908
FXUS63 KMQT 131846
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
246 PM EDT Sun Jul 13 2025

.KEY MESSAGES...

- Wildfire smoke from Canada will be over the area through at least
Monday resulting in air quality concerns and reduced visibility.

- 20% chance of a shower or storm in the far western UP tonight
between 8 pm and 1 am EDT. Any storms that occur are capable of
gusty winds and hail.

- Periods of rain and thunderstorms are expected Tuesday (20-50%
chance; highest north/west) and Wednesday (50-80% chance).

- Seasonably warm Monday and Tuesday, then sharply cooler Wednesday
into Thursday.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 245 PM EDT Sun Jul 13 2025

Early afternoon water vapor imagery and RAP analysis shows broad
midlevel troughing over the northern Plains and upper Great Lakes. A
weak impulse in NW flow is near the Grand Forks, ND area, with an
attendant surface trough cutting NE to SW across western ON and the
Dakotas. A seasonably dry airmass is in place over the UP with PWATs
around 0.8", and just some fair weather cu across portions of the
UP. This evening, as the midlevel impulse and surface trough
approach from the west, moisture pooling ahead of this feature is
expected to result in a broken band of showers and storms developing
over the Minnesota Arrowhead moving SE. Consensus in the CAMs is for
this activity to weaken as it crosses western Lake Superior, with
about a 20-30% chance of some showers/storms surviving into far
wester portions of the UP in the 8p-1a EDT frame. Severe weather
threat is low given marginal instability of 750 J/kg MUCAPE or less
(per HREF mean), but a gusty storm with hail can`t be ruled out with
dry air at low-levels and 35-40kt of deep layer shear. Otherwise,
fairly mild tonight with SW flow ahead of this trough, with lows
mainly in the 60s.

Monday is forecast to be seasonably warm with highs ranging through
the 80s, and little to no evidence for precipitation chances with
flat zonal flow aloft and little to no instability. An isolated
shower can`t be ruled out along lake breezes near Delta/Schoolcraft
with some enhanced low-level moisture pooling there, but less than
20% so will not mention.

Wildfire smoke will continue to plague the area through Monday. The
HRRR-smoke model suggests the smoke dissipating somewhat tonight
after the trough passage, but another plume is expected to follow
Monday. Air Quality Alerts remain in effect per MI EGLE.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 245 PM EDT Sun Jul 13 2025

Flat zonal flow over the northern tier of the CONUS to start the
week will amplify with time as a shortwave trough, as an extension
of a deep Hudson Bay low, will shift eastward across the northern
Plains midweek and into the Great Lakes by the end of the week. At
lower levels, a warm front will extend northeast from a low in the
central High Plains, sagging southward with time as high pressure
builds in behind it. The placement of this front in the vicinity of
the local area will be the main driver of impactful weather
through the midweek period.

Tuesday, model consensus suggests we will be mainly on the warm side
of the front, and with 850 mb temps averaging around 16C (+1 to +2
sigma), this will be the warmest day of the week. Highs are expected
to be in the mid to upper 80s (except perhaps for the Keweenaw which
will be cooler in closer proximity to the front and possible
rainfall), and with dewpoints approaching 70F, this could result in
heat indices in the lower 90s. Instability will likely be quite
healthy in this warm airmass, with the 06Z REFS mean indicating 1-2
kJ/kg by 18Z Tue. Thunderstorm potential will be maximized north of
the area in closer proximity to the front and lower midlevel
heights, but it`s possible that the front sags south far enough to
touch off some convective activity in the afternoon, especially over
the north/west. There likely exists some severe potential if this
occurs given the instability, although model consensus suggests deep-
layer shear may be on the weak side at less than 30 kt.

The low-level front continues to linger in the area Wednesday into
Thursday, with consensus supporting the surface portion of it
sagging mainly south of the area. This will result in sharply cooler
temperatures by Wednesday, with highs stuck in the 60s (and maybe
even 50s closer to the still below-normal temperatures of Lake
Superior) over most of the northern half. Additional rounds of
showers and perhaps thunderstorms are expected along the front,
especially Tuesday night into Wednesday. Some areas could see heavy
rainfall if repeated rounds develop. The pattern largely supports
this, with mid/upper level winds largely parallel to the slowly-
moving lower-level boundary, and PWATs around 1.5 (+1 to +2 sigma).

Gradual drying trend for the end of the week as high pressure builds
in the wake of this front, with temps likely rebounding closer to
normal Friday into Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 105 PM EDT Sun Jul 13 2025

Wildfire smoke continues to result in prevailing MVFR vsby this
afternoon, which is expected to largely continue into tonight. While
there may be a brief respite in the smoke and reduced vsby tonight,
another plume is expected to spread into the UP from the west on
Monday morning. VFR cigs are expected to prevail through the TAF
period. A weakening area of showers and perhaps a few embedded
thunderstorms will approach IWD in the 01-05Z timeframe; PROB30 for
TS added here. Probability of TS is around 20% at CMX in the same
timeframe and near zero at SAW so mention was not included in the
TAFs for those terminals.

&&

.MARINE...
Issued at 903 AM EDT Sun Jul 13 2025

Visibility will continue to be reduced in areas of fog and wildfire
smoke into Monday. Winds will increase with west-southwesterly gusts
around 20 kt through today, mainly over the western half. A
weakening band of showers and thunderstorms is possible over the
western lake this evening (40% chance). Winds diminish early in the
week, but could increase to near 20 kt from the north late in the
week behind a frontal boundary. Unsettled weather returns
Tuesday/Wednesday with additional rounds of showers and
thunderstorms possible, plus the potential for fog where rainfall
occurs.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Air Quality Alert until midnight EDT /11 PM CDT/ Monday night
     for MIZ001>007-009>014-084-085.

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

&&

$$

SHORT TERM...Thompson
LONG TERM...Thompson
AVIATION...Thompson
MARINE...Thompson