NWS Forecast Discussion

FXUS61 KBGM 080253

Area Forecast Discussion
National Weather Service Binghamton NY
953 PM EST Sat Dec 7 2019

Mostly clear, calm and cold overnight as high pressure builds
over the region. Dry and seasonable weather is expected Sunday,
followed by periods of rain and warmer temperatures Monday and
Tuesday. Then, turning much colder mid to late week with lake
effect snow showers around.



945 PM Update...Skies are now clear areawide, except for a few
lake clouds across Onondaga, Madison and SW Oneida counties.
Winds are now basically calm as the latest surface analysis
shows a 1032mb high right overhead. Temperatures have plummeted
this evening due to the clear, calm conditions and fresh
snowpack. It`s already in the upper single digits to mid-teens
most areas. The excepts to this are: 20-25 still around
Syracuse and the Wyoming Valley, but already near 0 across
northern Oneida county. Updated the near term grids for the
overnight to reflect these latest sky, wind and temperature

710 PM Update...Near term forecast is on track. Lingering lake
clouds have shifted north from Cortland to Auburn and Syracuse.
Otherwise, skies are clear and winds have decoupled...now
variable less than 5 mph. Temperatures are dropping quickly
this evening as expected...with many areas already into the
teens (where skies are clear). The cold spot is Woodgate, in
northern Oneida county, which has already dropped to 6 degrees
as of 7 PM. Adjusted overnight lows closer to the colder NBM
guidance. Clouds lifting north into Oneida county should halt
temperatures from falling much further by late evening
(hopefully keeping readings above zero).

Previous Discussion Below

Expansive surface high pressure will provide a
mostly clear and cold night. Strong radiational cooling is
expected, especially during the first half of the night. Lows
will likely drop to the single digits across portions of Oneida
county and the western Catskills with teens expected elsewhere.
Temperatures may begin to rise a bit after midnight as high
pressure begins to move east of the area along with increasing
higher clouds and south winds.

Temperatures moderate a bit on Sunday as the high pressure
system moves east of the area, and a warm front pushes through
bringing a southerly flow. Highs are expected to be in the mid
30s to lower 40s. With a tightening pressure gradient, it will
become breezy during the late morning and afternoon hours. The
strongest winds are expected across ridges and north/south
valleys of the Finger Lakes and Susquehanna region. In these
areas expect south winds of 15-25 mph with gusts up to 35 mph.
Elsewhere, look for south winds of 8-15 mph with gusts near 25mph.

Otherwise, expecting a partly sunny day with increasing clouds
late in the day in the western zones ahead of the next system.

It should remain dry with increasing clouds prior to midnight
Sunday night. Temperatures fall off a few degrees in the
evening, especially east...bottoming out between 30-35.
Temperatures then slowly rise a few degrees after midnight.
There will be a low chance for rain showers after midnight
(possibly mixed with isolated pockets of light freezing rain or
sleet east and north) but precipitation amounts will be very
light, under 0.05" by daybreak Monday. Temperatures should be
above freezing, in the mid to upper 30s just about everywhere by
daybreak. Decided to not yet mention any wintry mix in the HWO,
as confidence is very low in any measurable ice.


Lake runner pushes warm air and moisture into the area Monday.
System is fast moving and with the zonal flow does not tap
deeply into the subtropical moisture lurking over the SE and
gulf so while moderate rain and isolated heavy rain is possible,
hydrological concerns are limited for now. Track does put us in
the preferred entrance region of the jet so steady moderate
rain is expected Monday into Monday night before a dry slot
works in ahead of the cold front. That front passes through
early Tuesday followed by colder air that slowly turns the rain
to snow. Some brief anafront precipitation in the colder air
could give us a quick coating of snow, but by Tuesday night just
snow showers are expected, perhaps being lake enhanced before
morning, with additional light accumulations.

Temperature trend through the period will be non-diurnal as they
rise all day Monday and Monday night, then begin to fall on
Tuesday with the cold advection.


255 PM UPDATE...

Long term is generally a tranquil period with a slow warm up.
Some lake effect snow showers are possible early on, then The
upper trough and surface high slides east allowing for a
southwest flow to develop bringing increasingly milder air into
the area.

Once again made some minor adjustments to the period in the
weather and pop grids otherwise have stayed the course.

Previous discussion continues below.

430 AM Update...
We return to an Arctic regime later this week.

Strong cold air advection will begin Tuesday night which
continues right through Wednesday night. 850mb temperatures
start Wednesday morning around minus-10 Celsius but further
plummet to between minus-15 and minus-20 Celsius by Wednesday
evening, which persists into Thursday. This will indeed be a
cold air mass with highs of lower 20s-lower 30s Wednesday and
then only upper teens-upper 20s Thursday as the Arctic high
passes overhead. Overnight lows for Wednesday night-Thursday
night, will be mainly teens but perhaps some single digits.

With low level flow veering westerly Wednesday to eventually
northwesterly Wednesday night-early Thursday, we can anticipate
lake effect snow showers for much of the region with perhaps
more significant accumulations occurring north of the New York
Thruway. The air mass appears quite supportive of lake snows
with the dendritic growth zone down in the heart of the mixed
boundary layer. This will be figured out with more certainty in
coming days.

We get into a moderating return flow on the back side of the
departing high Friday, with dry weather and highs forecast back
into the upper 20s-mid 30s.


VFR conditions are forecast for the next 24 hours as a ridge of
high pressure slides over the terminals.

A small amount of low level wind shear is expected on Sunday due
to a 2000 foot 30-40 knot jet passing overhead. The best chance
for LLWS will be over our northern terminals.


Sunday night...Mainly VFR, with MVFR CIGS possible late.

Monday and Tuesday...Restrictions likely with a broad area of
rain across the region.

Wednesday...Restrictions possible in lake effect snow showers.

Thursday...A few lingering snow showers north near KSYR and
KRME; otherwise VFR expected.





NWS BGM Office Area Weather Forecast Discussion