140
FXUS63 KMQT 191150
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
750 AM EDT Fri Jul 19 2024

.KEY MESSAGES...

- Lake-breeze pop-up showers possible over the east this
  afternoon.

- Best chances for rain (up to 50%) in the interior west on
  Saturday. Impacts should be minimal.

- Daily 20-30% thunderstorm chances through much of next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 423 AM EDT Fri Jul 19 2024

High pressure is continuing to dominate much of the short term
forecast. Current RAP analysis currently shows the high pressure
center over northern IL, extending ridging over the UP. At the mid-
level, a ridge is parked over the Rockies with a trough well to our
north over northern Quebec. Also, a shortwave is analyzed over
Manitoba. The radar mosaic is quiet and satellite mainly shows some
high clouds drifting southeast over Lake Superior and the eastern
UP. This has kept calm winds for most and let temps fall into the
40s in the interior west with 50s to low 60s in the east and by the
lakeshores.

As we progress through today, this high pressure is progged to
expand east along the southern end of the Great Lakes. While ridging
extending over the CWA begins to weaken late in the afternoon and
the shortwave ripples over the west, conditions still remain
relatively calm. Temperatures will be warmer than yesterday with
highs expected in the upper 70s to mid 80s. Winds turn westerly by
the afternoon with strongest winds expected in the Keweenaw and
along the east near Lake Michigan where some gusts up to 20 mph are
likely. Otherwise, low level winds are expected to remain light
enough for lake breezes to occur. While CAMs seemed to have backed
off on possibility of lake breeze pop up showers, they still can`t
be ruled out over the eastern UP as there should be enough WAA and
moisture should increase with the onshore flow off the lakes; the
7/19 0Z HREF indicates mean PWATs increase from ~0.75" to 1" and
mean MUCAPE of ~250-400 J/kg over the east. If any showers are able
to form, accumulations should remain below 0.05". Altogether, today
should be a nice summer weather day with diurnal cumulus decorating
the skies.

A cold front drops down from northern Ontario tonight and reaches
into the northern end of Lake Superior by Saturday morning bringing
a round of convection with it. However, once this line makes it to
the stable waters of Lake Superior, this is expected to diminish
over the waters; this drop off is captured well by the CAMs.
Otherwise, temps fall into the mid 50s to mid 60s, warmer near Lake
Superior. Skies also clear out after sunset with the only
partly cloudy skies expected ahead of the cold front.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 346 AM EDT Fri Jul 19 2024

Expect generally quiet weather as we head through an extended period
governed largely by weak high pressure over Ontario and weak
midlevel troughing over the central CONUS.

A diffuse cold front will be dropping southward through the UP for
the daytime hours of Saturday. CAMs continue to keep the northern UP
mainly dry given the timing of the frontal passage (possibly already
south of Hwy 28 by mid-morning), with convection firing again along
the front to the south as the sun comes up and we destabilize. Bulk
shear is low, so organized, strong convection is not expected.
Still, will note that SBCAPE does become pretty impressive ahead of
the front, with ensembles and various deterministic runs indicating
values exceeding 1000j/kg especially closer to the WI border. A
potential for some individual storms to "overperform" as we head
into a busy summer weekend may be worth monitoring. Otherwise, look
for temperatures ranging from the lower 70s near Superior to the
lower 80s in the south-central UP by the afternoon.

As skies clear out Saturday night, with light winds and a cooler
airmass working in, expect temperatures to come in several degrees
cooler compared to the previous night. However, temperatures recover
nicely for Sunday, peaking in the 70s to lower 80s under sunny
skies. Once we move into next week, we could see daily chances (20-
30%) for showers and thunderstorms across our area as weak high
pressure ridging cycles over northern Ontario and weak low pressure
troughing lifts through the Central U.S. The Tuesday-Tuesday night
period does present the best window for convection as a deeper
shortwave moves through the Great Lakes, but strong/severe storms
are not expected. Otherwise, temperatures come in more or less
seasonal with highs ranging in the 70s to lower 80s most days.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 750 AM EDT Fri Jul 19 2024

VFR conditions are expected to prevail through the duration of the
12Z TAF period as high pressure expands east along the southern end
of the Great Lakes. Some gusty west winds up to 20 kts are expected
at CMX and some lake breezes in the afternoon likely will result in
a rapid wind direction change mainly at SAW. Otherwise, no major
concerns are expected today as scattered cumulus develop this
afternoon. A cold front drops south over the northern end of Lake
Superior by Saturday morning. Even though CMX will be the first site
to see lower cigs to around 6 kft, precip looks to hold off until
after the 12Z TAF period.

&&

.MARINE...
Issued at 346 AM EDT Fri Jul 19 2024

Winds mainly out of the SW are starting off light, but expect gusts
to increase to around 20-25kts across the western half of the lake
today as a weak shortwave trough moves through.  There is a
potential for some strongest gusts as high as 30 knots between Isle
Royale and northern Ontario near Thunder Bay. Winds die down to 20
knots or less again tonight while a cold front moves through
overnight into early Saturday. There is a slight (20%) chance for
storms developing along this boundary to make it across the lake
late tonight,  but confidence is low. Winds stay light, mainly below
20 kts at least through Monday. Winds increase out of the NE across
the western portions of the lake Tuesday with another shortwave
trough moving through. Gusts around 20kts are possible. This is also
our next decent window for showers/storms to move over the lake (20-
30% chance) before mainly dry weather returns midweek onward.

&&

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

&&

$$

SHORT TERM...Jablonski
LONG TERM...LC
AVIATION...Jablonski
MARINE...LC