114
FXUS63 KGRR 082000
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
300 PM EST Sat Nov 8 2025

.KEY MESSAGES...

- Synoptic snow southern Lower tonight

- Lake effect snow mainly northwest tonight/Sunday

- Lake effect snow east of US-127 Sunday night

- Cold Monday morning, then a warming trend next week

&&

.DISCUSSION...
Issued at 300 PM EST Sat Nov 8 2025

- Synoptic snow southern Lower tonight

Regional radar shows a band of rain and snow over Iowa moving
east toward Lower MI. This precipitation will move across the far
southwest cwa around 03...initially as rain...and then spread
eastward. Forecast soundings show above freezing temperatures
below 870 mb, but wet bulbing effects quickly take over after
that resulting in a quick transition to wet snow after that. ECMWF
ensemble model tracks of the surface low take it just north of the
Ohio River which will keep most of the synoptic precipitation
along/south of I-96. There will be several hours of light to
occasionally moderate snowfall after 05z across the
south/southeast cwa. An advisory was considered. However, ground
temperatures are above freezing and surface temperatures only cool
to 32-33 degrees by Sunday morning. This will tend to mitigate
accumulations and impacts. Synoptic snow should diminish by late
morning Sunday across the southern cwa.

- Lake effect snow mainly northwest tonight/Sunday

Favorable conditions for lake effect snow will develop tonight
across the cwa. Colder air will pour south over the lake tonight
as a couple of short waves help to carve out the upper trough over
the Great Lakes and the core of the upper low dropping south
Sunday. Abundant over-lake instability will produce lake effect
snow. The question is where will the main lake band develop?
Initially, boundary layer winds are North to NNE. CAMS show a
dominant lake band developing near mid lake and sinking south.
Using h85 omega as a proxy for lake band placement, several models
show the band clipping the points in Mason/Oceana counties. A
little wiggle in this band will make all the difference. At this
point, it looks like the far western portions of the
aforementioned counties will see some accumulation snow later
tonight with more snow possible Sunday. HREF ensemble
probabilities point toward 50-60 percent chance at greater than 6
inches of snow in this area through Sunday night. We issued a
winter weather advisory for Mason/Oceana counties from this
evening through Sunday. If the lake band really gets going,
though, I could see this needing a warning.

- Lake effect snow east of US-127 Sunday night

Nuances in the boundary layer flow may result in a sneaky lake
effect snow event across the eastern cwa, mainly south of Alma
Sunday. As the low moves by to the southeast, a northeast wind
flow develops Sunday. When combined with h8 temps near -9c, lake
effect snow will develop over Lake Huron and stream southwestward.
Initially, surface temperatures will be in the upper 30s, but cool
by late in the day. This band also shows up in model h85 omega
progs too, giving some credence this this scenario. Wasn`t
confident enough to issue headline yet, but we`ll keep an eye on
it.

- Cold Monday morning, then a warming trend next week

Temperatures Monday morning will be 15 to 20 degrees. Since ground
temperatures are still warm, we may see some hazards develop with
lake effect snow initially melting, then refreezing.

After Monday, the upper trough axis will move east and a warming
trend will develop. Highs will warm through the 40s mid week and
approach 60 by next weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1158 AM EST Sat Nov 8 2025

VFR conditions expected through the afternoon before conditions
deteriorate tonight. Based on this morning`s short and medium
range model guidance, the low and its associated precipitation
shield will be a bit more south and slower and have adjusted the
TAFs accordingly. Regardless, rain will mix with, and eventually
change over to, snow as a low pressure system passes to our south.
Conditions will deteriorate to MVFR, and eventually IFR for AZO,
BTL, JXN and possibly LAN. Snow moves out Sunday morning with lake
effect snow setting up behind it near the lakeshore. Any impacts
from the lake effect would mainly be limited to MKG through the
end of the TAF period. MVFR ceilings will continue after
precipitation exits through the end of the TAF period. North winds
will become northwest by Sunday morning.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory from 7 PM this evening to 7 PM EST
     Sunday for MIZ037-043.
MARINE...Small Craft Advisory from 7 AM Sunday to 7 PM EST Monday for
     LMZ844>849.

&&

$$

DISCUSSION...04
AVIATION...Thomas