026
FXUS63 KMQT 210838
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
438 AM EDT Sat Sep 21 2024

.KEY MESSAGES...

- Patchy fog possible early this morning, mainly central and
  east.

- The prolonged stretch of above normal temperatures ends today,
  cooler temperatures near normal return on Sunday.

- A round of showers and storms accompany a cold front tonight
  through Sunday. Severe weather is not anticipated, but some
  small hail and gusty winds are possible with stronger storms.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 356 PM EDT Fri Sep 20 2024

Latest water vapor imagery and RAP analysis shows shortwave trough
slowly progressing east through the east half of Upper Mi with the
visible satellite imagery showing widespread diurnal cu across the
U.P. Subsidence/mid-level drying behind this shortwave feature has
resulted in dry conditions today over western Upper Mi. Central and
eastern sections of the U.P. have seen a few isolated showers pop up
in the vicinity of the mid-level trough axis and focused along
outflow boundaries/lake breezes especially east of MQT in the past
hour. This environment has also been more favorable for convection
as lower to mid 60s dew points have led to MLCAPE values approaching
1000 j/kg central and east. However, build up of convection over the
central and eastern U.P. has been largely inhibited by strong mid-
level drying as noted on fcst soundings. Afternoon temperatures have
been mostly in the 70s although a few lower 80s readings have been
observed over the interior west.

Other than some lingering isolated showers/t-storms over the east
mainly early this evening, expect dry conditions to prevail as
shortwave ridging and associated subsidence builds across the area
from the west. Moist dew points in the upper 50s and lower 60s along
with clearing of diurnal cu and light winds will likely lead again
to patchy fog forming overnight into portions of central and eastern
Upper Mi. Fog could become locally dense over eastern portions.
Expect min temps generally lowering into the 50s with a few upper
40s readings possible over the typical cool spots of the interior
west.

&&

.LONG TERM /TONIGHT THROUGH FRIDAY/...
Issued at 435 AM EDT Sat Sep 21 2024

The extended forecast starts off with a ~1004mb sfc low north of the
MN arrow head tonight which lifts northeast through Sunday toward
Hudson Bay. This brings a cold front eastward across the UP and a
round of showers and storms with it. Although bulk 0-6km wind shear
will be ~35-40 kts with mid level lapse rates ~7C/km, instability is
expected to be limited; likely less than 500 j/kg of MUCAPE. So
severe weather is not anticipated, but some sub severe hail and
gusty winds could accompany stronger storms earlier on tonight. CAMs
are not in great agreement for arrival and placement of these
showers and storms over the west half this evening/early tonight,
but consistency increases early Sunday morning. At that point, there
is higher confidence in a line of showers and storms over central
Upper MI. This line gradually progresses eastward on Sunday with the
cold front; dry weather returns to the entire CWA by midnight.
Precip totals or this system look to be around a few hundreths to
0.25". Some northwest gusts up to 20-25 mph are likely on Sunday.
Otherwise, lows tonight will be in the 50s, warmer in the east.
Behind the cold front highs on Sunday will feel cooler, peaking in
the low to mid 60s.

For next week, quiet and dry weather likely returns for the first
half. Some shortwaves riding northeast from the Central Plains
through the southern half of the Great Lakes Basin Monday and
Tuesday bring a weak sfc low along a similar path. Most guidance
keeps best forcing and all precip south of our CWA save for the GFS
which just scrapes the south and eastern portions of our CWA. Also,
model soundings leave much to desire for available moisture and
ensemble guidance only shows ~10-20% chances for at least a trace of
precip, so opted for dry weather to start the work week. With
clearing skies Sunday night and mostly clear skies likely for Monday
might, some interior temps could get a bit cold, dropping into the
30s. Should these temps verify, some patchy frost could develop.
Model guidance begins to diverge for the latter part of the work
week, struggling to resolve the eastward progressing mid level
trough over the northern portions of the CONUS. What could further
complicate things are tropical systems in the Gulf of Mexico.
General consensus is for the mid level ridge in the western CONUS
Tuesday night and Wednesday to shift east, passing over the Great
Lakes region for late next week and into the weekend. This would
favor drier weather and eventually a return to above normal temps.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 119 AM EDT Sat Sep 21 2024

Expect VFR to prevail at CMX and SAW through the period. IWD will
have some MVFR/IFR fog overnight, otherwise will be VFR.

&&

.MARINE...
Issued at 435 AM EDT Sat Sep 21 2024

Light and somewhat variable winds today remain below 20 kts through
early this evening as weak ridging briefly returns. Southerly winds
increase up to 20 kts ahead of a cold front tonight. As this cold
front passes eastward across the lake, winds winds quickly veer
northwest gusting to 25 kts tonight through much of Sunday. There is
a low chance (~30%) for gusts up to 30 kts early on tonight west of
Isle Royale. Northwest winds veer north Sunday night, falling below
20 kts across the lake from west to east by Monday morning. This
stronger period of northerly winds will result in wave heights
building up to 4 ft along the western shores of the UP tonight as
well as 4-6 ft over the east half of the lake late tonight through
Sunday evening. Thunderstorms are possible with this front, but are
not expected to be severe. Otherwise, winds are expected to remain
below 20 kts the remainder of the forecast period.

&&

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

&&

$$

SHORT TERM...Voss
LONG TERM...Jablonski
AVIATION...TDUD
MARINE...Jablonski