National Weather Service - Area Forecast Discussion

FXUS63 KAPX 060452

Area Forecast Discussion
National Weather Service Gaylord MI
1152 PM EST Tue Dec 5 2023

Issued at 1046 PM EST Tue Dec 5 2023

Current forecast largely remains on track. Light scattered snow
showers are anticipated across parts of northern Michigan tonight
with accumulations staying under 1". Overnight temperatures have
been tweaked to account for cloud cover trends. As mentioned by the
previous forecaster, areas that see less cloud cover will
efficiently cool and quickly drop into the teens overnight where
those closer to the lakeshores with clouds overhead stay in the
upper 20s and low 30s.


.NEAR TERM...(Through Tonight)
Issued at 322 PM EST Tue Dec 5 2023

High Impact Weather...None is expected.

Primary Forecast Concerns...Cloud cover, low temperatures and pops.

A weak shortwave evident on water vapor imagery over southern
Ontario drops down through the flow tonight. This wave will provide
a bit of lift (upward motion) while increasing low level moisture as
well as increasing the low level flow. Meanwhile, it remains
marginally cold enough aloft for some light lake induced snow
showers to form off of Lakes Michigan and Superior, especially given
model guidance showing a slightly increased flow behind the
shortwave (to between 10 and 15 knots). The mean flow does veer from
a north northwesterly direction this evening into the northwest
overnight. This should spread light snow showers that are initially
expected to be closer to the shorelines a bit farther inland
overnight (perhaps to as far east as about Gaylord). Snow
accumulations are expected to remain under an inch. Temperatures
will be a bit tricky again tonight due to uncertainty over the
amount of cloud cover with lows ranging from the mid teens across
inland eastern upper and northeast lower to near 30 near the Lake
Michigan shoreline. Surface winds will be fairly light at under 10


.SHORT TERM...(Wednesday through Friday)
Issued at 322 PM EST Tue Dec 5 2023

High Impact Weather Potential: Minimal.

Pattern Synopsis/Forecast: Large scale pattern configuration across
North America consists of a trough east/ridge west...though the
ridge has become more prominent (amplified) over the past 24 hours
as it builds into the Prairie provinces and the northern Rockies.
Downstream trough is much more broad and tends across much of the
Atlantic basin...with a train of short wave troughs stretching back
to the Mississippi River.  Water vapor imagery shows a couple of
vorticity centers dropping down the front side of the building ridge
over Manitoba and north of Lake Superior.  Deep trough over the
northeast Pacific directing an atmospheric river into the Pacific
Northwest...though outside of that not a lot of moisture across the
CONUS in an absolute sense.  Broad thermal trough remains in place
across the eastern half of Canada/upper Midwest/Great Lakes/New
England...with warm air advection ongoing upstream ahead of building
upper ridge.  At the surface...1012mb clipper low crossing Illinois
with high pressure in its wake over the northern/central
well as across Quebec/northeast Ontario where sub-zero cold was
located earlier today.

Western ridge will expand east through midweek as remnants of
Pacific trough propagate inland.  Thermal trough will shift east
with time allowing for warmer air to overspread the Midwest/Great
Lakes through Friday.  Leading piece of Pacific short wave energy
still looks to come through the upper Midwest and at least clip the
upper Lakes by Friday...with a more amplified split trough taking up
residence across central North America which will have impacts for
the weekend.  Northeast-southwest oriented surface ridge will lie
across the Great Lakes for Wednesday morning...sliding east during
the day and allowing warm air advection/southerly boundary layer
flow to kick in later in the day and even hints of a warm front
crossing the state Wednesday evening.  This continues into Thursday
as lee cyclogenesis occurs over the northern High Plains ahead of
lead Pacific short wave trough...this low eventually expected to
track into northwest Ontario Friday.

Primary Forecast Concerns: Nuisance precipitation Wednesday...warm
advection precipitation Wednesday night...high temperatures

Nuisance precipitation Wednesday:  Just ahead of the low level ridge
axis...some lingering cold air (925mb temperatures around -4C) and
plenty of moisture around (just look upstream on the afternoon
visible image loop) probably allows for some shallow lake effect
snow/flurries (freezing drizzle?) Wednesday at least through midday.
Boundary layer flow gradually backs around to the southwest as the
surface ridge pushes into southern Ontario...and warming
temperatures should eventually bring this to an end (though between
low clouds and incoming warm advection mid clouds should be mainly
cloudy for the balance of the day).

Warm advection precipitation Wednesday night: Speaking of warm
advection clouds...Pacific moisture emanating from the current
atmospheric river will get advected eastward and across the thermal
gradient that sets up from the Great Lakes west into the northern
Plains.  This will increase the chances for some light precipitation
getting squeezed out of this axis of better moisture...starting as
snow but as low levels warm may mix with or change over to rain
before ending Thursday morning.  Can`t rule out some freezing rain
especially east of the US-131 corridor where surface temperatures
may lag a bit and hang near or just below freezing.

High temperatures Thursday/Friday: Bit of a warm up expected for the
end of the week...though cloud cover may temper expectations so not
going to go overboard here.  But highs around 10 degrees above
normal expected Thursday (around 40-mid 40s)...and more widespread
40s and some 50+ degree readings across parts of northern
Lower for Friday.

.LONG TERM...(Friday night through Tuesday)
Issued at 322 PM EST Tue Dec 5 2023

High Impact Weather Potential: Watching winter storm potential for
the weekend.

Split trough across central North America to start the weekend with
eyes on potential development in the southern branch of this trough
over the central/southern Plains Saturday...and up toward the region
for Sunday.  Some better agreement on the concept here...and perhaps
on the idea that at least Lower Michigan will start on the warmer
side of the system...with colder air arriving Sunday into Monday.
But evolution of upper level features and timing of cyclogenesis
still needs to come into focus...but the idea of unsettled weather
for the weekend (rain/snow and potential wind on the backside)
hasn`t changed and trends in precipitation probabilities for the
weekend are increasing especially Sunday.  But will still hold off
on public messaging for now...just way to tight in the margins
thermally to push the forecast one way or the other.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1151 PM EST Tue Dec 5 2023

MVFR CIGs are expected to hold across parts of northern Michigan
tonight, while some areas scatter out for a time heading into
Wednesday morning. Temporary VSBY reductions are also possible at
TVC and PLN over the next few hours, but FG/BR chances should
diminish as cloud cover continues to spread overhead. Otherwise, VFR
conditions are anticipated for a time Wednesday afternoon before
dropping back to MVFR for many areas away from the Lake Michigan
shoreline this evening. Weak/calm winds currently will gradually
strengthen through the day with south-southwest winds gusting to 20-
25 kts across northwest lower Michigan by the end of the issuance


Issued at 322 PM EST Tue Dec 5 2023

Winds expected to increase out of the south/southwest Wednesday
afternoon into Wednesday night in the wake of a surface ridge
axis crossing the upper Lakes from northwest to southeast. Small
craft conditions likely Wednesday night within Lake Michigan
nearshore zones as well as up on Whitefish Bay and perhaps
adjacent to Saginaw Bay on Lake Huron.





NWS APX Office Area Forecast Discussion