401
FXUS63 KMQT 070744
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
344 AM EDT Mon Jul 7 2025

.KEY MESSAGES...

- Cooler, more seasonable, temperatures return to the Upper
  Peninsula for the work week.

- Rain showers and a few thunderstorms return Tuesday.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 343 AM EDT Mon Jul 7 2025

Early morning satellite imagery across the Upper Great Lakes reveals
mostly clear skies under sprawling surface high pressure extending
southward from James Bay atop Lake Superior. Observations across the
UP have cooled to the upper 40s/low 50s. Some patchy fog may develop
prior to sunrise, otherwise another quiet day is expected to kick
off the work week as largely zonal flow aloft keeps sfc high
pressure overhead. Winds are expected to remain light, under 10 kts,
and generally out of the north save for direction changes influenced
by afternoon lake breeze development. Look for high temperatures to
peak in the 70s area wide with cooler conditions in the upper 60s
along the Lake Superior shorelines. Seasonable lows follow tonight
in the 50s, though incoming cloud cover in the west half may keep
lows a tad higher near 60.

Weak ridging/zonal flow aloft breaks down late into early Tuesday as
a shortwave ejects eastward out of the Northern Plains, potentially
providing two rounds of showers and thunderstorms. The first round,
mainly driven by weak isentropic ascent, will enter the far west
sometime Tuesday morning with individual CAM guidance varying on the
exact timing. This first round continues east and largely peters out
across the central UP. Confidence is lower on how the second round
progresses along a cold front / lingering outflow boundaries, and
CAMs struggle even more with where redevelopment will occur across
the central third. Latest HREF guidance suggests meager diurnal
instability (500-1000 j/kg of MUCAPE) building ahead of the second
round sometime Tuesday afternoon and marginal shear ~25-35 knots, so
cannot rule out some gusty thunderstorms. Additionally, no hydro
concerns expected with PWATs only climbing as high as 1-1.3" and
latest LREF guidance suggesting a 50-80% chance for QPF >0.25 in the
west-central.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 343 AM EDT Mon Jul 7 2025

Following this passing shortwave, ensemble and deterministic
guidance continue to show another trough digging into the Great
Lakes Wednesday out ahead of a ridge extending from the Plains into
central Canada. However, soundings are quite dry, so little more
than lingering cloud cover is expected from this secondary trough.
Afterwards, deterministic and ensemble guidance are in more
agreement on the Plains ridge moving over our region Thursday,
perhaps flattening some into Friday ahead of our next trough/frontal
system moving out of the Canadian Rockies later Friday into the
weekend. This would favor dry weather Thursday at least into early
Friday before chances for showers/storms move back in next weekend.
By Friday afternoon, deterministic and ensemble guidance show a
couple of features (a weak shortwave moving out of the Central
Plains and a deeper trough moving out of the Canadian Prairies)
phasing over the Upper Midwest. PoPs work back into the area Friday
with warm advection out ahead of the system, lingering into Saturday
as the cold front sweeps through. Severe parameters are also
lackluster with this next system, with just a few hundred j/kg of
CAPE and around 20-30kts of bulk shear. Guidance diverges after
Saturday, with some of the guidance showing the system becoming
vertically stacked and meandering over the Great Lakes, and others a
little more progressive. This will keep in at least some low-end
chances for lingering showers/thunder into the end of the forecast
period.

Otherwise, look for temperatures to come in more or less seasonal
through the coming week with highs ranging generally in the 70s and
lows in the 50s. Thursday and Friday are looking like the warmest
days of the week as temperatures in the interior peak in the lower
80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 118 AM EDT Mon Jul 7 2025

Under high pressure, VFR conditions with light and variable winds
will prevail at all terminals throughout this TAF period. FG
formation is only about 10 percent likely at any of the terminals
this evening. The only chance for disturbed weather will be in the
late evening hours of Monday evening when a front will approach IWD,
bringing 20-30 percent chances of -RA and about 15 percent chances
of TS.

&&

.MARINE...
Issued at 343 AM EDT Mon Jul 7 2025

Winds and waves will remain light, mainly from the north, today as
sfc high pressure becomes planted overtop the lake. South winds
develop early Tuesday ahead of a weak low pressure before veering NW
behind a cold front Tuesday night. However, winds are not expected
to top 15 kts. Showers and a few thunderstorms accompany the weak
low`s passage Tuesday, which may caused gusty and erratic winds.

&&

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

&&

$$

SHORT TERM...BW
LONG TERM...LC
AVIATION...GS
MARINE...BW