140
FXUS63 KGRR 101935
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
335 PM EDT Fri Oct 10 2025

.KEY MESSAGES...

- Chance of rain through tonight

- Mainly dry Saturday through Tuesday

- Above average uncertainty for Wednesday through Friday

&&

.DISCUSSION...
Issued at 335 PM EDT Fri Oct 10 2025

- Chance of rain through tonight

A few sprinkles or very light showers are in the process of passing
through the forecast area this afternoon. As of 3 pm, they extended
from Saginaw Bay, through Grand Rapids, and to Southern Lake
Michigan. These sprinkles are mainly the result of good forcing
aloft ahead of the incoming upper low, without much in the way of
moisture below 6k ft agl.

We will see low level moisture increase through this evening ahead
of the cold front, which stretches from near Manitowoc, WI to the
Tip of the Mitt as of 3 pm. However, as we increase the low level
moisture, the mid and upper level moisture is moving out quickly.
The bottom line to this is that there will be scattered light
showers around this evening until the front moves through late this
evening and overnight.

- Mainly dry Saturday through Tuesday

We are looking at dry conditions settling in over the area on
Saturday behind the sfc cold front. There has been a lot of
uncertainty regarding this low for the last week. Now that we are
looking at the whites of its eyes, it looks like it will end up well
east of the forecast area by tomorrow. This means that the coldest
of the air aloft will be also, and the threat of any showers has
diminished significantly. Can`t rule out maybe some lake effect
clouds or a few showers with the degree of colder air coming in at
the sfc with sfc-850 mb delta t`s in the mid teens C. The flow will
be from the NE, so anything from Lakes Michigan and Huron should
stay out of the area.

Upper ridging will build in then by Sunday, clearing out the area
nicely. The building upper heights, and low level flow becoming more
from the south will help max temps recover nicely to the 70s for
Sunday and Monday.

A weak cold front will be sinking SE into the area as the upper
ridge axis shifts east, and the upper jet approaches the area. This
will allow some weak short wave activity to clip the area across the
north. The front will approach, and will weaken with the lack of
sufficient upper support. In addition, any impacts in the way of
rain will be quite low as the low level feed of air comes from the
SE, downsloping off of the Appalachians. The small chance of rain
will linger into Tuesday when the front drops through.

- Above average uncertainty for Wednesday through Friday

Forecast certainty drops off significantly starting Wednesday and
beyond. This uncertainty all has to do with how long the slightly
lower heights and upper jet persist, before upper ridging builds
once again. NBM/the forecast has some small chances of rain at times
Wednesday-Friday. The bottom line is we should not see any
significant systems in that time frame, and temperatures will remain
seasonable to a little above average.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 157 PM EDT Fri Oct 10 2025

A cold front is situated upstream of the area this afternoon
stretching north/south across Wisconsin. A band of very light rain
showers well ahead of the front is currently moving through the
TAF sites. These showers should not affect visibility (VFR
weather will continue this afternoon). The front will move through
the area this evening with additional scattered showers. At this
point we feel the ceilings will remain VFR this evening as well. A
period of clearing will occur tonight in the 03z to 09z time
frame behind the front. After 09z lower ceilings will try to
spread in once again from the north. We have a more optimistic
forecast in place at this point, but we may need to add lower
clouds (MVFR) in the 12z to 18z time frame.

&&

.MARINE...
Issued at 335 PM EDT Fri Oct 10 2025

Waves of 4 to 6 feet are being reported at the buoys at 300pm. The
mid lake buoy west of Ludington reached 7.5 feet earlier today. Big
Sable Point is currently gusting to 30 knots. Webcams show whitecaps
to the horizon. The Small Craft Advisory (SCA) is working out well.

High end SCA conditions will continue this afternoon and early
evening. Winds will tone down a bit after 00z and especially after
02z. Wind direction will shift to the north this evening behind the
front, but winds decrease as the surface low is filling and we
remain in a slightly baggy gradient. The end time of our Small Craft
Advisory (11am Sat) still looks good as the winds will be veer
northeast/offshore. Winds into Saturday night and Sunday will remain
east/offshore and lighter, so we will remain at sub advisory levels
through the rest of the weekend.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 11 AM EDT Saturday for LMZ844>849.

&&

$$

DISCUSSION...NJJ
AVIATION...Duke
MARINE...Duke