494
FXUS63 KAPX 071918
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
318 PM EDT Tue Oct 7 2025

.KEY MESSAGES...

- Frost in parts of northern MI tonight

- Colder Wednesday night with frost and/or a hard freeze for
  many

- End-of-week warmup looking somewhat uncertain

- Only minor precip chances until the weekend and next week

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 318 PM EDT Tue Oct 7 2025

Pattern/synopsis: Initial cold front has departed se-ward, and
associated rain has long since ended here. Band of clouds along
a secondary cold front is entering eastern upper MI this
afternoon.

Forecast: Colder and drier air will invade tonight, with 850mb
temps just below zero across the entire area Wednesday morning.
Dry advection and vertical mixing are both lowering dew points,
especially in the north; into the 30s now in many locales.
However, conditions are not ideal for radiative cooling tonight
(they will be better tomorrow night). The pressure gradient
will briefly relax in the vicinity of the boundary moving thru,
but then tightens for several hours tonight post-frontal. There
is some relaxing again after 06Z/2am, and that will leave
sheltered places with a sufficient window to decouple. Temps in
the low-mid 30s will be common by dawn in the eastern UP, and
the interior of northern lower MI.

Frost advisories have been posted for the eastern UP (not
including Mack/Bois Blanc Isl), all of ne lower MI, and part of
n central lower MI. Though the immediate coast of ne lower MI
should see limited, there is enough expected frost inland to
warrant the advisory. This extends all the way south to Gladwin
and Arenac Cos, though most frost is in the north half of those
counties.

As the colder air comes in, some lake response will generate
partial cloud cover into western Chip/Mack Cos, and into nw
lower MI, tonight and Wed morning. Only a shallow cu
field is expected after that, as the incoming chilly airmass
dries out further. This will be our first decisively below-
normal temperature in a while, and our coolest wx outright since
May. Highs will range thru the 50s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 318 PM EDT Tue Oct 7 2025

Surface high pressure moves overhead Wed night, and it is more
confident than tonight that we will see light winds and
relatively clear skies. Temps should plunge, several degrees
colder than tonight. A hard freeze is likely across the majority
of northern MI, with some coastal areas escaping. Min temps
lower into the mid, or even low, 20s in the interior cold spots.

Sw-ne oriented 500mb ridge axis will be overhead by late
Thursday. This will get us started on a temp rebound, though
Thursday night will be potentially chilly/frosty again (though
not as much as Wed night). However, models have a lot of
disagreement on a digging shortwave trailing the upper ridge.
The 12Z operational GFS and ECMWF have both trended in an
unpleasant direction with this system. Both carve out an upper
low directly over MI by Friday evening, and leave it in the
vicinity for much of the weekend. Though the GFS may be too
deep/cold with this system, the overall trend in the long range
is toward a cooler and potentially wetter weekend. The current
grids/forecast are only taking a step in that direction, which
is fair; there are plenty of solutions that have a much weaker
wave passing thru.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1259 PM EDT Tue Oct 7 2025

VFR through the period. Variable cloud cover across northern
Michigan early this afternoon with mid-high cloud over eastern areas
and some developing shallow cu west. A band of scattered mid-
cloud sagging into the eastern U.P. associated with a reinforcing
cold front expected to trek south across northern lower mid-
afternoon through mid-evening. Perhaps we can wring out a rogue
shower as a result, but not nearly enough confidence to include
in the TAF at this time. Otherwise, occasionally gusty northwest
winds will be the rule through the remainder of the daylight
hours with winds trending downward after sunset.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from midnight tonight to 8 AM EDT Wednesday for
     MIZ017-018-022>024-027>030-032>036-041-042-086>088-095-
     096.
MARINE...Small Craft Advisory until 1 AM EDT Wednesday for LHZ345>347.
     Small Craft Advisory from 11 PM this evening to 6 PM EDT
     Wednesday for LHZ348-349.
     Small Craft Advisory until 1 AM EDT Wednesday for LMZ342.
     Small Craft Advisory until 1 AM EDT Wednesday for LSZ321.

&&

$$

SHORT TERM...JZ
LONG TERM...JZ
AVIATION...MJG