589
FXUS63 KGRR 201843
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
243 PM EDT Tue Oct 20 2026
.KEY MESSAGES...
- Dry and mild weather to continue through Sunday
- Rain chance arrive Monday with a pattern change starting Tuesday
&&
.DISCUSSION...
Issued at 243 PM EDT Tue Oct 20 2026
- Dry and mild weather to continue through Sunday
High pressure continues to dominate the weather over the region as
it has for the past few days. The upper ridge axis remains to our
west, allowing for plenty of subsidence to keep even cloud cover
limited across the area.
We do see one small caveat in the clear and dry weather, with little
to no impact expected. There is an upper trough across Canada that
spills over the ridge and drops down over the Lower Great Lakes
Wednesday night into Thursday. A weak front drops through our area
at that time. There is very little moisture associated with this
front, as the flow will be from NE Canada initially, and then the
Wisconsin area. Neither of these will advect any moisture in, so a
dry frontal passage is expected.
The only thing this frontal passage will do is drop temperatures a
couple of degrees temporarily. 850 mb temperatures drop from +9C on
Wednesday, to +6 to +7C on Thursday. This will take max temps from
around 70F on Wed, to mid 60s Thu and Fri. Temperatures will then
recover a bit for Saturday through Monday as the low level flow
becomes from the SW again. Highs will approach 70F once again on
Sunday before clouds and rain chances appear on Monday.
- Rain chances arrive Monday; Pattern change starting Tuesday
As mentioned above, a front will start to approach the area on
Monday. This occurs as a strong upper low moves across Canada. The
front initially slows down as it becomes parallel to the upper flow
with the low so far north, and due to how much the strong ridge has
to be flattened.
It will take another strong upper trough diving in from the NW to
push the front through around Tuesday of next week. This does not
look to be a major rain producer for the area as it will once again
not have a good moisture source to pull from.
What the front will do however is bring much cooler air down, with
the upper wave coming in from NW Canada. Models are showing 850 mb
temperatures dropping down to below zero in the wake of this system.
Definitely much cooler than this week.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 124 PM EDT Tue Oct 20 2026
Clear skies will continue through the period. Fog is possible
along the I-94 terminals after 09z, but will burn off shortly
after sunrise.
&&
.MARINE...
Issued at 243 PM EDT Tue Oct 20 2026
We are looking at no wind/wave headlines for the rest of this week
with the tranquil weather to continue. High pressure remaining in
control of the area will keep winds under 15 knots likely through
Friday.
Winds will increase late on Saturday and Saturday night out ahead of
a slow moving front approaching from the NW. These will be warmer
winds coming from the SW, which should limit the wind at the
surface. We do expect they will become high enough and build waves
sufficiently to require a Small Craft Advisory at some point.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...NJJ
AVIATION...04
MARINE...NJJ
NWS GRR Office Area Forecast Discussion
