000
FXUS63 KAPX 021914
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
214 PM EST Wed Dec 2 2020

.UPDATE...
Issued at 1051 AM EST Wed Dec 2 2020

Highly amplified pattern analyzed across NOAM this morning with
an omega block in place across the western CONUS feeding into a deep
cutoff low near the Texas/Oklahoma panhandles. Second deep closed
low...system that brought decent snow to the eastern lakes...continues
to migrate northward through Quebec. Across the western lakes and
Midwest, subtle short-wave ridging and surface high pressure is
in control for the time being. But there is a weak wave sliding
S/SE through western Ontario driving some colder air toward the
region.

Rest of today: Of course, we did manage to develop some shallow lake
cloudiness off Superior and Michigan despite very marginal
thermal support for lake effect. Batch of lake cloud cover has
been drifting inland into parts of eastern Upper and NW Lower
Michigan this morning as low level mean flow backs westward. This
will continue over the next few to several hours bringing briefly
partly to mostly cloudy skies to some areas. Otherwise quiet
weather anticipated today, outside of some lingering gustiness
that will add a degree of bite to the air today.

Aforementioned short-wave slides down through the region tonight
with colder air spreading into northern Michigan heading into
Thursday morning. There is a signal for a brief period of stronger
QG-forcing for ascent along the advancing thermal gradient, late
tonight through Thursday that may bring some light snow to the
region, along with some renewed lake effect. Still not
anticipating much snow at this juncture...half an inch or less
amounts.

&&

.NEAR TERM...(Today through Tonight)
Issued at 204 AM EST Wed Dec 2 2020

Impactful weather: Minimal/None. Gusty again with potential
lakeshore flooding in portions of NE lower Michigan.

Pattern synopsis and forecast:

There`s a couple of closed lows aloft out there early this morning.
One is just north of New York State, with an associated deep sfc low
pushing through Ontario. The other was quite broad, spinning out
over the Lee of the Rockies. Minor upper ridging extended from MN
into Ontario, while much stronger ridging and sfc high pressure were
out over the western states and into the western provinces. There
was no precipitation anywhere near nrn Michigan, as an axis of deep
dry air was over the region. This has resulted in clear skies most
areas, but there were some shallow lake effect clouds around the GTV
Bay region in remnant overlake instability. The pressure gradient
remained tight between that Quebec deep low pressure and higher
pressure extending through the Mississippi valley. As a result, most
areas remained gusty.

The deep Quebec low pressure will lift toward Hudson Bay through the
night, while high pressure settles into the Rockies, with a ridge
axis that will extend through the Central Plains to the mid
Atlantic. Nrn Michigan will remain in a fairly tight pressure
gradient with gusty conditions just not wanting to subside. Gusts
will not be as high as the last couple of days though. Any shallow
lake effect clouds ought to easily mix out into the overall very dry
air mass overhead, leaving skies with plenty of sun today. This will
not last long however. A fairly defined shortwave dives down the
forward flank of the upper ridging upstream, and pulls a sfc
trough/cold front into the region tonight. Clouds above 10kft will
be thickening, as well as in the low levels, with stratus likely
pushing southward and over most of the CWA by daybreak. Forcing
isn`t anything impressive, and the air mass isn`t really all that
moist, with the mid levels looking to have a hard time moistening
per fcst soundings. Only small chances for rain and snow expected,
mainly after midnight and in W/WNW lake effect flow regimes.

The strongest winds today will be around Presque Isle county and far
NE Alpena county. High waves from these winds may still result in
the chance for lakeshore flooding in those areas, until waves can
subside late today and tonight.

High temperatures will mostly be in the upper 30s to lower 40s,
warmest in downsloping areas of NE lower. Lows tonight will
largely be in the upper 20s and lower 30s.

&&

.SHORT TERM...(Thursday through Friday)
Issued at 204 AM EST Wed Dec 2 2020

High impact weather potential: Minimal, although sporadic light snow
showers/flurries possible at times.
.
Pattern synopsis/forecast: By Thursday morning through the remainder
of the short term forecast period, broad upper-level troughing
remains entrenched across the Great Lakes region while the well-
advertised system early this week continues it`s northward
progression towards James Bay. Primary focus will revolve around a
well-defined wave that`s progged to pinwheel around the backside of
this parent troughing to our north, diving southward into the
western Great Lakes on the nose of a 120+kt jet stream during the
Thursday afternoon - Friday time frame. Despite increased forcing
aloft and the arrival of cooler low-mid level temperatures/increased
over-lake instability, a lack of moisture is expected to prevent
much in the way of widespread precipitation. That being said, some
light snow showers/flurries certainly look like a possibility at
various times, although no high impact period of weather is
anticipated.

Primary forecast concerns/challenges: Light snow shower chances
Thursday through Friday.

The aforementioned wave is progged to approach the western Great
Lakes from the north during the day Thursday into Thursday night
before crossing the fcst area Friday morning. Latest trends continue
to suggest that while most locations across northern Michigan remain
precipitation-free under partly sunny skies, increased mid-upper
level forcing combined with falling H8 temps/increased over-lake
instability may prove to overcome paltry deep layer moisture fields
in the form of light/scattered snow showers and/or flurries. Initial
chances for this remain fairly limited to eastern upper and the Tip
of the Mitt during the day Thursday before chances gradually spread
southward Thursday evening/overnight into Friday. Again, this isn`t
expected to be anything too widespread with total accumulations over
the 48-hour period likely less than half an inch for those that do
see snow.  This wave and associated moisture do bear watching moving
toward the end of the week, however, as even a slight uptick in
synoptically aided moisture would likely result in localized
heavier accumulations.

High temperatures both Thursday and Friday expected to range from
the low-mid 30s across the typically cooler/interior areas to the
upper 30s near the Great Lakes shorelines.

.LONG TERM...(Friday night through Tuesday)
Issued at 204 AM EST Wed Dec 2 2020

High impact weather potential: Minimal. Watching storm system
expected to pass to our south this weekend.

Over the past 24 hours, guidance has ever so slowly begun to come
into better agreement regarding the overall pattern evolution beyond
Friday with the primary focus through the upcoming weekend revolving
around cutoff upper-level low pressure and developing surface
cyclone over the lower Mississippi Valley Friday evening. This
system is expected to strengthen as it ejects northeastward towards
the Ohio Valley during the day Saturday, continuing toward the
eastern seaboard to wrap up the weekend. Current trends suggest that
nearly all synoptically-driven precipitation related impacts
remain well to our south and east; however, this this system may
draw in cooler air locally on its backside...perhaps kicking off
some lake effect snow shower activity, although confidence in this
remains low. Will continue to monitor this weekend time frame as
details become ironed out over the next several days. Temperatures
expected to remain near to a few degrees above early December
normals for the bulk of the long term forecast period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 214 PM EST Wed Dec 2 2020

...VFR weather through the rest of today...

Dry air and surface high pressure will lead to overall VFR weather
across northern Michigan this afternoon and into tonight. However,
colder air spreads southward out of Ontario tonight into northern
Michigan. With it, expect lake induced cloud cover to develop and
expand across the western Great Lakes later tonight into Thursday
along with some minor lake effect snow showers developing across
the region...particularly through the tip of the mitt. CIGS will
likely lower to MVFR across northern Michigan late tonight and
remain there through Thursday. Risk for IFR CIGS for some areas
through the higher terrain.

&&

.MARINE...
Issued at 204 AM EST Wed Dec 2 2020

A deep low pressure system will lift north through Quebec today, and
toward Hudson Bay tonight when a disturbance aloft and sfc trough
arrive. Another disturbance arrives late Thursday night into Friday.
This will result in small chances for light rain tonight through
Friday. The pressure gradient will remain tight, especially today
over Lake Huron, and gale warnings will continue today around
Presque Isle Light. All other nearshore waters will be in solid
advisory conditions through Thursday/Thursday evening.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 11 PM EST Thursday for LHZ345>349.
LM...SMALL CRAFT ADVISORY until 11 PM EST Thursday for LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY until 11 PM EST Thursday for LSZ321-322.
&&

$$

UPDATE...BA
NEAR TERM...SMD
SHORT TERM...MG
LONG TERM...MG
AVIATION...BA
MARINE...SMD

NWS APX Office Area Forecast Discussion