841
FXUS63 KMQT 011734
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
134 PM EDT Fri Aug 1 2025

.KEY MESSAGES...

- Drier and warmer weather persists this weekend into early next
  week.

- Smoke from Canadian wildfires will continue impacting air
  quality and may locally reduce visibility at times. An Air
  Quality Alert remains in effect for all of Upper Michigan
  through Saturday.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 1218 PM EDT Fri Aug 1 2025

Upper ridging across the Rockies is supporting sfc high pressure
across the Northern Great Lakes and Upper Midwest this early
afternoon, keeping the UP cloud and precipitation free. Light N to
NW flow aloft, however, continues to usher in wildfire smoke from
fires ongoing in portions of central Canada. Air Quality Alerts for
elevated levels of PM2.5, courtesy of the Michigan Dept. of
Environment, Great Lakes, and Energy, remain in effect through
Saturday and may be further extended through the rest of the
weekend. Seasonal high temps in the mid 70s are still expected
today, but may be muted a few degrees by the smoke aloft. Otherwise,
temps cool to the 40s again tonight, potentially low 40s to upper
30s in the typical summertime radiational cooling spots as seen last
night.

Expect more of the same through Saturday though slightly warmer high
temps pushing the low 80s as winds turn S to SW on the backside of
the SE descending sfc high pressure. Overnight lows into Sunday fall
into the 50s interior / low 60s lakeshores.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 133 PM EDT Fri Aug 1 2025

By Sunday, the global deterministic 500mb charts show cutoff highs
over northwest Mexico and Saskatchewan leading to split flow between
and upstream of those features. The troughing portion of that split
flow will stay too far south to bring precip to the UP prior to
Monday afternoon as the ridging portion keeps high pressure over the
Upper Great Lakes (LREF mean around 1028mb). With the cooler NW flow
aloft being interrupted somewhat, temperatures climb to around the
80 degree mark, slightly above normal. This may bring some relief to
the smoke but the details of smoke dispersion timing are still
difficult to pin down.

Moving into next week, ensembles diverge significantly about how the
pattern breaks down and how embedded shortwaves track through the
region. This makes the precipitation forecast challenging, though
with less certainty in stifling high pressure, a diurnal
precipitation pattern emerges in the interior west in the NBM as
even in weakly forced atmospheres, the chances of the summertime
airmass over the interior western UP acquiring 1000+ J/kg of SBCAPE
climbs above 50 percent by the mid to late week period per the NBM.
Part of this increasing trend in instability is due to the
increasing trend in surface moisture as connection to Gulf or Corn
Belt moisture becomes more likely. The LREF shows chances of surface
dew points exceeding 65 degrees climbing over 50 percent by
Thursday. Should the models start to coalesce around any particular
shortwave trough, severe weather potential will be in play, but no
particular day`s setup stands out at this time. While high
temperatures are still expected to hover around the 80 degree mark
throughout the week, the increased moisture will make for a slight
warming trend in low temperatures well into the 60s by the end of
the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 133 PM EDT Fri Aug 1 2025

VFR conditions with light winds are expected to prevail through the
18z TAF period, however, MFVR smoke may persist at SAW. Confidence
is low on visibilty less than 5SM tonight into tomorrow morning,
thus have opted to keep 5SM in the TAF. Guidance suggests a brief
respite from the heavy smoke concentrations into Saturday.

&&

.MARINE...
Issued at 133 PM EDT Fri Aug 1 2025

Under primarily high pressure, winds will remain below 20 kt for
most of this forecast period. The exception will be across western
Lake Superior today through Saturday, where funneling southwest
winds between the Keweenaw and Thunder Bay will cause some localized
wind gusts 20 to 25 knots. Otherwise, expect wildfire smoke to cause
poor air quality at least through Saturday. There will be some
chances of thunder next week, though model guidance is widely spread
in the timing and location details at this time.

&&

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

&&

$$

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