000
FXUS61 KBGM 040226
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
926 PM EST Fri Dec 3 2021

.SYNOPSIS...
Slightly warmer temperatures are expected Saturday with
scattered rain and snow showers in central NY north of the Twin
Tiers. A stronger storm system will produce strong south winds
and a period of mixed precipitation, turning to all rain Sunday
night into Monday. Colder temperatures return Monday night and
Tuesday with scattered lake effect snow showers.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
925 pm update...
Little change except to increase cloud cover again in CNY. Not
much yet for flurries or snow showers yet.

630 pm update...
With clouds increasing across most of the area increased cloud
cover tonight. With clouds coming off Lake Ontario already
increased the chance of snow showers in the northern counties.
CAMs showing a band to form in the usual locations with a 300
low level flow shifting to 270 late tonight. Some light snow
accumulations possible in northern Onondaga, northern Madison,
and Oneida Counties. Adjusted rest of grids only slightly.

238 pm update...
Primary forecast concerns in the near term are focused on the
light snow showers possible late tonight along and north of the
NY Thruway, then mixing with or changing to rain and spreading
south across central NY Saturday afternoon as west winds
strengthen, and a change back to snow north of the Thruway
Saturday night.

Weak high pressure at the surface slowly tracking east across
the Northeast US this afternoon, with broad cyclonic flow aloft
within a cold but seasonal air mass. This surface high will keep
weather conditions quiet most of tonight with the exception of
a few flurries possible north of Syracuse. There could be enough
breaks in the clouds this evening to induce pockets of strong
raditional cooling, especially in the Catskills and into far
northern Oneida County, where temperatures could drop 5 to 10
deg rapidly. Overnight lows are expected to drop into the 20s
across much of the area with some upper teens in the coldest
spots.

A weak short wave embedded within the cyclonic flow will move
from the nrn Great Lakes into nrn NY/VT/NH Saturday into Sat
night. A weak cold front will sweep through and work with some
deep moisture to produce a mix of snow and rain across a good
portion of central NY...mainly north of line from Corning to
Binghamton to Sidney. Locations above 1500 ft elevation may
actually remain cold enough for snow all day, but areas below
1000 ft will see a mix go to all rain by the afternoon as
surface temperatures warm into upper 30s and lower 40s. Parts of
northern Oneida are forecast to remain in the lower 30s and
have the best chance of seeing snow throughout the day with up
to 2 inches by the late afternoon.

Behind the quickly departing short wave to the northeast, a
swift punch of cold air will arrive into central NY and cross
over Lake Ontario to trigger some lake effect snow showers.
850mb temperatures around -10 to -11 deg C and a 290-310 flow
with a relatively long fetch over the lake should lead to at
least a brief window of opportunity for at least a semi-
organized band of lake effect snow which will extend from sern
Lake Ontario into central NY. This band could be capable of
producing a quick 1-2 inches of snow from Saturday evening
through the overnight hours before the flow shifts to the south
and warmer air moves in to break up the band.

Overnight lows Saturday night will fall once again into the 20s
for much of the region, with a few upper teens in the higher
elevations of central/n-central NY.

Winds will be of some concern late Saturday through Saturday
night as well as the surface low moves east across southern
Ontario into Quebec and runs into the area of high pressure to
the east. A tight pressure gradient will set up during this time
where sustained winds will increase to 15 to 20 mph and gusts
could reach up to 30 mph at times.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
330 PM Update

A surface high will be overhead during the day on Sunday. This will
keep the region dry through the early evening hours. Temperatures
will be mild with highs in the upper 30s to mid 40s. Precipitation
chances increase Sunday night as a warm front approaches the region
from the south, with the chance for some snow showers to start. As
the warm front pushes northward, temperatures will warm up, leading
to a transition to rain showers. The National Blend of Models (NBM)
did seem a bit high with the PoPs during the overnight so they were
reduced to be limited to no more than likely during the early
morning hours as the 12z models appeared to have slowed down a
little with the timing. This warm front is associated with a
with a low pressure system located over the central Great Lakes
Region. The pressure gradient over our region will tighten
Sunday night. There will also be a strong 850mb jet streak
overhead with winds around 60 kts. While these strong winds will
struggle to mix down initially, there are could be some
locations around the Finger Lakes that observe gusts up to 40
mph. Overnight lows will be in the 30s.

By Monday morning, the region will be in the warm sector as strong
southwesterly flow will advect warm air into the region. High
temps will easily be in the 50s. Rain showers will be likely
throughout the day on Monday as a cold front associated with
the aforementioned low approaches the region. While still
within the tight pressure gradient and strong low-level flow
above, sustained winds will remain quite breezy and are expected
to be around 20 mph, locally higher, throughout the day. Gusts
of 30-35 mph will also be possible.

The front should be through by late Monday night. Rain showers will
taper off from west to east. With the flow becoming more
northwesterly, there will be a transition to light lake effect
snow showers, mainly across Oneida County. Light accumulations
are expected; less than an inch. While still a bit breezy,
winds become calmer as well with the low well to the northeast.
This system will continued to be monitored. As the timing of
this event gets closer and confidence increases, then wind
headlines might be needed. Temperatures during the overnight
will fall into the mid to upper 20s.

It should be noted that from Sunday evening through Monday night, a
50/50 blend of the NBM and NBM 90th percentile was used for the
sustained winds and wind gusts. Based on the tight pressure gradient
will be and a strong 850mb jet streak overhead during most of
that period, NBM seemed too low.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
330 PM Update

There will be some lingering lake effect snow showers Tuesday.
Otherwise, weak high pressure will build into the region,
resulting in mainly dry conditions. While there could be some
snow showers Tuesday night, the next best chance for snow
showers will be Wednesday as a weak low pressure system
approaches the region. Rain showers could mix in during the
afternoon as temperatures warm up some. Then snow will be the
dominant ptype by Wednesday evening. There are some timing
differences between model guidance with this system as the ECMWF
and CMC models are a little quicker than the GFS. There is some
agreement on the track as all have it moving up along the
coast. While it is a little too early to pinpoint any snowfall
amounts, this system looks like it will bring some measurable
snowfall. The GFS and ECMWF ensembles are indicating that a few
inches of snow will be possible. Any change in track though can
have an impact on how much the region will observe.

There is a slight chance for lingering snow showers on Thursday.
Otherwise, a weak ridge of high pressure quickly passes through,
bringing a brief dry period. Another system approaches the area
late in the week, bringing another chance for precipitation.

Temperatures will be closer to seasonable during this period
with a warm up possible at the end of the week.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
A few lake effect snow showers will be possible tonight at SYR.
At this time, confidence is low on the intensity of any lake
effect snow showers that develop, so have only brought MVFR
conditions to SYR for now, however, IFR visibilities could be
possible if any lake effect bands move directly overhead.

Elsewhere, MVFR ceilings will be possible with moisture coming
from off the lakes, however any snow shower activity will remain
north of ITH. Winds will remain light overnight and then winds
become south/swly around 10 to 15 kt...with gusts 20 to 25 kt on
Saturday.


Outlook...

Saturday night...Mostly dry/quiet weather except for some lake
effect snow showers possible around KRME.

Sunday...High pressure should bring a return to VFR conditions
across the area.

Late Sunday through Sunday night...Approaching low pressure
system brings increasing chance of rain with restrictions.
Strong southerly winds and wind shear also possible.

Monday...Rain changing over to snow likely with associated
restrictions. Strong southwest winds.

Tuesday and Wednesday...Light snow mixing back with rain in the
afternoon.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.

&&

$$
SYNOPSIS...BJT/TAC
NEAR TERM...BJT/TAC
SHORT TERM...BTL
LONG TERM...BTL
AVIATION...MPK

NWS BGM Office Area Forecast Discussion

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