673
FXUS63 KAPX 231914
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
214 PM EST Sat Nov 23 2024

.KEY MESSAGES...

- Lake effect rain and snow showers will continue into the night
  tonight

- System brings potential for rain and snow Monday into
  Tuesday.

- Turning colder Tuesday through the remainder of the forecast
  period with periodic instances of lake effect snow.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 210 PM EST Sat Nov 23 2024

Forecast Pattern: Current satellite and radar depict widespread open
cell lake effect convection over northern MI. Stratus exist south of
M-72 west of I-75 and are limiting shower activity this afternoon
there. Breezy north to northwest winds continue to stream in
moisture off of a relatively warm lake (sfc temps of Lk MI in the
50F`s still). Temps and Tds are kept mostly above freezing today
yielding mostly light rain showers under this convection. Drier air
exists above 4kft, and with surface temps reaching the convective T
from this mornings RAOB one cannot rule out some graupel or tiny hail
with some of the strongest convection today. A weaker boundary
currently exists over Lk Superior, as a NW upper jet (~140kts)
approaches. This combination will lead to lake effect showers
lingering through the evening and tonight. Temperatures will likely
be cold enough for snow. Best chances exist over the higher terrain
of northern lower, tip of the mitt, and eastern upper. Any
precipitation will be light, with accumulations light (up to a few
tenths of an inch in eastern upper and the highest terrain).

Precipitation will clear out early Sunday morning, however skies
will remain mostly cloudy as more moisture moves in from the west.
Winds will be light most of Sunday, and gradually back southeast in
the afternoon.

Forecast Concerns: Although there is high confidence that
accumulations will remain light tonight, temperatures will likely
dip down into the low 30s and high 20s for most of the CWA. As rain
and/or snow showers linger into the night tonight, most of the
surface will be wet as temperatures drop. There is still a decent
amount of heat under the surface, however some bridges/overpasses
and a road or two where temperatures could dip even lower than
forecasted will be subject to some of that moisture freezing.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 210 PM EST Sat Nov 23 2024

Pattern Synopsis / Forecast:

Ridging moving overhead early next week will be suppressed southward
with time as a pair of 500mb waves build into central North America:
the first being an ejecting (albeit, somewhat disorganized) wave
into the western Corn Belt with origins from the ongoing Atmospheric
River event in the Pacific, and the other a more potent northern
stream wave (clipper type) originating as the leftovers of an
exceptionally strong cyclone over the northern Pacific. These
features will attempt to phase near the Great Lakes (or just east).
Result will be surface cyclogenesis across the lower Great Lakes,
and with modest moisture advection, a return of more widespread
precipitation Monday into Monday night. Meanwhile, continued ridging
over Greenland provides a blocking mechanism to draw in colder air
into much of the eastern 2/3 of North America via a deep zonal NW
flow regime. This will be a pivotal player in how the forecast
unfolds later next week for an important holiday travel time, with
most guidance bringing in another developing wave through the
southern Great Lakes that leads to ample moisture and far deeper
arctic cold moving over unseasonably warm Great Lakes waters...
which could set the stage for what could be the season`s first
higher end lake effect event if everything can come together
perfectly.

Primary Forecast Concerns:

Monday/Tuesday System: Developing low pressure with Pacific origins
over the Corn Belt region will draw in a modest amount of theta-e
advection, which with surface temperatures responding accordingly,
puts much of northern lower Michigan in the mid-to-upper 30s for
temperatures, and the eastern Yoop / interior northern lower in the
30-34 degree range. Result will be mainly snow across the eastern
Yoop, and a more mixy / complex p-type scenario for northern lower.
At this juncture, the best chances for some accumulating snow still
lies north of the Mackinac Bridge and across interior northern
lower... but considering warm grounds and latent heat flux off the
lakes, anticipation is that areas around the lakeshores struggle to
accumulate any snow (or even stay mainly rain). Meanwhile, across
the eastern Yoop and interior northern lower, any rain that
transpires will mix back to snow Monday night. With winds flipping
NW to WNW in the wake of the system, continued lake effect late
Monday night through the day Tuesday could bring about accumulation
of a few inches to these areas, though how much of that sticks due
to marginal temps and warm grounds remains to be seen. Nonetheless,
could be a tricky commute in some places Tuesday morning.

Rest of the Period: Guidance remains bullish on a zonal flow regime
in the northern stream building across the northern CONUS, while
another southern stream wave ejects and produces snowfall across the
mid Mississippi Valley into the southern Great Lakes / Ohio Valley.
So what does that mean for us? Well, first off, this time around, a
much deeper shot of arctic air is in play, which could send daytime
highs near or slightly below freezing. In addition, the lake effect
snow machine sure looks like it will be fired up just in time for
Thanksgiving travel, which could bring about impacts for those
planning on hitting the road or catching flights. With highs in the
upper 20s to lower 30s and lows in the teens and 20s, this will
probably be a bit of a jolt to the nervous system considering how
mild the fall has been so far. More details to come in the ensuing
forecast cycles, but confidence continues to increase in a much
colder and snowier end to November.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1233 PM EST Sat Nov 23 2024

Lake effect -SHRA impacting a few northern lower and eastern
upper terminals, resulting in VFR to MVFR cigs. BKN-OVC skies
will persist through much of the period, with mostly VFR/MVFR.
Occasional IFR for eastern upper & tip of the mitt terminals
after 00Z as chances for -SN exist. Precipitation should come
to a gradual stop after 06Z. Winds currently NW/N AOB 12kts
with occasional G15kts. Winds will diminish after 00Z to AOB
06kts.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for
     LHZ345>349.
     Small Craft Advisory until 7 AM EST Sunday for LSZ321.

&&

$$

SHORT TERM...ELD
LONG TERM...HAD
AVIATION...ELD