756
FXUS63 KMQT 170802
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
402 AM EDT Sat May 17 2025

.KEY MESSAGES...

- Light rain showers continue today through Sunday, mainly over
  the northern half of the U.P.

- Dry period expected to begin Monday and linger until Wednesday.
  High temperatures in this period are expected mostly in the
  50s to low 60s each day.

- Some frost is possible in the interior west next week.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 252 AM EDT Sat May 17 2025

Expect light rain showers to dominate the northern tier of the U.P.
today through the rest of this weekend as a vertically-stacked low
is moving eastward along the southern shore of Lake Superior early
this morning. The wrap-around moisture from the low will continue
light rain showers across the area, mainly over the traditional
northwest wind lake effect belts. While the light rain showers won`t
bring too much liquid to even these areas, the wrap around moisture
from the low will keep things moist across the area today. In
addition, with weak warm air advection moving in via the wrap around
moisture, expect high temperatures today to generally get into the
50s, coolest near the Keweenaw and warmest south central and far
east.

A secondary shortwave low moves into the area as the initial low
leaves for the St. Lawrence Seaway tonight and the Canadian
Maritimes/Maine on Sunday. This will keep upslope showers going over
the northern tier of the U.P. tonight into Sunday, although liquid
amounts from the (mostly) light rain showers will be only a few
hundreths. We could see some marginal lake enhancement take effect
as 925mb temperatures cool to around -4C over the north wind lake
effect belts late tonight into Sunday. In addition, there is a
chance that we could see the light rain showers transition over to a
very light wintry mix late Sunday as highs over the northern tier
are expected to not get above the upper 30s. Regardless, not
expecting any impacts if wintry precipitation does occur as the
ground should be too warm for accumulations.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 401 AM EDT Sat May 17 2025

The extended period is expected to be fairly quiet as high pressure
ridging from a Hudson Bay high dominates the start of the work week,
before wrap around moisture from a low lifting into southern Ontario
brings some more light rain showers back to the area to end the work
week. Because of the northerly air being cycled over our area next
week, expect below normal temperatures, although with dry conditions
Monday and Tuesday, it is possible we could see elevated fire
weather concerns those days, particularly over the interior west.
Additional details follow below.

The last of the precipitation from this weekend ends Sunday night
over the northern tier of the U.P. as high pressure ridging builds
in from a descending Hudson Bay high. By Monday, expect mostly sunny
to partly cloudy skies as ridging is projected to keep a developing
low pressure system over the Central Plains well away from our
region. Given the dry Canadian airmass, even though high
temperatures are expected to mainly get in the upper 40s to upper
50s, expect RHs to tank into the mid 20 percents across the interior
areas; this includes even the interior east, although the driest
conditions are currently expected over the interior west Monday
afternoon. With the pressure gradient between the Hudson Bay high
and developing low pressure over the Central Plains being fairly
modest, we could see northeasterly gusts up to 20 knots across the
area by Monday afternoon. We have the same song and dance on Tuesday
too, although RHs look to be even drier (getting down to around 20%
in the interior west), temperatures look to be a couple of degrees
warmer, and wind gusts could be a few mph faster. Overall, thinking
we will see at least limited fire weather concerns Monday and
Tuesday if not elevated concerns (particularly Tuesday over the
interior west); will keep an eye on this part of the forecast as we
approach early next week.

Our next chance at precipitation looks to come beginning Wednesday
next week as a mid to upper level low over the Upper Great Lakes
attempts to phase with the lower levels of the low moving from the
Central Plains to the Mid-Atlantic. While models are trending toward
a wetter solution for the end of the work week, a soaking rainfall
is still not expected as moisture will be somewhat limited; wouldn`t
be surprised if most of the precipitation is forced by upslope flow
(kind of what we will see today into Sunday). With cloud cover
remaining over the area, expect high temperatures to be limited to
around 50 (or less) along Lake Superior to generally the lower 60s
in the south central. While we do start to see ridging beginning to
build in at the end of the work week, we may also see the light
precipitation continue until next weekend.

One more thing worth noting in the extended period: we may see some
frost develop over the interior west during the overnight hours next
week. With lows projected to get down into the upper 20s to lower
30s Sunday night and onward, we could see patches to potentially
even areas of frost develop over the interior west during the
overnight hours; be sure to cover the plants you want to keep safe.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 102 AM EDT Sat May 17 2025

Expect all sites to fall to MVFR/IFR by sunrise, continuing through
Sat as a low pressure system tracks E overhead. Some LIFR is
possible at CMX and also IWD, but left mention out of the IWD TAF
for now as confidence is too low. Periods of showers are likely
across the UP with moisture wrapping around this system, but model
guidance is not in great agreement on timing.

&&

.MARINE...
Issued at 401 AM EDT Sat May 17 2025

Some dense marine fog is expected over the eastern open lake this
morning as the low pressure over our area continues trudging
eastward towards the St. Lawrence Seaway today; expect the marine
dense fog to dissipate behind the low (aka by late this morning).
However, once we get behind the low, expect northwest to northerly
winds of 20 to 30 knots to develop over the central and eastern lake
with a few gale force gusts up to 35 knots expected at times.
Indeed, over the north central lake, northerly gales to 35 knots are
expected this afternoon; thus a Gale Warning has been issued for the
north central between 2 PM and 8 PM EDT. As the departing low is
replaced by a secondary shortwave behind it tonight, expect the
winds to weaken to 20 to 25 knots from the north by Sunday morning.
These winds continue across the lake until Sunday evening, when high
pressure ridging building in from Hudson Bay drops winds down to 20
knots or less. That being said, with a modest pressure gradient
developing between the high over Hudson Bay and a low over the
Central Plains Monday, expect the winds to increase from the
northeast to 20 to 30 knots across the lake, with the highest winds
expected over the far west. While the winds will temporarily weaken
Monday night, expect the return of northeast winds of 20 to 30 knots
Tuesday, with a few gale force gusts up to 35 knots being possible
over the far west Tuesday afternoon (the NBM shows a 25% chance).
The northeasterly winds Monday into Tuesday could bring high waves
towards Duluth Harbor. As a low pressure over the Upper Great Lakes
tries to phase with the lower levels of the low moving from the
Central Plains to the Mid-Atlantic Wednesday into Thursday, expect
northeast winds of 20 to 25 knots to continue over the lake Tuesday
night into Wednesday, before the winds turn more northerly later
Wednesday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 2 PM this afternoon to 8 PM EDT this evening
     for LSZ264.

  Dense Fog Advisory until 11 AM EDT this morning for LSZ266-267.

Lake Michigan...
None.

&&

$$

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