979
FXUS63 KMQT 071838
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
238 PM EDT Sun Jul 7 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms over mainly the west half of
Upper MI this afternoon/early evening.

-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. Could see
highs into the 90s by Friday/Saturday.

&&

.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 SATURDAY/...
Issued at 311 AM EDT Sun Jul 7 2024

While we`ve seen a very progressive pattern thus far this summer, a
blockier pattern is now being realized as a large 500mb high
pressure ridge over the western U.S. slowly drifts eastwards into
the central and eastern U.S. this week. While this will allow weak
shortwaves to rotate over us during the first half of this week, the
blocky pattern will bring high pressure ridging to finish out the
last half of this week, probably (70% chance) bringing drier weather
with it, possibly the driest weather we`ve seen since the start of
summer. Additional details for the extended forecast follow below.

The scattered rain showers and thunderstorms over the western U.P.
this evening dwindle as the CAPE produced by the sunshine earlier in
the day dies down with the setting sun and as the remaining
convective cells utilize what`s left of the energy in the
atmosphere. While no severe weather is expected, there is just
enough instability and shear in the early evening hours to maybe
squeak out some sub-severe winds and small hail in some of the
stronger storms, in addition to lightning and heavy rainfall. Behind
the convection over the west half, we could see some patchy fog
develop around midnight tonight and stay until a couple of hours
after dawn Monday morning. As the shortwave behind the convection
today continues northeastward, a few isolated light rain showers and
maybe a stray thunderstorm or two looks to develop over the central
U.P. tonight before a secondary shortwave low from the Central
Plains lifts into the area and redevelops scattered rain shower and
thunderstorm activity over the eastern U.P. late tonight/early
Monday morning. As we move into the daylight hours Monday, CAMs have
convection redeveloping over the rest of the U.P. by the early
afternoon too. While there won`t be as much CAPE to work with during
the day Monday given the cloudier skies, with the secondary
shortwave being slightly stronger, expect to see a similar day to
what we will see today, with a couple of stronger storms possibly
producing sub-severe hail and winds. As the secondary shortwave
continues northeastward into Canada, expect the convection to
dwindle after sunset and to become relegated mainly to the east. A
tertiary shortwave moves through on Tuesday and brings more light
rain showers and thunderstorms over the inland areas by the
afternoon hours due to convection being highly dependent on the
instability caused by diurnal heating (weak forcing from the
shortwave low). The last of the showers and thunderstorms looks to
die out over the interior west Tuesday evening.

Moving into the latter half of this week, model and ensemble
guidance shows sfc ridging building over northern Ontario as the
high pressure block currently over the western U.S. slowly shifts
eastward. This high pressure ridge could very well keep us dry
through the rest of this week as early as Wednesday onwards. That
being said, there is a chance (~30%) that yet another weak shortwave
will bring light rain showers and thunderstorms back over the
interior areas Wednesday before we remain dry for the rest of the
week. Also worth noting is that the remnants of now Tropical Storm
Beryl have trended further north over the past 24 hours as it
traverses the interior U.S.. While the chance of seeing rainfall
from Beryl`s remnants is slim (<20%) given that the model and
ensemble consensus brings the track through Detroit, we could see
some light showers and maybe a thunderstorm or two over the eastern
U.P. come Wednesday/Thursday should the model guidance continue the
northward trend in Beryl`s track (see the 00z run of the GFS for an
example). Otherwise, the only other thing worth noting is the
gradually increasing temperatures throughout the last half of this
week into early this upcoming weekend; we could see high
temperatures reach into the 90s by Friday/Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 134 PM EDT Sun Jul 7 2024

VFR will be the predominant condition at IWD/CMX/SAW through the
forecast period. A disturbance moving through northeast MN will
result in scattered shra/tsra activity over the western half of the
U.P. with brief periods of impacts to IWD and CMX. Further east
confidence is lower in coverage of shra activity and is not mention
in the SAW TAF.  Visibilities may also reduce to MVFR at IWD after
midnight tonight in BR.

&&

.MARINE...
Issued at 311 AM EDT Sun Jul 7 2024

Light winds of generally 20 knots or less continue through this week
as high pressure ridging over the western U.S. slowly drifts
eastwards throughout the forecast period. That being said, some
thunderstorms are possible across the lake this afternoon through
tonight, and then along the nearshores Monday and Tuesday; while no
severe weather is expected, some notably stronger winds and small
hail could be seen in some of the stronger storms today and Monday.

&&

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

&&

$$

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