552
FXUS63 KMQT 100755
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
355 AM EDT Wed Jul 10 2024

.KEY MESSAGES...

- Areas of fog early this morning, mainly in the north central
  and east. Some spots could be dense.

- Isolated showers and storms possible in the interior west and
  far east this afternoon.

- Showers and thunderstorms enter the picture again over the
  weekend. Severe storm risk will need to be monitored for
  Sunday and Monday, maybe Tuesday as well.

- Very warm and humid over the weekend with high temperatures
  well into the mid and upper 80s F. About a 10% chance of
  widespread high temperatures at or above 90F. Cooling trend
  begins Monday.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 226 AM EDT Wed Jul 10 2024

Some areas of fog are looking to develop over the north central and
east in the pre-dawn hours this morning as marine fog over Lake
Superior advects onto shore. Indeed, webcams show that a patch of
fog has already developed up the hill from Munising in Wetmore, and
M-28 near I-75 has also developed some fog as well. With upslope
flow continuing through the pre-dawn hours, we could see patchy fog
develop well inland into the interior west, as well as the Keweenaw.
Conditions will continue to be monitored this morning on whether
dense fog occurs; if it does, then an SPS or a Dense Fog Advisory
could be forthcoming. Once we get past dawn, expect the fog to burn
off, but a little bit slower this morning over the north central and
east as high-level clouds from Beryl`s remnants remain over the
area. These higher-level clouds will help the central and east to be
a little cooler today than yesterday, in addition to the high
pressure over Lake Superior strengthening and creating a stronger
lake breeze. Overall, expect highs in the 70s inland with maybe a
few spots hitting 80 in the interior west, whereas near Lake
Superior highs will probably be around 70. In the afternoon hours,
as the remnants of Beryl move through Detroit into southern Ontario,
we could see enough forcing from the former hurricane to create some
isolated showers and storms over the far east (Newberry and
eastward) this afternoon, with a secondary shortwave digging from
the Northern Plains towards the Ohio Valley possibly bringing some
isolated showers and storms to the interior west by mid afternoon.
Any rainfall we do see today looks to rather light, and no severe
weather is expected.

&&

.LONG TERM /TONIGHT THROUGH TUESDAY/...
Issued at 354 AM EDT Wed Jul 10 2024

Last 24hrs of medium range model runs have maintained consistency on
the large scale evolution of the flow across N America over the next
7 to 10 days, and if anything, agreement has improved a little.
There has been slight progression of western N America mid-level
ridging and central N America troffing over the last 24hrs. This
progression will continue over the next few days as a shortwave
moving off of the ne Pacific into Canada flattens the ridge and
forces height rises/positive height anomalies to spread downstream
across southern Canada. A second wave will quickly follow off of the
ne Pacific Fri/Sat. As ridging then rebuilds over western N America,
that wave will be forced se, leading to modest trof amplification
over eastern Canada and the ne U.S. during the mid week period next
week. For Upper MI, this evolution of the pattern will support a
drier pattern for the next few days. There are still indications for
a shortwave to pass early weekend, supporting the potential of
shra/tsra later Sat/Sat night. The next potential of greater
coverage pcpn events as well as possible svr storms will be late
weekend/early next week in advance of and in association with the
onset of eastern troffing. As for temps, the spreading of positive
height anomalies downstream across southern Canada will herald a
warming trend beginning Thu, leading to a very warm/humid weekend
with highs well into the 80s to 90F. Cooler weather will follow once
eastern troffing develops early next week. Still looks like there
will be a couple of pleasant U.P. summer days in the midweek period
next week as Canadian high pres settles over the Great Lakes region.

Beginning tonight, any shra from this aftn over the interior w and
far eastern fcst area will move out of the area or dissipate before
sunset. Some fog/stratus may continue to persist e near Lake
Superior. Otherwise, a quiet night with little/no wind may support
some radiation fog development, especially w where lower level winds
will be lightest. Min temps should range from the upper 40s to 60F,
coolest at traditional interior cold spots across the w.

Models have definitely trended toward a more hostile environment for
any potential aftn isold convection on Thu and Fri. Compared to
24hrs ago, fcst soundings now show a notably drier column both days,
especially on Thu, and that also includes a somewhat drier look in
the boundary layer. Not only does the much drier air aloft thru a
much deeper layer make convection less likely, but the drying in the
boundary layer also results in parcels not being able to get passed
weak capping. Thus, expect dry weather across the board Thu thru
Fri. High temps in the mid 70s to lwr 80s on Thu will rise to mostly
the 80s on Fri. Expect locally cooler conditions along Lake Superior
and Lake MI on Thu and mainly just near Lake MI on Fri as a s to sw
gradient wind takes over.

Over the weekend, warming under sw flow will send high temps well
into the mid and upper 80s F. NBM probabilities of exceeding 90F
have slipped slightly from 24hrs ago. Potential of widespread high
temps aoa 90F is now down to around 10pct, but probabilities are
higher locally near Lake Superior in areas that see downsloping
under s to sw winds.

Arrival of a shortwave supports the potential of sct shra/tsra Sat
aftn/Sat night. Then late weekend/early next week, timing of main
shortwave that brings cooling to the area is still fairly uncertain.
However, ahead of that wave, models continue to show other subtle
waves that will be progressing thru wnw flow into the Upper Great
Lakes. Given the substantial instability that will build due to the
very warm/humid conditions over the Upper Mississippi Valley/Upper
Great Lakes and the climatologically favored wnw flow regime for
summer svr storms in Upper MI, there will be a risk of svr storm
complexes with these waves. Of course, at this time range, timing of
these subtle waves and the resulting convection, including where
convection develops, is highly uncertain. Will certainly be
something to monitor Sun/Mon, maybe Tue as well. Fcst reflects a
broad brushing of chc pops, generally 30-40pct, Sun thru Tue.
Cooling should get underway Mon or Tue, more likely Tue, leading to
what should be pleasant U.P. summer weather Wed/Thu as Canadian high
pres settles over the Great Lakes.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 119 AM EDT Wed Jul 10 2024

Main forecast challenges revolve around fog potential for the
morning hours today. Shallow radiation fog is possible at IWD
through around sunrise as winds remain calm. At SAW, the expectation
is for low clouds/fog to advect inland off the lake. There is still
uncertainty revolving around how thick and long-lived the fog will
be, but enough confidence with this cycle to bring in prevailing IFR
with tempo LIFR conditions. Conditions return to VFR once this burns
off, most probably around 14-15Z but with some uncertainty. Latest
model runs suggest fog/low clouds do not make it into CMX, but still
around a 20% probability for some vis/cig reductions there 09-13Z.

&&

.MARINE...
Issued at 354 AM EDT Wed Jul 10 2024

A weak pres gradient will dominate over and in the vcnty of Lake
Superior for the next several days. Result will be winds across Lake
Superior under 20kt and often under 15kt. Some increase in winds may
occur over the weekend with high pres to the se and low pres
troffing to the w and nw.

Areas of fog, locally dense, currently over portions of eastern Lake
Superior will become confined to southern portions of the lake to
the east of the Keweenaw today due to northerly winds. Difficult to
say how long this fog will persist, but it would seem that advection
of drier air across the lake should lead to the fog clearing out
later today and this evening.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Dense Fog Advisory until 11 AM EDT this morning for LSZ249>251-
     266-267.

Lake Michigan...
None.

&&

$$

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