740
FXUS63 KMQT 190817
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
417 AM EDT Tue Aug 19 2025

.KEY MESSAGES...

- Remnant drizzle and occasional fog persists today into tonight,
especially upslope from Lake Superior.

- Dry weather expected Wednesday and Thursday before the next
chances of showers and thunderstorms return to the UP Friday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 416 AM EDT Tue Aug 19 2025

GOES-East Nighttime Microphysics RGB imagery shows high, cold cloud
cover evacuating to the south and east of the UP this morning though
a considerable amount of low, warm cloud cover filling in behind.
Morning METAR reports show a similar weather picture across the UP,
light fog, drizzle, and low cloud ceilings. Despite the system
departing, plenty of remnant moisture remains, as NAEFS humidity
plots show surface humidity values over the 90th percentile of
climatology for this time of year. Throughout today, synoptic
conditions do not change much, with northwest flow at virtually all
levels above the boundary layer. With soundings showing dry air
aloft struggling to intrude into the lowest ~200mb, a persistence
forecast seems to be in order. While the hi-res guidance shows some
bands of light rain (likely forced by impulse shortwaves embedded in
the NW flow), have elected to go with a more broad-brush approach to
the PoPs today, as while a drizzly day (especially in the upslope
regions near Lake Superior) is expected, certainty in whether any
given location is actually able to have measurable (0.01+ inches) of
rainfall in a given hour is low (15-30%). Visibility should improve
somewhat throughout the day as the dew point separates at least a
little from the ambient temperature, though fog looks to return
tonight with little to no reduction in dew points expected. Expect
little variation in temperatures today and tonight, with high
temperatures today rising to around the 70 degree mark with lows
tonight falling to around 60. With high pressure around 1020mb
pushing into the Upper Great Lakes late tonight, the drizzle should
end UP-wide early Wednesday morning with breaks in cloud cover
becoming more common and cloud bases lifting some.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 302 PM EDT Mon Aug 18 2025

High pressure remains in place through midweek before ridge-riding
shortwaves cause the ridge to receded southwards by Friday. Expect
dry weather to persist to at least early Friday. Then, a deeper
trough and associated surface low move through Manitoba and Ontario
Friday into the weekend. This will bring in our next chances for
rain as a cold front sweeps through. Additionally, though a warming
trend is expected after through the mid-week, temperatures may turn
cooler than average next weekend behind the front.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 155 AM EDT Tue Aug 19 2025

Flight restrictions will persist well into this afternoon at all TAF
sites as low level moisture is slow to exit Upper Michigan. SAW is
currently being impacted the worst with LIFR conditions. And, IWD
and CMX could also deteriorate to IFR/LIFR by daybreak. Anticipate
the low cigs to persist through the morning with gradual improvement
to MVFR by early afternoon. IWD could see a return to VFR by late
afternoon being the westernmost TAF site.

&&

.MARINE...
Issued at 302 PM EDT Mon Aug 18 2025

Southeast winds of 15-25 kts across most of the lake, strongest
north central, continue into this evening. Winds gradually settle
below 20 kts through tonight from west to east as the pressure
gradient weakens. Winds then back northerly for Tuesday and become
variable through the remainder of the week as broad ridging over the
region keeps winds mainly below 20 kts. The next shot at widespread
20-30 kt winds arrives this weekend as a low pressure system tracks
to the north.

&&

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

&&

$$

SHORT TERM...GS
LONG TERM...BW
AVIATION...TDUD
MARINE...Jablonski