Scientific Forecaster Discussion
fxus61 kbgm 181750
Area forecast discussion
National Weather Service Binghamton New York
issued by National Weather Service State College PA
1250 PM EST Mon Nov 18 2019
coastal low passes well to our east today, but an upper level
disturbance will bring the chance for mixed precipitation
tonight through Tuesday morning. High pressure returns again
mid week, followed by another low pressure system on Friday.
Near term /through tonight/...
1045 am update... based on surface temperatures within the New York state
mesonet, it appears that readings have largely climbed above freezing across
the western Catskills. The same appears to be the case for the Poconos in
nepa, with Road surface temperatures also well above freezing in this area.
Thus, even with some patchy drizzle likely to continue over the higher
terrain into the early afternoon, we feel comfortable letting the Winter
Weather Advisory expire on schedule at 11 am.
Otherwise, it will be a cloudy and chilly, but largely precipitation-free
afternoon, with highs ranging from the mid 30s-lower 40s.
Previous discussion... 345 am update...
Nor'easter will be tracking south and east of the 40/70
benchmark this morning. However, forecast model soundings
continue to indicate abundant low level moisture pushing in from
the Atlantic. The moisture layer is generally below 800 mb with
thermal profiles just below 0c and temperatures at the surface
below freezing. Ground temperatures also remain below freezing.
These conditions are conducive for pockets of freezing drizzle
to develop across the Poconos and Catskills early this morning.
However, there is some concern that the moisture layer may not
be quite deep enough and we could end up with just some low
clouds and freezing fog this morning. Going to wait and see how
things materialize over the next couple of hours and if freezing
drizzle does not develop then we will have to cancel the
advisory early. Only a glaze of ice is expected in the advisory
area, however, this would be enough to cause some travel issues
for the morning commute.
Temperatures will eventually warm above freezing later this
morning and then just a plain drizzle or light rain is
expected. However, with the coastal low tracking further east,
we have lowered precip chances through the day and kept the
higher chances east of the i81 corridor for this forecast
Short term /Tuesday through Wednesday/...
430 am update...
main concern will be for wintry mix causing reemergence of ice
glaze potential, with some light snow accumulations possible as
well, especially higher terrain along- east of Interstate 81.
Coastal low will be long gone, but a separate northern stream
upper wave will take on a negative tilt to pivot through the
area tonight. As it does so there will be upward forcing aloft
as per continued depiction of quasigeostrophic lift/q-vector
convergence in the models. Models have also trended and
consolidated towards east of Interstate 81 as being the main
target for precipitation in whichever form; the further east one
GOES the higher the potential. Thermal profiles indicate that
within the primary band moisture will be deep enough for snow
crystals to fall through the column, then be either rain or snow
depending on near surface temperatures. Outside of the primary
band, moisture layer will be shallow; or more accurately to say,
there will be a dry midlevel layer between high altitude moisture
and low altitude moisture. Thus the lower saturated layer will
be mainly warmer than minus-8 degrees celsius, making Crystal
introduction more difficult. Very light rain/freezing rain or
drizzle/freezing drizzle could thus occur, with higher terrain
along and east of Interstate 81 being more vulnerable to a
patchy light glaze of ice on untreated surfaces where below
freezing. In time, the atmospheric column gets cold enough for
primarily snow towards dawn, yet by then there will be very
little precipitation left. A skiff of an inch or so of snow will
be possible overnight in higher terrain of Catskills-Otsego-
Delaware counties with trace to several tenths of an inch
elsewhere mainly along and east of I-81. Combination of light
snow and ice accumulations may necessitate another advisory for
portions of the area. Lows tonight will be upper 20s to mid 30s.
Tuesday itself looks rather quiet under positive vorticity
advection as upper wave departs. Shallow stratocumulus will be
pervasive for most of the area, though partial sunshine may work
its way up to at least the Poconos-Catskills in the afternoon.
Pockets of drizzle or flurries may occasionally skirt the
northern Finger Lakes to New York thruway corridor at times courtesy
of lake moisture; nothing of real consequence. Highs will range
from upper 30s to mid 40s, though some higher elevation
locations of central New York will not get out of mid 30s.
Long term /Wednesday night through Sunday/...
1230 PM update... on the large-scale, an upper-level trough is expected to
sharpen up a bit later this week into next weekend, extending from central
Canada down into the Great Lakes region. This will lead to falling heights
aloft across New York/PA, eventually causing a return to unsettled and seasonably
As for the daily sensible weather, Thursday looks like the mildest day of
the period, with a broad SW flow ahead of an approaching cold front. As this
front nears and then crosses cny/nepa, rain showers will become likely
Thursday night into Friday. Decent cold air advection Post-frontal passage
should lead to lake enhanced rain/snow showers Friday afternoon, going
over to all snow showers/flurries Friday night into Saturday.
Later in the weekend, another fast moving cold front is expected to move
across the region, but this system looks weaker and more moisture starved
than its predecessor, so associated shower activity looks fairly light and
inconsequential from this early Vantage Point.
Aviation /18z Monday through Saturday/...
18z update... persistent low cloudiness and assorted restrictions (ifr
at kbgm, IFR to fuel alternate at kavp, and MVFR at krme) will continue
this afternoon across our eastern-most terminal sites. Farther west, the
mass of lower clouds has begun to break up, thus lengthy periods of
VFR are foreseen at ksyr, kith, and kelm through the afternoon and into
the early evening period.
Overnight, lower clouds will once again become entrenched throughout
cny/nepa, with widespread IFR-fuel alternate restrictions. Patchy drizzle
and fog appears most likely at kbgm and kavp, with temperatures perhaps
cold enough late at night for a bit of light snow at krme.
Tuesday, early morning lower clouds will slowly lift over time. However,
a return to VFR before 18z is only likely for kavp and ksyr.
Fri...restrictions likely in lower clouds and rain showers, perhaps
changing to snow showers by afternoon.
Sat...snow showers/flurries could bring restrictions, at least in the
morning, most likely to occur at ksyr and krme.