Scientific Forecaster Discussion
fxus61 kbgm 180527
Area forecast discussion
National Weather Service Binghamton New York
1227 am EST Mon Nov 18 2019
high pressure slides east today and temperatures will be a bit
warmer this afternoon. Our next system will bring the chance
for mixed precipitation late tonight through Monday night. High
pressure returns again mid week.
Near term /through today/...
1120 PM update...there are some snow flurries across the
twin tiers and into Tompkins and Cortland counties, so have
updated the forecast to include a chance of flurries with little
to no accumulation. Also, keep an eye on Sullivan County, as
some pockets of freezing drizzle may be developing as Monticello
is currently reporting unknown precip with a temperature of 30
degrees. Will hold off from bumping up the start time of the
advisory for now, unless we start to receive some ground truth
reports in those areas.
10 PM update...
no major changes made to the forecast at this point. Precip in
the form of freezing drizzle still appears to be possible across
the Poconos and Catskills Monday morning...before changing to
liquid drizzle when temperatures climb above freezing. Winter
Weather Advisory remains in effect for the same area and for the
same time frame.
overall, a fairly busy and tricky forecast for the near term
Rest of this afternoon: continued increasing clouds is expected
as high pressure over northern New England departs and the
cloud shield from the next system approaches. Highs have topped
out in the mid to upper 30s across the majority of the area,
with a few lower 40s as well.
A coastal low pushes north tonight along the East Coast and
this provides a very tricky forecast for early Monday morning.
Models continue to indicate some low level moisture with
temperatures increasing aloft. Meanwhile, ground temperatures
will be below freezing. This will set the stage for some light
freezing rain or freezing drizzle across the Poconos and
Catskills early Monday morning. That being said, models have
trended a bit further east/offshore with the coastal low with
the 12z runs. In addition, with drier air still in place, the
freezing rain/freezing drizzle over the Catskills and Poconos
will likely take a few more hours to begin than previously
forecast, likely not until after 09z/4am or so. As a result,
decided to change the start time of the Winter Weather Advisory
in effect for these areas to 09z/4am (start time was 05z
before). Overall, just a glaze of ice is expected in these
The Winter Weather Advisory still ends at 16z/11am Monday, as
most of the precipitation will likely change over to mostly
plain rain by then. This rain will likely continue through the
afternoon hours (with the highest chances the further east you
go) as the majority of the area will warm above freezing.
While the coastal low will be moving away from the New England
coast Monday evening/night, the potential for an additional
wintry mix remains during this timeframe, especially areas east
of I-81 as a separate upper level wave takes on a negative tilt
and pivots through the area, along with plenty of upwards
forcing. What remains highly uncertain is the exact form and
amounts of precipitation that will be found. Thermal profiles
indicate that a wintry mix of sleet, freezing rain, and snow may
occur, before transitioning to all snow after midnight or so.
During this time, a quick thump of 1-3 inches of snow is
possible, especially across the higher elevations of Otsego and
Delaware counties. Across areas west of I-81, precipitation will
be on the lighter side and therefore may not completely change
over to snow (remaining as a light wintry mix).
While an additional Winter Weather Advisory may be needed at
some point for the wintry mix Monday night, opted to not issue
one at this time due to uncertainty in precipitation types and
amounts. This will continue to be monitored during upcoming
forecast updates. Otherwise, lows Monday night will likely be in
the upper 20s to lower 30s.
Short term /tonight through Wednesday night/...
negatively tilted upper level trough/wave will be over the
region Tuesday morning, with a weak inverted surface trough
hanging back from New England to the western Catskills.
Therefore, expect some lingering wintry precipitation (likely
snow), mainly east of I-81 in morning. Used a blend of the
namnest, GFS and European model (ecmwf) for pops and quantitative precipitation forecast Tuesday morning...this
gives likely pops mainly NE of Delhi, Oneonta, and Rome...and up
to a tenth of an inch quantitative precipitation forecast (around 1/2" of snow). This system
quickly pulls east leaving behind a cool west-northwest flow for the rest
of Tuesday. It should become mainly dry, aside from perhaps a
few rain or snow showers in Oneida/Steuben counties off the
Tuesday night: another mid/upper level wave races into the area
from the central Great Lakes. This wave will not have very much
moisture to work with, but could possibly pick up just enough
off the lakes for a few more snow showers across our central New York
zones. Any accumulations look to be under a half inch at this
time...with overnight lows dipping into the upper 20s to low
Wednesday: lingering northwest flow a the surface, and cool
850mb temps around -5c. Lake Ontario and Erie are both around
+7c...so this cool airmass could be just cold enough to initiate
a limited lake response. However, ridging aloft will build in
from the west through the day, so we have chance pops in the
morning fading to just a slight chance of rain or wet snow
showers by afternoon. Again, NE PA should be generally dry under
partly sunny skies. Seasonable temperatures with highs 35-45. A
ridge of high pressure at the surface and aloft moves overhead
Wednesday night bringing dry weather areawide and partial
clearing. Light west winds with lows around 30.
Long term /Thursday through Sunday/...
400 PM update...no major changes to the long term with this
forecast update. The Thursday afternoon/Friday system still
looks on track with previous forecast. There is still much
uncertainty with the forecast for next weekend. The operational
GFS would keep colder weather and chances for lake effect snow
across the area. Meanwhile the 12z operational ecwmf would bring
a quick warm up out ahead of another low pressure system moving
in from the Ohio Valley by next Sunday. For now stuck close to
the previous forecast and nbm during this timeframe, until model
guidance can come into better agreement
430 am update...brief bump up in temperatures Thursday, will be
followed by as system Thursday night into Friday which will
send temperatures back cooler into the weekend.
Models are in better agreement on opening a quiet window for
most of Thursday with brief upper ridging getting almost the
whole area into the 40s. This would only be reaching to near
climatological averages and it will be temporary. Though there
is uncertainty on the strength of the associated low, timing of
the next cold front is skewing later to sometime late Thursday
night into Friday. Rain appears likely ahead of and with the
front, with temperatures that may rise Thursday night. This
will be followed by cold air advection later Friday into the
weekend. Remaining precipitation will thus mix with snow while
also probably become More Lake-moisture dependent in the wake of
the front. Too early to say that this will definitely include
accumulating lake effect snow but there will be some potential
for it east or southeast of Lake Ontario Friday night into
Aviation /06z Monday through Friday/...
MVFR ceilings will be moving in across the region as a coastal
low moves north and pushes low level moisture inland. Some
pockets of freezing rain/drizzle will be possible at avp and or
kbgm through this morning, but at this time confidence is still
too low to include in the tafs. Restrictions possible in
occasional rain and snow Monday night from avp to bgm to rme.
Tuesday and Wednesday...possible restrictions, mainly in New York from
light snow and rain showers.
Wednesday night into Thursday morning...likely VFR.
Thursday afternoon through Friday...restrictions possible in
periods of rain, changing to snow.
PA...Winter Weather Advisory from 4 am to 11 am EST this morning
New York...Winter Weather Advisory from 4 am to 11 am EST this morning