936
FXUS63 KMQT 180728
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
328 AM EDT Thu Jul 18 2024

.KEY MESSAGES...

- Dry weather Thursday and Friday.

- Best chances for rain (up to 40%) in the interior west on
  Saturday. Impacts should be minimal.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 328 AM EDT Thu Jul 18 2024

Current RAP analysis and WV imagery show the positively tilted mid
level trough axis now centered over southern Quebec with a 1022 mb
high pressure centered over MN. With the trough out of the way,
skies have cleared across the UP. This alongside the dry northerly
flow and near calm winds has allowed radiative cooling to bring
temps down into the 40s to low 50s. As we continue to cool down
ahead of sunrise, temps in prone low lying cold spots may still dip
into the 30s yet. Some patchy fog is possible where temps have
reached the dewpoints, although widespread restricted visibility is
not expected.

As the high pressure continues to build over the Great Lakes, low
level winds will turn more westerly and WAA will bring temps near
normal today with highs expected in the 70s. Some lake breezes are
also expected off the Great Lakes this afternoon, leading to some
variability in the winds. With mixing, min RHs will drop into the
30s. That said, there are no wildfire concerns today given that
winds will remain light below 15 mph. Outside some diurnal cumulus
that looks to develop over the interior west and south central UP,
quiet and dry conditions are expected today.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 259 PM EDT Wed Jul 17 2024

The pattern aloft is fairly stagnant over much of the CONUS as a
large ridge over the Four Corners region will not progress much
through the forecast period, paired with broad troughing over
the US Southeast. To the north in Canada, anomalous 500mb
ridging extending north from the Four Corners right will cause
height anomalies to 20+ dam by Sunday. Despite the ridge causing
prevailing northwesterly flow aloft which typically brings
cooler air to the UP, the upstream anomalous heat associated
with that ridge will counter the usually cooler pattern,
resulting in mainly seasonal temperatures over the UP through
this forecast period. A deep trough passing through the eastern
Hudson Bay and Quebec will perturb the flow pattern enough to
cause some weak shortwaves that in junction with diurnal
heating, will cause some periodic low (15-35%) chances of
showers and isolated thunder in the interior west particularly
later in the forecast period.

Thursday and Friday will be dry as a 1022 mb high pressure slides
south of the region. Highs will continue a warming trend, with highs
in the 70s Thursday and low 80s Friday.

The next credible chances of precipitation reenter the forecast
Saturday as a weakening surface trough passes through the area in
response to a trough aloft passing through Quebec and the eastern
Hudson Bay area. Given how weak the synoptic forcing is, the showers
that do form will need a boost from diurnal heating, thus the
highest PoPs are in the interior west. With 00Z LREF mean SBCAPE
values around 400 J/kg, some thunder is possible especially along
the MI/WI state line but nothing severe is expected. Ensemble
solutions that keep the track of the surface trough a bit slower are
present enough to keep some slight (15-20%) diurnal PoPs right along
the state line for Sunday afternoon, but otherwise it should be a
pleasant Sunday with highs around 80. Ensembles diverge into next
week, but ensemble mean 500mb plots do show the ridge over the
Canadian Plains retreating somewhat and northwesterly flow
dominating over the UP, which should support weak clipper shortwaves
bringing periodic, low-impact rain chances for next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 138 AM EDT Thu Jul 18 2024

Expect VFR conditions at all the terminals through the period as
ridging builds in from the west and drier air advects across the
area. Expect fairly light winds and calm/SKC conditions early this
morning. Forecast soundings suggest the potential for diurnal
cumulus clouds to form Thursday mainly at SAW but again no impact on
aviation as VFR conditions expected. Light winds will take on a
lake breeze component at all sites by afternoon.

&&

.MARINE...
Issued at 259 PM EDT Wed Jul 17 2024

Northwest winds of 20-25 knots will diminish tonight across eastern
Lake Superior as a trough axis departs from the lake. After that,
the remainder of the forecast will have sub-20 kt wind gusts with
the exception of Friday afternoon, where the region of Lake Superior
between the Keweenaw Peninsula and Isle Royale will see
southwesterly wind gusts of 20-25 knots due to a disturbance in
Canada tightening the pressure gradient. Once wave heights fall
below 4 feet tonight, expect waves to remain below 4 feet through
the forecast period.

&&

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

&&

$$

SHORT TERM...Jablonski
LONG TERM...GS
AVIATION...Voss
MARINE...GS