551
FXUS63 KMQT 291643
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1243 PM EDT Sun Jun 29 2025

.KEY MESSAGES...

- Thunderstorms are expected this evening and tonight. There is
  a slight chance that storms could be strong to severe storms
  this evening over central Upper Michigan. Should organized
  storms occur, large hail and damaging winds will be possible.

- Isolated and scattered thunderstorm activity is possible Wednesday.
  Thunderstorms are also possible in the afternoon and evening
  of Friday, the Fourth of July.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 1242 PM EDT Sun Jun 29 2025

GOES Water Vapor and RAP analysis position a broad mid-level trough
over the Northern Plains and central Canada with a few different
shortwaves across the Upper Midwest atop a slowly progressing cold
front and warm front. This warm front lifted into the forecast area
behind this morning`s showers and thunderstorms, allowing for
heating into the 70s and 80s for much of the region. With dewpoints
in the mid to upper 60s and plenty of clear skies noted, we`ve been
able to destabilize to 500-1000j/kg of SBCAPE, per SPC mesoanalysis.
Increasing low level jet is expected this afternoon, which will help
initiate convection this evening ahead of the approaching cold front.
CAMS continue to lack considerable consensus, but generally suggest
a line or clusters of storms moving into the forecast area with a
growing consensus on it being mostly during the evening hours. 30-
35kts of effective bulk shear and a 25-35kt 925-850mb LLJ should be
sufficient for an environment capable of storm organization and
stronger updrafts. Should this occur, strong to severe storms will
be possible. The HREF matches the aforementioned general consensus
and given the anticipated timing of the background environment, peak
convective potential looks to fall 22-4z over Upper Michigan, with
strong storms potentially lingering over Lake Superior to near 8z.
Main severe weather risks appears to be strong to damaging winds,
but large hail can`t be ruled out. Otherwise, downpours and frequent
lightning should be expected in any thunderstorm. Thunderstorms will
track east or northeast and likely exit the east near sunrise.

Monday, a secondary cold front/slug of cold air advection will move
southeastward into the forecast area in the afternoon/evening,
coincident with the mid-level trough axis. There continue to be
questions about 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. Any convective activity that occurs should diminish
overnight. Expect daytime temps to climb into the mid-upper 70s to
low 80s and lows Monday night to fall mostly in the low 60s to mid
50s.

&&

.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 /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 744 AM EDT Sun Jun 29 2025

Primarily VFR conditions are expected during the 12Z TAF period, but
shra/tsra this afternoon and evening could bring back periods of
MVFR as well as LLWS. Confidence in LLWS timing was not high enough
to include in the current TAFs. Otherwise expect light S to SW flow
today around 5-10 kts.

&&

.MARINE...
Issued at 744 AM EDT Sun Jun 29 2025

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 is this evening into tonight and late
Monday into Tuesday.

&&

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

&&

$$

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