492
FXUS63 KGRR 202308
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
608 PM EST Thu Nov 20 2025

.KEY MESSAGES...

- Showers possible near cold front tonight

- Dry and mild through the weekend

- Rain changing to snow mid week, colder

&&

.DISCUSSION...
Issued at 228 PM EST Thu Nov 20 2025

- Showers possible near cold front tonight

Local radar shows light echos indicative of drizzle/fog moving
north across the cwa. 12z soundings match previous forecast
soundings in showing abundant low level moisture trapped beneath
an inversion near 840 mb. Short range models point toward this
inversion remaining in place overnight, resulting in areas of fog
and drizzle.

A cold front will drop south across Lower MI after midnight and
there may be enough convergence along the front to squeeze out a
brief shower. Otherwise, RH progs suggest the low cloud deck will
begin to thin around 12z from north to south.

- Dry and mild through the weekend

Ridging will build into the cwa Friday and keep any precipitation
from the low pressure system moving across the Ohio Valley south
of the cwa. We`ll see some sunshine develop from north to south as
the day progresses. Another weak cold front will move across the
cwa Saturday night but moisture is lacking and there isn`t any
cold air behind it. Riding will quickly build in from the west and
temperatures will rise; Highs in the lower 50s are expected Sunday
through Tuesday.

- Rain changing to snow mid week, colder

Models are showing some phasing between the northern and southern
streams early next week, such that a southern Rockies low rides
northward along a cold front moving east across the upper MS
Valley. Models show a compact short wave associated with the low
and showers (80 percent) are expected to develop late Monday and
continue into Tuesday. All of it will be rain. However, colder air
will wrap into the system as a strong short wave drops south into
the Great Lakes and any lingering rain showers will mix with and
turn to snow. This transition is a bit quicker than models
suggested yesterday. H8 temperatures fall from +4c Tuesday night
to -8c by Wednesday evening.

ECMWF ensembles show the middle of next week as the transition to
a colder pattern continuing into December.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 608 PM EST Thu Nov 20 2025

Moisture remains trapped under the robust inversion this evening
leading to IFR and lower conditions for much of the night into
Friday morning as a result of low stratus and areas of
fog/drizzle. A period of LIFR ceilings is possible (20-30
percent) at all TAF sites from roughly 06z-12z, with the best
chance at AZO/BTL where TAFs have been adjusted down to borderline
LIFR conditions tonight. A cold front crossing the terminals
Friday morning will lead to improving ceilings over the course of
the morning, with RH progs suggesting TAF sites should reach VFR
by the early afternoon.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...04
AVIATION...Thomas