578
FXUS63 KGRR 250738
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
338 AM EDT Sun Oct 25 2026
.KEY MESSAGES...
- Sunday Morning Fog
- Cooler Monday-Tuesday, Then Warming Again
- Chances for Showers Late Week
&&
.DISCUSSION...
Issued at 338 AM EDT Sun Oct 25 2026
- Sunday Morning Fog
An overnight flow of near-surface moisture off Lake Erie is
resulting in another morning of dense fog, this time mainly east
of US-127, with patchy/shallow fog possible to the west. The REFS
has been handing fog probabilities fairly well the past few
nights. Fog potential Sunday night is lower given cloudier skies.
- Cooler Monday-Tuesday, Then Warming Again
A cold front sagging through on Monday will knock temperatures
down to closer to normal for Monday and Tuesday. Roughly, highs
are favored to be in the mid 50s in Central MI to mid 60s in
Southern MI. This front is likely to be dry, although there could
be light rain showers or sprinkles in Central MI Sunday night to
Monday morning.
There is good agreement among the ensembles for temperatures to
rebound Wednesday, back well into the 60s to around 70, as low-
level southwesterly flow on the backside of an eastern CONUS high
transports 10C 850 mb air overhead. There is the also good
potential for this relative warmth to persist through the end of
the week/month, though a minority of members (20 percent) cool off
highs into the 50s on Friday/Saturday with a deeper eastern
Canadian trough or weaker southeast CONUS ridge.
- Chances for Showers Late Week
About a 20-30 percent chance for rain showers amounting to less
than a quarter inch returns between late Wednesday and late
Thursday, with increasing midlevel moisture and a hint of
instability ahead of a weakening cold front. Still too soon to say
whether rain will affect Halloween or hold off until after,
though PoPs are presently around 40 percent for Saturday evening.
There is a fairly large constituency of ensemble member solutions
that brings a soaking rainfall (around 0.5 to 2 inches) in early
November, as the southern jet stream becomes more active across
much of the CONUS.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 143 AM EDT Sun Oct 25 2026
Areas of fog remain the main concern through 14 Z. At 06 Z, the
thickest fog can be seen on nighttime microphysics satellite
images vicinity east of JXN with a north-northwest movement. This
has been where the REFS has been picking up on the greatest fog
potential. Confidence is reasonably high in JXN being near
minimums much of the early morning. IFR mist or fog may be
relatively shallow or patchy at other terminals.
&&
.MARINE...
Issued at 338 AM EDT Sun Oct 25 2026
South-southwest winds 10-20 knots over Lake Michigan this morning
will bring 2-4 ft waves into the nearshore north of Grand Haven.
Some models including the HRRR have a potential for 20-25 knot
wind gusts from the north late tonight around Big and Little Sable
Points associated with a cold front. Waves could become hazardous
for small craft, around 3-5 feet, on Monday around Big and Little
Sable Points, though the greater potential will be over the open
waters as the wind direction will be north-northeast.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Dense Fog Advisory until 9 AM EDT this morning for MIZ067-074.
MARINE...None.
&&
$$
DISCUSSION...CAS
AVIATION...CAS
MARINE...CAS
NWS GRR Office Area Forecast Discussion
