287
FXUS63 KMQT 080730
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
330 AM EDT Mon Jul 8 2024

.KEY MESSAGES...

-Today through at least Tuesday, daily chances of showers and
thunderstorms, highest chances in the afternoons.

-Drier weather expected for the last half of this week, though ~25%
chance Beryl`s remnants complicate the forecast.

-Hot weather possible into the weekend, with ~35% chance of isolated
high temperatures in the 90s over the weekend.

&&

.UPDATE...
Issued at 737 PM EDT Sun Jul 7 2024

As of 730 pm EDT, cluster of showers and thunderstorms straddles the
WI/MI border in eastern Gogebic County associated with a broad lower-
level confluence zone. One storm briefly perked up SW of Marenisco
earlier in an environment of 30 kt deep layer shear and 1000 J/kg
MLCAPE, showing a broad mesocyclone and likely producing around 0.5"
hail, but otherwise, activity has been fairly shallow. Still not out
of the question for a stronger core to develop and result in small
hail and gusty winds to the east and northeast of current activity
through Baraga/Iron Counties given the aforementioned
thermodynamic/kinematic environment, especially where storm mergers
occur with some downstream showers moving more northerly. Storms are
rather slow moving so locally heavy rainfall can be expected as
well. HRRR suggests this activity may persist through around 03Z as
it moves E/NE before weakening.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 238 PM EDT Sun Jul 7 2024

Water vapor imagery showing upper low over northern MN with several
weak shortwaves rotating around it over WI and western Lake
Superior. Given proximity to the U.P. combined with diurnal heating
have already seen scattered shras and tsras develop over the western
third of the U.P.  A couple other shras have developed along the
Lake Michigan lake breeze along the Seney stretch. While a brief
stronger storm can`t be ruled out this afternoon given marginal
shear up to 25 knots and CAPE around 1000-1250 J/kg, expect storms
to lack organization. Most activity will diminish this evening with
sunset but as weak shortwave migrates eastward will maintain
slight/low chance pops over the eastern U.P. through the night.
Areas that do see some rain over the west, especially near evening
time may then see some patchy fog develop overnight tonight.  Lows
tonight will mainly be in the upper 50s to lower 60s.

&&

.LONG TERM /TONIGHT THROUGH SUNDAY/...
Issued at 329 AM EDT Mon Jul 8 2024

Overall, expect the middle of the extended period to be fairly dry
with a slight warming trend to finish off the end of this work-week
into this weekend. However, we could see some showers and
thunderstorms through some shortwave low action tonight through
Tuesday and again this weekend into early next week. In addition,
while the chance remains low (~25%), we could have the remnants of
Beryl bring rain showers over the south central and east Wednesday.
A more detailed discussion of the weather for the rest of this week
into early next week follows below.

Rain showers and thunderstorms dwindle from west to east this
evening and tonight as the shortwave low lifting through today
continues northeastwards out of our area and the setting sun cuts-
off diurnally induced CAPE. While wind shear is not strong enough to
support severe storms this evening, we could see some gusty winds,
small hail, frequent lightning, and heavy downpours in the strongest
storms right before to an hour or so after sunset across the U.P.,
mainly in the central and east where the convection will be focused
early tonight. By late tonight, expect the rain chances to drop to
0%. However, like the past few nights, we could still see some
patchy fog develop across the region, mainly in the east, north
central, and near the Keweenaw. Like the past few nights and days,
the patchy fog looks to burn off by the mid morning hours.

Expect Tuesday to be a bit drier as yet another weak shortwave moves
through the region. With the forcing being so weak, convection will
be relegated to the afternoon hours. While we could see sfc-based
CAPE get up to 1 to maybe even 2 kJ/kg, with model guidance showing
bulk shear values below 30 knots, only garden-variety showers and
storms are expected. The convection will die-off in the evening as
the sun sets.

Wednesday is when we begin to see differences between the different
model suites as the remnants of Beryl and a high pressure ridge over
northern Ontario come into play. As the high pressure block over the
western U.S. slowly waddles eastward this week, a high pressure
ridge moves through the Canadian Prairie provinces and into northern
Ontario by Wednesday. Simultaneously, the remnants of Hurricane Beryl
look to undergo cyclogenesis as it moves from the Ohio Valley
towards Detroit. While the model and ensemble consensus seems to be
pretty set in stone about the track of Beryl`s remnants, whether we
get some light diurnally-induced convection from it is still up in
the air as it will depend on the strength and placement of the high
pressure ridge over northern Ontario. Currently, the track of the
high remains just to the south of Hudson Bay. Therefore, with weak
ridging looking to be over our area, it is plausible, but not likely
(around a 20 to 30% chance) that we could see some light rain
showers and maybe a stray thunderstorm or two over generally the
south central/interior west and east on Wednesday. Afterwards, a
localized high pressure ridge builds to 1017-1020mb over Lake
Superior Thursday, causing us to remain dry from then until this
weekend.

As we head into this weekend from the middle of this week, expect to
see a slow increase in temperatures across Upper Michigan as warmer
air trains in from the west due to the high pressure block moving
eastwards into the central and eastern U.S.. By the time we reach
our warmest temperatures come Friday through Sunday, we have a 15-
25% chance of seeing high temperatures at least reach 90F across
many of the interior areas, with some isolated spots getting up to a
30 to 40% chance; currently, the days that are most likely to get
that hot are Friday and Sunday. However, don`t expect the heat to
stick around for too long, as model guidance suggests that a Clipper
low will bring rain showers and thunderstorms back across our area
as soon as Saturday and some cooler temperatures by early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 134 AM EDT Mon Jul 8 2024

Main potential impacts in the 06Z TAF cycle are fog potential early
this morning and thunderstorm potential this afternoon and evening.
Given earlier rainfall at IWD/CMX and low dewpoint depression,
MVFR/IFR fog/mist is possible through around daybreak. VFR
conditions should return shortly after sunrise as any fog burns off.
Afternoon destabilization combined with an approaching wave should
touch off showers and thunderstorms primarily in the afternoon and
evening. Though not totally out of the question for IWD/CMX to
see a shower or storm this afternoon, only VCTS/VCSH,
respectively, was included in the TAF as more stable air looks
to arrive fairly early in the afternoon to limit potential at
both terminals. Potential for multiple rounds of showers/storms
at SAW today from early afternoon through the evening with low
confidence on timing. PROB30 was included during the most
probable timeframe for tsra. VFR should prevail outside of any
showers or storms, but brief heavy downpours could result in IFR
vsby reductions in any storms.

&&

.MARINE...
Issued at 329 AM EDT Mon Jul 8 2024

Light winds of 20 knots or less continue through the rest of this
week into early next week as a high pressure block over the western
U.S. slowly trudges eastwards with time throughout the next several
days. That being said, we could see some isolated thunderstorms over
the eastern lake this morning and then along the nearshores today
into this evening. In addition, some patchy fog could be seen over
the lake today.

&&

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

&&

$$

UPDATE...Thompson
SHORT TERM...MZ
LONG TERM...TAP
AVIATION...Thompson
MARINE...TAP