Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 081142
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
642 AM EST Wed Dec 8 2021

.SYNOPSIS...
Weak low pressure will settle over the Lower Great Lakes through
tonight, bringing some widespread light snow along with some lake
enhanced snows east of the lakes. A SIGNIFICANT warming trend can be
expected for the end of the week, but this will be accompanied by
the likelihood for another strong wind event.

&&

.NEAR TERM /THROUGH TONIGHT/...
An upper level trough will move across the region today, along with
a weak surface low. This synoptic pattern will produce two rounds of
general light snow. The first will pass through early this morning
with a weak embedded shortwave, and the second will be with PVA just
ahead of the 500 mb trough axis. Outside of lake enhancement, the
first wave will only drop a dusting to half inch of snow at most
locations through daybreak. The shortwave will bring steadier light
snow this afternoon, but still very limited general accumulation of
less than an inch.

The more challenging part of the forecast is the lake effect snow
with this system. Radar shows a meso-low across eastern Lake
Ontario. Surface to 850mb wind fields become better aligned just
before daybreak, with mesoscale guidance developing a southerly flow
directing snow from this streaming across far western Jefferson
county. It now appears steadiest snows will remain north and west of
Watertown, centered near Cape Vincent where 3 to 6 inches of snow is
expected today. Winds shift to the northwest behind the shortwave,
which will bring another round of lake enhanced snows through
Jefferson county late afternoon/early evening. As the band drops
south there will be a longer fetch down the lake and some upslope
enhancement across the Tug Hill. A 10k ft cap accompanied by a 5kft
thick DGZ will support a brief burst of heavier snows across western
Oswego county this evening. Extended the Winter Weather Advisory for
Jefferson County through this evening, and issued an advisory for
Oswego county for late this afternoon through tonight. Some lake
enhancement northeast and east of Lake Erie, but the band will be
moving which should limit accumulation to 1 to 3 inches.

Otherwise, it will be a chilly day with highs struggling to reach
freezing at most locations.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Lingering northwest flow may bring some light snow showers/flurries
southeast of Lake Ontario Thursday morning, otherwise a brief dry
period is expected Thursday as a ridge slides across the region.
Despite the influence of high pressure, probably will not see much
in the way of sunshine with some lake clouds early in the day
followed by increasing clouds ahead of approaching shortwave and
surface warm front.

By Thursday night, the approaching shortwave and warm front will
bring a round of light precipitation. Warming temperatures aloft
could bring a small risk for freezing rain/drizzle mixing in with
light snow/rain. Precipitation amounts during this time look quite
light so not excepting much if any impact, but will monitor trends
as the event gets closer. Once the warm front moves through Friday,
any precipitation will taper off with most areas seeing temperatures
warm into the mid to upper 40s.

Models showing great continuity with dynamic system approaching the
area Friday night and Saturday. High confidence exists that the area
will remain in the warm sector, as the deepening surface low tracks
by to our northwest. Plume of Gulf moisture will stream northward
ahead of system cold front Friday night into Saturday morning. Some
elevated instability showing up on model soundings late Friday night
and Saturday morning could bring a few thunderstorms. A 50-60 knot
low level jet impinging on the area will bring some the potential
for strong winds to favorable south-southeast downslope area off the
Chautauqua Ridge and off the north slopes of the Tug Hill and
western Dacks, potentially exceeding 45 mph. Strong warm air
advection also allowing for rising overnight temperatures with far
western New York into the lower 50s by Saturday morning.

The first part of the day Saturday will see the warmest temperatures
ahead of the front with many areas getting into the lower to mid
60s, with temperatures falling behind the front some 15-20 degrees
by late in the day. Concern for Saturday will be the potential for
strong post-frontal winds in the typical southwest flow areas from
Lake Erie shore across the Niagara Frontier from Buffalo and Niagara
Falls to Rochester. BUFKIT momentum transfer profiles showing a
several hour period of 45+ knots mixing down, so certainly could be
looking at the potential for gusts reaching 60 mph for a time
Saturday afternoon. Will continue to mention in the HWO product.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
Model consensus remains in good agreement that a much more tranquil
period is on tap weatherwise for the second half of the weekend into
the first part of the new work week.

Main upper trough remains progressive with its` axis crossing the
area on Sunday. The deeper moisture will have moved east of the area
by the start of the period, however there will still be the small
chance for a few light rain or snow showers with the passage of the
upper trough axis, especially during the first half of the day.

Otherwise, large area of surface high pressure centered from
the Tennessee Valley to the Carolinas will ridge north into the
lower Great Lakes. This in combination with broad mid and upper
level ridging aloft should provide dry conditions for the
Monday/Tuesday timeframe.

Temperatures will average some 5 to 10 degrees above normal through
the period.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A weak upper level disturbance will bring general light snow to the
entire region through around 14Z this morning, then a trough axis
will bring more general light snow between 17Z and 23Z today. These
will produce a period of MVFR/IFR flight conditions with general
snow lowering visibility to 2-4SM.

There also will be some lake enhancement. This will impact KART
where periods of IFR or lower are possible with steadier snows
passing just west of the terminal. Then this afternoon, lake
enhanced bands will pass through KIAG/KBUF/KJHW.

Tonight, W to NW flow will direct lake snows east of the lakes,
which will leave most TAF sites VFR. The exception is KJHW which
may drop MVFR or lower at times tonight in lake snows.

Outlook...

Thursday...VFR.
Thursday night...VFR to MVFR in light snow.
Friday...VFR.
Friday night...VFR to MVFR in showers. LLWS likely.
Saturday...VFR to MVFR in showers. Strong sfc winds likely.
Sunday...VFR.

&&

.MARINE...
Weak low pressure will pass through today, with southwesterly winds
ahead of this system followed by a W-NW flow behind it. Winds
briefly increase to around 15 kts on Lake Erie this afternoon, but
appears to fall just shy of small craft criteria. Northwesterly
winds across Lake Ontario behind the system will likely support
small craft headlines across eastern portions of the lake. A high
pressure ridge will build in quickly during Thursday leaving
the region headline free.

A strong storm system passing by to the west and north Friday night
through Saturday night may result in gales across the lower Great
Lakes.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 7 PM EST this evening for NYZ007.
     Winter Weather Advisory from 3 PM this afternoon to 4 AM EST
     Thursday for NYZ006.
MARINE...None.

&&

$$

SYNOPSIS...Apffel
NEAR TERM...Apffel
SHORT TERM...TMA
LONG TERM...JM
AVIATION...Apffel
MARINE...Apffel


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