473
FXUS63 KMQT 281850
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
250 PM EDT Sat Jun 28 2025

.KEY MESSAGES...

- Rain showers and thunderstorms lift into Upper Michigan this
  evening and tonight. Some strong storms can`t be ruled out
  into tonight, mainly near Wisconsin over the west half of
  Upper Michigan.

- There is a slight chance of strong to severe storms Sunday
  afternoon and evening. Should organized storms occur, large
  hail and damaging winds will be the main severe weather
  hazards.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 249 PM EDT Sat Jun 28 2025

Surface ridging across Upper Michigan has kept the region mostly dry
with increasing clouds from west to east. Temperatures have mostly
been observed in the 60s by Lake Superior and 70s elsewhere. RAP
analysis and GOES Water Vapor imagery highlight a remnant shortwave
pressing into western Upper Michigan, which has supported light
rain/sprinkles. This feature is expected to continue transiting the
region this afternoon with increasing clouds being the main impact.
Another shortwave, is observed over southern Minnesota as well as an
associated surface front.

This boundary will lift northeast this afternoon as the surface
ridge axis shifts through the Great Lakes. By this evening, guidance
continues to suggest this boundary will be the focus for this
afternoon/evening`s convection, which will drive east and
southeastward along the boundary overnight. How far northward the
boundary makes it continues to be the main forecast question.
Between 06 and 12z guidance, the general consensus appears to have
dialed into the front migrating through the forecast area late
tonight, with dwindling convective activity following. CAMS suggest
varying degrees of thunderstorm organization, oscillating between a
more organized MCS/linear structure to cellular structures. While
this is still a question, severe weather isn`t expected with this
given weakening elevated instability and weak shear. With this being
said though, mid-level lapse rates increasing to near 7C/km suggests
small hail could exist if a stronger cell can get going. Speaking of
timing, the all CAMS are in good agreement on initial shower and
storm activity occuring overnight and beginning after midnight.

Any precip should ship out of the region Sunday morning, which will
position Upper Michigan within the warm sector ahead of a cold
front. This front will press west to east through our forecast area
late in the day and into the evening. Should the initial wave of
precip end early enough, thus maximizing time for potential
destabilization, MUCAPE values of 2000-3000j/kg may be realized. With
near 30-35kts of deep layer shear, DCAPE increasing to near 1000j/kg
and mid-level lapse rates potentially increasing to 7-8C/km,
organized storms would be capable of producing large hail and strong
to damaging winds. However, CAMS continue to suggest different
timing and the magnitude of these aforementioned parameters, thus
vary on the degree of severe weather potential. At this point, those
with outdoor plans late Sunday and Sunday night are advised to stay
weather aware and not only check in on forecast updates, but to have
a way to receive warnings should the severe potential pan out.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 249 PM EDT Sat Jun 28 2025

Long term period begins Monday with mid-level troughing extending
southwest from Hudson/James Bay into the Northern Plains and Upper
Midwest. To the south, sprawling mid-upper level ridging stretching
across most of southern CONUS, with a trough slowly lifting north
along the California coastline. Ahead of the trough, ridging extends
north across the Rockies and Intermountain West into western Canada.
At the surface, a cold front looks to be draped across western or
central Upper Michigan, with showers and thunderstorms ahead of the
boundary across eastern Upper Michigan - central too if the front
ends up starting the day over the west. This front will continue
pushing eastward through the morning hours, with a secondary cold
front/slug of cold air advection pressing southeastward into the
forecast area in the afternoon/evening, coincident with the mid-
level trough axis. Its unclear how much we`ll destabilize during the
day, but if we`re able to destabilize enough, scattered showers and
thunderstorms should develop by afternoon/evening. Severe weather
isn`t expected, but if enough thunderstorm organization can occur, a
stronger storm capable of stronger winds and small hail will be
possible in the evening. Any convective activity that occurs should
diminish overnight. Expect daytime temps to climb into the mid 70s
to low 80s and lows Monday night to fall mostly in the low 60s to
mid 50s.

Mid-upper level ridging across western North America will continue
Tuesday, then begin to slowly shift eastward through the Rockies
Wednesday and Plains Thursday. This will position Upper Michigan
within northwest flow aloft and at the mercy of any shortwave riding
the ridge`s eastern flank southeastward. The first wave looks to
press into Great Lakes sometime Tuesday afternoon or night. With
surface ridging extending into the region and little destabilization
expected, shower and thunderstorm activity looks to stay north of
Upper Michigan in Ontario. The next wave looks to drop southeastward
through Ontario Wednesday or Wednesday night into Thursday morning;
while timing differences among the deterministic packages increase
with this wave, a bulk of the shower/thunderstorm activity looks to
remain focused to the north and south, where better forcing exists.
With that being said, can`t rule out at least isolated afternoon
showers/thunderstorms activity at the moment. Surface high builds in
afterwards which will linger Thursday overhead. This will work to
keep the region mostly dry.

Friday, the 4th of July, weak ridging to near zonal flow sets up
across the northern tier with multiple weak impulses embedded within
the flow. Closer to the surface, a warm front looks to stretch
across the Northern Plains or Upper Midwest.  12z guidance appears
to be trending toward precip spreading into the region from the west
by afternoon/evening, but there hasn`t been run to run consistency
about this, except by the GFS. Should this trend continue, showers
and thunderstorms may impact any evening firework plans.

Daytime temperatures Tuesday and into the weekend look largely to
span the upper 70s to low 80s while overnight temperatures fall
mostly into the 50s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 113 PM EDT Sat Jun 28 2025

VFR conditions this afternoon and evening under mid-high level
clouds will prevail. Showers and thunderstorms tonight will lift
into Upper Michigan, potentially impacting terminals overnight into
Sunday morning. Still questions about the degree of thunderstorm
activity at the terminals, but opted to include prob30 groups for
this potential.

&&

.MARINE...
Issued at 249 PM EDT Sat Jun 28 2025

Winds will settle below 15 kts lake wide this afternoon as high
pressure continues to build into the Lower Great Lakes region.
Although winds and waves will remain mostly calm as only weaker
pressure systems affect the lake for the rest of the weekend into
next week, periodic thunderstorms may occasionally be over the lake,
bringing chances for gusty erratic winds and small hail. The best
chance for thunderstorms moves west to east late tonight into the
early morning hours of Sunday, then again following a similar
timeframe late Monday into Tuesday.

&&

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

&&

$$

SHORT TERM...JTP
LONG TERM...JTP
AVIATION...JTP
MARINE...BW