711
FXUS63 KGRR 231837
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
237 PM EDT Fri Oct 23 2026
.KEY MESSAGES...
- Dense Fog Saturday Morning; Patchy Fog on Sunday
- Pattern Change ahead with chances for rain beyond midweek
&&
.DISCUSSION...
Issued at 157 PM EDT Fri Oct 23 2026
- Dense Fog Saturday Morning; Patchy Fog on Sunday
High pressure will continue dominate the weather pattern with
light winds and warmer air through the weekend. The light winds,
high pressure, clearing skies is a great recipe for morning fog.
There is some question if it forms later. However, the flow from
the east should allow for moisture to converge overnight and fog
to form across the region. Models remain consistent with highs 10
to 15 degrees above normal with Max temps in the upper 60s to low
70s across the lower Peninsula.
The flow will shift Saturday night into Sunday and this will
lessen the chance for fog development. However, given radiational
cooling, clearing skies and light winds overall, patchy fog will
be again possible Sunday morning, though it should be less dense
than Friday and Saturday.
- Pattern Change ahead with chances for rain beyond midweek
The upper level pattern has the high shifting southward and
flattening next week. However, sfc high pressure should remain
stout enough to keep any moisture bands to only effect the
northern half of the lower Peninsula Monday and Tuesday. The
ensembles diverge on timing but the cold front associated with a
low pressure system tracking from the Canadian Rockies to Hudson
Bay will likely bring cooler air into Michigan dropping highs
closer to normal, in the upper 50s to mid 60s.
Warm air advection midweek will correspond with a deepening
trough that will swing through the region and is the next chance
showers. Pwats are potent so about a quarter inch of rainfall is
possible.
Models continue to diverge after in the movement, timing and
postilion of the upper level pattern. So a continued low
confidence in the forecast for the end of next week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 147 PM EDT Fri Oct 23 2026
VFR conditions and light winds are expected through this evening.
However, another round of LIFR dense fog is expected at many
terminals overnight through tomorrow morning, particularly at LAN,
JXN, GRR, and MKG. 1/4 mile (or lower) visibilities can be
expected at times, and fog may be slow to diminish once again
tomorrow morning, but flight categories should improve to VFR by
late morning.
AT AZO and BTL, fog did not materialize last night or this
morning, and as such, but forecast confidence is low that these
areas will remain fog-free again tonight. Some MVFR fog has been
added to these terminals to represent the possibility of at least
some fog filling in this gap overnight tonight.
&&
.MARINE...
Issued at 157 PM EDT Fri Oct 23 2026
Fair winds and waves will dominate the pattern today. Another
round of fog will be possible Saturday and Sunday morning and may
affect the harbors and portions of the nearshore, mainly north of
Grand Haven. Southerly winds will increase tomorrow, upwards of 10
to 20 kots and will build waves to 2 to 4 feet north of
Whitehall, persisting into Sunday morning.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...JMC
AVIATION...BRC
MARINE...JMC
NWS GRR Office Area Forecast Discussion
