357
FXUS63 KMQT 211920
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
320 PM EDT Fri Aug 21 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms move eastward with a cold
  front over central and eastern Upper Michigan through this
  evening.

- Additional scattered showers and thunderstorms are possible
  across mainly central Upper Michigan tomorrow with minimal
  rainfall totals.

- Seasonable temperatures are expected through next week with
  the exception of slightly below normal temperatures Sunday and
  Sunday night.

&&

.DISCUSSION...
Issued at 319 PM EDT Fri Aug 21 2026

Afternoon RAP analysis indicates the weak sfc low has made it over
central Lake Superior, opening up into a trough which extends
northward into northern Ontario. Sfc obs place the cold front just
past the far western UP with temps in the upper 60s to mid 70s ahead
of it. Tds in the low to mid 60s support SBCAPE in the 500-1500 J/kg
range, but lapse rates are unimpressive. Bulk shear is also below 25
kts, so strong to severe storms are not expected. Latest radar
mosaic has showers along this boundary with Day Cloud Phase RGB
satellite imagery showing glaciation and GLM/ground networks
indicating lightning activity is just starting. These are expected
to progress eastward through this evening before diurnal instability
decreases and lingering convection falls apart. PWATs of ~1.3 inches
indicate some isolated higher amounts up to 0.5 to 1 inch are
possible (30-50% chance, highest central UP), but most likely
accumulations will be less than 0.25 inches.

In the wake of this front, isolated showers and a few rumbles of
thunder are possible (15-30% chance) with a shortwave and limited
elevated instability tonight. Lows settle into the upper 40s to low
60s, coldest interior west. Additional scattered showers and weak
storms are possible on Saturday as another cold front and shortwave
drop southeast overhead. That said, CAMs are even less impressed
with this round. Outside the south-central where some spots could
reach up to 0.25 inches, accumulations remain below 0.1 inches.
Highs will be in the upper 60s to mid 70s.

Temps continue to decrease this weekend, bottoming out Sunday as a
mid level trough deepens over the Great Lakes. CAA lowers 850 mb
temps to between 3-6C, yielding highs in the 60s to low 70s and lows
in the 40s to mid 50s. Some interior spots likely will dip back into
the upper 30s Sunday night. Northerly winds are expected to gust up
to 20 mph on Saturday and between 20-30 mph on Sunday, highest
east...particularly near Lake Superior. High pressure moving in from
the west keeps weather dry through Monday, likely through most of
Tuesday as well before the next mid level trough moves through the
region. This brings back shower and storm chances for Tuesday night
and Wednesday, then dry weather is favored the rest of the work week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 156 PM EDT Fri Aug 21 2026

A weak low pressure system working across Upper Michigan is bringing
MVFR/IFR cigs to the area. The main aviation concerns for the 18z
TAF cycle are the timing of showers/thunderstorms at SAW, which are
presently developing in the western UP. Guidance continues to move
them across SAW between 20-00z, so have included prob30s for -tsra
at SAW for that time. Otherwise, conditions improve to VFR
overnight. As winds fall some patchy fog is possible at SAW, but
confidence is not high enough to put into the TAF at this time.
Gusty NW winds increase tomorrow morning and afternoon at all sites.
Winds 20-30 kts will be common at CMX and SAW.

&&

.MARINE...
Issued at 304 PM EDT Thu Aug 20 2026

Lake Superior - ESE wind gusts pick up to around 20kts over the east-
central portions of the lake tonight, then gusts fall back below
20kts Friday afternoon while a passing cold front causes winds to
shift over to the NW. The main marine hazards return Saturday and
Sunday as a pair of systems bring modest pressure rises and cold air
advection over the Lake resulting in gusty N to NW winds upwards of
20-30 kts beginning Saturday morning through Sunday night. At this
time, there is a low chance (30-50%) for a few gales to 35 kts
mainly between Marquette and Whitefish Point. Winds fall back below
20kts Sunday night, and stay mainly below 20kts through early next
week.

Northern Bay of Green Bay and northern Lake Michigan - Southerly
wind gusts up to 15-20kts will be possible over the Bay beginning
later this evening, but become more common over the Bay and northern
Lake Michigan late tonight and linger through Friday as low pressure
traverses the area. This results in waves building between 1-3 ft
(greatest in the open waters closer to Lake Michigan). A brief
reprieve in winds comes Friday night behind a weak cold front,
however, two systems then dive into the area Saturday and Sunday,
resulting in gusty north to northwest winds 15-25 kts through Sunday
night. Wind gusts briefly fall back below 20kts for Monday before
potentially increasing again into the midweek period.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 10 PM EDT this evening for
     MIZ014.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

DISCUSSION...77
AVIATION...BW
MARINE...LC