270
FXUS63 KMQT 210823
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
423 AM EDT Fri Jun 21 2024

.KEY MESSAGES...

- Widespread rain is likely tonight through Saturday.
- The heaviest rainfall should stay south of the UP, but there is
still a slight chance (5% chance) for locally heavy rain resulting
in minor flooding impacts.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 252 PM EDT Thu Jun 20 2024

Generally tranquil weather will persist through tonight. Surface
ridging over Lake Superior is allowing for light onshore flow along
the shoreline keeping temperatures in the 50s along the immediate
shore to 60s inland. Where sun has been prevalent over the eastern
U.P., temperatures have climbed into the 70s.  A weak disturbance
aloft lifting northeast in the southwesterly flow aloft is producing
widespread mid-level clouds over the western half of the area with
even a few sprinkles. Much drier air in the sub cloud layer,
however, is causing many of the returns being seen on radar to
evaporate before hitting the ground. Not many changes are expected
through the night. Best chance for enough sprinkles or light showers
to wet the ground will be over the far west and along the WI border
through the early evening.  Temperatures will be seasonable tonight
around 50 and into the lower 50s with clouds keeping temperatures
from falling too much despite light winds.

&&

.LONG TERM /TONIGHT THROUGH THURSDAY/...
Issued at 422 AM EDT Fri Jun 21 2024

This weekend will be an active period as troughing currently over
the western U.S. coast moves east through the Great Lakes. A brief
dry period starts Sunday evening continuing through Monday, but
another trough progressing east through Canada early next week
brings a round of shower and storm chances for Monday night/Tuesday.
A drier pattern then sets up for the rest of next week. The CPC`s 6-
10 day precipitation outlook reflects this extended forecast well
with 40-50% chances for above normal precipitation for the entire UP.

Showers continue tonight with the warm front stalled out over
central WI, with the best chances over the southern UP. However,
coverage of showers increase Saturday as a shortwave lifts out of
the Rockies and a surface low deepens while tracking into the Upper
Great Lakes. As the low moves northeast, the warm front lifts with
it, reaching as far north as the northern end of Lake Michigan and
northern WI; this is where the axis of heaviest rainfall is
expected. Guidance over the past 24 hours has continued to trend
more southward with this swath of heaviest, 2in or greater
accumulations. This latest forecast continues to cut back on QPF
across the UP, but this still will be a wet period for the area.
Total QPF Friday through Saturday is around 0.5" in the Keweenaw,
increasing southeastward to 1" across the southern UP with higher
amounts to 2" possible across southern Menominee county. Also with
this southward trend, the Keweenaw may not see any measurable precip
until Saturday morning when the low lifts through the area.
Meanwhile, though soundings and HREF guidance do show a few hundred
j/kg of MUCAPE over the area, as well as anywhere from 35-50kts of
deep layer shear depending on your  model of choice, there is a
pretty impressive cap in soundings. The SPC slight risk over our far
southern zones therefore seems a bit ambitious, but regardless, will
not rule out some rumbles of thunder.

Another trough dives southeast over the area on Sunday, bringing an
additional round of showers and possibly some thunder. However,
model soundings are rather moisture-starved and instability remains
fairly low, so showers should be light and strong storms are not
expected. A brief dry period then follows through early next week as
weak ridging and high pressure moves southeast over the area. The
next round of showers and storms arrives late Monday night into
Tuesday as another shortwave moving through Ontario drags a cold
front through the area, but then ridding over the Great Lakes will
once again bring in dry weather for the midweek period.

As for temperatures, we will trend cooler than normal through the
weekend with our rounds of rainfall, then we warm up early next week
before the cold front ushers in cooler-than-average temperatures by
Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1244 AM EDT Fri Jun 21 2024

VFR conditions will prevail for most of the TAF period. Ceilings
will begin to lower at IWD by Fri afternoon to MVFR. Light rain
chances will also increase at IWD by late Fri morning. MVFR
conditions move in to CMX and SAW Fri evening.

&&

.MARINE...
Issued at 422 AM EDT Fri Jun 21 2024

A stretch of light north to northeast winds mainly below 15 kts is
expected through early Saturday with surface high pressure over Lake
Superior. This high pressure weakens throughout the day today and a
surface low lifts northeast through the Upper Lakes Saturday and
Saturday night. This results in northeasterly winds to around 20 kts
over the west half of the Lake during the day Saturday.
Northwesterly winds behind the departing low should stay around or
below 20 kts on Sunday. South winds return on Monday veering
southwest Monday night and increasing to 20-25 kts ahead of another
weak cold front by Tuesday afternoon. Winds fall below 20 kts again
mid week.

&&

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

&&

$$

SHORT TERM...MZ
LONG TERM...LC
AVIATION...07
MARINE...LC