941
FXUS63 KMQT 251944
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
344 PM EDT Tue Jun 25 2024

.KEY MESSAGES...

- Gusty winds up to 40 mph across the Keweenaw into early
  evening.
- Pattern remains active, especially from late week into early
  next week, with yet more rounds of showers and storms

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 343 PM EDT Tue Jun 25 2024

Water vapor imagery and RAP analysis show that the convectively
enhanced shortwave that brought shra/tsra to the area last night is
over Georgian Bay. Another shortwave trof extends from James Bay to
nw of Lake Superior and a third shortwave is over southern
Saskatchewan. At the sfc, a trof extends across eastern Lake
Superior and central Upper MI, and a cold front extends from James
Bay to just nw of Lake Superior. Rapidly deepening mixed layer to
the w of the sfc trof is leading to sharp drying this aftn as sfc
dwpts are plummeting into the mid 40s to lwr 50s F across western
Upper MI. To the e, sfc trof and lake breeze development off of Lake
Superior has led to a few shra developing recently.

For the next couple of hrs, expect isold shra over the eastern fcst
area ahead of sfc trof/lake breeze. Otherwise, dwpts will continue
to fall from w to e in the wake of passing sfc trof, leading to more
comfortable conditions under temps in the mid 70s to mid 80s F.
Across the Keweenaw, fcst soundings suggest wind gusts to around 40
mph over the next several hrs. Wouldn`t be surprised to see a few
gusts to around 45 mph for a couple of hrs based on winds at top of
mixed layer. Otherwise, wind gusts of 20-30mph will be fairly common
over roughly the w half of Upper MI.

Cold front approaching Lake Superior will drop s across the area
later this evening/overnight. Other than a wind shift to n to ne, it
should pass uneventfully given the drying that is currently
underway. Expect clear to partly cloudy skies thru the evening. Late
tonight, attention turns to shortwave currently over southern
Saskatchewan. This wave will reach nw WI/western Lake Superior
around 12z Wed. Given the decent, small cluster of shra currently
associated with this feature, models seem on track bringing shra
into nw Upper MI in the 10-12z timeframe. Cold front that drops into
the area tonight will be aligned from northern MN se thru northern
WI early Wed morning, and that should also provide some focusing of
forcing as well due to weak waa over the boundary in response to the
wave. Temps tonight will fall back to the mid 40s to mid 50s F.

&&

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 320 PM EDT Tue Jun 25 2024

An inverted trough along a descending cold front from northern
Ontario moving through the U.P. Wednesday looks to bring some light
rainfall across mainly the Keweenaw during the morning hours before
degrading throughout the day and only bringing slight rain chances
to the east and south central later in the day. As high pressure
ridging builds in from our west throughout the day, expect the cloud
cover to dissolve away with time Wednesday. However, with fairly
cool temps aloft moving over us in association with the ridging
moving in and the cold air advection behind the front (4-6C), highs
Wednesday should be limited to the 60s inland and the mid 50s to
around 60 along the Lake Superior shoreline. With ridging continuing
to build into the Upper Great Lakes Wednesday night, expect clear
skies, allowing temperatures to plummet in the interior areas; some
spots could get into the mid to upper 30s or lower. That being said,
given the drier air moving in, no frost is expected to form over the
interior areas Wednesday night.

Calm weather continues Thursday as the high pressure ridging peaks
over us during the morning hours. More active weather looks to
return late Thursday night/Friday as a low lifts off of the Rockies
through the Canadian Prairies/Northern Plains into northern Ontario.
Along the cold front moving through Friday through Saturday expect
some showers and thunderstorms. In addition, a shortwave low
rotating around the low pressure system could bring additional light
rain shower activity (that`s possibly upslope enhanced) late
Saturday into possibly Sunday morning behind the cold front. With
MUCAPE between 500-1500 J/kg ahead and along the cold front and 0-6
km bulk shear around 40 to 50 kts, there is a non-zero chance that
we could see some severe weather as the cold front passes.

More quiet weather returns early next week as yet another high
pressure ridge moves overhead. Behind it, another low pressure
lifting through the Canadian Prairies looks to bring more rain
showers and thunderstorms to end the extended period. Overall,
expect temperatures around normal for the next several days, with
showers and thunderstorms coming and going every few days.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 140 PM EDT Tue Jun 25 2024

With drier air advecting into the area on gusty wnw winds this aftn,
VFR will prevail at IWD/CMX/SAW. These winds will gust to around
20kt at IWD, to around 30kt at CMX and to around 25kt at SAW. Winds
will diminish toward sunset and then veer n to ne. In the 09z-12z
timeframe, low clouds (MVFR cigs) will arrive at all terminals. A
few shra may also occur at CMX btwn 11-14z. The MVFR cigs will
scatter out to VFR at IWD by aftn and at CMX/SAW during the aftn.

&&

.MARINE...
Issued at 320 PM EDT Tue Jun 25 2024

The last of the patchy fog over the eastern lake ends late this
afternoon/early this evening as a cold front descends from northern
Ontario this evening into Wednesday. As this happens, the southwest
to west winds of 25 to 30 knots across the lake this afternoon die
down to 20 knots or less behind the cold front. The light winds look
to continue Wednesday to Friday morning as high pressure ridging
moves over the region. Once we get into Friday, thunderstorms look
possible over the lake again as a low pressure lifting from the
Rockies moves towards northern Ontario. Currently, thunderstorms
look possible Friday through Saturday; as of right now, there is a
non-zero chance of severe weather. In addition to the thunderstorms,
winds pick back up to around 20 knots from the southeast Friday as
the low`s center approaches. With the surface low looking to move
through Lake Superior Friday night/Saturday, we could see winds
shift suddenly and sharply near the center of the low. Behind the
low, expect winds from the north and northwest to pick to 20 to 25
knots across the lake. That being said, if the cold air advection
behind the low is strong enough, we could see gusts up to 30 knots
or even gales (see the 12z run of the GFS for an example). These
stronger winds look to die down to 20 knots or less again by
Saturday night as ridging starts building back in once again over
the region. The light winds continue Sunday into next Monday as high
pressure ridging dominates the Upper Midwest.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 9 PM EDT this evening for MIZ014.

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

&&

$$

SHORT TERM...Rolfson
LONG TERM...TAP
AVIATION...Rolfson
MARINE...TAP