829
FXUS63 KMQT 131121
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
621 AM EST Thu Nov 13 2025

.KEY MESSAGES...

- Patches of black ice could form on untreated roadways over the
  central and western U.P this morning in areas where snowmelt
  occurred during yesterday.

- A Gale Warning is in effect for eastern Lake Superior for northwest
  34-40 knot winds through tonight.

- A gradual warm up to above normal temperatures is expected by
  this weekend.

- Saturday night into Sunday, 40 mph winds are possible in the Keweenaw
  and near Lake Superior (~50% chance).

- Next shot for precipitation comes Saturday, followed by lake
  effect snow showers into next week. Impacts are not expected
  at this time.

&&

.DISCUSSION...
Issued at 211 AM EST Thu Nov 13 2025

Lake effect clouds and light showers have been confined to mostly
eastern Upper Michigan overnight, which is providing most of the
south and west clear skies and a view of the aurora. Shower activity
has been trending down over the past few hours and this should
continue for the rest of the night as surface ridging builds into
Upper Michigan from the west. Temperatures have fallen into the 20s
and 30s where skies have cleared but have remained mostly in the 30s
where the cloud cover and shower activity has been more persistent.
Through the rest of the night, patches of black ice may form in the
central and west where snowmelt occurred yesterday.

Mid to upper level ridging currently extending north from the
Rockies will press east through the Plains and into the Great Lakes
through the remainder of the work week. This will continue the trend
of diminishing lake effect this morning and support mostly dry
conditions today and Friday. The surface ridge will slide through
the region this afternoon and tonight, which will also allow
upstream warm air over the Plains to stretch into the region. Expect
daytime highs to climb in the 40s today and then mid 40s to low 50s
Friday. Guidance continues to suggest temperatures Friday night
could remain above freezing across the forecast area (20% chance
west and ~70% chance east).

The eastward sliding ridge will also allow an upstream shortwave
currently pressing into British Columbia to slide eastward through
Canada. By Friday, the system`s surface low will lift into Manitoba,
then slowly through Ontario through Sunday. Guidance continues to
suggest the system`s cold front will swing through the forecast area
Saturday which will result in the next best chance for precip
Saturday morning and afternoon. It will also be followed by strong
cold air advection, on the order of ~15-20C in 24 hours per EC and
GFS deterministics. This and the lingering pressure gradient forces
over the region will make for breezy northwest winds Saturday night
into Sunday night, particularly in the Keweenaw and by Lake
Superior. Latest NBM suggests ~50% chance for 40+ mph winds in these
spots at the moment. As for the trailing lake effect, GFS and EC
soundings show a dry, inverted v signature in the post frontal
environment, which suggests snow accumulations won`t be significant
and impacts are unlikely to occur. This matches with their
accompanying ensembles which ping ~30-60% chance of 0.10 inches of
QPF across the east half`s lake effect snow belts in 24 hours. From
there, guidance continues to differ slightly on when the lake effect
will end. This appears most related to the spatial differences of
the next surface ridge building across the Northern Plains/middle
Canada Monday/Tuesday. Overall though, should lake effect continue
into Tuesday, impacts are not expected.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 621 AM EST Thu Nov 13 2025

VFR prevails at all sites through the forecast period. Winds will be
out of the west at 5 to 10 kt at IWD and SAW today until becoming
light and variable overnight. CMX will remain gusty today with
westerly gusts of 25-30 kt before also becoming light and variable
overnight tonight.

&&

.MARINE...
Issued at 211 AM EST Thu Nov 13 2025

Winds have slowly fallen over Lake Superior, but a few observations
continue to hit the low end gale category across the east half.
Given this, I opted to extend the far eastern zone in Lake Superior
through 12z this morning. Didn`t make any other changes to the
inherited Gale Warning though, and plan to let all warnings expire
at 12z. Expect winds to continue lightening through the day,
eventually falling below 20kts lake wide this evening.

Winds begin ramping up again Friday from the south as the pressure
gradient increases and a low level jet moves over the region.
Guidance continues to lack much consensus on the strength of the low
level jet, but all have narrowed in on a slightly later arrival,
which now matches the timeframe when the airmass aloft is just as or
warmer then the lake surface. This stable environment should make
mixing difficult or non-existent, so don`t believe gales will reach
the surface. However, 25-30kt winds could be common Friday evening
north and east of the Keweenaw.

The system`s cold front moves west to east through the lake
Saturday, followed by a strong cold air advection period Saturday
afternoon/evening through Sunday evening. This period still looks to
be the next best chance for gales given this airmass change and the
pressure gradient over the region. More ensemble members are
gravitating toward this idea as well, and the latest NBM
probabilities for at least 34kts has increased to 40-60% from the
areas surrounding the Keweenaw and east. There are questions about
the pattern beginning Monday, but these minor differences largely
suggest decreasing winds back to 20kts or less by Monday afternoon
lake-wide.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 7 AM EST this morning for LSZ265>267.

Lake Michigan...
None.

&&

$$

DISCUSSION...JTP
AVIATION...GS
MARINE...JTP