095
FXUS63 KGRR 011912
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
312 PM EDT Sat Nov 1 2025

.KEY MESSAGES...

- Diminishing Showers and Patchy Fog Tonight

- A Few Showers Early Monday and Then Again Wednesday

- Rain and Wind Possible Next Weekend

&&

.DISCUSSION...
Issued at 312 PM EDT Sat Nov 1 2025

- Diminishing Showers and Patchy Fog Tonight

Scattered rain showers in proximity to a weakening surface low
and trough, near and south of I-96, will gradually diminish this
evening. A mix of clouds and clearing overnight will result in low
temperatures landing on either side of 32 degrees. Light winds
and moist air in the low levels tonight may favor patchy fog or
freezing fog development underneath areas with clear skies. The
consensus of short term guidance indicates areas between
Kalamazoo, Lansing, and Jackson may be most prone to fog
development.

- A Few Showers Early Monday and Then Again Wednesday

A couple shortwave troughs Mon and Wed, the first with an upper
level jet exit region, and the second within an entrance region,
will sharpen as they pass over the Great Lakes, resulting in rain
shower chances but amounts that won`t be very significant. Monday
morning`s rain chances, with a minor cold front extending from a
Hudson Bay low, will be greater in central to northern Michigan,
amounts topping out around 0.10 to 0.25 inches. Gusts to around 30
mph are also possible throughout Mon. There is greater ensemble
spread in rain amounts for Wed as an Alberta-clipper-like surface
low may deepen as it passes through the Great Lakes. There are
more ECE members offering a deeper low and a breezy day on Wed
compared to the GEFS, but still plenty of spread within the ECE
depending on low intensity and track. Rain amounts Wed plausibly
range from zero to a quarter inch with outlier amounts over a half
inch.

- Rain and Wind Possible Next Weekend

Ensembles generally paint active weather potential from Friday
through the weekend, as a seasonably deep low may intensify over the
Great Lakes, bringing periods of rain and gusty winds. However there
remain meaningful differences in the timing, track, and strength of
the low, resulting in a greater range of possible temperatures, rain
amounts, and wind speeds each day. Some instability may also be
present between Fri and Sat, so a thunderstorm cannot be ruled
out.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 102 PM EDT Sat Nov 1 2025

Cloud bases are chaotic across the area this afternoon.
Conditions will primarily be VFR through the period but the
combination of low-level cu development, showers, and a nearby
low/front are supporting some MVFR to IFR cloud bases. Confidence
is low in location and timing, but brief periods of MVFR and
lower ceilings are possible as a result through today and into
tonight. Winds will be mainly light and variable through tonight
with the low nearby. Winds shift to southerly and increase Sunday,
which also causes lake effect stratocu development to shift north
of the terminals allowing skies to clear somewhat. The
aforementioned showers may also lead to temporary MVFR visbys
through the afternoon. However with the sporadic and chaotic
nature of showers have kept the PROB30s/VCSH in place. There are
some signals for fog development tonight similar to last night.
Probability is too low in restrictions (10-20%) for TAF inclusion
now, but will re- evaluate with the 00z package.

&&

.MARINE...
Issued at 312 PM EDT Sat Nov 1 2025

Have issued a Small Craft Advisory south of Holland through this
evening. The compact low over Lake Michigan aided by mesoscale
enhancement from the ongoing convection has led to enough bursts
of wind to send waves into the 3-5 foot range in this region.
Expect that to continue into this evening before winds diminish.
Cannot completely rule out a waterspout under any rain showers
this afternoon given the cold air aloft, though with convective
cloud depths of only 13kft confidence is low.

Southwest winds increase later Sunday creating conditions
hazardous to small craft across the waters continuing into Monday.
Best chance of Gales is Sunday night/early Monday morning north
of Pentwater where a Gale Warning is now in effect. Isolated gales
are possible as far south as Holland, however given warm air
advection and poor low-level lapse rates, only a moderate chance
(30-50 percent) that we can mix gales down south of the Watch
area. Have gone with a high end Small Craft Advisory south of
Pentwater and will continue to monitor wind trends, especially
near Muskegon where the best chance of isolated gales will be.
Waves in excess of 10 ft are possible in addition to the gusty
winds. Conditions hazardous to small craft are likely to last
through at least Tuesday morning.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844-845.
     Small Craft Advisory from 4 PM Sunday to 7 AM EDT Tuesday for
     LMZ844>848.
     Gale Warning from 4 PM Sunday to 7 AM EDT Monday for LMZ849.

&&

$$

DISCUSSION...CAS
AVIATION...Thomas
MARINE...Thomas