000
FXUS61 KBGM 252338
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
638 PM EST Sat Jan 25 2020

.SYNOPSIS...
Low pressure will continue to track slowly to the northeast
along the U.S. Canada border through the rest of the weekend
with cold air moving in behind it and scattered snow and rain
showers. Seasonable temperatures continue next week before a
dry period returns by the middle of the week.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
330 pm update...
Main concern in the near term remains focused on the tail end
of the heavier precipitation moving through the western
Catskills, which may produce periods of heavy snow, sleet and
rain...causing slippery/hazardous road conditions. Will also
focus on the snow and rain wrapping around the slowly departing
low pressure system tonight, Sunday and Sunday night.

Large cut-off low pressure system over the Great Lakes will
continue to track slowly to the e/ne tonight and Sunday with a
couple spokes of embedded short waves rotating around the
system. The initial s/w is associated with a surface low which
formed near Delaware earlier today and continues to lift to
north...and will eventually phase with the parent low to the
west. Strong WAA, plenty of moisture advecting in from the
south, and upper level support from the short wave provided all
the ingredients for a persistent band/area of enhanced
rain/sleet/snow right through the center of the forecast area.

The short wave will continue to lift to the northeast late this
afternoon and into the early evening. The center of the primary
upper low will track east along Lake Ontario tonight and
combine with cooling temperatures into the upper 20s and lower
30s at the surface...and around -4 to -6 C at 850mb to trigger
the chance for more scattered snow showers. There may be
somewhat a lull early Sunday and into the afternoon as the low
centers moves to the east and weak ridging aloft moves overhead.
The snow is also expected to mix with some rain at times through
the day as temperatures climb a few deg above freezing. This
will cut back on any light snow accumulations. Winds are also
expected to back to the w/sw...and weaken the threat for lake
enhancement.

By Sunday night into Monday, a secondary lobe of energy rotating
around the back side of the departing system will drop in from
the north, and bring with in a slightly colder air mass...850mb
temps around -8 C, and a more nwly fetch across Lake Ontario.
The combination of lake enhancement and the forcing from the
upper s/w should allow for an uptick in shower intensity and
coverage Sunday night. Overnight lows Sunday night will be only
a couple degrees colder...down into the mid to upper 20s.

Snow amounts will be relatively minor with around 1 inch
tonight...then another inch or so Sunday/Sunday evening, and
then 1-2 inches Sunday night. Total snow amounts tonight
through Sunday night will range from around 1 inch or less for
most areas...but 1-3 inches in the hills south of Syracuse, and
1-4 inches into northern Oneida County.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
For Monday and Monday night, a nearly vertically stacked
(barotropic) cyclone will persist over New Brunswick or there abouts
leading to a deep west to northwest flow over NY and PA. This flow
will have copious moisture but it won`t be that cold with 850 mb
temperatures around -6C to -8C. Lake Ontario temperatures are about
+7C so this leaves marginal lake induced instability. So with some
lake moisture plus a lot of synoptic moisture and a west to
northwest flow upslope into central NY and northern PA, scattered
snow showers and flurries should be widespread Monday into Monday
night with highest POPs in north central NY. This includes the
highlands between BGM and SYR. Farther south POPs will be lower with
maybe a few flurries reaching toward the Poconos. The other issue,
especially later on Monday into Monday night/Tuesday is the
height of the inversion which tops out around 850 to 800 mb.
Temperatures at the top of the inversion are around -8C or so
which suggests potential that not all clouds glaciate leading to
patchy freezing drizzle/drizzle. This becomes more likely later
Monday and especially Monday night/Tuesday as the inversion
falls a bit. This is as per latest NAM and GFS model soundings.
Ran forecast builder`s POT_winter weather procedure and it comes
up with decent probabilities for freezing drizzle based on the
temperatures aloft. We will introduce some freezing drizzle for
Monday into Monday night/Tuesday.

For Tuesday, northwest flow continues but the lower levels begin to
dry out with the inversion dropping more. An upper level short wave
passes by which cools the upper part of the inversion enough for
more ice crystals. But, this occurs with drying so we will have
flurries/freezing drizzle/drizzle with POPs diminishing.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
High pressure builds in across NY and PA from Tuesday night into
Thursday on the GFS and Euro with the CMC showing an upper level
wave moving across NY and PA Thursday. The CMC is an outlier here.
NBM shows less than 15 POPs so we will keep dry this far out. Next
more significant system for next weekend is looking highly
uncertain. Latest 12z GFS, euro and CMC are not phasing the northern
branch wave with the southern wave and hence this looks to not be
that big of a deal. Of course we are 6 to 8 days out and we are at
the edge of predictability given the details we need for our
forecasts. So best course this far out is to go with NBM POPS and
temps, winds etc given it is a blend of many models, and ensembles.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...

Abundant moisture, wet ground and snow, and light winds will
result in occasional LIFR conditions overnight with drizzle and
light snow. Towards morning, a westerly flow of somewhat drier
air will develop slow mixing the column allowing for improving
conditions, but snow and rain showers will still be possible at
times, especially at RME and SYR.

Outlook... Sunday...IFR and MVFR conditions likely with a mix
of rain and snow.

Monday through Tuesday...Occasional restrictions especially CNY
in snow showers. Mainly VFR at KAVP.

Wednesday and Thursday...Clear with VFR conditions.

&&

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

&&

$$
SYNOPSIS...BJT
NEAR TERM...BJT
SHORT TERM...DJN
LONG TERM...DJN
AVIATION...BJT/DGM

NWS BGM Office Area Forecast Discussion