994
FXUS63 KMQT 030729
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
329 AM EDT Sun Aug 3 2025

.KEY MESSAGES...

- Drier and warmer weather persists into the first half of the work
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 this evening.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 329 AM EDT Sun Aug 3 2025

Early morning RAP analysis shows an expansive 1024mb high pressure
over the Great Lakes, with flow aloft characterized by longwave
troughing over eastern North America and ridging over western North
America interrupted by some shortwaves -  most notably over the
Northern Plains. The Great Lakes remain under generally WNW flow
aloft. Nighttime microphysics shows nary a cloud in the sky, but a
peek outside shows a hazy quarter moon, and webcams are also looking
rather hazy. Local air quality monitoring stations are still
elevated, so we have smoke aloft and at the surface.

For the rest of today, as flow aloft backs more to the SW, we should
become cut off from the main source of wildfire smoke. However,
plenty of smoke has already drifted into the region, and subsidence
from the high pressure will keep the air stagnant and prevent
dispersion and ventilation of the smoke, so an Air Quality Advisory
remains in effect through this evening. For more information about
impacts and resources, check out the AQA. Beyond the hazy skies from
the smoke, slightly warmer than normal conditions are expected with
high temperatures around the 80 degree mark for most of the area.
Nearer to Superior, temperatures should range in the mid/upper 70s.
In spite of background winds out of the west to southwest around 5-
10 mph, CAMs show a lake breeze off the Great Lakes, which will
cause a wind shift in the afternoons near the Great Lakes but wind
speeds themselves will largely be under 10 mph (except for the
Keweenaw Peninsula where wind speeds will be slightly higher).
Expect temperatures to fall back into the mid 50s under hazy skies
tonight.

Monday, Upper Michigan will be situated on the backside of the
surface high that will by then be centered over the Lower Great
Lakes by then. Light southerly winds won`t do much to disperse the
smoke/haze, so some reductions in air quality may continue. A weak
shortwave moving slowly out of the Dakotas into Minnesota will stay
west of us, but will note that some of the CAMs do favor some
convection firing during the afternoon as the lake breeze moves in
off the Great Lakes once again. Soundings are quite dry, however, so
rain chances have been left out of the forecast. Expect an otherwise
quiet day as temperatures peak in the lower 80s for most.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 334 PM EDT Sat Aug 2 2025

Moving into the work week, a rather complex setup emerges that the
ensembles and global deterministics are struggling to define. The
key elements at 500mb are a ridge moving over the Canadian Prairie,
a trough over the Mississippi River valley, semi-permanent highs
over the southwest US and Bermuda, and deep troughs over British
Columbia and Atlantic Canada. While all of these features are large
and slow-moving, their complex interactions are handled
differently depending on model of choice. Blending most
solutions together, the NBM keeps chances of precip over the UP
sub-15 percent until Wednesday afternoon, where PoPs through
Thursday and Friday and into the following weekend are around
15-30%. This reflects high certainty that the pattern will break
down to some degree but a low certainty in how it will break
down. Early indications are that the Canadian ridge will go
omega-shaped, and the western trough may pivot into the Upper
Great Lakes for the latter part of the work week. Into next
weekend, the pattern breakdown becomes chaotic, so further
shortwaves are possible but determining which one is the most
likely solution is difficult. With persistent diurnal heating
and height rises, and prevailing flow at mid to lower levels
having a more southerly component, temperatures will trend above
normal with the NBM showing widespread 30-60% chances of 90
degree highs by Friday (and up to 90% chances for the
downsloping Lake Superior shores). This in conjunction with a
moistening trend in dew points thanks to reestablished
connection with Gulf or Corn Belt moisture will increase
instability through the week with mean LREF SBCAPE values of
over 1500 J/kg for the interior west by 00Z Thursday. As a
result, if given forcing, thunderstorms will be back in the
conversation for the latter half of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 136 AM EDT Sun Aug 3 2025

High pressure remains over the Great Lakes through the duration of
the 6Z TAF period keeping the weather dry, but widespread Canadian
wildfire smoke across the region will continue to yield periods of
low-end VFR/high-end MVFR vis. IWD/CMX should see slight improvement
above 6SM through early this morning before 6SM HZ returns. SAW is
anticipated to hold ~6SM the entire duration of the TAF,
periodically rising above 6SM mid to late morning and possibly
dropping below 6SM this afternoon and evening. Lake breezes will
provide rapid wind shifts/variable winds this afternoon at IWD/SAW.
This also may affect additional periods of MVFR vis at SAW late in
the period as smoke lifts in from the S.

&&

.MARINE...
Issued at 334 PM EDT Sat Aug 2 2025

Under primarily high pressure, winds will remain below 20 kt for
most of this forecast period. Otherwise, expect wildfire smoke to
cause poor air quality at least through Sunday. 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...LC
LONG TERM...GS
AVIATION...Jablonski
MARINE...GS