818
FXUS63 KGRR 121125
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
625 AM EST Mon Jan 12 2026
.KEY MESSAGES...
- Mild with rain/snow chances through early Wednesday
- Colder with frequent light snow chances late week and next weekend
&&
.DISCUSSION...
Issued at 301 AM EST Mon Jan 12 2026
- Mild with rain/snow chances through early Wednesday
Today looks like it could be both the quietest and mildest day of
the foreseeable future for SW Lower. Typical cool season low clouds
are in place this morning, along with another layer of mid clouds
associated with a weak upper short wave riding north of the area.
The short wave will be exiting the region this morning, with ridging
building back in for a short duration. It looks like we are likely
to see at least some clearing this afternoon, with highs around 40
supported by 850 mb temps of around +2C.
The break of precipitation chances will be short as we see the next
short wave in the series come in around daybreak Tuesday on the WNW
flow aloft. This short wave is a little stronger than the one this
morning, and is a little further south for a more direct hit on the
forecast area. The mild air in place, along with more warm air
advection ahead of the wave supports more of the precipitation being
rain vs. snow.
We are not looking at a lot of precipitation as moisture is not all
that deep. The deeper moisture is ahead of the system with a likely
quick burst of mainly rain. Then we are likely to see the
precipitation go to more drizzle as moisture depth shrinks, and the
DGZ is not saturated. Liquid precipitation is likely to continue
until Tuesday evening/night as the colder air arrives. The column
should be all below freezing by daybreak Wednesday, and the DGZ will
become saturated once again.
- Colder with frequent light snow chances late week and next weekend
We will see much colder air arrive with an arctic front first thing
Wednesday morning. Good run to run consistency over the last 48
hours now has increased the confidence on this timing. It is all
driven by a strong ridge building over the Western U.S.. That in
return is dislodging the arctic air from Northern Canada, northwest
of Hudson Bay. 850 mb temps of around -19C will be aimed right at
the area, as will the strong upper wave supporting it. There is
likely to be a burst of snow with the arctic frontal passage, but
lake effect does not look favorable after the passage as the low
level flow will be offshore from the NNE. This continues right into
Thursday as ridging builds in for a period or so, with highs
struggling to hit 20F.
The pattern change to much more amplified flow will be mostly
complete with long wave troughing encompassing just about all of the
Eastern half of the country. We will see additional short waves dive
in over the region straight from the arctic region, and continue to
reinforce the cold air and keep snow chances in with the waves and
lake effect.
Exact timing and tracks of the waves this far out for Friday and
beyond is tough to pin down. What we do know is that we will be in
the prime area under cyclonic flow aloft and the upper cold pool to
support good lake effect chances for Friday and beyond. This pattern
is looking such that we will see snow chances everyday, and gradual
accumulations will begin to pile up with frequent nickel and dime
events for the western half of the forecast area, along with
prolonged colder than normal temperatures. That is about right as we
approach the climatological coldest time of the year.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 625 AM EST Mon Jan 12 2026
All of the terminals except KMKG and KGRR have seen the low clouds
from earlier lift north as of 1120z/620 am. We do expect the low
clouds to eventually lift north of KMKG and KGRR this morning, it
is just going to take a little while longer with the flow off of
the lake. We will then see just high clouds left through most of
the day. Winds are already gusty this morning, and the sunshine
will actually help mix some of the better wind down. We do not
see any changes coming with them until around sunset this evening.
Some mid clouds will come in overnight, but sites should stay VFR
through 12z.
&&
.MARINE...
Issued at 301 AM EST Mon Jan 12 2026
We have the ongoing Small Craft Advisory in effect for the current
wind event ahead of and behind the wave moving through the northern
Great Lakes. Our bigger concern is the strong Gale event that is
looking more and more likely late Tuesday into Wednesday. This looks
like a solid Gale, with even a small chance of some Storm Force
gusts. We are still a little ways out, so no headlines yet for this
event.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until midnight EST tonight for LMZ844>849.
&&
$$
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
NWS GRR Office Area Forecast Discussion
