715
FXUS63 KMQT 182259
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
659 PM EDT Wed Sep 18 2024

.KEY MESSAGES...

- Extended stretch of well above normal temperatures continues
through at least Saturday with highs mainly in the upper 70s and 80s.

- A cold front brings scattered showers and a few thunderstorms late
Thursday into Friday. Some stronger storms are possible in western
Upper Michigan Thursday evening.

&&

.SHORT TERM /THROUGH TODAY/...
Issued at 122 PM EDT Wed Sep 18 2024

Another warm and dry day over Upper Michigan has developed. This,
after morning temps in the 40s and 50s, and fog, some dense, across
portions of central and eastern Upper Michigan. So far, temps have
warmed into the 70s to low 80s, with the warmest spots being the
southerly wind downsloping locations near Lake Superior. Effective
mixing into a very dry airmass aloft has enabled dewpoints to fall
into the upper 40s to 50s in the driest interior locations, which
with the heat, is supporting RH values in the 30s and 40s in many
locations. Thankfully, winds have been mostly light, which is
limiting fire weather potential.

As we progress through the remainder of the afternoon and tonight,
expecting some additional warming before the heat wanes. Still
expecting widespread low to mid 80s everywhere away from Lake
Michigan`s influence where 70s will dominate. RH will respond as
well and will support continued near and/or isolated elevated fire
weather concerns into the evening. Overnight lows will again dip
into the 40s and 50s. Also expecting another round of raditional fog
to develop in interior locations of Upper Michigan`s south-central
and eastern locations.

Upstream, vertically stacked low spining over North Dakota will lift
northeast into Canada. An associated cold front will march east into
western Minnesota overnight. Ahead of the front, theta-e ridge with
a plume of robust instability will support showers and thunderstorms
overnight. Its possible that some of these showers/storms may
continue into western Lake Superior by morning.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 341 PM EDT Wed Sep 18 2024

The long term forecast starts off Thursday morning with patchy dense
fog closer to Lake Michigan under a strong inversion and light
southeast flow off the marine layer. This fog should burn off
through the morning leading the way to a warm and dry afternoon.
Fire weather concerns for tomorrow are minimal. RHs in the
interior will only dip down into the mid 40s since better
moisture advects into the UP as a surface low moves northeast
into Manitoba. The aforementioned surface low sends a cool front
across Upper Michigan late Thursday evening through Friday,
finally providing us with slight relief from the summertime heat
and much needed precipitation to fight the ongoing second fire
season.

Come late Thursday, the front will be approaching the far western UP
where it could kick up a few thunderstorms, some possibly strong,
before heading further east. Model soundings indicate elevated
instability in excess of 1000 j/kg with bulk shear nearing 25-35
kts, therefore its worth mentioning the potential for a few strong
thunderstorms before instability wanes with sunset. Unfortunately,
overall precip amounts look to be on the lighter side with a range
of only a tenth to a quarter of an inch of rain possible as the
front passes by the UP through Friday. Pwat values push 1-1.5
inches, so a few fortunate folks could receive a heavier downpour in
embedded thunderstorms.

Brief ridging behind the departing shortwave action keeps things
fairly quiet on Saturday. Looking into the late weekend and early
workweek, model guidance begins to diverge on the timing and
location of a few upcoming features that could bring more active
weather to the UP. The first feature is a digging shortwave across
central Canada Sunday into Monday, which ushers in a cold front and
additional chances for rain. Behind this front, 850 temps in the
single digits are possible, allowing us to finally tweak surface
temperatures to near normal (60s and 40s) for this time of year. The
second feature, a closed low currently diving south off the
California Coast, will make its way into the Plains by the end of
the weekend and approach the Upper Great Lakes Monday. The
interaction of these features and any associated weather impacts
will be targets of opportunity for upcoming forecast packages.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 658 PM EDT Wed Sep 18 2024

VFR conditions will prevail in this TAF period.

&&

.MARINE...
Issued at 341 PM EDT Wed Sep 18 2024

Light winds of generally 20 knots or less continue into Thursday
before southeast to southerly winds pick up to 20 to 25 knots over
the north central lake late Thursday into Friday morning ahead of an
approaching cool front from the west. Showers and a few embedded
thunderstorms are possible along the front, with a better chance of
thunderstorms in the far western lake Thursday afternoon and
evening. Winds die down below 20 knots Friday morning and remain so
through the weekend.

&&

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

&&

$$

SHORT TERM...JTP
LONG TERM...BW
AVIATION...07
MARINE...BW