265
FXUS63 KGRR 092351
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
651 PM EST Fri Jan 9 2026
.KEY MESSAGES...
- Snow Returns Saturday into Sunday
- Mild Break Monday into Tuesday
- Falling Temps Wednesday, Wintry End to Week
&&
.DISCUSSION...
Issued at 315 PM EST Fri Jan 9 2026
- Snow Returns Saturday into Sunday
An upper low is forecast to impact the Great Lakes Saturday into
early Sunday with cooling temperatures aloft allowing for some
snow production to occur. The upper low will be in the process of
deepening on Saturday, with weak surface low development over
Lower Michigan Saturday afternoon and some signal for lake
aggregate troughing over Lake Huron to aid the cause as the low
tracks overhead.
1000-700mb wind streamlines via the NAM12 and RAP13 indicate low
level southwest flow is favored from 12z-18z Sat, then W to NW
flow after that. Initially this will be a synoptic snow, likely
wet to start. Precipitation begins Saturday morning as either a
rain/snow mix or, more likely near and north of I-96, just snow.
Air temperatures and road surface temperatures in the low to mid
30s to begin the event (likely starting in the 7am-9am timeframe
on Saturday) will probably aid in some initial melting of what
falls on the ground, thus 100% snow accumulation efficiency is
unlikely initially. Cobb SLRs early on are between 5:1 to 10:1,
especially when looking at the 12z HRRR and GFS. Therefore, this
snow is likely to be on the wetter side of normal during the
morning to early afternoon hours Saturday.
As low level flow shifts more WNW to NW Saturday evening into
Saturday night and cold air advection aloft is underway, the lake
enhanced component begins, transitioning to lake effect. SLRs will
be higher during this time frame. Moisture depth and omegas look
good for this period with 1000-700mb lift on the order of 3-6
ubar/s with high RH. NAM12 lift within the DGZ looks locally
significant across our lakeshore counties from 03z Sun through
15z Sun. Bufkit soundings reveal deep moisture in place during
this time. The current expectation is for the region along and
north of a Muskegon to Big Rapids line to have the highest
probability of 4" or greater, where odds are as high as 75%. South
of this region, areas are unlikely to receive 4" or greater but
will still get some accumulating snow. As a result, have decided
to issue a Winter Weather Advisory from Muskegon to the north and
northeast for the expectation of 3"-5" of total snow from Saturday
morning through Sunday morning, locally 6" or greater possible.
Areas south and east of the Advisory should top out in the 1"-3"
range with locally 4" possible.
- Milder Monday into Tuesday
Upper heights build on Monday with 850mb WAA as temperatures at
that level are favored to get above 0C. Highs should top out in
the mid to upper 30s each day. However, upper troughing will be in
the process of reclaiming the pattern across the Great Lakes on
Tuesday and rain showers are in the forecast Tuesday morning and
afternoon as a weak surface cold front moves through.
- Falling Temps Wednesday, Wintry End to Week
The primary cold front that ushers in colder temperatures is
favored by ensemble guidance to move through sometime Wednesday.
This looks to be a pretty sharp boundary that moves through with
mid 30s ahead of it and teens to around 20 behind it. NBM washes
out the temperature gradient signal at this range, but
realistically this may be a case where temperatures drop 10 to 20
degrees in a few hours. Given a sharp upper trough moving in and
a tight low level thermal gradient along and behind the front
conditions may be conducive for rain showers quickly changing to
snow showers and possibly heavier bursts of snow as the front
moves through.
Ensemble guidance favors a more typical mid January setup by the
end of next week into the weekend with some deeper upper troughing
settling in and likely periods of lake enhanced or lake effect
snowfall.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 650 PM EST Fri Jan 9 2026
A restriction filled TAF period will continue through tomorrow.
Northwest flow continues but has slackened. MVFR cigs will
continue with a drop to IFR towards morning. There remains a
chance for FZRA/FZDZ between 07Z and 13Z before precipitation
slowly transitions to snow. Wet heavy snow which will allow for a
rain snow mix will bring periods of IFR cigs and vsbys at times
through 00Z Sunday. Between 16Z and 23Z Periods of LIFR cigs and
vsbys are possible in heaviest snow showers, especially if the
snow is melting and if there is any RASN mix lingering. These
conditions will affect all TAF sites west to east.
Another round of snow due to lake effect will set up tomorrow
night.
&&
.MARINE...
Issued at 315 PM EST Fri Jan 9 2026
The Gale Warning will be ending this evening as the worst of the
winds are over, but another gale event is possible by Sunday
morning. Will allow current headlines to expire before going into
another potential set for late in the weekend as strong NW flow
develops between 06z-12z Sunday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory from 7 AM Saturday to 1 PM EST Sunday
for MIZ037>039-043>045-050.
MARINE...Gale Warning until 7 PM EST this evening for LMZ844>849.
&&
$$
DISCUSSION...Hoving
AVIATION...Ceru
MARINE...Hoving
NWS GRR Office Area Forecast Discussion
