807
FXUS63 KGRR 271248
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
748 AM EST Thu Nov 27 2025

.KEY MESSAGES...

- Lake effect snow today

- Another Winter Storm on the horizon this weekend

- Cold to continue next week

&&

.DISCUSSION...
Issued at 746 AM EST Thu Nov 27 2025

- Lake effect snow today

 The upper level low continues its trek to the east with a backside
trough swinging through Southern Lower Michigan this morning. Due to
this, the winds have shifted to the northwest and any snowfall is
purely lake effect. Latest radar shows that there continues to be a
lull this morning.

Snow will continue through the morning though there continues to be
a downward trend in amounts. Guidance continue to show some downward
trend, though persistent flow and temp differentiation over the lake
should allow for several bands to set up this afternoon and evening.
Potentially there should be at least an additional 1 to 2 inches,
however snowfall amounts today will be more isolated than yesterday.

 The biggest question is whether to keep or downgrade the winter
storm warnings. The biggest concern is that as the lake effect snow
bands ramp up this afternoon there is a chance for isolated
abouts of at least 4 to 6 inches. However those bands will be by
there very nature but will bring with them potential impacts. So
given the potential for late morning and afternoon lake effect
snow bands, have kept the winter headlines going.

Winds this morning will continue to be brisk and strong, along the
lakeshore today. They could ramp up a bit this afternoon. However
once you get away from the lakeshore they diminish compared to
yesterday. Have ended the high wind warning but due to strong winds
along the lakeshore, have a wind advisory out today.


- Another Winter Storm on the horizon this weekend

Another large upper level system will be making its way across the
USA this week. This one is further south and extends from an upper
level trough. The difference compared to the low that moved through
on Wednesday is that Saturday`s system is much colder and will not
have any warm surface temps out ahead of it. So while the
Thanksgiving eve system had rain and warm surface temps to moderate
snowfall accumulations, this storm will remain cold with 850mb temps
well below zero. The incoming system will have a significant time
period of isentropic lift along with frontogenetic forcing. That
coupled with a strong low level jet and Snowfall ratio`s trending
at times of 16 or 17 to 1 and you have a recipe for periods of
heavy snowfall. Given that potential and the amount of QPF in this
storm, there is a decent potential for 4 to 8 inches with upwards
of 10 inches possible. Timing is still up in the air, some
guidance brings it in as early as daytime Saturday, with some
Saturday evening. So stay tuned.

- Cold to continue next week

 Cold air will continue to dominate the pattern with lows well below
normal through next week. Highs are expected in the upper 20s to low
30s, with lows dropping into the teens and potentially the single
digits by mid next week.


&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 746 AM EST Thu Nov 27 2025

Lake effect snow will dominate the pattern today so while MVFR cigs
will be persistent today periods of IFR vsbys are not out of the
question. Main period of concern is 18Z until 03Z with TAF sites
AZO, BTL, MKG and GRR the main concern.  Winds will be gusty out of
the northwest through the day. Winds will slowly slacken this
evening.

&&

.MARINE...
Issued at 351 AM EST Thu Nov 27 2025

The winds have continued to slacken as discussed above and
Gales are dominating this morning. Expect these gales to continue
through the first half of the day. As the upper level system moves
eastward the northwest flow will dampen and winds will decrease
throughout the day with gales dropping to scy advy level probably
by this afternoon .

 The strong persistent flow, the colder air and the strong fetch
will keep waves going through this time with waves remaining 14 to
20 foot this morning and 10 to 15 foot through the rest of the
day and into the evening.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Storm Warning until 7 PM EST this evening for MIZ037>039-
     043>045-064-065-071>073.
     Wind Advisory until 7 PM EST this evening for MIZ037-043-050-056-
     064-071.
     Winter Weather Advisory until 7 PM EST this evening for MIZ040-
     046-050-051-056>058-066.
MARINE...Gale Warning until 1 AM EST Friday for LMZ844>849.

&&

$$

DISCUSSION...Ceru
AVIATION...Ceru
MARINE...Ceru