943
FXUS63 KMQT 081130
AFDMQT

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

.KEY MESSAGES...

- Scattered showers and thunderstorms this afternoon. In
  addition to heavy downpours, brief gusty winds and/or small
  hail are possible, but severe storms are not expected.

- At least through 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.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 345 AM EDT Mon Jul 8 2024

Water vapor imagery and RAP analysis show mid-level troffing
extending from Hudson Bay thru the central U.S. One shortwave is
over far ne MN/adjacent Ontario. A more notable wave is over IA, and
it has a cluster of shra/tsra associated with it. At the sfc, the
pattern is ill-defined with really no discernible boundaries noted,
just simply broad troffing extending from northern Ontario into the
Upper Mississippi Valley. Last of the shra/tsra that were lingering
over portions of western Upper MI last evening have recently
dissipated. Otherwise, it`s been a quiet overnight. There is little
to no wind, and temps currently range from the upper 50s to mid 60s
F.

Shortwave currently supporting the convection across eastern IA may
further support isold shra/tsra development downstream to the ne
into s central and eastern Upper MI over the next few hrs.
Otherwise, attention is on the mid-level trof axis to the w that
will reach western Upper MI this aftn, providing a favorable setup
for convection to develop. Perusal of 00z models suggests about 500-
1200j/kg of MLCAPE will build today. As was the case yesterday, the
HRRR is around or blo the low end of that range, and the NAM is
mostly above that range, as high as 2000-2500j/kg. Deep layer shear
should be on the order of 20-30kt with the greater shear over
roughly the e half of Upper MI. Some storm organization is possible
where storms develop in the higher shear environment, but at this
point, don`t anticipate any svr storms today given the currently
expected parameters. Brief gusty winds and/or small hail are a
possibility in addition to the brief hvy downpours that will
accompany some of the storms. Expect shra/tsra to begin developing
btwn 16-18z. There should be a focusing of convection vcnty of lake
breeze pushing inland over western and northern Upper MI during the
aftn. For the most part, high temps will be in the upper 70s/lwr 80s
F.

&&

.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 /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 729 AM EDT Mon Jul 8 2024

While VFR is likely to prevail at IWD/CMX/SAW during this fcst
period, there are some exceptions. Sct shra/tsra are anticipated
across much of Upper MI this aftn. Developing stabilizing flow off
of Lake Superior should result in less potential of shra/tsra at
IWD/CMX, especially CMX. Fcst includes a VCTS mention at IWD and
only VCSH mention at CMX. At SAW, there is the potential of a few
rounds of shra/tsra during the aftn and early evening. While fcst
has MVFR mention with the tsra, brief IFR certainly possible if any
hvy rainfall occurs. Late tonight, there is some potential for fog
to develop, bringing the prospect of MVFR or IFR.

&&

.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.

&&

$$

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