642
FXUS63 KMQT 141813
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
213 PM EDT Mon Jul 14 2025

.KEY MESSAGES...

- Wildfire smoke from Canada continues to reside over the area,
  resulting in air quality concerns and reduced visibility. See
  the Air Quality Alert for more information.

- A few showers and thunderstorms are possible (20-35% chance)
  across the south-central and east UP this afternoon.

- Periods of rain and thunderstorms, some strong to severe, are
  expected Tuesday through Wednesday along a slow moving frontal
  boundary.

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

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 212 PM EDT Mon Jul 14 2025

Afternoon RAP analysis and GOES satellite imagery reveal a mostly
quiet scene across the UP and Lake Superior under quasi-zonal flow
aloft. At the surface, a very diffuse frontal boundary is being
dragged along the s-central and eastern UP. Here, now agitated cu
and a few isolated showers are starting to take shape amidst
building instability. This boundary, aided by developing lake breeze
circulations may be the foal point for additional
showers/thunderstorms this afternoon. Marginal shear below 25 kts,
weak mid-level lapse rates, and a somewhat dry sfc layer indicated
by model inverted-v profiles will work to limit convective potential
and organization, however. Have included some low chance PoPs for
development within the next few hours.

Elsewhere, under mostly clear skies temps have risen in the 70s to
low 80s. Smoke from Canadian wildfires continues to plague the
region as webcams depict hazy/milky skies where elevated smoke is
being mixed down to the sfc. Air quality sensors range from the
yellow to orange (moderate to unhealthy for sensitive groups) range,
while upstream sensors in MN have fallen into the red unhealthy
category. RAP/HRRR model smoke guidance suggests the near sfc smoke
expanding across the UP from upstream this afternoon and evening,
where sensors across the UP could fall further into the unhealthy
ranges before clearing out early Tuesday.

Attention turns upstream to a few shortwaves within the zonal flow
aloft descending into the N Rockies, introducing height falls across
the Upper Midwest and developing sfc low pressure into the northern
Plains. This will push a warm front into the UP Tuesday
morning/afternoon, allowing afternoon temps to climb into the 80s to
near 90. Additionally, increasing moisture characterized by PWATs
climbing ~1.5", moderate isentropic ascent, and ample instability,
will lead to the development of showers and thunderstorms. 12z CAM
guidance, however, varies wildly on the timing, strength, and
overall placement of developing convection- some developing a line
of convection passing through the west and Keweenaw as early as 12z,
and some missing the UP completely until the front sags back south
Tuesday afternoon/evening. CAMs have better agreement on a secondary
line of convection developing during the afternoon/evening hours,
where strong diurnal instability and moderate speed shear could lead
to thunderstorms producing severe wind gusts and hail, thus, SPC has
included the west half of the UP in a Slight Risk (2 of 5) for
severe thunderstorms tomorrow. Further, with the general movement of
storms parallel to the WSW/ENE boundary, training showers and storms
could produce rainfall totals between 1-2" through Tuesday night,
particularly in the west half. For this reason, WPC has included the
far western UP and Keweenaw in a Slight Risk (2 of 5) for flash
flooding through Wednesday morning.

&&

.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 TUESDAY/...
Issued at 212 PM EDT Mon Jul 14 2025

VFR conditions prevail under mostly clear skies, save for haziness
caused by Canadian Wildfire smoke. So far, this smoke has remained
elevated enough to not impact visibility at any site. Guidaance
suggests an increase in near sfc smoke concentration this evening,
so have included HZ into the TAFs, but decided against any major
visibility reductions. Otherwise, quiet weather prevails tonight.

&&

.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/ tonight for
     MIZ001>007-009>014-084-085.

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

&&

$$

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