761
FXUS63 KGRR 011958
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
258 PM EST Thu Jan 1 2026
.KEY MESSAGES...
- Lake Enhanced Snow This Afternoon and Evening
- Snow Sunday Night into Early Monday
- Milder and Drier Much of Next Week; Wetter Late?
&&
.DISCUSSION...
Issued at 258 PM EST Thu Jan 1 2026
- Lake Enhanced Snow This Afternoon and Evening
Once again, the lake will be providing a boost to some synoptic
scale light snow moving over the region this afternoon and
evening. Observations across WI this afternoon indicate 1-2 miles
in light snow. Preexisting lake effect clouds and snow showers
here are perking up as deeper moisture (1000-700mb RH values
reaching 90-100%) moves in and periods of decent lift at and below
the DGZ occurs while the DGZ itself becomes nearly isothermal for
a depth of almost 10k ft through 00z (per 12z HRRR Bufkit
soundings at GRR). This is thanks to the synoptic scale moisture
and falling flakes above 5k ft into the lake modified boundary
layer. The deeper moisture and at least some modest lift hangs
around through about 03z before decreasing. Snow showers will
likely be fairly persistent until then although rates may top out
at a quarter inch per hour, maybe a half inch per hour under the
heaviest bands.
The current surface analysis shows wind convergence occurring near
and west of US 131. Low level convergence may help aid in some
snow shower intensity for a time this afternoon and evening. With
primarily WNW to W low level flow off the lake, some of the
steadier snow bands will likely be impacting Muskegon, Kent,
Ottawa, and Allegan Counties. After loading in the latest 12z high
resolution guidance, QPF amounts have nudged up along and west of
US 131 compared to the 00z guidance. Cobb SLRs are quite high for
sites such as BIV and GRR (30:1 or even close to 40:1 at times)
but WPC SLRs are lower (20-25:1), which we`re favoring at this
point. This produces 1"-2" through this evening with some spots in
the 2"-3" range. Given the areal average will likely be 1"-2"
total we are not planning on an Advisory, though slick travel is
likely for some areas given falling snow and temps in the teens
making road treatment more challenging. Allow extra time to reach
your destinations this evening.
- Snow Possible Sunday Night into Early Monday
It is looking more likely than not that the next system slated to
impact the region Sunday night into early Monday should stay all
snow, with Central Lower Michigan currently favored. A coupled
upper jet structure arrives as part of a coastal California
system moves toward the Great Lakes at a rapid pace between
Saturday and Sunday, arriving in the upper levels as seen on the
250mb upper jet plot and 500mb height/vort plot but also the
MSLP/precip fields. While 850-925mb temps try to make a run at
above 0C across Lower MI, the warm layer likely won`t get here
until after the precipitation ends. As a result this system will
likely just be a snow producer but can`t totally rule out some
light sleet or freezing rain across southern Lower MI if temps
aloft warm with subsequent model runs. ECE 24hr QPF 50th
percentile is showing 0.10"-0.25" along and north of I-96. ECE
probability for 1" or more of snow is 40-60% along I-96 and
80-100% along US 10. This won`t be a major snow producer but could
impact the Monday morning commute especially near and north of
I-96.
- Milder Next Week; Wetter Late?
Ensemble guidance is generally in good agreement regarding
moderating 850mb temps next week and some rising upper heights,
with an occasional shortwave ripple in the flow that could bring
light (mainly liquid) precip to the area. Highs are favored to
range from the mid 30s to low 40s. By Thursday into Friday, there
is some indication for a deep SW flow pattern trying to take
shape across the central CONUS and this could bring some anomalous
PWAT values to the area along with a risk for rain or mixed
precipitation by week`s end.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1236 PM EST Thu Jan 1 2026
Light snow will be working into west Michigan over the next couple
of hours. This will bring some visibility reductions with MVFR
and IFR conditions prevailing at times through the first 6-9hrs of
the forecast period. Once snow moves on...MVFR ceilings could
persist into mid to late Friday afternoon.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for LMZ844>849.
&&
$$
DISCUSSION...Hoving
AVIATION...Maczko
NWS GRR Office Area Forecast Discussion
