Smyrna, Michigan Weather Forecast Discussion

784
FXUS63 KGRR 031746
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
146 PM EDT Fri Oct 3 2025
.KEY MESSAGES...
- Near record warmth and dry through Sunday
- Rain chances increase on Monday through Tuesday
- More typical fall air mass and dry conditions Wed-Thu
&&
.DISCUSSION...
Issued at 331 AM EDT Fri Oct 3 2025
- Near record warmth and dry through Sunday
More of the same conditions are expected to continue through Sunday
with dry conditions expected, and temperatures increasing a bit
to near record levels for the next three days.
We are seeing a subtle transition taking place over the region as
the upper ridge overhead for the first half of the week has shifted
east, and another ridge axis is taking shape to our west and will
move in to help bring our near record temperatures.
One caveat with this scenario is there is a weak trough between
these ridges, cooling the mid levels ever so slightly. Some of the
CAMs are indicating maybe a few showers forming toward Green Bay
late this afternoon, and maybe surviving the trip over Lake Michigan
tonight and bringing a non-zero chance of a shower to the Ludington
area.
The building upper ridge to our west moves over the area then for
Saturday. This will warm the mid levels, likely capping the
atmosphere. Low level moisture is on the increase, and some
mesoscale convergence is shown to possibly pop a shower. This is
another non-zero chance that maybe a small area would see it. 99% of
the area will stay dry, and quite warm with 850 mb temps climbing to
around 16C with the building heights. Sunday`s highs should be
similar even as 850 mb temps drop slightly. This is because we will
see better mixing with the ridge slipping east of the area.
- Rain chances increase on Monday through Tuesday
We will see rain chances slowly increase through the course of
Monday, but most areas will see one more day of warm and dry
conditions continue.
The cold front itself looks to move through most of the area during
the daylight hours. Models are generally showing the front making it
to the SE corner of the forecast area by sunset Monday. The front
itself will likely come through dry with a lack of deep moisture
ahead of the front. That is due to the extended period of ridging
over the area keeping the atmosphere dry, and with the flow not
really advecting much moisture ahead of the front, coming from the
SE U.S. vs. the Gulf.
Better moisture and large scale forcing will increase late Monday
for our NW area, and all of the area Monday night into early Tuesday
for the rest of the area. The better forcing comes in via upper
divergence under the RRQ of the upper jet streak to our north. In
addition, better moisture aloft comes in with moisture advection,
and with the fgen circulation near the front. Monday night and early
Tuesday looks like the best chance of rain in over a week, before we
dry out again.
- More typical fall air mass and dry conditions Wed-Thu
The front and the associated moisture/rain will all be swept out of
the area by late Tuesday as a northern stream long wave trough
sweeps through. In the wake of this system, we will see quite strong
subsidence set back up being downstream of the ridge over the
Plains.
Of more interest though is we will see much cooler temperatures
settle in over the area behind the Mon/Tue system. This air mass
will be quite a bit cooler, but actually near average. This just
puts into perspective how anomalously warm the current air mass is.
850 mb temps dropping down into the single digits C will be advected
down from the north ahead of a strong Canadian sfc ridge to our NW.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 146 PM EDT Fri Oct 3 2025
VFR is expected through tomorrow. Cumulus clouds bubbling up mid
day through late afternoon today and tomorrow will be based around
5,000 feet. Fog potential late tonight / early morning appears
low with 15-20 knot winds several hundred feet above ground.
&&
.MARINE...
Issued at 146 PM EDT Fri Oct 3 2025
A period of breezier south-southwest winds this weekend, prior to
the arrival of a cold front early next week, is expected to build
waves which will become hazardous to small craft along portions
of the West Michigan shore.
Saturday afternoon, at least 2-4 footers are likely north of
Whitehall. Waves increase Saturday night through Sunday night,
with 3-5 feet likely near and north of Holland, and 5-7 feet
likely north of Whitehall. It is possible in this pattern of air
warmer than the water (a little unusual for this time of year),
models are somewhat overdoing the winds and therefore also the
waves. Nonetheless, Small Craft Advisory conditions are
anticipated at least for Saturday night into Monday morning.
&&
.CLIMATE...
Issued at 331 AM EDT Fri Oct 3 2025
Once again, the current records are listed for the next three days,
when they will be approached, or likely exceeded at many sites.
Today, except for Lansing, forecast highs are mostly within a degree
of the current records at the rest of the sites.
Fri              Sat                 Sun
Grand Rapids    86 - 2023       87 - 1951         85 - 1946, 1922
Lansing         90 - 1898       86 - 1951, 1900   87 - 1922, 1900
Muskegon        85 - 2023       84 - 2023         83 - 2007
Kalamazoo       88 - 1953       90 - 1951         87 - 1922
Battle Creek    88 - 1953       87 - 1951         89 - 1900
Holland         86 - 1919       89 - 1951         85 - 2007
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...NJJ
AVIATION...CAS
MARINE...CAS
CLIMATE...NJJ

NWS GRR Office Area Forecast Discussion