502
FXUS61 KBGM 151749
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
1249 PM EST Sun Dec 15 2019

.SYNOPSIS...
Lake effect snow showers will continue this afternoon and
tonight with light accumulations. Another winter storm will
bring a wintry mix to the area Monday afternoon into Tuesday as
it moves through the Mid- Atlantic region.

&&

.NEAR TERM /THROUGH MONDAY/...
12 pm update...
Keep the snow showers going across the twin tiers this
afternoon. No signs of quitting yet. connection to Lake Huron
continues. That should all change toward sunset with low level
lift waning due to the short wave passing now and diurnal
heating.

930 am update...
Light lake effect snow continues this morning across most of the
area with cloudy skies. Accumulations are light to almost
nothing in the valleys with temperatures mostly in the mid 30s.
Winter weather advisory runs until 1 PM for northern Oneida.
This looks fine and will let it finish. Radar returns close to
30 dbz so maybe another inch or two on the Tug. Upped pops,
temps, and clouds.

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.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Weak wave of low pressure associated with a positively tilted
upper level trough moves up the Tennessee Valley, to near DC
and then off the NJ coast Monday night into Tuesday. Latest
model guidance continues to trend colder, and further south with
this winter system as a strong surface high remains anchored
over New England Monday evening. Light snow, possibly mixed with
sleet and pockets of freezing rain will be ongoing across much
of NE PA Monday evening. Still expect precipitation (snow or
wintry mix) to overspread the area from south to north later
Monday evening and Monday night. Again, latest guidance has
really slowed down the progression northward...so now the best
estimates are for snow to reach the NY/PA border region late
evening or around midnight...then the US-20 corridor during the
predawn hours Tuesday. Finally reaching the NY Thruway corridor
and points north around daybreak Tuesday. Periods of snow or
wintry mix continue areawide Tuesday morning, before tapering
off to showers in the afternoon. See below for more details on
precipitation types and forecast amounts.

With the colder trends (both aloft and at the surfaces) it now
looks like some sleet and pockets of freezing rain could mix in
at times as far north as the Rte-17/I-86 corridor, then south
of I-88 in the Catskills. North of this line, the event will
likely be all snow and no mix. Best chance for freezing rain
will be across NE PA; especially the higher elevations, where up
to two-tenths of an inch of ice is looking possible. Surface
temperatures look to hold steady Monday night into Tuesday
morning between about 25-32 degrees areawide...the Wyoming
Valley, and upper Susquehanna Valley locations in NE PA could
reach the mid-30s Tuesday; changing the precip over to a mix of
rain, sleet and wet snow...it could even go to all rain for a
time south of Pittston in Luzerne county. Current forecasts are
for 1-3 inches of snow and sleet with coatings of ice across NE
PA. Then, 2-4 inches of snow (and sleet across Southern Tier)
with localized amounts up to 5 inches for Central NY. These
precip types and amounts could certainly change depending on the
future model trends. Considering the uncertainty, and that this
is mostly a 4/5th period event, will hold off on any winter
headlines at this time, and try to better pin down the details
in subsequent forecast updates. Will continue to mention this
potential for winter weather in the HWO; as it could impact
travel areawide.

Tuesday night: The previous system exits quickly eastward, with
a weak surface ridge nudging into the region. There could still
be some scattered snow showers or flurries north from lake
effect, as cold air advection takes hold and 850mb temps fall
to around -10C. Late at night a large, very cold upper level low
begins to approach from the Great Lakes region...this should
turn the low level winds more southwesterly, shifting the lake
effect snow showers further north...but shower off of Lake Erie
could spread into Steuben county, and even into the rest of
central NY as the fetch and wind speeds increase.

Wednesday: Model guidance has come in rather good agreement that
a strong, arctic frontal boundary will cross the region during
the day. Southwest winds early in the day shift west-northwest
behind the front. Snow showers and possible squalls are expected
along and behind the front. This looks to be a high PoP, low
QPF/snow amount scenario. However, as temperatures fall into the
teens and low 20s late in the day winds will also increase
between 15-25 mph, with higher gusts. This will mean that there
could be blow snow, and significantly reduced visibility in the
snow showers and squalls. We will continue to closely monitor
this potential...generally snow amounts should be a coating to 2
inches across Central NY, with less than 1 inch in NE PA before
sunset. High temperatures will be lucky to reach 25-30 out
ahead of the front....850mb temperatures fall to around -20C by
sunset with 1000-500mb thicknesses falling below 504dm.

Wednesday night: The coldest air mass thus far of the winter
season will be over the area. Guidance is in good agreement for
850mb temperatures between -20 to -25C and thicknesses bottoming
out around 500dm. A blustery, frigid northwest flow will
continue to spray lake effect snow showers and flurries across
the region. Northwest winds remain between 10-20mph, creating
areas of blowing snow and wind chills between 0 and 15 below.
Actual air temperatures should fall into the single digits for
most areas...except lower teens in the Wyoming Valley of NE
PA...and 0 to 5 below across northern Oneida county.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
No major changes to the extended; still looking cold with snow
showers to start...then drying out and slowly moderating some
by next weekend.

Thursday: A piece of arctic air remains over the region as an
upper level low swings across the region. Very cold air mass and
unsettled conditions are expected with scattered snow showers
for our lake snow effect areas and flurries or a few snow
showers further south. Highs will struggle to get into the mid
teens to lower 20s 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 still have to be adjusted even
further downward given the modeled boundary layer temperatures.

Friday and Saturday: The cold upper level low slowly moves
east, with ridging, both aloft and at the surface trying to
move in from the west. However, there are now model differences
with the GFS stalling the cold upper level low nearby much
longer than the ECMWF due to downstream blocking. For now, went
close to the NBM guidance for temperatures this period...which
is trending colder. The lake effect snow showers should end
either way as a strong and dry surface high builds over the
region. Latest forecast now has high in the mid 20s to low 30s
Friday, reaching the low to mid-30s on Saturday. Still cold
under light winds Friday night...lows in the teens.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
1230 pm update...

lake effect snow showers will continue across all the sites this
afternoon. In general VFR conditions in flurries and light snow
showers. Restrictions are likely at RME/SYR/BGM/ITH as bands of
heavier snow move through. For this have a tempo for MVFR.
vsbys could drop to IFR briefly too. This evening the snow
showers will only be at SYR/RME. SYR could have MVFR cigs for
most of the night due to a weak band of lake effect snow.

Monday VFR but still broken to cloudy. AVP may fall to MVFR
around 18z ahead of the next system.

West to northwest winds at 10 to 20 kts will gust at 20 to 30
knots this afternoon then drop to 5 to 10 kts this evening. Late
tonight light and variable winds become south to southwest at 5
kts Monday morning.

Outlook...
Monday...VFR in CNY and MVFR at AVP.

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

Wednesday and Wednesday night...MVFR/IFR restrictions in CNY.
MVFR AVP.

Thursday...VFR. Possible restrictions in CNY due to dying lake
effect snow showers.

Thursday night and Friday...VFR.

&&

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

&&

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

NWS BGM Office Area Forecast Discussion