158
FXUS63 KMQT 141116
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
716 AM EDT Fri Aug 14 2026

.KEY MESSAGES...

- Widespread moderate rain chances (40-60%) Saturday afternoon into
Sunday, along with low thunderstorm chances (15%) during the
overnight hours. Severe weather is not expected at this time.

- High temperatures are expected to be in the mid-70s to low 80s
into next week, with low temperatures in the 50s to low 60s.

&&

.DISCUSSION...
Issued at 257 AM EDT Fri Aug 14 2026

GOES-East Nighttime Microphysics RGB imagery over the UP this
morning shows a band of stratus over the south-central and some
isolated high cirrus elsewhere, but not much of any impact
elsewhere. While a few patches of fog cannot be entirely ruled out,
GLAMP guidance suggests probabilities of fog at any given place are
around 10 percent, so fog impacts should be minimal.

RAP Analysis shows 500mb ridge extending from the Gulf Coast to the
Northern Plains flanked by broad troughs over both the East and West
coast. The ridging advancing towards the Great Lakes will result in
high pressure extending over the UP today and as a result, enough
subsidence to keep chances of precipitation 10% or less today.

Attention turns upstream to a pair of troughs, a shortwave currently
in eastern Colorado and a broader trough currently in Alberta. These
troughs will each bring precipitation to the Upper Midwest and
northern Ontario regions, but neither individually track
particularly close to the UP, leaving the strongest forcing for
thunderstorms elsewhere. Additionally, the CO shortwave looks to
track directly south of the UP, interrupting the potential Gulf
connection of moisture transport to supply the Canadian trough.
PWATs still surge to around 1.5 inches, which is above the 90th
percentile of climatology, but the UP will miss out on the 2+ inch
PWATs that the HREF projects as far north as Green Bay. With
suboptimal forcing and moisture supply, the rainfall totals have
trended down slightly. LREF 75th percentile rainfall (so, a little
higher than the average solution) by Sunday evening is about a
quarter to a third of an inch, with the 90th percentile (reasonable
wettest scenario) still showing half to three quarters of an inch of
rain. On the dry end of scenarios, the 10th and 25th percentiles do
at least show measurable rain for the entire UP, but it may not be a
wetting rain as even the 25th percentile is around a tenth of an
inch or less. While any rainfall will be welcome to the UP which is
running a half inch to an inch below the August normal precipitation
pace, a little more precip would have been even more helpful. The
thunderstorm threat remains present, but unlikely to be severe as
Euro ensemble mean MUCAPE is around 100-350 J/kg, though peaking in
the overnight Saturday into Sunday period, so thunderstorms would
have to be well-forced and elevated in nature. With only moderate
shear (around 30 knots mean sfc-500mb shear), severe weather remains
unlikely.

While ensemble spread sharply increases on the pattern that follows,
it is generally expected that by Sunday evening and through Monday
night, ridging resumes in the wake of the trough, leading to dry
weather. Ensembles are beginning to coalesce around a deep 500mb
closed low in the vicinity of Hudson Bay that will send a trough to
the Upper Great Lakes Tuesday. While there is considerable spread in
the details, confidence in at least a wetting rainfall (0.1"/24hr)
has increased to 50-75%, with ridging behind the trough expected to
bring more dry weather for the back half of the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 715 AM EDT Fri Aug 14 2026

VFR conditions will prevail through the TAF period under high
pressure. Will continue to leave out mention of fog formation with
probabilities only around 10% (and if any vis/ceiling reductions
occur, they should be short-lived). Expect winds fluctuating from
the NE to the SE at around 5-10kts for the daytime hours before
becoming light again tonight.

&&

.MARINE...
Issued at 257 AM EDT Fri Aug 14 2026

Winds remain at or below 20 kt through this morning. As surface high
pressure settles over the Lake Superior vicinity this evening,
northeast wind gusts ramp up to 20-30 kt out of the northeast over
the far west end of the lake as the pressure gradient tightens with
developing low pressure to the southwest and winds funneling to the
east and west of the Bayfield Peninsula and Apostle Islands. Wind
gusts again relax sub-20 kt overnight into Saturday. Saturday
afternoon immediately east of the Keweenaw Peninsula, southeast wind
gusts to 20-25 kt will form ahead of an approaching disturbance.
Winds fall sub-20 kt as the disturbance passes, but reinvigorate to
near 25 kt northwesterlies over the east half of the lake behind the
front. Uncertainty then grows in the details, but winds are broadly
expected to remain sub-20 kt into next week.

&&

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

&&

$$

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