138
FXUS63 KGRR 270854
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
354 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 330 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 the Southern Lower Michigan this
morning. Due to this, the winds have shifted to the northwest and
any snowfall is lake effect. Latest radar shows that though there
was a lull through the late evening hours, there is a slight
uptick early this morning. Mainly along and north of the US 10
corridor though snowbands continue to form elsewhere.

Snow will continue through the morning though there continues to
be a downward trend in amounts. Guidance continue to show a
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.

 Winds this morning will continue to be brisk and strong, however
they will continue to trend downward, especially once you get
away from the lakeshore. The High wind warning will continue
through the next few hours. Though probably will probably end the
Advisory due to the lack of winds inland. While they remain
gusty, they are below advisory criteria and not expected to
strengthen. This is due to the slackening of the pressure
gradient as the low continues to move eastward.



- Another Winter Storm on the horizon this weekend

Another 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

- 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 /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1156 PM EST Wed Nov 26 2025

The forecast is going largely as expected. Radar echos have
decreased a bit as moisture from the synoptic low moves away.
However, another short wave moving across Wisconsin will move
across the lake toward morning resulting in an uptick in lake
effect snow. We should see a bit more banding develop overnight
which will result in more variability in ceilings and visibility.
TAFs may very easily vary between IFR and VFR through the
period.

Winds will diminish slowly overnight but remain gusty through
the period.

GRR Airport DSS Update
No changes to the airport briefing
information provided from the day shift.

&&

.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...High Wind Warning until 7 AM EST this morning for MIZ037-043-050-
     056-064-071.
     Winter Storm Warning until 7 PM EST this evening for MIZ037>039-
     043>045-064-065-071>073.
 Winter Weather Advisory until 7 PM EST this evening for MIZ040-
046-050-051-056>058-066-074. MARINE...Gale Warning until 1 AM EST
Friday for LMZ844>849.

&&

$$

DISCUSSION...Ceru
AVIATION...04
MARINE...Ceru