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-- Discussion containing changed information from previous version are highlighted. --
437
FXUS61 KBGM 150743
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
243 AM EST Sun Dec 15 2019

.SYNOPSIS...
Another winter storm will bring a wintry mix to the area Monday
afternoon into Tuesday as a cyclone moves through the Mid-
Atlantic region.

&&

.NEAR TERM /THROUGH MONDAY/...

-- Changed Discussion --
240 AM update...

Lake effect snow showers will continue to skirt Northern Oneida
County, where a winter weather advisory remains in effect. An
additional 1 to 3 inches of snow is expected in the advisory
area north of a Camden to Remsen line.

Elsewhere, a mainly quiet day is forecast for Sunday. Winds will
remain gusty through the afternoon with frequent gusts of 20 to
30 mph. Temperatures will reach the middle 30s under cloudy
skies.

A thin band of lake effect snow will form in northwest flow
Sunday night and affect Onondaga County. Light snow amounts are
forecast.

A winter storm sliding out of the Mid-Atlantic will spread snow
and mixed precipitation into our forecast area Monday
afternoon. The snow will reach our PA counties initially and
spread northward after dark. A light coating of freezing rain is
anticipated over portions of NEPA Monday afternoon.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Low pressure developing over the Ohio valley begins to head
northeast towards the area Monday evening into Tuesday, touching
off light snow across the area by late MOnday morning before a
trust of warmer, more moist air brings in better lift and
increases chances for snow across the area from south to north.
GFS and Euro continue to agree on a more southerly track of this
system, with the center of the low moving first into southwest
PA, then generally heading towards Long Island and finally
quickly pushing off the coast. Meanwhile, the NAM takes this
system a little more northward into eastern NY state, with a
more pronounced warm nose nudging into the Southern Tier Tuesday
morning. The cooler, more southerly track continues to seem like
a more reasonable solution, as a cold Canadian high over Quebec
should continue to funnel in colder air into Monday night.

Therefore, with this latest update, the snow/mix line has been
moved more southward. Cold air in place will allow for
precipitation to start off entirely as snow across our area
before 0Z, quickly changing over to a mix of rain, snow, and
freezing rain in northeast PA. The freezing line continues to
push northward through midnight, finally resting somewhere
around the Twin Tiers into Tuesday morning. However, there is
the aforementioned disagreement among the models, with 850 mb
temperatures staying near and below 0C according to the GFS,
Euro, and ensembles, and the latest NAM bringing above-freezing
temperatures more northward. At this time, mainly snow is
expected northeast of a line from Cooperstown to Cortland to
Hornell, with a mix of freezing rain, snow, and sleet through to
the Twin Tiers. A change over to mainly rain is expected into NE
PA, especially across the river valleys, as temperatures there
climb into the upper 30s and low 40s.

Tuesday afternoon, a change back over to snow is expected as the
system moves offshore, and the cold front pushes through. A dry
slot works in, shutting off snow for most of our area by 0Z,
with just a few lingering showers across our eastern zones and a
change over to lake effect snow showers downwind of Ontario into
the evening.

Several inches of snow would be expected area-wide - with up to
1 to 3 inches across northeast PA and generally 3 to 4 inches
across central NY. Lesser totals would be expected in the river
valleys, where mainly rain will be seen during the day Tuesday.
A glaze of ice will be possible across much of our area,
southeast of the Cooperstown-Cortland-Hornell line.


Otherwise, we`re still looking at non-diurnal temperatures
through the short term period. Temperatures starting in the 20s
Monday morning will climb generally into the low/mid 30s by the
afternoon, and won`t budge much after sunset as warm air starts
moving in. Temperatures increase a couple degrees later Tuesday
morning and into the early afternoon ahead of the front, then
quickly fall back into the low/mid 20s early Wednesday.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
No major changes to the extended; still looking cold with snow
showers mid to late week...then drying out and moderating some
by next Saturday.

Wednesday and Thursday: A piece of arctic air moves into the
region as an upper level low swings across the region. Very cold
air mass and unsettled conditions are expected with numerous
snow showers for our lake snow effect areas and flurries or
scattered snow showers further south. Highs will struggle to get
into the 20`s with overnight lows in the single digits north
and teens for NE PA. If the operational GFS and ECMWF are to be
believed temperatures will have to be adjusted even further
downward given the modeled boundary layer temperatures.

Friday and Saturday: The cold upper level low moves east, with
ridging, both aloft and at the surface moving in from the west.
This should bring the lake effect snow showers to a gradual end
and we should see a gradual moderating trend. Friday will likely
still be below average, with highs in the mid-20s to lower 30s,
and overnight lows Friday night still cold, in the teens to low
20s. By Saturday, early indications are for dry weather and near
to slightly above average temperatures. Highs look to reach the
mid to upper 30s for most areas.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
A mix of IFR/MVFR restrictions will persist overnight as a cold
front exits the region. The most persistent restrictions will be
at KRME, where light lake effect snow will skirt the terminal
through the next several hours.

LLWS is expected from KSYR to KRME through early morning. Winds
will gust at 25 to 30 knots throughout the morning and into the
afternoon at all terminals.

Slow improvement is expected for flight conditions.
Precipitation will end this morning, then ceilings will rise to
VFR/MVFR this afternoon.


Outlook...
Monday...VFR with winds decreasing.

Monday night and Tuesday...MVFR/IFR restrictions with a wintry
mix.

Wednesday...MVFR/IFR restrictions in CNY maybe reaching AVP.

Thursday...VFR.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...Winter Weather Advisory until 1 PM EST this afternoon for
     NYZ009.

&&

$$
SYNOPSIS...DJP
NEAR TERM...DJP
SHORT TERM...HLC/MJM
LONG TERM...HLC/MJM
AVIATION...DJP