955
FXUS63 KMQT 031830
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
230 PM EDT Wed Jul 3 2024

.KEY MESSAGES...

- Breezy westerly winds through the early evening with gusts up to
20mph common area-wide, and higher gusts to 30-35mph possible across
the Keweenaw.

- Pop-up showers/thunderstorms (20-30% chance) will be possible into
the evening.

- Low chance (~25%) of afternoon showers/storms across interior
western Upper Michigan on Independence Day.

- Widespread moderate rain expected early Friday into Saturday. Some
thunder possible.

- While not a washout...scattered shower and thunderstorm chances
continue this weekend...especially Sunday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 230 PM EDT Wed Jul 3 2024

RAP analysis shows mainly zonal flow setting up over the area this
afternoon as a closed low continues to move through northern
Ontario, towards Hudson Bay. Over the Great Lakes, skies have been
able to turn sunny with large-scale subsidence indicated in water
vapor imagery. However, with diurnal mixing, plenty of agitated
cumulus has popped off over the UP. This remains fairly well capped
over the west, but cooler cloud tops are apparent in the eastern UP.
This hints at a chance for some isolated to scattered showers and
storms across the central and eastern UP as we head through the late
afternoon and evening hours. Given only a few hundred j/kg of CAPE
over the area, no severe weather is expected. Though any rain totals
should be light for the most part, areas where multiple storms can
move through could see QPF in excess of a quarter inch. This is most
likely in Luce county, where the highest cloud tops are already
developing (perhaps some lake breeze convergence?).

Otherwise, temperatures are turning much warmer than yesterday, with
most of the area already well into the 70s and lower 80s. The
exception is in the eastern UP, where areas along Lake Michigan
continue to struggle to get out of the 60s courtesy of onshore flow.
Meanwhile, winds remain on the breezy side, with gusts up to 20mph
common across the western half of the UP. Higher gusts in excess of
30mph continue to be observed at times across the Keweenaw. Winds
should fall back as we head into the evening and the boundary layer
decouples.

Tonight, ridging will continue to strengthen over the forecast area,
with any lingering convection over the eastern UP wrapping up by
midnight. Outside of that, though, it will be a dry night with
overnight lows generally in the 50s, low 60s to the south.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 349 AM EDT Wed Jul 3 2024

Guidance continues to present a consistent picture of the coming
pattern, with the main item of interest being a slow moving system
through the central Plains and Upper Great Lakes late Thursday into
the weekend. Another system looks to swing through late this weekend.

Starting off on Thursday, Independence Day, a meso high over Lake
Superior looks to largely keep the region dry. However, questions
surrounding the placement of an inverted surface trough and diurnal
destabilization are still present, and some showers and thunderstorms
by afternoon and evening still look possible. CAM runs have dialed
this potential back some from the largely medium range guidance that
went into previous forecast packages, but there are still some
models that bring light rain across the south or west that could
impact afternoon/evening outdoor plans. Expect daytime highs to into
the 70s with some low 80s being possible south-central and interior
west.

Upstream, a mid-upper level low skating through the north-central
Plains will continue its eastward journey into the Upper Great Lakes
by Friday morning. Its then expected to lift northeast into Ontario
through Saturday morning. At the surface, a low will deepen on
Friday as it slowly moves through Wisconsin, reaching northern Lower
Michigan Friday night. For the past few days, guidance has
consistently tracked in this fashion, which positions our forecast
area on the northern flank of the low and within its
deformation/inverted trough axis. Recent GEFS and EC ensemble
surface low clustering continues this, with the broad clustering
present being mostly attributed to timing differences among the
ensemble members. The effect of this relative position will mean
widespread moderate rainfall will be possible through the day Friday
and into early Saturday. Recent EC probability of exceeding 0.5
inches in our forecast area is largely 50-80%. This is a little
higher then its GEFS counterpart. Something of note is the
deterministic spread vs ensemble mean spread is noticeable. For
example, the 0z GFS is suggesting 2-3 inches of rain across the west
while the ensemble mean struggles to reach 0.5 inches. This suggests
that a good bit of timing and convective influences still need to be
resolved as this system moves into the region.

The rain should end west to east through the morning hours on
Saturday, with weak and brief ridging spreading over the area
through the day. This should result in a dry day for the west and a
dry afternoon/evening in the east. A weakening shortwave moving
through the Dakotas/Minnesota will follow by Sunday. This may
support another round of showers/thunderstorms Sunday into early
Monday. If a surface low develops along the transiting cold front to
our south, as the EC is suggesting, this may extend through Tuesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 128 PM EDT Wed Jul 3 2024

VFR prevails through the forecast period, with just some diurnal
cumulus developing this afternoon. There is a chance for an
afternoon shower and even a rumble of thunder, but confidence in
timing and location of any one thunderstorm is too low to include in
the TAF. Our best chances would be around SAW. Otherwise, the main
concern for the forecast period continues to be gusty westerly
winds, with gusts up to 30kts at CMX this afternoon, and up to 20-25
kts at IWD and SAW. Gusts fall back this evening, then winds stay
below 10kts the rest of the forecast period.

&&

.MARINE...
Issued at 349 AM EDT Wed Jul 3 2024

Winds continue to settle this morning, falling to 20kts or less
before southwest winds near 25kts develop in the western portions of
Lake Superior, mainly between Isle Royale and the Keweenaw. Light
winds of 20kts or less settle in tonight and persist into Friday. At
this point, a low moving through the Upper Great Lakes may support
winds increasing to near 20-25kts Friday evening into Saturday.
Winds lighten after this through the remainder of the weekend to
20kts or below.

&&

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

&&

$$

SHORT TERM...LC
LONG TERM...JTP
AVIATION...LC
MARINE...JTP