Area Forecast Discussion
Issued by NWS Marquette, MI

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725
FXUS63 KMQT 161137
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
737 AM EDT Thu Oct 16 2025

.KEY MESSAGES...

- Seasonable temperatures today followed by a warm start to this
  weekend.

- Rain chances increase late today and continue into the weekend.

- A few southerly gale force gusts to 35 knots are possible
  tonight along the southern Lake Superior downslopes.

&&

.DISCUSSION...
Issued at 255 AM EDT Thu Oct 16 2025

As high pressure continues to retreat from the U.P. today, expect
clouds to move in throughout the day from the west and southwest as
a warm front approaches from the Upper Mississippi Valley. While we
may see some areas of fog over mainly the central and east early
this morning, expect it to erode away a couple of hours after
sunrise. With seasonable antecedent air over us ahead of the warm
front today, expect highs to be around to just above normal, getting
into the upper 50s to around 60 across most of Upper Michigan; the
incoming cloud cover from the warm front will help keep temperatures
from rising any further as most of the area looks to be mostly
cloudy to overcast by late this afternoon. However, it looks like it
may take a bit for rainfall to begin hitting the sfc, as the
antecedent dry-ish air from the retreating high pressure will first
need to be overcome. Thus, thinking rain shower chances may be kept
at bay until the mid afternoon hours over the far west, with the
rest of the U.P. waiting until late this afternoon to this evening
before seeing the first measurable rainfall. Most of the best
forcing and frontogenesis along the warm front looks to miss the
U.P. to the north this afternoon and evening, meaning that the
greatest chances for rainfall will be near Lake Superior and the
Keweenaw. However, given the unseasonably high PWAT air (near the
max of modeled climatology according to the NAEFS), we could still
see light rain chances over the southern U.P. too this evening
before we get dry-slotted Friday morning.

As we remain dry-slotted Friday, IVTs from the European ensemble and
NAEFS shows an anomalously strong signal of moisture being advected
in from the Gulf. As this occurs, expect dewpoints and temperatures
to rise well above normal on Friday, with high temperatures reaching
the lower to mid 60s in the east to the lower 70s in the west. As a
cold front pushes in from the west late Friday, expect showers and a
few thunderstorms to develop ahead and along the frontal line Friday
afternoon through Friday night. With guidance nudging the better
forcing and rain chances to the south and east, rainfall chances
have decreased to around 20 to 40% over the western U.P. Friday
afternoon, whereas the east half has a 50 to 80% chance for rain
showers and potentially a few thunderstorms Friday evening. As the
cold front stalls by Saturday, we could see another shortwave low
lift through Lower Michigan and bring additional rainfall to the
eastern U.P. as guidance is still trending the track of the low a
little further south and east; solutions like the Canadian even
keeps rainfall from even hitting us for the most part from Saturday
morning through the rest of the weekend. That being said, the
deterministic GFS still remains the outlying solution, bringing the
low much further north and causing rain to fall across the entire
U.P.. As the low deepens and lifts into the Upper Great Lakes, we
could see some wrap-around rain showers develop over the area; the
further north the track of the low, the further west in extent over
the U.P. the wrap-around showers will go; the further south and east
the track of the low, the further east the wrap-around showers will
be limited to. As the low pulls away on Sunday, expect the cold air
advection behind it to bring breezy conditions across the U.P. as
mixing should be robust (this is aided by the clearing skies behind
the low).

Moving into early next week, guidance has converged on dry
conditions for early Monday as a high pressure ridge is projected to
move through the Upper Great Lakes around that time. However, as the
high pressure is quickly replaced by a troughing pattern moving in
from the Plains late in the day, we may see some rain chances
return, although there is currently high uncertainty on the
placement and timing of shortwave lows moving through the Upper
Midwest and Plains at this time. That being said, model guidance is
now converging on a solution where a low deepens over or near the
Upper Great Lakes around mid next week; should this occur, we may
see a couple of days of lake effect or lake enhanced rain showers as
well as breezy conditions from the middle to end of next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 737 AM EDT Thu Oct 16 2025

Clear skies prevail across most of Upper Michigan beneath surface
high pressure centered over eastern Lake Superior as of 12z Thu.
Infrared satellite imagery shows the leading edge of cloud cover
spreading into the western UP ahead of a warm front lifting through
the Northern Plains and Upper Midwest, with upstream obs over
northern and western WI showing cigs mainly around FL040-060. Cloud
cover will continue to spread into the area today, with conditions
initially expected to remain VFR for the most part. Rain arrives at
IWD as early as 17-18z Thu, but should become more prevalent by 21z
as the warm front draws closer, with southerly winds increasing to
~20 kt. Rain and gustier winds then spread into CMX after 21z and
SAW after 00z Fri. For the most part expect VFR to prevail through
the period, but could see a few bouts of MVFR as latest
probabilistic guidance depicts a 20% chance for MVFR cigs at IWD and
a 40-50% chance at CMX. Any MVFR cigs will likely hold off at SAW
until after 06z Fri. The arrival of a strong southwesterly LLJ will
bring a chance for LLWS to IWD and CMX beginning towards the end of
the TAF period, with model soundings showing winds increasing to 40-
50 kt at FL020 after 03z Fri.

&&

.MARINE...
Issued at 255 AM EDT Thu Oct 16 2025

As high pressure retreats today in the wake of an approaching warm
front, expect the light winds over Lake Superior this morning to
eventually give way to southeast to southerly winds of 20 to 30
knots over mainly the eastern half of the lake by this evening as
the front moves overhead; while not expected frequently, we could
see some gale force gusts up to 35 knots from time to time tonight
along the downslope areas of the southern shoreline (up to as high
as a 50% chance). The strong southerly winds continue through Friday
over the eastern lake behind the warm front and ahead of the
approaching cold front from the west. As the cold front pushes
through Friday night from west to east, we have a 30 to 70% chance
of seeing gales up to 35 knots along the frontal boundary (the
highest chances are over the western lake), with winds progressively
veering westward behind the front Friday night. Behind the cold
front, the southwest to west winds weaken to 20 to 30 knots by
Saturday morning, being strongest between the Keweenaw and Isle
Royale. As another shortwave low lifts through Lower Michigan this
weekend, we could see winds increase Saturday night into Sunday
depending on how far north the low tracks; if it tracks further
north towards Lake Superior, expect the winds to be more
north/northeasterly and stronger; if it tracks further south and
east away from the lake, expect weaker, more northwesterly winds. As
the low lifts away from the Upper Great Lakes on Sunday, the cold
air advection behind the shortwave low could produce strong
northwest winds of 20 to 30 knots or even gales of 35 to 40 knots;
again, though, the strength of the winds behind the shortwave low
will depend on its track, with a closer track to Lake Superior
bringing stronger winds. As ridging moves back through the Upper
Great Lakes Sunday night to Monday morning, expect the winds to
generally calm down to 20 knots or less by Monday morning.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

DISCUSSION...TAP
AVIATION...CB
MARINE...TAP