000
FXUS61 KBGM 211953
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
253 PM EST Tue Jan 21 2020

.SYNOPSIS...
Some lingering lake effect flurries will occur today and
tonight mostly in central New York. High pressure over the Mid
Atlantic states will provide our region with mainly quiet
weather, and slowly warming conditions through Friday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
12 pm update...
Temperatures have jumped quickly and had to raise high
temperatures as valleys from Scranton to Elmira have gotten into
the mid 20s already.

930 am update...
Clouds and a few flurries continue this morning. Clouds
increasing in CNY and moving south. Some flurries happening now
in western Steuben County.  Temperatures are rising slowly and
had to adjust hourly temperatures down. High temps look good
still.

645 AM Update... Minor adjustments made to chase fickle early
morning temperatures, dewpoints and sky cover...otherwise,
forecast on track to see temperatures rise into the low and mid
20s for highs this afternoon with mainly sunny skies over NEPA
and variable cloudiness across CNY. Wind backing to west will
push solid cloud cover now over western NY back through portions
of the central Southern Tier and Finger Lakes region with some
erosion of moisture on the leading edge.

Previous discussion... Lake effect conditions continue to
plague central NY early this morning with varying degrees of
cloud cover and patchy snow flurry activity. This has resulted
in a potpourri of temperatures ranging from near 20 in the
western Finger Lakes to near zero on the Tug Hill and Catskills,
with everything in between and changing by the hour. High
resolution models have performed poorly at capturing the
moisture in RH, reflectivity and QPF fields, so it`s seat of the
pants, old school forecasting time. Current laminar flow from
the NW becomes increasingly sheared today while backing to the
west below 850 mb. This should disrupt the upslope lake
moisture/clouds by this afternoon and knock down the flurries
with partly sunny conditions returning to CNY and mostly sunny
for NEPA. Frosty morning temperatures should rebound into the
20s today.

Then a weak disturbance moving through the top of the upper
level ridge brings an increase in mid level moisture by
tonight. Sounding profiles suggest a distinct dry layer below
700 mb but saturation below 900 mb. I get the sense that we will
be in a seeder-feeder situation with areas of flurries
rekindling on the 260-280 trajectory from this evening well into
the night. Shallow moisture, warmer than the dendritic layer,
also introduces the possibility for freezing drizzle. The main
focus for this mention of light precipitation will be along the
Onondaga-Madison border through Northern Oneida.

After that...models suggest a pronounced backing of the low-mid
level flow toward the west and southwest on Wednesday with a
stronger indication of subsidence developing over the forecast
area. Limited moisture will signal sunshine, while the return to
southwest flow indicates substantial warming. After another
start in the low to mid teens...we`re looking for temperatures
on Wednesday to climb well into the 30s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
High pressure will remain from off the New England coast to the
Middle Atlantic coast and lead to a mild and mostly sunny day with
highs in the upper 30s to lower 40s or so. Thursday night will be
fair and continued mild with southerly winds in advance of the
weekend storm system. Friday will see this storm approach the region
from Ohio Valley.  The 12z NAM and GFS has a strong southerly low-
level jet with moisture advection beginning. The 12z GFS has a
little QPF reaching the Finger Lakes with the NAM dry.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Main concern this time period is the evolution of the next storm
system and its impacts on our forecast area. Models all show a
closed upper level low moving into Indiana and Ohio Friday night and
then tracking across southern PA/West Virginia and
Virginia/Maryland/Delaware and NJ Saturday and then to off the New
England coast by Sunday. This upper level low brings a low-level
cyclone up to Ohio where is occludes and goes barotropic. The
baroclinic zone shifts to the coast on Saturday and this upper level
low as it moves east will eventually spin up another low-level
cyclone with baroclinic development. Models continues to have track
that is south and east of northeast PA and central NY meaning a
higher chance for mainly snow. We still could see some boundary
layer warmth Saturday during the day which could lead to mixed rain
and snow especially in our valleys. By Saturday night precipitation
should be all snow. We will continue with mainly chance POPs Friday
night, Likely Saturday and chance to likely POPs for snow showers
Sunday and flurries and scattered snow showers into Monday begin
this system.

The main question is how much QPF will our forecast area get. It is
way too early to begin snow amounts. There is a lot of bust
potential with this storm even if its track remains similar. The
issue is how quickly will the coastal low develop. If it is delayed
our area will just get mainly light to moderate snow with the
heaviest snow east of our area. Basically we would have an upper
level low with limited moisture and a minimum between the Ohio
Valley low and the coastal low. The 12z GFS scenario develops the
coastal low more rapidly and hence would be a decent snowstorm for
our area especially Saturday night. But in these transfer lows we
could easily miss out if the coastal low doesn`t take off in time.
So for now we will continue to mention the possibility of a winter
storm this weekend in our Hazardous weather outlook and we will edit
our graphical hazardoMain concern this time period is the evolution of the next storm
system and its impacts on our forecast area. Models all show a
closed upper level low moving into Indiana and Ohio Friday night and
then tracking across southern PA/West Virginia and
Virginia/Maryland/Delaware and NJ Saturday and then to off the New
England coast by Sunday. This upper level low brings a low-level
cyclone up to Ohio where is occludes and goes barotropic. The
baroclinic zone shifts to the coast on Saturday and this upper level
low as it moves east will eventually spin up another low-level
cyclone with baroclinic development. Models continues to have track
that is south and east of northeast PA and central NY meaning a
higher chance for mainly snow. We still could see some boundary
layer warmth Saturday during the day which could lead to mixed rain
and snow especially in our valleys. By Saturday night precipitation
should be all snow. We will continue with mainly chance POPs Friday
night, Likely Saturday and chance to likely POPs for snow showers
Sunday and flurries and scattered snow showers into Monday begin
this system.

The main question is how much QPF will our forecast area get. It is
way too early to begin snow amounts. There is a lot of bust
potential with this storm even if its track remains similar. The
issue is how quickly will the coastal low develop. If it is delayed
our area will just get mainly light to moderate snow with the
heaviest snow east of our area. Basically we would have an upper
level low with limited moisture and a minimum between the Ohio
Valley low and the coastal low. The 12z GFS scenario develops the
coastal low more rapidly and hence would be a decent snowstorm for
our area especially Saturday night. But in these transfer lows we
could easily miss out if the coastal low doesn`t take off in time.
So for now we will continue to mention the possibility of a winter
storm this weekend in our Hazardous weather outlook and we will edit
our graphical hazardous weather outlook to "elevated" level for
Saturday. us weather outlook to "elevated" level for Saturday.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
1240 pm update...

Mainly VFR into Wednesday morning. Lake moisture is slowly
moving east as low level winds shift east. With this is a 3k ft
cig. A few flurries could also occur. MVFR cigs are possible
this aftn at BGM/Deterministic models and ensembles continue to develop a
coastal low around the Delmarva, tracking up the east coast into
the weekend. Latest guidance tracks this slightly more to the
south of us than in previous runs, keeping temperatures a couple
degrees colder as morning lows in the 20s to low 30s Saturday
peak in the 30s. With temperatures aloft falling back below
freezing, this should allow for precipitation to come in mainly
as snow, mixing in with rain mainly across the river valleys and
lake plain during the afternoon. Snow lingers into Sunday as
the surface low tracks into New England and finally towards the
Canadian maritimes. Drier air starts to work back in Sunday
night into Monday with a ridge building across the southern US,
but with west/Northwest flow and another shortwave moving
through, rain/snow showers with some lake enhancement will
remain in the forecast across central NY through the early part
of next week.ITH and low end VFR at other NY sites. AVP will
remain scattered to clear at this level. Above these low clouds
are high clouds. In addition a cig at 10k ft will move in for
tonight. Wednesday skies become clear.

Westerly winds 5 to 10 knots this afternoon and early evening.
Late tonight and Wednesday winds light and variable.

Outlook...
Wednesday afternoon through Friday night...VFR.

Saturday through Sunday...Chance IFR. Snow possible.

&&

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

&&

$$
SYNOPSIS...JAB/TAC
NEAR TERM...JAB/TAC
SHORT TERM...DJN
LONG TERM...DJN
AVIATION...TAC

NWS BGM Office Area Forecast Discussion