250
FXUS63 KGRR 042240
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
640 PM EDT Sat Oct 4 2025

.KEY MESSAGES...

- Near-record highs and dangerous swimming conditions through Sunday

- Rain chances and a cooldown arrive Monday and beyond

&&

.DISCUSSION...
Issued at 317 PM EDT Sat Oct 4 2025

- Near-record highs and dangerous swimming conditions through Sunday

Our weather pattern continues to be dominated by a large high
pressure system centered over the eastern CONUS. Widespread
cloudiness is hard to come by around the Great Lakes as strong
subsidence continues to keep conditions mostly sunny and dry. Some
fair wx cu fields have developed over Indiana, Ohio, and Lower
Michigan as of this writing. It`s neat to see the lines of diurnal
clouds matching the anti-cyclonic flow pattern that is occuring at
the low and mid levels of the atmosphere. An upper low ejecting into
the high plains is coincident with a cold front draped across the
area and up into Canada... with this whole complex slowly moving
eastward. While this will eventually make it to our part of the
world, the rest of today and Sunday will feature plenty of sunshine
and unseasonably warm temperatures. Most locations in Lower Michigan
will be close to record high temperatures both today and again
tomorrow, with at least 1 record high (Lansing) having recently
occurred. For more info on record highs today and tomorrow, see
the climate section below.

Meanwhile, the pressure gradient across Michigan is slowly
tightening up, resulting in some gusty south/southwest winds today.
This will become even more pronounced tomorrow as the cold front
starts to make more progress toward the Great Lakes. With another
hot and sunny day on track for tomorrow, beaches will be more
popular than normal for October, and swim risks will climb quickly.
For more information, see the Marine section below. Another risky
element of this unusual weather pattern will be the hot and windy
conditions leading to elevated fire danger - which is especially
strange considering the time of year. While conditions will not be
bad enough to warrant a Red Flag warning, concern is definitely
elevated as any fires that do start will have the potential to
spread quickly. Please continue to exercise caution with campfires,
and as always heed any local burning restrictions.

- Rain chances and a cooldown arrive Monday and beyond

The cold front arrives during the day Monday, bringing a good chance
of rain to most of the area along and ahead of the front. With a few
hundred joules of MUCAPE in the area, and with decreasing subsidence
aloft, several lines of showers and non-severe storms seem likely
from Monday afternoon through Tuesday morning. Ensemble guidance
shows an approx 30% chance of exceeding 0.50" widespread rain
totals, though if some training of thunderstorms can occur some 1-2"
rain totals are not impossible. With worsening drought across the
area, any rains that we can get will be beneficial.

Temperatures cool down closer to normal with highs in the 60s or low
70s for the midweek and beyond period. Another chance for rain
arrives late in the week as the overall flow becomes more zonal -
allowing shortwaves to move quickly from west to east, but specific
confidence in timing or rain amounts is low. The main takeaway at
this point should be that we`ll be moving into a period with better
periodic rain chances compared to the dominating blocking high
pressure we`ve had for much of the last week.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 640 PM EDT Sat Oct 4 2025

VFR conditions are expected over the next 24 hours as a dry
airmass remains in place across the region. Lingering diurnal Cu
will diminish within an hour or so with clear skies favored
overnight. Scattered high clouds are forecast across the region
late in the TAF period. Light southerly winds are expected
overnight before increasing from the south/southwest Sunday. Winds
of 10-15 knots are favored with gusts to 20 knots inland and 25
knots at MKG due interactions along the lake/land interface.
Gusty conditions should then continue through the remainder of the
TAF period.

&&

.MARINE...
Issued at 317 PM EDT Sat Oct 4 2025

Will be issuing a Small Craft Advisory/Beach Hazards Statement for
the late Sunday Morning through early Monday afternoon timeframe.
Increasing south to southwest flow will drive gusts to around 25 kts
north of South Haven and waves of 3-6 feet north of Holland.
Increased concern exists with the well above normal temperatures
increasing beach traffic above normal for the time of year given the
expectation for dangerous winds and waves. These same temperatures
do provide some uncertainty as to how strong will gusts be but with
strong gradient winds at minimum waves will be a hazard. Gradient
winds decrease into Monday causing a brief period where winds and
waves subside. Tuesday into Tuesday Night a period of increasing
north winds is expected behind a cold front. This may bring an
additional round of hazardous winds and waves, particularly south of
Holland.

&&

.CLIMATE...
Issued at 317 PM EDT Sat Oct 4 2025

With one record already set (88 in Lansing today sets a new record),
more may follow. For reference, here are the established high
temperature records across our area for both Saturday and Sunday.

                  Sat                 Sun
Grand Rapids    87 - 1951         85 - 1946, 1922
Lansing         86 - 1951, 1900   87 - 1922, 1900
Muskegon        84 - 2023         83 - 2007
Kalamazoo       90 - 1951         87 - 1922
Battle Creek    87 - 1951         89 - 1900
Holland         89 - 1951         85 - 2007

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from Sunday morning through Monday
     afternoon for MIZ037-043-050-056.
MARINE...Small Craft Advisory from 10 AM Sunday to 5 PM EDT Monday for
     LMZ845>849.

&&

$$

DISCUSSION...AMD
AVIATION...Thomas
MARINE...Thomas
CLIMATE...AMD