762
FXUS63 KMQT 210125
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
Issued by National Weather Service Gaylord MI
925 PM EDT Tue May 20 2025

.KEY MESSAGES...

- Showers into Tonight?

- Breezy through Wednesday...

- Showery and cool into the end of the week...

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 434 PM EDT Tue May 20 2025

PATTERN SYNOPSIS/FORECAST:

Negative tilt longwave trough axis stretches from British Columbia
to the Mid MS Valley today...with strong punch of PV over MO/IA
attm. As a result...1000mb occluded surface low hanging out over
IA...with surface trough axis stretching back through the Northern
Plains...warm front extending into the OH Valley...and cold front
stretching back into TX. 1032mb surface high standing relatively
firm over Hudson Bay...though pressure is falling over the Upper
Great Lakes. In the middle, beneath upper col region...strengthening
pressure and moisture gradient over the Midwest attm with strong
E/NE winds across the region and a swath of precip from Minnesota
through central WI into SW Lower MI. Temps holding in the 40s to
near 50 across the UP thus far today...with dewpoints in the 20s and
30s...as mid/high clouds slip overhead. Low-levels this afternoon
are quite dry through about 850-700mb just to our south over
northern WI...the dry air mass runs even deeper, up toward 450-500mb
across the western Yoop. A few rain showers being reported upstream
over parts of WI...though satellite and radar trends generally
indicate this swath of moisture is struggling to stay strong in the
face of dry Canadian air that is being reinforced in the low levels
by easterly flow.


Trough axis to continue to punch ESE into the OH Valley
tonight...leaving some niblets of PV energy stalled across the Upper
Midwest for a time. This eastward punch will ultimately result in a
lobe of PV retrograding into the Upper Midwest Thursday...with
influence of upper trough likely holding on into the weekend.
Certainly possible this idea could hold on longer, as there are some
signals for overall troughing to hang on across the central
US/Midwest going into the start of next week...though quite a bit of
uncertainty in how this evolves attm.

Primary Forecast Concerns:

Short Term (Tonight through Wednesday)...

Showers into tonight?... Primary concern through the overnight is
whether or not enough moisture/forcing gets into the western UP to
generate any showers that actually make it to the ground through the
deep dry layer. The moisture/radar returns are slowly creeping
northward attm, inching ever so slowly toward the tip of the Yoop
(drizzle being reported as far north as KCOQ as of 20z). E/NE flow
is still holding firm...suggesting we should be able to maintain
enough of a dry layer to preclude most, if not all precip chances
today across most, if not all of the area. Best chance of any shower
activity should be near the WI/MI border...generally along and south
of the US-2 corridor, where mid-levels may saturate enough to
squeeze a little bit of something out of the air. Menominee has the
best shot at seeing much in the way of any rainfall accumulations
through the next 24hrs.

Breezy through Wednesday...Think the strongest pressure gradient
will be in the vicinity this afternoon and
/should/ wane going into this evening and overnight...which
should tamp down the sustained winds a bit as we go through the
overnight. Think gusts will be lesser over the north half of the
CWA...and a little bit better across the southern half where there
is a better shot at things remaining a little more mixed.
However...should remain gustiest over western Lake Superior toward
Duluth where northeast flow should continue to be enhanced...and
looking at gales continuing here through at least midday Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 434 PM EDT Tue May 20 2025

Showery and cold through the end of the week...low-level moisture
increases ahead of PV max pinwheeling back toward Lake
Superior...and as we start to tap into a slightly more moist air
mass compared to the current one. Think the best shot for showers
will be Thursday into Friday attm with the PV max and also with some
diurnal instability to contend with on Thursday. Some potential for
high pressure to try to build in from the west going into the
weekend (holiday weekend!)...which could bring frost/freeze concerns
to parts of the area if radiational cooling is allowed to take
hold.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 916 PM EDT Tue May 20 2025

Currently VFR at all sites with generally BKN-OVC skies AOA
5kft. East winds of 10kts will persist through 12Z, then
strengthen to 10-15kts with G20kts. VFR conditions will continue
through the period.

&&

.MARINE...
Issued at 434 PM EDT Tue May 20 2025

Strong gradient remains intact between surface high over Hudson
Bay...and east-west oriented surface low over the Mid Mississippi
Valley, the latter of which is expected to trek eastward through the
Ohio Valley tonight/Wednesday. Think the gales will hang on over the
western tip of Lake Superior into at least Wednesday morning
(LSZ162) and have extended this appropriately. Winds should diminish
overnight for areas between Marquette and Grand Marais...but think
they will try to pick back up again Wednesday during the day. Winds
slowly diminishing through Wednesday, though still gusty at times
near 30kts.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 2 PM EDT /1 PM CDT/ Wednesday for LSZ162.

  Gale Warning until 10 PM EDT this evening for LSZ263.

Lake Michigan...
None.

&&

$$

SHORT TERM...APX
LONG TERM...APX
AVIATION...APX
MARINE...APX