303
FXUS63 KGRR 261848
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
248 PM EDT Mon Oct 26 2026
.KEY MESSAGES...
- Cool and dry again tomorrow
- Warmer mid-week, with shower chances Thursday
- Rain chances steadily increase this weekend onward
&&
.DISCUSSION...
Issued at 131 PM EDT Mon Oct 26 2026
- Cool and dry again tomorrow
In spite of the persistence of anomalous ridging aloft,
temperatures are a bit more seasonable this afternoon behind this
morning`s weak cold front, albeit technically still a few degrees
above average overall. We`ve also seen a modest increase in cloud
cover across primarily the northern lower peninsula thanks to a
plume of mid-level moisture, but this has largely remained to our
north, and is not producing any precipitation aside from a few
pockets of virga. Overnight, surface winds will slowly veer to the
east, which should maintain weak cold air advection and lead to a
chilly morning in the mid 30s to low 40s, in spite of some lingering
cloud cover. Surface winds will continue to slowly veer to the
southeast tomorrow, but cooler low level air will remain in place
for one more day of seasonable, fall-like temperatures.
Precipitation is also not expected tomorrow as we await another
weak cold front late Wednesday and Thursday.
- Warmer mid-week, with shower chances Thursday
Between Wednesday and Thursday, a synoptic scale ridge aloft will
remain firmly in place across the eastern U.S., and a weakening
shortwave and associated surface low will move around its
periphery across southern Canada. This will bring the return of
south to southwesterly winds and modest warm air advection
Wednesday, followed by a diminishing cold front Wednesday night
and Thursday. The former is expected to drive another warming
trend and bring temperatures back to comfortably average values
Wednesday afternoon (low 70s). Meanwhile, confidence is increasing
that the weakening front will bring a round of light showers to
the area Thursday, although precipitation amounts should be quite
modest (10-30% chance of more than 1/4 inch). There remain some
hints of very weak instability as well, so we can`t rule out a
weak rumble of thunder or two, either. Similarly warm temperatures
can also be expected Thursday, although perhaps a few degrees
cooler thanks to the increasing cloud cover.
- Rain chances steadily increase this weekend onward
Confidence in the day-to-day details decreases considerably Friday
onwards, thanks to the gradual development of a more unsettled
pattern and increasingly divergent ensemble members. The
aforementioned weak cold front is expected to sink south of the
area sometime Thursday, but anomalous ridging aloft will be
difficult to dislodge over the weekend, and this front will
likewise not be followed by a significant surge of cooler air.
However, shortwaves will continue to impinge on the western
periphery of the ridge over the weekend, and shower chances are
expected to increase in kind. While this gradual pattern
shift does favor an overall increase in precipitation chances over
the weekend, confidence in the timing details remains is very
low, and ensemble probabilities peak at only 30-40% on Sunday.
This does leave open a low-end potential (20-30%) for rain on
Halloween (Saturday), although currently rain remains slightly
favored on the following day.
Early next weekend onward, there continues to be in increasing
signal for a deeper wave and associated storm system, although
cluster analysis reveals drastic differences in the timing and
strength of such a system at this time range (8+ days out).
While we may not be able to nail down the daily specifics just
yet, confidence is relatively high that our current pattern will
break down sometime next week, bringing the return of more active
weather and increasing rain chances.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 114 PM EDT Mon Oct 26 2026
Scattered to broken mid/high clouds will continue across the
terminals through the period. Light northeast winds will shift to
the east by Wednesday morning.
&&
.MARINE...
Issued at 131 PM EDT Mon Oct 26 2026
North-northeast winds are expected to increase to between 15 and
25 kt in the vicinity of Big and Little Sable points early this
afternoon, and weaken again gradually this evening and overnight.
While a slight offshore wind component will keep the strongest
winds and steepest waves in the vicinity of the points themselves,
steep waves of 2 to 3 feet should be common in the nearshore
waters, with larger waves approaching 5 feet near the points. As
such, a Small Craft Advisory has been issued for a brief window
from 2 pm to 8 pm today. Winds will weaken and turn even more
offshore overnight, allowing waves to settle. Waves are likely to
build again late Wednesday and Thursday thanks to breezy onshore
southwesterly winds.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ848-849.
&&
$$
DISCUSSION...BRC
AVIATION...04
MARINE...BRC
NWS GRR Office Area Forecast Discussion
