531
FXUS63 KMQT 172014
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
414 PM EDT Tue Sep 17 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.

&&

.SHORT TERM /THROUGH TODAY/...
Issued at 121 PM EDT Tue Sep 17 2024

Dry and warm airmass continued to sit over the Upper Great Lakes
today. Outside of some mid-high clouds here and there, and some
recently developing diurnal cumulus in the west, the forecast area
has been mostly clear which enabled many to easily break into the
70s before noon. In fact, many locations were beating hard on the 80
degree door at that point. As of publishing this discussion, most
surface observations were in the upper 70s to low 80s, which is
approximately 10 to 15 degrees above normal for mid-September. Under
mostly light southerly flow, daytime mixing has supported dewpoints
in the mid 50s to low 60s. This is yielding RH values mostly in 50s
and 40s in areas removed from Lake Michigan`s influence. Some drier
locations have fallen into the 30s as well. As we progress through
the remainder of the afternoon, I expect temps to climb a little
more and RH values in the 40s to be more widespread with some 30s
here and there before recovering with the waning heat. Expecting
clear skies to continue through tonight, which will yield overnight
lows in the 50s and 60s, save the interior portions of south-central
and east, which could slip into the 40s. Patchy overnight fog will
be possible as well, particularly in the interior spots of central
and eastern Upper Michigan.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 412 PM EDT Tue Sep 17 2024

Continued warm and dry weather is expected through the midweek before
a cold front brings much needed rainfall and a slight reprieve from
the endless summerlike temperatures this weekend.

Beginning Wednesday, ridging aloft and high pressure extends from
the eastern seaboard across the Great Lakes, while a closed low
spins overhead the Northern Great Plains. Some minor fire weather
concerns arise Wednesday as forecast high temperatures will
generally reach in the 80s across the UP and mixing allows RHs to
bottom out near 30% in the afternoon. The recent lack of rainfall
and dry fuels have introduced abnormally dry D0 conditions for the
entire Upper Peninsula away from the Keweenaw. Luckily, light
southerly winds only peaking near 10 kts keep fire danger low.
Otherwise, a weak shortwave embedded in the broad southwest flow may
kick off some showers over far western Lake Superior and Isle Royale
(10-15%).

Thursday starts off similarly with warm and dry conditions, although
better moisture advection limits fire danger further. The closed low
pushes northward into Manitoba, sending height falls and a cold
front across the Upper Midwest late Thursday into Friday. Much
needed rainfall accompanies the frontal passage, reaching the far
western UP Thursday evening. A few thunderstorms are possible as
model soundings indicate weak elevated instability, but with shear
lacking <20kts no severe weather is expected. Unfortunately, these
scattered showers won`t bring much in terms of QPF. Ensembles barely
squeeze out 0.25" across portions of the west-central as the front
passes to the east through Friday, but any rainfall is welcome to
help curtail fire weather conditions. Temps wont drop significantly
since positive 850 anomalies near 3-4C continue through the weekend
into next week. Cloud cover will bring daily highs down closer but
still above normal for this time of year.

Finally some more active weather is on the horizon as global models
resolve a handful of shortwaves digging across the central US and
Canada this late weekend into the beginning of next week. After a
brief period of ridging and clearing Saturday, guidance suggests a
closing upper low translating into western Ontario Sunday morning
and another system entering the lower Midwest Monday. Deterministic
models start going catawompus on the placement and timing of these
features, however, much needed rainfall is looking more likely.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 121 PM EDT Tue Sep 17 2024

Dry airmass over the region will continue VFR conditions at
KIWD/KCMX/KSAW in this TAF period. Winds will be mostly southerly
save for the afternoon lake breeze at KCMX. There may be 15 to 20 kt
gusts at KIWD and KSAW this afternoon.

&&

.MARINE...
Issued at 412 PM EDT Tue Sep 17 2024

Light winds of generally 20 knots or less continue for the next
several days has high pressure ridging this week finally gives way
to a cold front moving through Thursday night through Friday. This
front could bring some showers and storms over Lake Superior,
particularly north and east of the Keweenaw, as well as some
stronger winds above 20 knots as it slowly crawls from west to east.

We may see winds increase above 20 knots again come late this
weekend/early next week as a few shortwaves approach the Great Lakes

&&

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

&&

$$

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