807
FXUS63 KMQT 222035 CCA
AFDMQT

Area Forecast Discussion...CORRECTED
National Weather Service Marquette MI
435 PM EDT Sun Sep 22 2024

.KEY MESSAGES...

- High swim risk through this evening for the Lake Superior
  beaches of Marquette and Alger counties.

- Other than a low chance (15-30%) of showers Tuesday into
  Wednesday southeast and east, dry weather is expected this
  upcoming week with a trend toward much above normal temps
  again late in the week.

- Patchy frost is possible (~20%) for typical cold spots of
  interior western Upper Michigan both Monday and Tuesday
  mornings.

- Supportive setup for typical fall radiative patchy fog (~25%)
  each morning next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 217 PM EDT Sun Sep 22 2024

Water vapor imagery shows a well-pronounced midlevel shortwave
moving through northern Ontario, while at the surface, the
associated cold front is already through most of Upper Michigan.
Rain showers lingering in the far eastern UP should come to an end
by the evening. Skies are largely clearing behind the front with
ridging extending out from the Plains. Still, with cool NW flow
(around 4C at 850mb) over the 15-18C waters of Lake Superior, some
lake clouds are apparent over the northwest and north-central UP.
Soundings really begin to dry out at lower levels into the evening,
however, so we may be able to see some more clearing while flow
turns more anti-cyclonic.

Meanwhile, NW winds remain elevated, with gusts up to 20mph common
across the area. Higher gusts to 20-30mph will remain possible
across the Keweenaw through the afternoon. Where skies are clearing
out, temperatures have been able to climb up into the lower to mid
60s, but to the east, we may struggle to get out of the 50s this
afternoon.

Temperatures quickly fall back into the 40s across most of the UP
under clear skies tonight, and with a pretty sharp inversion present
among some of the model soundings, patchy fog will be possible. As
temperatures dip further into the 30s in the typically cooler
locations throughout the interior-western UP, some patchy frost may
also develop. However, if lake clouds can be more persistent than
expected, temperatures may come in a couple degrees warmer.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 420 PM EDT Sun Sep 22 2024

Beginning Monday, the mid-level trough over the area today will
shift east tonight as weak shortwave ridging and an associated weak
sfc ridge build in from the west ensuring dry conditions and partly
cloudy to mostly sunny skies. With a ne-e mostly onshore flow and
850 mb temps of 6-8C lingering over the area through much of the
day, expect max temps in the lower to mid 60s.

Monday night through the mid portion of next week, the trough over
the Dakotas dives southeast toward the Lower Mississippi Valley
which helps ejects a shortwave northeastward from the Mid
Mississippi Valley/Central Plains. This shortwave and its associated
sfc low are expected to track northeast through Lower MI and the
Central Great Lakes late Tuesday into Wednesday. While a few models
suggest some light showers associated with this system may scrape
the southeast and eastern portions of the UP Tuesday into Wednesday,
accumulations will be very light as the better forcing remains se of
the CWA. Otherwise, highs on Tuesday and Wednesday should trend
above normal from the mid 60s to mid 70s, warmest Wednesday.
Monday night could be another cool night with lows in the upper
30s to upper 40s with maybe some patchy frost possible again for
the interior west cool spots. Model soundings show a more
impressive inversion Monday night compared to tonight, so there
is more radiation fog potential Monday night.

The amplified mid level ridge over the western CONUS shifts east
toward the Great Lakes late week into the weekend as models show a
Rex block developing over the central CONUS including the Upper
Great Lakes region. Models indicate an amplified 588-590 dam 5H
ridge dominating the Upper Great Lakes/Upper Midwest region getting
undercut by the closed low over the Southern Plains/Lower
Mississippi Valley. There are some model discrepancies on how the
closed low to the south interacts with the forecast tropical system
lifting out the Gulf of Mexico later in the week and whether any
moisture from that tropical system can reach north to bring any rain
chances into the Upper Great Lakes next weekend. That said, the
stronger ridging moving over the Upper Great Lakes region will favor
continued dry weather for the late week through probably much of
next weekend with a trend toward well above normal temps. Expect
highs Thu-Sat reaching into the mid to upper 70s across much of the
area and wouldn`t be a bit surprised to a few lower 80s possible
over the western interior.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 116 PM EDT Sun Sep 22 2024

While low cloud cover is scattering out at IWD with mainly VFR the
rest of the day, MVFR ceilings persist at CMX and SAW with satellite
showing some lake clouds developing amid cooler NW flow. Drier air
working in should allow ceilings to lift to VFR into the evening,
then VFR is expected at all terminals the rest of the forecast
period. However, with light winds and clear skies tonight, there is
a slight chance for some patchy fog development tonight. However,
confidence is too low to include in the TAF at this time. Otherwise,
expect NW winds to turn gusty at times today, with gusts up to 20-
25kts possible especially at CMX.

&&

.MARINE...
Issued at 420 PM EDT Sun Sep 22 2024

Northwest winds gradually fall below 20 kts from west to east across
the lake this afternoon through this evening, veering north tonight.
Although a low pressure system tracks through Lower MI and the
Central Great Lakes late Tuesday into Wednesday, winds are expected
to remain below 20 kts through the remainder of the forecast.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 10 PM EDT this evening for
     MIZ005-006.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...LC
LONG TERM...Voss
AVIATION...LC
MARINE...Voss