416
FXUS63 KGRR 171131
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
631 AM EST Mon Nov 17 2025

.KEY MESSAGES...

- Wintry Mix Late Tonight into Tuesday

- Rain Chances Thursday into Friday

&&

.DISCUSSION...
Issued at 240 AM EST Mon Nov 17 2025

- Wintry Mix Late Tonight into Tuesday

The shortwave trough currently over the rockies will ride the high
pressure ridge east into the southern Great Lakes late tonight
into Tuesday. We will be on the north side of the low with most of
the low level warm air advection and frontogenesis to our south,
however 700mb to 500mb frontogenesis, warm air and vorticity
advection will be our main source of lift. We will also have some
upper level divergence at the start of precipitation. Sounding
profiles show saturation from top down as it gradually eats away
at the dry air toward the surface. Dry air is more likely to be
overcome between the 4-7am timeframe. Initially temperatures
should be cold enough with cloud ice present for snow, but as we
continue into Tuesday morning the loss of cloud ice will come into
play. In that transition we could see a mix of snow, sleet, and
rain before transitioning to rain/drizzle. Dry conditions return
for Tuesday evening, but we`ll need to monitor the potential for
some lingering drizzle/freezing drizzle. Temperatures will be
around freezing during the morning before warming into the mid 30s
for the afternoon. Warm ground temperatures will limit
accumulations and the ice potential, but elevated surfaces could
become icy initially, especially if there is more sleet. A sharp
gradient between precipitation and no precipitation is likely with
this system, and a slight shift in track will impact
precipitation type and amounts. With the warmer temperatures the
10th to 90th percentile keeps snowfall amounts in the 0 to 1 inch
range with only a 20 percent chance of snow greater than an inch.
Any ice would be a light glaze.

- Rain Chances Thursday into Friday

As mentioned in the previous discussion the threat for heavy rain
has decreased due to the lack of phasing between the southern and
northern troughs. However, we still will see some rain Thursday
night into Friday morning with the northern trough moving
through. Afterwards the pattern becomes a bit more uncertain due
to the evolution of the southern trough. chances could linger into
the weekend or conditions could be dry, this is highlighted by
the low PoPs of 20 percent on Saturday.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 631 AM EST Mon Nov 17 2025

VFR conditions are expected today with some FEW to SCT clouds
around 4000 feet this morning. Northwest winds become light and
variable tonight and turn to the southeast into Tuesday morning.
Toward the end of the forecast period snow is expected to start
falling mainly after 9Z with AZO potentially seeing more of a
rain/snow mix. Snow is expected to melt as it hits the ground,
however light accumulations could occur on elevated surfaces with
temperatures around freezing.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 1 PM EST this afternoon for
     LMZ844>849.

&&

$$

DISCUSSION...RAH
AVIATION...RAH