light flurries/very light snow showers will be possible through 06z with no impacts expected.

MARINE

Issued at 303 AM EDT Mon Apr 6 2026

The next marine headline event is poised to start later today, with the Small Craft Advisory issued last evening for today and tonight looking good. This event looks like a solid Advisory event with winds to 30 knots expected from the North behind the front moving through.

The next event after the one for later today will develop late Tuesday night and last into Thursday night. That will encompass increasing winds ahead of the next system, and stronger winds on the backside. Small Craft Advisory conditions are expected, with Gales possible.

HYDROLOGY

Issued at 128 PM EDT Sun Apr 5 2026

Over a dozen river flood warnings are in effect for the next few days as the crests on area rivers works downstream. Although light rain is a possibility during the next couple of days, rain totals will be less than a tenth of an inch and won't significantly impact the ongoing flooding. More rain later in the week may be a bit heavier than what's expected early this week, but will be significantly less than the last few days.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory from 11 AM this morning to 8 AM EDT Tuesday for LMZ844>849.