235
FXUS63 KMQT 030750
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
350 AM EDT Wed Jul 3 2024

.KEY MESSAGES...

-After a brief dry break for the late afternoon and early evening,
additional showers move back in tonight with around a 20% chance for
thunder early on.

- Widespread southerly wind gusts of 25 to 30 mph (potentially up to
40mph in the downsloping areas near Superior) continue this
afternoon, falling back into the evening.

- Low chance (~25%) of afternoon showers/storms across interior
western Upper Michigan on Independence Day. Rain/isolated thunder
spreads over the region Thursday night and Friday.

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

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 307 PM EDT Tue Jul 2 2024

Water vapor and RAP analysis continue to highlight an upper trough
and surface low over Manitoba, and a couple of shortwaves ahead of
this. The first, currently moving out of the Great Lakes, touched
off our initial round of rain showers that is slowly tapering off
across the eastern UP this afternoon. After a brief dry break, the
next shortwave ejecting out of the Plains will bring in our next
round of light showers after 00Z. Though some thunder is possible,
confidence is low with rather limited instability (a few hundred
j/kg of MUCAPE by the evening and capped soundings).

Meanwhile, with plenty of lower cloud cover over the area,
temperatures are on the cool side with most of the area only peaking
in the lower 60s. However, some spots in the western UP are
struggling even to get out of the 50s. Southerly winds remain gusty,
especially across the downsloping areas long Lake Superior, with a
strong 40-50KT LLJ directed over the area. Gusts up to 20-30mph are
common area-wide, but where downsloping becomes a factor, stronger
gusts in excess of 35mph and even up to 40mph are not out of the
question. Winds fall back into the evening while the jet shifts
eastward out of the area.

As the next shortwave moves in, rain showers become most likely
across the eastern half of the UP with areas west of M-95 possibly
staying dry the rest of the night. Another quarter to half an inch
of rain is possible across the eastern UP. Otherwise, temperatures
shouldn`t fall back too much with rain and lingering low cloud
cover. Expect lows to range in the upper 50s to lower 60s.

&&

.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 /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 124 AM EDT Wed Jul 3 2024

Lingering showers at SAW will taper off shortly, but IFR cigs are
expected to linger through daybreak if not a bit after. Cigs should
scatter out with VFR expected by mid-morning. A similar trend toward
VFR should be seen at IWD/CMX, though likely earlier. Winds shift
westerly during the day today, with gusts around 20 kt at IWD and
approaching 30 kt at CMX.

&&

.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...Thompson
MARINE...JTP