665
FXUS63 KGRR 240748
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
348 AM EDT Sat Oct 24 2026
.KEY MESSAGES...
- Morning Fog
- Warm Weekend
- Cooler Monday-Tuesday
- Unsettled End of October
&&
.DISCUSSION...
Issued at 348 AM EDT Sat Oct 24 2026
- Morning Fog
Overnight observations and short term guidance gives fair to good
confidence in dense fog Saturday morning throughout much of Mid
Michigan including along US-127 and reaching portions of US-131.
There is some potential for the fog to expand west of US-131
mainly west of Kalamazoo and Grand Rapids. Similar to a couple
other fog events this week, the most widespread visibilities less
than a quarter mile may occur between 8 AM and 10 AM when the
winds around 500 feet relax. The fog and low clouds should mix out
and evaporate between 10 AM and noon, leaving the rest of the day
with some cirrus.
- Warm Weekend
Global ensemble systems and recent short term guidance continues
strong support for highs in the upper 60s to around 70 this
weekend, with a flow of mild air on the back side of high pressure
over the Northeast to Ohio valley. A light breeze and some
increased coverage of high clouds can also be expected.
- Cooler Monday-Tuesday
Ensemble spread has tightened up a little on cooler temperatures
Monday and Tuesday as a cold front sinks through the area. There
is still some spread in the expected highs with a range between
the mid 50s and mid 60s, depending the southward progress the
front makes before stalling. This cool down isn`t exactly
significant as it just brings temperatures closer to normal for
late October. The front is also favored to come through dry.
- Unsettled End of October
Ensembles have a good signal for high temperatures rebounding
into the 60s to near 70 on Wednesday ahead of a northern Plains
low. After Wednesday, there was a significant amount of spread and
lower confidence in the forecast depending on how that low would
phase with the northern jet stream, and at what longitude a large
scale trough within the northern stream would set up later in the
week. There was a variety of solutions for late in the week with
highs ranging between the 40s to near 70, however, recent cycles
have increased the membership of warmer solutions. There are
increasing chances for rain toward the end of the month, though
confidence in that remains relatively low for now.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 158 AM EDT Sat Oct 24 2026
ASOS/AWOS reports, satellite images, and area webcams confirm
LIFR fog development is underway at JXN and MOP, and is likely to
spread west/north through 14 Z. Short term model guidance has a
good signal for fog development affecting JXN, LAN, and BTL. GRR
and AZO will be on the western edge of the fog bank and it may
take a little longer for fog to develop there. There is lower
confidence for fog to reach MKG. Vis and/or cigs may be at or
below minimums. Similar to yesterday, about 15 knots of wind at
500 feet could delay fog development and instead result in 200 ft
cigs, but winds relaxing after 11 Z may result in more widespread
vis less than 1/4SM until it improves around 14 to 15 Z. After 15
Z, VFR and light south-southeast winds are expected.
&&
.MARINE...
Issued at 348 AM EDT Sat Oct 24 2026
There is a chance for an area of fog over Southwest Michigan to
move over the nearshore waters this morning. Otherwise, should
have good visibility with partly cloudy skies this weekend. South
winds strengthening today to 10-20 knots will build 2 to 4 foot
waves north of Muskegon, persisting into Sunday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Dense Fog Advisory until 10 AM EDT this morning for MIZ039-040-
045-046-051-052-057>059-065>067-072>074.
MARINE...Dense Fog Advisory until 11 AM EDT this morning for LMZ848-849.
&&
$$
DISCUSSION...CAS
AVIATION...CAS
MARINE...CAS
NWS GRR Office Area Forecast Discussion
