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878
FXUS61 KBGM 180305
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
1005 PM EST Fri Jan 17 2025

.SYNOPSIS...
Partly to mostly cloudy and not as cold tonight. A gusty breeze
will develop around the Finger Lakes region. The dry conditions
will be brief as the next storm system brings a mix of rain and
snow to the area Saturday. A chance of snow Sunday will be
followed by very cold Arctic air that settles in through the
first half of next week.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...

-- Changed Discussion --
1000 PM Update..

Southerly winds are increasing and an area of mid level clouds
is streaming into CNY at this time. Bumped overnight lows up a
few degrees, especially in the Syracuse metro area, where
temperatures are currently rising through the mid-30s. Touched
up PoPs, weather type, QPF and snow amounts for Saturday; but
overall the latest data was still on track with the forecast,
and any snow amounts will be low and slushy during the day
Saturday, as highs reach well into the 30s areawide.

00z guidance is starting to come in for the Sunday/Sunday night
system. The 00z HRRR continues with a more westward track,
spreading steady snow back well west/NW of Binghamton. The 21z
RAP is also in-line with, if not even further NW than the 00z
HRRR. The 00z NAM remains further south and east with the low
and steady snow area (compared to the HRRR and RAP). Still
awaiting the 00z CMC-regional, GFS, ECMWF and other guidance.

640 PM Update...

Low stratus is clearing out with the strengthening SW flow this
evening. With winds increasing through the boundary layer the
temperatures should hold pretty steady or slightly increase
across higher elevations despite the clear skies with the warm
air advection.

350 PM Update...

Dry conditions will be in place across the area tonight with
weak high pressure building in at the surface and ridging aloft.
Clouds continue to linger around the area, but are expected to
give way to some clearing this evening before thickening back up
again prior to daybreak tomorrow. Southwesterly winds are
expected to increase tonight with wind gusts of 25 to 30 mph
possible, especially around the Finger Lakes region and higher
terrain south of the I-90 corridor. With SW flow in place it
won`t be quite as cold tonight with low temperatures in the low
and mid 20s for most. Areas immediately around Finger Lakes
will be in the upper 20s to near 30 degrees.

The break from precipitation will be brief as high pressure
slides off to the east early tomorrow morning giving way to a
shortwave trough and surface cold front. Showers, mainly in the
form of snow initially push into the area from the south and
west during the mid to late morning hours, then transition to
elevation dependent rain and snow through the remainder of the
day. Model guidance and the high res CAMS do support there being
a dry slot developing across portions of NE PA and the
Catskills during the afternoon, so PoPs generally top out around
50% in this area tomorrow vs. likely (>60%) elsewhere. The
mixed precipitation is expected to change back over to all snow
showers tomorrow evening before tapering off. Snowfall amounts
tomorrow through tomorrow night are expected to be light on the
order of a coating to around an inch, with the exception being
northern Oneida County where two to three inches is possible as
precipitation looks to stay mainly in the form of snow combined
with a little lake enhancement during the afternoon. High
temperatures are expected to be in the low to mid 30s with upper
30s in some valley locations.

Winds shift back around to the northwest tomorrow night and it
will turn colder again with lows mainly in the teens. The
southern Catskills and portions of NE PA drop back into the
lower 20s.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
430 PM Update...
Accumulating snow may occur for much of the area as a second
wave of low pressure passes during the second half of the
weekend, especially towards the Poconos and Catskills where an
Winter Storm Watch has been issued.

Models have been trending towards a likelihood of snow for a
good chunk of the area Sunday midday through evening, though
there is still a good deal of uncertainty for how far west the
heavier snow potential could reach. Before the associated wave
of low pressure, cold air will already have advected into the
region, which will allow all new precipitation to be in the
form of snow; generally of a dry and fluffy texture. Highs will
e mostly 20s Sunday, to perhaps around 30 in the lower reaches
of the Delaware-Susquehanna valleys; yet even there as soon as
the snow starts temperatures will fall.

The right entrance region of the northern stream jet maximum
will have some overlap with the left exit region of the southern
stream jet with the surface low. This will cause a period of
forced ascent including the dendritic growth layer for a period
of steady snow, peaking mid afternoon through evening Sunday
when snowfall rates could reach or perhaps slightly exceed 1
inch per hour. For locations that get squarely under the
heaviest snow, 6-9 inches could easily occur. This is most
probable in the Poconos-Catskills, and thus the Winter Storm
Watch. There does appear to be an upper bound of what is
possible, because the system moves rather briskly; there is only
so much that can occur in that timeframe. Even the reasonable
worst case values, that is with a 10 percent chance of
occurring, are still under a foot. Monitor the forecast for
updates, because slight shifts in the storm track could relocate
the axis of heavier snow. Even outside of the heavier snow,
there should be a sizable area that receives at least a plowable
snow.

Snow heads out later Sunday night, and temperatures will plummet
into the single digits-lower teens by dawn. That will be just
the start of the Arctic Blast headed our way.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
430 PM Update...
Bitterly cold arctic air will impact the region through at least
the first of half of next week. There will also be some
potential for lake effect snow and/or snow squalls on Monday.
This is likely to be the coldest air we have seen in the last
couple of winters.

Low level flow will be mostly westerly and lake effect from
Lake Erie may push far enough eastward to impact the Twin Tiers
for a short time. Some of the snow showers could take the form
of mini-squalls Monday, though actual additional snow
accumulations should be on the low side as temperatures are
almost too cold and outside the Dendritic Growth Zone. Also,
there will be very little moisture available after Monday
afternoon. That said, temperatures will be very cold which may
limit the effectiveness of snow treatments on roads.

Forecast confidence is very high that the coldest air thus far
this season will occur Monday night through Wednesday.
Temperatures are forecast to dip well below zero overnight with
lows dipping below zero and only single digit to to low teens
for highs each day Monday through Wednesday. When incorporating
the winds, apparent temperature values of 15 to 25 below zero
look very achievable through the overnight hours. Widespread
Cold Weather Advisories, at the very least, can be anticipated.

Some moderation in temperatures is anticipated for Thursday-
Friday, but it will still be below freezing.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected through at least 12Z for all
terminals tonight. An increasing low level jet will lead to some
LLWS at most terminals that have winds fall below 10 mph. BGM
and SYR look to stay windy at the surface so the LLWS was not
added.

Tomorrow, precipitation moves in from the west. At first, enough
cold air in place will support mostly snow so around 16Z to 21Z
there is a chance at IFR or worse vis from snowfall at all
terminals. As temperatures warm, snow chances to mostly rain
with improved vis by the late afternoon. Cigs fall as better
moisture moves in through the day with IFR cigs at most
terminals by the evening.

Outlook...

Saturday afternoon...A mix of rain and snow and associated
restrictions.

Saturday night...A mix of rain and snow showers changing back to
all snow with restrictions possible.

Sunday...Some snow and associated restrictions possible.

Monday through Wednesday...Lake effect snow showers and
associated restrictions possible, especially for KSYR-KRME.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Storm Watch from Sunday morning through late Sunday
     night for PAZ040-044-047-048-072.
NY...Winter Storm Watch from Sunday morning through late Sunday
     night for NYZ062.

&&

$$

SYNOPSIS...DK/MDP
NEAR TERM...AJG/DK/MJM
SHORT TERM...MDP
LONG TERM...MDP
AVIATION...DK/JTC