127
FXUS63 KGRR 150800
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
300 AM EST Wed Jan 15 2025

.KEY MESSAGES...

- Snow showers diminishing today

- Light snow tonight into Thursday then milder through Friday

- Arctic air and light snow showers first half of next week

&&

.DISCUSSION...
Issued at 300 AM EST Wed Jan 15 2025

- Snow showers diminishing today

Light westerly flow lake effect snow showers will continue in
progress this morning with h8 temps of -14 to -16 C yielding
delta t/s in the upper teens. However they will gradually diminish
through the day as upper flow becomes anticyclonic as upper
ridging builds in.

- Light snow tonight into Thursday then milder through Friday

The combination of sw flow waa/moisture advection and upper
shortwave moving in from the nw will combine to bring light lake
enhanced synoptic snow tonight into Thursday morning. Light
accumulations of mostly around an inch or less are expeted near to
east of US-131.

Amounts closer to two inches are expected west of US-131 due to
some lake enhancement and isolated totals to near three inches are
possible. A brief period of dz/fzdz may occur Thursday aftn as
the dgz becomes unsaturated as deeper moisture moves out. Overall
though any impacts from this system should be minor and we do not
anticipate needing any headlines for this relatively weak system.

High temps by Thursday and Friday will reach the low to mid 30s
before a cold front moves through Friday night with colder air
to follow beginning Saturday.

- Arctic air and light snow showers first half of next week

A medium range guidance consensus and ensembles continue to
indicate an arctic airmass will move in Sunday through the middle
of next week. H8 temps will get down to -24 to -26 C by Monday
into Tuesday. As such high temps both days will be in the single
digits to near 10 degrees above zero. Any snow accumulations early
next week will be light given the dry and very cold arctic
airmass in place. Snow microphysics at temps this cold will favor
very small snow crystal structures in the form of mostly plates
and columns rather than larger dendrites.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 117 AM EST Wed Jan 15 2025

As winds have backed to the west off of Lake Michigan,
stratocumulus clouds have surged into Western Lower Michigan. At
06Z, the low clouds (MVFR) have surged through all the TAF sites
with the exception of LAN and JXN. By 09Z or so, the clouds will
likely have moved into those sites as well. Some light lake effect
snow is occurring with GRR recently dipping to 5SM. The bulk of
the lake effect snow is flurries with little to no reduction to
visibility.

Through the course of the day we will see winds shift to the
southwest which will likely bring AZO, BTL, JXN and possibly LAN
back to VFR. A fairly typical setup for Western Lower Michigan in
the winter today with lake stratocumulus and flurries.

Tonight a warm front will bring snow back into the area and
provide lowering ceilings and visibilities. MKG will be the most
impacted within this TAF time frame. Snow and deteriorating
conditions can be expected between 03Z-06Z tonight at MKG.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EST Friday for LMZ844>849.

&&

$$

DISCUSSION...Laurens
AVIATION...Duke