929
FXUS63 KAPX 231438
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1038 AM EDT Mon Sep 23 2024

.KEY MESSAGES...

- Rain chances return late tonight into Tuesday

- Mild and quiet weather mid and late week

&&

.UPDATE...
Issued at 1037 AM EDT Mon Sep 23 2024

Disturbance from yesterday now largely off to our east...though PV
strand drapes back over us in its wake...extending back to IA where
the next niblet is currently located...as yesterday`s boundary gets
strung out to our south:  surface low over northern Lake Erie with
cold front extending back to OK/MO...and warm front from this low
outlining the eastern side of the Appalachians through the Mid
Atlantic region...with another cold front stretching northward to
Hudson Bay. Moisture trapped south/east of this boundary; cool and
dry advection in its wake...as surface high pressure settles in here
beneath confluence aloft. 850mb temps here between 5 and 10C this
morning; some lingering boundary layer moisture present as
well...with a stratus deck/fog starting to mix out into more of a
diurnal convective rolls look...particularly off the waters of Lake
Huron and even GT Bay, where overlake instability is playing a role
in cloud cover as well. Weak PV strand stretching by north of Lake
Superior this morning...with much better PV noted even further north
(cool bowling balls of PV energy through Ontario, training back into
Manitoba). Otherwise...surface high pressure encompasses the bulk of
the central US attm...with some disturbances between it and an upper
high focused just off the Pac NW coast; potent 120-140kt upper jet
cresting this ridge into central Canada. Expecting things to remain
largely quiet and slightly lake-cloudy in a few spots today...with
high pressure hanging out overhead. Looking at much more seasonable
temps today for late September (normal highs in the mid to upper
60s; we should be somewhere in this vicinity for a change).

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 339 AM EDT Mon Sep 23 2024

Pattern/synopsis: 1009mb low pressure is near the St Clair
River. Most precip is east thru north of this low; synoptic
precip has largely exited northern MI. There could be a touch of
lingering DZ or a sprinkle where low clouds still linger (in
northern lower MI).

Forecast: High pressure will s and sw-ward into northern MI, as
the low departs to the e and se. This will push drier air into
the region. Widespread cloud cover is already se of a ROgers-CAD
line. Our pressure gradient is reasonably tight, but that
hasn`t stopped some inland locales from decoupling and seeing
some fog. And a few lake streamers are noted as well. Once we
get past sunrise, diurnal heating may allow for some stratocu,
especially where the lakes are contributing moisture. But we
will mix up into increasingly drier air today, and cloud cover
should decrease with time.

Tonight, a shortwave trof lifts ene-ward toward the sw Great
Lakes. As it does, cyclogenesis occurs a bit south of lower MI.
Our low-level flow becomes easterly, and will start tap into a
moisture plume present over the far eastern lakes. Truly deep
moistening will remain downstate (though edging northward). But
we look to become cool and moist enough for the lakes to become
more active. Cloud cover will generally increase from se to nw.
Ne lower MI will likely see some rain showers move in off of Lk
Huron overnight. There are also signs in guidance of an inverted
surface trof developing northward into nw lower MI, with
associated moisture pooling. A few showers could also be
generated here, especially very late.

Max temps today mid 60s to lower 70s. Lows tonight 40s to near
50f.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 339 AM EDT Mon Sep 23 2024

Pattern Synopsis and Forecast:

Current split flow pattern over North America with northern branch
flow over the Great Lakes region will continue another day of cool
fall-like temperatures. Embedded troughing along both north and
southern branch flow will keep us somewhat active early in the
period, before things quiet.

Embedded shortwave troughing currently over the central plains will
progress easterly and make its way to the Mid-Mississippi/Ohio
Valley by Tuesday. While the majority of energy will be south of the
CWA, scattered showers can still be expected on Tuesday. Upstream
ridging currently over the northern Pacific will make its way to the
midwest by the Thursday timeframe, resulting in surface high
pressure and quiet weather for the remainder of the forecast period.

Primary Forecast Concerns/Key Messages:

Scattered showers return this Tuesday. Surface high pressure and
quiet weather builds this Wednesday: No impactful weather is
expected through the entirety of the long term period. Only
active weather will be at the start as aformentioned troughing
settles into the Ohio Valley. Relatively weak forcing dynamics
along with a lack atmospheric moisture will keep rainfall
amounts low. A general tenth or so of QPF can be expected this
Tuesday before ridging begins to build around the Wednesday
timeframe. Midlevel southern branch riding will keep conditions
quiet and dry for the remainder of the long term. Temps are
expected to return to above average for late September with
highs in the low to mid 70s for most locations. Looking ahead
towards the end of the week, ensembles do depict chances of
precip returning to the Great Lakes region, but discrepancies in
guidance will keep chances along with messaging pretty minimal
at this time.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 637 AM EDT Mon Sep 23 2024

Early morning fog and lower clouds will quickly burn off (by
14Z), with VFR conditions for the rest of the day and evening.
Clouds increase late tonight ahead of our next system. MVFR cigs
are expected at APN very late tonight, and a few showers are
possible at MBL/TVC/APN.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for LHZ348-
     349.

&&

$$

UPDATE...FEF
SHORT TERM...JZ
LONG TERM...SJC
AVIATION...JZ