739
FXUS63 KGRR 130722
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
322 AM EDT Mon Oct 13 2025

.KEY MESSAGES...

- Another Foggy Morning

- A Couple Chances for Rain this Week

&&

.DISCUSSION...
Issued at 322 AM EDT Mon Oct 13 2025

- Another Foggy Morning

Stratus and fog is filling in across most of the area this
morning. Visibilities are varied beneath the stratus, but what
reductions there are are largely in the 1 to 3 mile range. We
could see visibilities worsen as we approach sunrise, depending on
visibility trends a Dense Fog Advisory may be needed. Fog should
burn off and stratus scatter out by late morning. Clouds will be
streaming in from the west, but most of the area should still see
mostly sunny to party cloudy conditions this afternoon with
temperatures warming into the upper 60s to low 70s.

- A Couple Chances for Rain this Week

There will be a couple opportunities for rain over the week
and into the weekend. An advancing high paired with warm air
advection and a low level jet to the west will develop an area of
frontogenesis Tuesday night. Within this region of frontogenesis
there may be enough lift within the moist mid levels for showers
to develop and move into the area. Low level moisture is lacking
and could limit rainfall to virga or sprinkles. The best chances
(40 percent) will be along the lakeshore with lower chances to the
east. Any rainfall will be light due to the lack of deep moisture.

A better set up moves in for the latter portion of the week as a
deep trough shifts east into the area. Showers could develop as
early as Thursday night with the warm front. Looking at cluster
analysis more solutions than not keep Friday relatively dry until
Friday night/Saturday morning when an area of rain moves in with
the upper level trough. Most of the clusters have the trough axis
moving through Sunday keeping rain chances through the weekend.
There is a slower solution among the clusters however that keeps
us in the warm sector longer and lingers the low over the Great
Lakes into the following week. This is reflected in the NBM
probabilities (20 to 30 percent) through Sunday night into Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 153 AM EDT Mon Oct 13 2025

LIFR to IFR stratus is developing from JXN to AZO to GRR and is
expected to expand into the morning impacting most of the area.
LAN may stay just east of the stratus, but with the close
proximity added a tempo group for ceilings below 1000 feet right
around sunrise along with lower visibilities. While most areas may
see visibilities in the 1-3 SM range, do expect areas around 1/2
SM to develop with the best chances toward JXN. Fog should clear
and the stratus scatter out around 14-15Z this morning.

Winds will be light and variable throughout the day. Winds will
initially be from the southeast this morning and then veer to the
north tonight as the front moves through. Some diurnal cumulus is
possible around 3000 to 4000 feet this afternoon with additional
clouds around 15000 feet streaming in from the west.

&&

.MARINE...
Issued at 322 AM EDT Mon Oct 13 2025

There could be some fog this morning along the lakeshore dropping
visibilities down to a mile. If fog impacts the lakeshore, it
should clear by late morning. Winds will be veering from the
southeast to west this afternoon and then turn to the north
tonight. Northerly winds then expected through most of the week
before turning to the southeast Thursday and building into Friday.
Small Craft Advisory conditions are possible Friday with southeast
winds gusting around 25 knots and then waves building into
Saturday and winds turn to the southwest.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...RAH
AVIATION...RAH
MARINE...RAH