668
FXUS63 KMQT 080016
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
816 PM EDT Mon Jul 7 2025

.KEY MESSAGES...

- Seasonable temperatures return to the Upper Peninsula for the
  work week.

- Rain showers and a few thunderstorms return tonight and Tuesday.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 118 PM EDT Mon Jul 7 2025

Quasi-zonal flow is noted across northern CONUS with a notable
shortwave upstream in Saskatchewan/Manitoba/Dakotas and a few others
in the Central Plains/Middle Mississippi River Valley. At the
surface overhead, RAP analysis paints high pressure, which is
helping to support mostly clear skies above Upper Michigan. Cooler
temperatures than what has been realized the past few days have also
been observed thanks to light northerly surface flow and an 850mb
airmass of 10-13C, per SPC mesoanalysis. As of noon eastern time,
widespread 60s were still observed with mid to upper 50s by Lake
Superior. These cooler and dry conditions should persist for the
remainder of today, although most locations should warm into the 70s
this afternoon.

Convection associated with the upstream wave in the Northern Plains
will press eastward tonight. CAMS suggest better organization with
each run and now suggest a line of showers and storms will hold
together as they press into western Upper Michigan after midnight.
Given the decreasing instability and deep layer shear as they move
closer to our forecast area, thunderstorms should be waning. These
will press into central/eastern Upper Michigan through the morning
and early afternoon hours Tuesday. Behind this initial wave Tuesday
afternoon/evening, dinurally driven destabilization upwards of 1000-
1500 j/kg and deep layer shear near 40 kts ahead of a weak surface
front/trough, should be enough for afternoon showers and
thunderstorms to develop west and central. Any precip should end in
the evening as the front/trough press through the region and forcing
dives southeast of the forecast area. Temperatures tonight will fall
into the 50s, perhaps with 40s in the interior east. Should warm
into the 70s Tuesday before falling back into the 50s Tuesday night,
maybe low 60s for southern Menominee County.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 203 PM EDT Mon Jul 7 2025

Quasi-zonal flow across the international border Wednesday breaks
down as ridging across middle North America amplifies in response to
a deep trough digging through the Rockies. As the ridge presses east
for the remainder of the week, a cutoff low off the California coast
will get pulled into the trough, resulting in split flow eventually
phasing over the Northern Plains or Great Lakes this weekend.

High pressure at the surface should keep the forecast area dry
through the day Wednesday and Thursday. Temperatures climbing into
the 70s Wednesday are expected in locations removed from Lake
Superior, with lake-side communities only peaking in the mid to
upper 60s. Thursday, another day of widespread interior temperatures
in the 70s, perhaps low 80s interior west, and low 70s by Lake
Superior, is expected. Wednesday night temperatures look to cool
into the upper 40s to low 50s.

The ridge axis presses into Upper Michigan Thursday followed by a
weak wave rolling atop the ridge Thursday night. Shower and
thunderstorm chances are co-located with diurnally driven instability
upstream in Minnesota, so any activity in western Upper Michigan or
Lake Superior overnight should be waning. Upstream Thursday into
Friday, a southern stream system, fueled by Gulf moisture, and a
robust shortwave moving through the Dakotas will begin to phase,
then lift northeast through the Midwest/Great Lakes region. Its
still unclear where the resultant surface low(s) will end up being,
but the rough approximation between the deterministic and ensemble
guidance packages suggest between Ontario north of Minnesota and
Wisconsin, before lifting north or northeast into Sunday. While
there are still differences on structure and location, fronts or
surface troughs with most options nearly all agree that precip will
lift through the forecast area Friday night into Saturday.
Instability appears to be lacking, with GEFS suggesting 20-30%
probabilities of 500-1000j/kg CAPE and similar, although slightly
higher, probabilities in the EC. While strong to severe
thunderstorms aren`t expected, thunder can`t be ruled out. Enhanced
by the Gulf`s influence, PWATs should climb to 1.5-2 inches (50-90%
chance per GEFS, GEPS, and EC ensemble systems), which alongside the
apparent modest synoptic forcing and lack of notable instability,
rainfall amounts under an inch look most likely (80-90% per LREF and
NBM). Precip will exit the region from west to east late Saturday,
perhaps returning late Sunday into Monday if a secondary shortwave
within the now-phase upper level low moves through the forecast area.

For temperatures, generally expect upper 70s to low 80s for a
majority of Upper Michigan on Friday, but more widespread cooler mid
70s for the weekend. Overnight lows also look to be mostly in the
mid 50s to low 60s.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 816 PM EDT Mon Jul 7 2025

VFR conditions and light winds are expected tonight with today`s
lake breeze already through SAW. Late tonight, showers and
thunderstorms will move into the region, resulting in increasing low
level moisture and falling ceilings. Expect precip to press eastward
overnight into Tuesday morning.

&&

.MARINE...
Issued at 203 PM EDT Mon Jul 7 2025

Light winds of 20 knots or less are expected through the rest of the
week as quasi-zonal flow sets up shop aloft. That being said, a low
over the Northern Plains lifts into the Lake Superior late tonight
through Tuesday, bringing showers and a few thunderstorms to the
area. Expect the rainfall to end by Tuesday evening as the low
slowly travels southeastward with time. Additional showers and
storms could enter the far western lake Thursday evening, although
with convection being diurnally driven expect the showers and storms
to die out with time. As low pressures phase over the Northern
Plains and lift into northern Ontario from Friday into this weekend,
expect additional showers and thunderstorms to develop over Lake
Superior for that time period.

&&

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

&&

$$

SHORT TERM...JTP
LONG TERM...JTP
AVIATION...TDUD
MARINE...TAP