250
FXUS63 KGRR 201928
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
228 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 /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1156 AM EST Thu Nov 20 2025

Moisture trapped under an inversion in combination with the
unfavorable sun angle is keeping IFR to LIFR ceilings in place,
with a brief window of improvement to low-end MVFR likely late
this afternoon before IFR ceilings redevelop tonight. Periods of
LIFR are possible as well. Have favored short term model guidance,
particularly the NAMNEST which has handled this setup well over
the last 24 hours. After 12z, conditions slowly begin to improve
from west to east behind a cold front. MVFR fog also mixes out
this afternoon, before returning overnight.

&&

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

&&

$$

DISCUSSION...04
AVIATION...Thomas