999
FXUS63 KGRR 262029
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
329 PM EST Wed Nov 26 2025

.KEY MESSAGES...

- Lake effect snow and wind event ongoing

- System snow expected this weekend...possibly heavy

&&

.DISCUSSION...
Issued at 328 PM EST Wed Nov 26 2025

- Lake effect snow and wind event ongoing

Ongoing event is going according to plan and therefore no headline
changes needed this afternoon. We expect conditions to deteriorate
late this afternoon and evening, which matches prior thinking, as
lake effect snow ramps up in intensity, wind increases just a bit
and temperatures cool to near freezing. So, while this morning
featured a mix of rain/snow and the midday hours mainly produced a
wet non accumulating snow, that is all about to change. A
pronounced shortwave mid level shortwave is seen in the water
vapor imagery over Wisconsin which is just now pushing into an
increasingly unstable lake environment. The shortwave is adding
lift and moisture to the equation and we are already seeing a
significant uptick in lake effect snow across northern portions of
the forecast area across Central Lower Michigan. Temperatures at
GRR have dropped to 33-34 degrees in the last hour and we expect
readings to dip below the freezing mark by 7pm. In the heavier
snow, accumulations have already begun as seen on the Fremont MI
webcams. The snow should increasingly stick to the pavement as we
work through the evening. Road temps have fallen into the lower to
middle 30s which also indicates that conditions are likely to
become slick as we head into the evening and overnight hours.

Accumulating snow potential looks solid both tonight and on
Thursday so we have roughly 24 hours to snow totals to increase.
The BUFKIT overview at MKG shows the situation the best, with deep
moisture through 10,000 feet and lift in and below the Dendritic
Growth Zone. We`d like to see the lift centered in the DGZ a bit
more, but accumulating snow is still going to occur. Instability
will increase as we work through the remainder of the event with
delta T`s (difference between the lake water temp around +9C and
850mb air temps of -10 to -12 C) of around 20 C to the lower 20s
C. Winds will transition from westerly this evening to northwest
tomorrow. The highest snow totals are still expected to occur in
the northwest and southwest corners of the CWA where we have the
warning in place. 3 to 8 inch totals can be expected up towards
U.S. 10 and 3 to 7 inch totals are possible in the southwest CWA
towards I-94 and points just north of there like Allegan and Barry
Counties.

As for the wind, we still expect the core of the wind to work
through the area this evening. We have already had gusts along the
lakeshore around 55 mph and we expect slightly higher winds late
this afternoon and evening. Winds along the lakeshore will push to
around 60 mph in gusts this evening and to around 50-55 mph inland
across the remainder of the area. The cold air advection will aid
in producing some of the higher gusts this evening.

Again, both wind and winter headlines remain unchanged.

- System snow expected this weekend...possibly heavy

Once we get beyond this event focus will need to quickly shift to
the next event which is a Colorado Low moving our direction for
the weekend. The low gathers in the lee of the Rockies Friday
night and moves through our area Saturday into Sunday. This system
has a lot going for it with a surface low tracking through
Southern Lower Michigan with cold air already firmly entrenched in
the area so we will not have to worry about precipitation type
issues. The 850mb low tracks through the heart of the area moving
northeast. Both surface and 850mb low tracks are favorable for
heavier snow. There is a prolonged period of isentropic lift on
the order of 18 hours which should stack up the snow. The long
period of warm air advection snow is aided by a coupled jet
structure. The length of warm air advection snow is notable as
warm air advection snow is some of the heaviest we typically see.
The warm air advection snow may be followed by a brief deformation
zone snow on the back end and then finally some lake effect into
Sunday. As it stands now the operational GFS is indicating a
widespread 4-8 inches of snow and the operational ECWMF is a bit
higher with 5-10+. Winter weather will remain our focus from
tonight right through the weekend. Folks with travel plans will
need to keep a close eye on the latest forecasts.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 110 PM EST Wed Nov 26 2025

IFR will be driven by areas of Lake-Michigan-enhanced snow this
afternoon into tonight, while ceilings generally range from 1,000
to 2,500 feet. Strong wind gusts from the west are expected to
peak at 40 to 50 knots this evening. Blowing snow and bands of
lake effect snow continue into Thursday/Thanksgiving, with
variable visibility down to IFR.

&&

.MARINE...
Issued at 328 PM EST Wed Nov 26 2025

We have maintained the Storm Warning on Lake Michigan as the core
of the wind is just beginning to work into the area. The Saugatuck
Pier WxFlow site has hit 57 mph so far, Grand Haven Pier WxFlow
site reached 56 mph and the Holland NOS site on the north pier
reached 55 mph. Again, we feel the strongest winds are about to
come in, between 300pm and 1100pm. Wind gusts around 60 mph will
continue through that time in the nearshore waters and along the
shoreline. Around 100am, we will transition into a Gale Warning as
the wind begins to back down. In case the Storm Warning needs to
be extended though we will hold off on that Gale for now. The Gale
will likely be needed through roughly midnight on Thanksgiving
night.

As for waves, the Southern Lake Michigan Buoy which is at mid lake
reached 12 feet earlier today and is currently at 11 feet. There
is still 40 miles of fetch this side of the buoy, so our waves
have likely been slightly higher than that. Another item to keep
in mind is cold air is more dense than warm air. The cold air is
just now flowing in across the lake. Cold air being more
dense/heavy digs into the water surface more effectively and
creates larger waves. So, we still expect the peak in the waves to
occur sometime this evening when the cold air in combination with
the strongest winds occur. Waves will top out in the 14 to 20
foot range between Muskegon and South Haven.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...High Wind Warning until 7 AM EST Thursday for MIZ037-043-050-056-
     064-071.
     Winter Storm Warning until 7 PM EST Thursday for MIZ037>039-
     043>045-064-065-071>073.
     Wind Advisory until 7 AM EST Thursday for MIZ038>040-044>046-051-
     052-057>059-065>067-072>074.
     Winter Weather Advisory until 7 PM EST Thursday for MIZ040-046-
     050-051-056>058-066-074.
MARINE...Storm Warning until 1 AM EST Thursday for LMZ844>849.

&&

$$

DISCUSSION...Duke
AVIATION...CAS
MARINE...Duke