textproduct: Grand Rapids

KEY MESSAGES

- Small chances of rain mainly North each night through Fri night

- Warming temperatures this weekend

- Rain chances return Sunday for southern areas

DISCUSSION

Issued at 225 PM EDT Tue Oct 6 2026

- Small chances of rain mainly North each night through Fri night

Not much change expected in the upper air pattern for the region as compared to previous forecasts. Rain chances have increased just slightly for each night through Friday night.

The northern branch of the upper jet core is expected to remain just north of the area through Thursday night. It is far enough north to keep the forecast area out of diurnal chances of rain and more widespread cloud cover. However, it is just close enough that we continue to get barely clipped by short wave troughs embedded in the flow.

For tonight, Wednesday night, and Thursday night, the timing of the short waves are such that they are bringing the very limited rain chances each night. This limits the amount of instability helped by the diurnal boost. In addition, these waves have no access to any low level moisture below 7-8k ft. This will limit any rain to mainly sprinkles, to just isolated coverage of any showers that would produce measurable rain.

The upper jet nearby will finally lift northward after Thursday night as the long wave trough is able to move out. The building ridge will help a sfc warm front lift NNE toward the area Friday night. This is likely to be another round of sprinkles and a few light showers with limited low level moisture once again.

- Warming temperatures this weekend

The warm front will move away from the area by Saturday morning, allowing the warm sector to move up and over the area for Saturday. The models have been fairly consistent in bringing +20C air over the area at 850 mb. This would translate to max temperatures at the sfc approaching 80F. Plenty of subsidence over the area on Saturday will protect the area from any rain through Saturday night.

- Rain chances return Sunday for southern areas

We have been mentioning a system that will be over the Gulf late in the week that will try to approach the area later Sunday. This system has some potential tropical moisture as it will be over the Gulf to start with. The long wave flow will be arranging itself on the backside of the ridge to be oriented from SW to NE. This flow, and a short wave that is embedded with the upper flow will will be oriented from SW to NE, and will try to absorb the tropical system and drive it toward the region. The trend for this system has been for it to inch toward the area as it rotates out of the Western Gulf.

Upper lows are notorious for wobbling and not following the forecast track very well. This one would be becoming extra-tropical as it leaves the Gulf coast region. We will need to monitor the movement of this system as if it can rotate a bit further north, it will bring more rain chances on Sunday than we have been advertising.

Once this low rotates away from the area later Sunday, we will fall under back under upper ridging, dry out, and warm back up.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 708 PM EDT Tue Oct 6 2026

No significant changes from the going forecast. A 45kt LLJ will precede a cold front tonight, resulting in a few hours of LLWS. Otherwise, VFR conditions are expected through the period.

MARINE

Issued at 225 PM EDT Tue Oct 6 2026

No changes needed at this time to the marine headlines. The strongest of the winds are just beginning to move in at this time behind the warm front that moved through earlier. The strongest of the winds will be north of Whitehall, where we have the Gale Warning out. Winds and waves will taper off, with the far southern marine zone likely staying just below Small Craft Advisory criteria. This will last until Wednesday when everything will settle down for a bit.

Much of the period through the weekend will see elevated winds and waves with a decent gradient remaining in place. The only time winds look to stay below 15-20 knots will be Thursday night under a ridge.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 4 PM EDT Wednesday for LMZ845>847. Gale Warning until 11 PM EDT this evening for LMZ848-849.