Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kbgm 111737 
afdbgm

Area forecast discussion
National Weather Service Binghamton New York
1237 PM EST Wed Dec 11 2019

Synopsis...
lake effect snow showers return late this afternoon and
evening. Some brief periods of heavier snow are possible. Snow
continues across the New York thruway corridor tonight, followed by
dry weather for Thursday before another system brings in rain
for Friday night into Saturday night.

&&

Near term /through Thursday/...
930 am update...
update to today's forecast. Cloudy skies slowly moving out of
the western Catskills and nepa. Some flurries occurring still
along and east of i81. A short wave is moving through providing
weak lift. Added snow showers to the forecast. Temperatures and
winds look good.

630 am update...
little changed with this update. Snow showers continue to pull
out of the Poconos/Catskills this morning, and though radar
continues to show weak returns west of I-81 across the twin
tiers, this appears for the most part not to be reaching the
ground. Lingering snow chances end completely over the next
couple of hours, with skies turning sunny for the morning and
much of the afternoon before our next round of snow later today.
Changes with this update have been to push back timing on the
arrival of snow ever so slightly, with the majority of it
holding off until after 21z.

Previous discussion continues below.
Snow showers are moving out of our southeastern zones this
morning, with generally dry weather this morning into the
afternoon. Clouds even start to break up with a dry airmass in
place, but then a weak cold front moving in will bring in
additional snow showers into the late afternoon and evening. The
front starts to move into our western zones after 21z, with the
NAM, regional Canadian, and mesoscale models indicating an area
of strong frontogenesis coincident with steeper low-level lapse
rates across The Finger lakes and northward to the thruway
corridor and western Mohawk Valley. This will present a risk for
some snow squalls to develop, which we have mentioned in our
hazardous weather outlook.

Though columns will be saturated through the snow growth layer
and any snow squall could lead to 1" per hour rates, the better
chances for higher snow totals into the evening will be across
northern Oneida County. There will be better synoptic forcing
across northern New York with the base of the shortwave trough
tracking through that area, and as the front moves through, a
shift generally to westerly flow will provide for some Ontario
lake enhancement before a transition mainly over to a lake
effect event after 0z. Lake effect snow showers continue mainly
along and north of the thruway the rest of the night, wrapping
up entirely soon after sunrise.

Snow totals up to 3 to 6 inches will be concentrated across
northwestern Oneida County, with lighter totals up to 1 to 2
inches possible across northern Onondaga and Madison counties.
However, we can't rule out a slight shift in the axis of heavier
totals if the band is able to set up a bit more to the south.
That said, a Winter Weather Advisory has been hoisted for northwest
Oneida County for heavier snow totals.

Thursday: lake effect snow wraps up after sunrise with a shift
to southwest flow as high pressure builds into the eastern US.
Skies turn sunny, though temperatures will stay cool and peak
only in the upper 20s and low 30s. High clouds will start to
build back in from west to east into Thursday evening as high
pressure begins to move offshore and warmer, more moist air
works in.

&&

Short term /Thursday night through Saturday/...
345 am update...
temperatures will be on their way back up, along with the
likelihood for rain eventually as we head into the weekend.

High pressure will shove offshore Thursday night through midday
Friday, though a surface ridge will extend from it to keep dry
air in the lower levels and thus quiet weather. Aloft, southwest
flow will gradually bring in warming temperatures and increasing
moisture. High thin clouds will thus thicken with time,
especially by midday Friday Onward. Temperatures mainly in the
20s Thursday night, will moderate to highs of mid 30s to lower
40s on Friday.

An upper trough will amplify while taking on a negative tilt
across the Mississippi to Ohio valleys Friday-Friday night. This
will cause deepening low pressure to shoot up roughly the
eastern side of the Appalachians or along the East Coast late
Friday into Saturday. The models do differ somewhat in this
detail; European model (ecmwf) GOES pretty much directly over our region whereas
GFS and Canadian models are more right along the coast. Tail end
of the NAM run seems to be somewhere in between; if anything,
closer to the European model (ecmwf). The footprint of this system is large
enough to where the end result is similar in terms of rain
being very likely Friday night into saturday; the question will
be how much based on which school-of-thought turns out correct.
Also, with such warm thermal profiles aloft, we will have to
monitor potential for brief freezing rain/ice if initial
precipitation develops early enough for higher terrain east of
I-81 on friday; and perhaps northern Oneida County into Friday
evening. Model consensus has been to delay the precipitation a
bit however, to the point that much of Friday could be dry
albeit cloudy before rain presses south to north late
afternoon-evening.

Other than northern Oneida which may be near freezing initially,
lows Friday night will generally be mid 30s-near 40 and rising,
followed by highs of 40s-near 50 Saturday.

&&

Long term /Saturday night through Wednesday/...
345 am update...
colder air wraps back across the area during the second half of
the weekend into early next week, with snow showers perhaps
mixed with rain showers at times. Another system may then move
into the area by next Monday night-Tuesday.

Low pressure will pass by the area by Saturday night, with cold
air advection changing remaining precipitation to snow or mixed
rain-snow. There could be some snow accumulation especially in
parts of central New York Saturday night-early Sunday, and
perhaps lake-enhanced/lake-effect snow showers later Sunday
through Sunday night focused more on the typical northern zones.

With our active pattern continuing unabated, a brief brief
Monday appears likely to give away to another system advancing
out of our southwest Monday night or Tuesday. While models all
generally have the system, they differ considerably on track and
strength of the associated wave/low. Right now, odds favor some
sort of all snow, to snow/mix scenario. There could be some
accumulations with this, but things could easily change
considering it is still about a week out; we will sort it out in
coming days.

&&

Aviation /18z Wednesday through Monday/...
1220 PM update...

VFR conditions to start. The clouds have been mostly pushed east
of the area. Restrictions from lake effect snow will be most
prevalent at rme/syr starting 21z. Rme could have IFR vsbys 2 to
6z. Around 06z snow will be north of syr so VFR there. Rme will
have lingering MVFR in -shsn until 14z.

In south central NY, conditions could fall to MVFR from 00z to
03z in snow showers. Outside of that VFR.

Avp will be VFR throughout with scattered to clear skies.

Southwest to west winds at 10 kts with gusts to 20 kts into the
evening. Around 05z winds drop to 5 to 10 kts out of the west
and northwest. Thursday mostly southwest winds at 5 kts.

Outlook...
Thursday afternoon through Friday morning...VFR.

Friday afternoon...VFR to start, then rain moves in late with
possible restrictions.

Friday night through Sunday...restrictions likely in periods of
rain through Saturday then rain and snow showers on Sunday.

Monday...VFR.

&&

Bgm watches/warnings/advisories...
PA...none.
New York...Winter Weather Advisory from 4 PM this afternoon to 4 am EST
Thursday for nyz009.

&&

$$
Synopsis...hlc/tac

National Weather Service Glossary of Abbreviations