NWS Forecast Discussion

000
FXUS61 KBGM 190712
AFDBGM

AREA FORECAST DISCUSSION
National Weather Service Binghamton NY
212 AM EST Wed Dec 19 2018

.SYNOPSIS...
High pressure will provide dry weather into Thursday. A storm
will bring rain to the area Thursday night through Friday.
Cooler weather is expected Saturday and Sunday with scattered
snow showers.

&&

.NEAR TERM /THROUGH TONIGHT/...
130 AM update...

Lake clouds still remain over the northeast counties keeping
temperatures up. There is a push to the east as low level winds
shift to the southwest. These clouds should only be in Oneida
County at sunrise, then shift northeast by 10 AM.

Mainly clear skies across the rest of the area has allowed
temperatures to fall into the teens and single digits. Have
lowered temperatures further. Despite these cold temperatures
this morning an increasing southerly flow of warm air will move
in today and last into Friday. Highs today will be in the lower
40s and upper 30s under mostly sunny skies and light winds.

Tonight lows in the 20s with light to calm winds. Clouds don`t
start to increase until late and at upper levels.

Thursday will be mild with skies becoming cloudy. Highs will be
in the low and mid 40s. Southeast and south winds increase to 10
mph. With the warm air, snow will ripen and valleys will lose
it completely by the end of the day. Rain comes into NEPA and
Sullivan County NY late in the day well ahead of the stacked low
in the southeast US.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Low pressure will develop over the deep south on Thursday then track
northward into the region on Friday. Yet another surge of warm air
advection will come northward into the region. Ahead of a warm front
associated with this system moisture will overrun the front leading
to widespread rain Thursday night through a good portion of Friday.
Modeling has locked in on a late afternoon arrival time with the
rain spreading south to north across the region. We will have to
watch for a heavy rain threat as we closer to the event with modeled
QPF from 1/2 to 1.5 inches of rain, highest the further east you go.
This amount of rainfall at this time does not look like it will lead
to anything more than poor drainage or nuisance flooding. However,
MMEFS guidance does have a couple of river points touching minor and
this will be watched with further forecast updates. Our HWO for most
of NE PA and the southern Catskills now reflects this possibility as
well.


Daytime temperatures should rise into the 40`s Thursday after
starting out in the upper 20`s. However, temperatures at night are
likely to rise with the warm front approaching the region as well
through the 40`s and getting into the 50`s Friday in spots. A few
locations in the Catskills may have some stubborn low level cold air
around Thursday evening. However, even in these locations
temperatures should rise above freezing before any precipitation
arrives. Temperatures Friday afternoon differ considerably based on
the degree of a dry slot. The ECMWF solution would allow for a shot
of 60 degree temperatures with the GFS hanging onto more rain
keeping us in the 40`s and low 50`s. Also, in the dry slot some
ensemble members are still showing some slight instability as
well that may result in a touch of thunder if it occurs.

As the low moves north of the region Friday night, temperatures
should fall back into the 30`s. Modeling along with a good cluster
of ensemble members are now keying on a second wave of low pressure
moving through eastern portions of the region. A period of snow with
light accumulations or rain/snow mix could very well occur late
Friday night to the north and west of the low track with the cooler
temperatures.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Saturday through Sunday: As the low pressure system pulls away from
the area, there will be wrap-around moisture Saturday. Temperatures
will be steadily dropping throughout the day with temperatures
becoming cold enough for a gradual transition to snow showers. Areas
at lower elevations may still see some rain mix with the snow. A
light additional snow accumulation is possible. As winds shift to a
more westerly/northwesterly direction and the system continues to
pull away, any snow showers will be more of a result of lake effect
by Saturday evening. Greatest chances of snow showers Saturday night
will be further north across CNY to as far south as the Southern
Tier. Lower chances across NEPA. Some lake effect snow showers
possible again on Sunday, mainly across CNY.

As the system departs, colder air will be filtered in as the winds
shift from southerly to more westerly/northwesterly. As a result,
temperatures Saturday will likely be non-diurnal, as they will
gradually drop throughout the day with daily highs reached shortly
after midnight or so. Temperatures may rise a degree or two Saturday
morning, before continuing to drop in the afternoon. By the
afternoon, temperatures will be in the lower to mid 30s. Highs and
lows on Sunday will remain seasonable (30s highs, 20s lows).

Monday through Tuesday: Monday`s forecast is a bit more uncertain
with considerable differences between some of the models. The ECMWF
and has a weak clipper system quickly moving through the area.
Meanwhile, the GFS and Canadian has a much flatter upper level flow
with just some lake effect snow showers possible across CNY. Should
a scenario like what the ECMWF shows pan out, we would expect a
light accumulating snow across much of the area. If a scenario
similar to what the GFS and Canadian shows pans out, most of the
area should remain dry with just some possible lake effect snow
showers across CNY. To account for this uncertainty, kept only
chance POPs in for most, with slight chance further south across
NEPA. High pressure should briefly build in over the area for
Christmas Day/Tuesday, with perhaps some partial sunshine in the
morning, before clouds build back in ahead of the next system for
Wednesday.

Temperatures will remain near normal for both Monday and Tuesday
(highs in the lower to mid 30s, lows generally in the 20s).

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
1230 am update...

MVFR over SYR/RME now. This lake moisture will lift northeast
this morning. RME will have it the longest until around 10z. SYR
will only have it for an hour.

Outside of this is only high clouds and VFR which will continue
into tonight.

Light and variable to calm winds early this morning. During the
day today south winds at 5 kts. This evening, southeast to south
winds at 5 kts or less.

Outlook...

Wednesday night through Thursday...VFR.

Thursday night through Friday night...Large system impacts area
with restrictions and rain.

Saturday/Sunday...A lingering chance of mixed rain-snow showers
and associated restrictions.

&&

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

&&

$$
SYNOPSIS...TAC
NEAR TERM...TAC
SHORT TERM...MWG
LONG TERM...BJG
AVIATION...TAC

NWS BGM Office Area Weather Forecast Discussion