711
FXUS63 KMQT 081952
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
352 PM EDT Mon Jul 8 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms this afternoon.

- Another round of diurnal thundershowers Tuesday.

- Drier weather expected for the last half of this week, though
  ~25% chance Beryl`s remnants could impact the eastern UP.

- Hot weather possible into the weekend, with ~25% chance of
  isolated high temperatures in the 90s over the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 243 PM 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 the Arrowhead of MN and western Lake Superior. Another
shortwave has moved from northeast Iowa earlier this morning into
northeast WI.  Mid level clouds and a few sprinkles have kept
convection at bay over the west half of the U.P. thus far. With
better forcing over Green Bay and the eastern U.P. shra/tsra
activity has been more organized there. Clouds are now breaking up
over the western U.P. and beginning to see some shras/tsras popping
up over northern WI so still anticipate scattered shras/tsras to
develop across the west especially where any convergence is
maximized along the lake breeze. However, coverage will likely be
less widespread than earlier thought.

Any remaining convection will quickly dissipate with loss of heating
this evening and as upper trough axis finally pushes through the
area skies will clear for most. Some patchy fog will once again be
possible especially where there are any late afternoon rains.
Overnight temperatures tonight will be in the mid 50s to around 60.

&&

.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 351 PM EDT Mon Jul 8 2024

By Tuesday morning, cutoff 500mb high will be over the SW CONUS with
a ridge axis extending north to British Columbia, leading to 500mb
height anomalies of up to +17 approaching the Canadian Rockies per
the 12Z GEFS. The high will remain largely stationary throughout the
week, but the ridge axis to the north will rotate through the early
portions of the week as a Gulf of Alaska trough will kick the ridge
axis to the east. For the early portions of the week, the weak
shortwaves spilling down from the peak of the ridge with some help
from diurnal heating will allow for daily thundershower chances
until the ridge axis progresses far enough east for a surface high
pressure to dampen precipitation chances. The remnants of Beryl may
throw a wrench in the forecast as it passes south of the UP in the
back half of the week, but regardless, some hotter weather will
return to the UP for the weekend with 90s not out of the question
(10-25%) for typical hot spots.

Tuesday`s daily shortwave passing over the UP looks to be among the
weakest of the batch, which combined with general 500mb height
rises, will lead to pretty weak forcing. Destabilization is still
expected as 12Z HREF SBCAPE peaks to almost 1000 J/kg, so diurnal
thundershowers are expected once again, but with 15-25 kt of bulk
shear, the thundershowers should be pretty disorganized and should
be well sub-severe. Expect showers to quickly end after sunset as
radiational heating ends.

The complications come Wednesday through the end of the week as the
ridge axis moves over the Canadian Prairie and forces a 1015-1020mb
high pressure over the Ontario Hudson Bay shores Wednesday morning.
However, the remnants of Beryl will arrive in Indiana by Wednesday
morning. The strength and path of both Beryl and the ridge will have
implications on the forecast through the end of the week. Beryl may
keep the high pressure far enough away Wednesday afternoon that more
diurnal showers are possible (15-25%), but around Wednesday evening
is when ensemble spread greatly increases on Beryl (and the high to
the north) tracks Thursday and beyond. The most likely solution (and
the one that the forecast reflects) is a faster cluster of solutions
for Beryl that allows for the high pressure to build over the Great
Lakes and keep dry weather over the UP until at least Saturday.
However, there are still around 20-30% of slower solutions in the
ensembles that allows Beryl to slide north further, which could
bring showers to the far eastern UP. Regardless of solution, after
Beryl`s remnant low passes through the Great Lakes and flow aloft
shifts from northwesterly to be more westerly, hot temperatures
could return to the UP, with the NBM showing about a 25% chance of
isolated 90 degree highs and 5-10% chance of more widespread 90s
highs. The heat wont stick around forever, as model guidance
suggests that a Clipper low passing through northern Ontario may
bring rain showers and thunderstorms back across our area as soon as
Saturday and some cooler temperatures by early next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 127 PM EDT Mon Jul 8 2024

VFR will be the predominant condition at IWD/CMX/SAW through the
period. While the development of convection has been hindered by
widespread clouds thus far, approaching clearing breaks should allow
scattered shras/tsras to develop across the central U.P. through the
afternoon. Lake breezes appear to be through CMX and IWD so
probabilities of thunder are much lower at IWD and CMX. Any shra/tsra
activity will quickly diminish with sunset. Some patchy fog may
develop at SAW and IWD late tonight similar to this morning with
MVFR visibilities for a short time. Otherwise cigs will be VFR with
light winds.

&&

.MARINE...
Issued at 351 PM 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
US slowly trudges eastwards with time throughout the next several
days. As a result, waves will be less than 2 feet throughout the
forecast period. Isolated thunderstorms are ongoing over the eastern
lake along the nearshores and will continue into this evening. In
addition, some patchy fog could be seen over the lake through
tomorrow, especially in the wake of precipitation.

&&

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

&&

$$

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