820
FXUS63 KMQT 220516
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
116 AM EDT Mon Jul 22 2024

.KEY MESSAGES...

-Showers and thunderstorms from as early as Monday afternoon to as
late as late Wednesday across the area. No severe weather is
expected.

-High pressure and dry weather return to the forecast Thursday
through Saturday along with a warming trend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 257 PM EDT Sun Jul 21 2024

High pressure is centered over Lake Superior this afternoon with
light northerly Lake breeze flow the primary wind direction across
the U.P. While the center of the surface ridge may nudge a little
bit eastward through the night tonight winds will remain light and
variable under mainly clear skies. Low temperatures last night fell
below the lowest available guidance across the interior west with
even a few upper 30s lows. Will undercut by a degree or two the
lowest guidance for tonight especially across the interior east as
that area will be right under the ridge axis. Otherwise...lows will
fall into the 50s closer to the lakeshores and in the far west
where light southerly return flow and some higher clouds will
arrive towards morning.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 354 PM EDT Sun Jul 21 2024

Weak high pressure of 1018-1020 mb leaves Lake Superior Monday
morning as a weak trough of 1014-1015 mb drops down from around Lake
Winnipeg to Minnesota throughout the day. Because of this, expect a
battle between the lake breezes by the afternoon hours over the east
(with the Lake Michigan lake breeze probably/70-80% chance of moving
further inland than the Lake Superior one), while scattered rain
showers and thunderstorms look to move over the west half.
Initially, expect Monday to start out fairly similar to today, with
mostly sunny skies; high temperatures even look to be similar in
comparison to today`s, albeit a few degrees warmer. The main
difference comes in the afternoon when the aforementioned shortwave
begins firing off convection in the western U.P. around noon Central
Time with the assistance of diurnal heating. While there is plenty
of instability to work with over the interior areas, with little
forcing and lack-luster shearing overhead, no severe weather is
expected.

The showers and thunderstorms continue into the rest of
the U.P. Monday night into Tuesday morning as the shortwave low
becomes better organized and deepens to 1012-1015 mb. Uncertainty
still remains on rainfall totals and even rain chances Monday
afternoon through Tuesday as guidance as a whole has trended the
shortwave low deepening earlier and further to the northwest (near
us) in comparison to yesterday; so far, the European ensemble and
deterministic models are the most aggressive with rainfall amounts,
with the ECMWF EFI highlighting QPF amounts well above modeled
climatology, with a third of the models hinting at rainfall amounts
in the 10th percentile of modeled climatology (shift-to-tails of 0).
In addition, the LREF shows a 10-30% chance of 1 inch or greater of
rainfall Monday night through Tuesday across most of the area,
although much of this is due to the inclusion on the European model
suite. Meanwhile, other model guidance systems, including many of
the CAMs, have backed-off on rainfall totals and chances Monday
through Tuesday, with the WRF-ARW, NSSL, FV3, and HRRR keeping the
highest precipitation chances over Lake Superior and just to our
south in Wisconsin. Therefore, while there is signal for a soaking
rainfall, there is also the possibility that we will only see light
scattered showers and storms early to mid this week. Also, expect no
severe weather Monday night through Tuesday as well given the cloud
cover and the bulk shear being fairly marginal (around 30 knots).

If you were missing the lake-effect precipitation this summer, you
could be in `luck`, as inversion temperatures just may be cool
enough to get delta-Ts to around 13C right behind the main line of
precipitation Tuesday night and Wednesday. With some upslope
northerly flow to help out, we could see some lake-effect
drizzle/light rain showers over the north wind lake-effect belts
Tuesday night into Wednesday. Given the marginal delta-Ts, only a
few hundreths of an inch of rainfall are expected with these
showers. As high pressure pushes in from the west earlier than
previously expected, model guidance as a whole generally shows the
rainfall ending from west to east Wednesday, first the main line
precipitation followed by the lake-effect rainfall. Expect mostly
clear skies by Wednesday evening.

High pressure ridging dominates the latter half of the extended
period as the high pressure block over the Southwestern U.S. finally
brings ridging over the Upper Midwest the rest of this week into at
least the middle of this weekend. As the ridging moves through and
we get on its backside, expect warming temperatures from Thursday
onwards; temperatures could get up to 90F in the downslopes near
Lake Superior this weekend as surface flow picks up from the
south/southwest.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 115 AM EDT Mon Jul 22 2024

Clear and calm conditions are expected to continue into much of
Monday as high pressure continues to dominate the UP. A weak
shortwave moving into western Lake Superior Monday evening could
kick up some showers and a possible thunderstorm during the late
afternoon and evening hours in the west half near IWD and CMX, but
confidence in overall coverage is low so only included a VCSH at IWD
by late afternoon and at CMX by late evening.

&&

.MARINE...
Issued at 354 PM EDT Sun Jul 21 2024

High pressure over Lake Superior will keep lake winds 20 knots or
less the rest of today through Monday, until a cool front dropping
down from Canada increases winds from the northeast over the west
half Monday night into Tuesday; winds could gust between 20 and 25
knots throughout the day Tuesday. Behind the cool front, expect the
winds to slowly lighten, becoming 20 knots or less again by Tuesday
evening; the light winds look to remain through the rest of this
week as ridging begins building in from the west.

As for t-storm chances this week, we could see some storms as early
as Monday over the far western lake as a weak 1014-1015 mb shortwave
low drops down from Lake Winnipeg to Minnesota ahead of the cool
front. As the shortwave deepens and becomes better organized Monday
night into Tuesday near the U.P. (possibly due to interacting the
cool front), the thunderstorm chances move east with time and
generally become more confined to the southern Lake Superior
shoreline; the thunderstorm chances look to end over the far eastern
lake Tuesday night.

&&

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

&&

$$

SHORT TERM...MZ
LONG TERM...TAP
AVIATION...Voss
MARINE...TAP