154
FXUS63 KMQT 111129
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
729 AM EDT Tue Aug 11 2026

.KEY MESSAGES...

- Potential (20-50% chance) for showers and storms today
  through Wednesday afternoon. Severe storms are not expected.

- Temperatures are expected to be seasonably warm to slightly
  above average through Wednesday, before cooling to slightly
  below average through the weekend.

- Dry weather Thursday and Friday ahead of the next chances for
  more widespread rain this weekend (around 45% chances).

&&

.DISCUSSION...
Issued at 253 AM EDT Tue Aug 11 2026

Early morning RAP analysis shows broad northwesterly flow aloft as
sprawling ridging over the southern half of the CONUS is only
partially depressed by a closed low over Hudson Bay. Minor ripples
in the flow reflect mesoscale disturbances embedded within the
northwest flow, and while the most impactful disturbances will
remain south of the UP, some small troughs in the vicinity will
erode the presence of ridging aloft/surface high pressure that would
otherwise have too much subsidence for any precipitation to occur.
CAMs show little agreement in the details of showers and potential
thunder today (which is to be expected in weakly forced, nebulous
patterns such as this), but lake breezes may serve as a focal point
for showers and a few thunderstorms today. With weak, unidirectional
flow, the shear pattern will not be supportive of severe weather,
though the HREF SBCAPE solutions offer a wide spread as to how
buoyant updrafts may become. While the ensemble minimum for SBCAPE
is genuinely 0, the ensemble mean is around 500 J/kg with ensemble
maximums in the 1000+ J/kg territory, so some thunder remains
possible (maybe 1 or two strong thunderstorms cannot be ruled out).
As to what probability exists for those storms to occur, that will
be a moving target through the day. For now, HREF chances of a
shower capable of producing a tenth of an inch of rain within 25km
of any point in the interior UP is between 30-60% with chances of a
thunderstorm capable of producing modeled radar reflectivity
exceeding 40 dBZ is around 15%.

Clarity on the weather pattern is not really provided on Wednesday
either as the 500mb pattern remains much the same as today, so a
general repeat of today is expected. All eyes turn upstream to a
trough that will be over the Seattle/Vancouver area by Wednesday
18Z. This trough will provide the best mechanism to progress the
weather pattern, though it will first kick ridging from over the
Rockies and Plains to be over the Midwest and Great Lakes late this
week. This will lead to rising surface pressure and dry conditions
for virtually all of the UP Thursday and Friday.

The aforementioned kicking trough arrives over the UP Saturday.
Unfortunately, spread in the track and depth of this trough passage
is high as at the same time as the trough arrives, ridging builds
over the Southeast, allowing for ensembles to have a spread of
solutions regarding how this trough fares against either a weaker or
stronger Southeast ridge. Current LREF chances of a wetting rain
(around a tenth of an inch/24hr) is around 45% by Sunday afternoon.
Thunderstorms are uncertain as well, though the LREF mean SBCAPE by
00Z Sunday being around 15 J/kg is not an encouraging sign for those
looking forward to a rumble of thunder. While there is
understandable spread on the pattern that follows, it is generally
expected that by Sunday evening and through Monday night, ridging
resumes in the wake of the trough, with next Tuesday looking to
resume the ongoing pattern of weak precip signals in persistent
NWerly flow.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 729 AM EDT Tue Aug 11 2026

Besides a brief patch of FG at IWD that is improving as of 11Z,
VFR conditions are ongoing and will dominate most of the period
at all sites. Afternoon SHRA/TSRA development will be primarily
south of CMX and east of IWD, though model spread is high
enough that probabilities of precipitation at SAW for most of
today are only 20- 35%, so PROB30s will cover those conditions
today. Tonight, chances of FG development at IWD/CMX are only
around 20%, so have left out at those sites, but chances are a
bit better at SAW (especially in the scenario that notable
rainfall during the day keeps near-ground conditions moist
tonight), so a TEMPO group for reduced visibility is included
for SAW with this issuance. Expect mostly light winds at 6 KT or
less, with direction varying significantly, especially with the
Lake Superior lake breeze.

&&

.MARINE...
Issued at 253 AM EDT Tue Aug 11 2026

Winds will be less than 20 kt throughout the week this week as high
pressure dominates. An isolated thunderstorm cannot be ruled out (up
to 35%) over the Bay of Green Bay and Lake Michigan waters this
afternoon through Wednesday afternoon. Gusty conditions return to
Lake Superior Saturday afternoon with an approaching disturbance,
but confidence is low in the timing, location, and intensity of such
gusts.

&&

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

&&

$$

DISCUSSION...GS
AVIATION...GS
MARINE...GS