NWS Forecast Discussion

000
FXUS61 KBGM 160552
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
Issued by National Weather Service State College PA
152 AM EDT Tue Oct 16 2018

.SYNOPSIS...
A cold front will move east of the area overnight. High
pressure with dry weather will build in from the west Tuesday.
Another cold front will move through the region Wednesday,
followed by another high pressure system on Thursday. Rain
showers will change to snow showers Wednesday through Thursday
morning.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Showers have tapered behind the front as drier and cooler air
overspreads the area. Winds have shifted to the NW behind the
front, and now the focus for the overnight becomes the arriving
colder air and expected development of an E-W oriented lake
effect rain band to set up across Lake Ontario...which will
eventually feed into Oneida county...and potentially clip far
nrn Onondaga and nrn Madison counties with another round of
light rain. There could be a few flakes mixed in across far nrn
Oneida county...with no accumulation expected. Areas to the
south will see mostly clear skies with temperatures dropping
into the mid 30s tonight.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
1050 PM Update...
High pressure builds across the mid Atlantic region on Tuesday
and the winds will back to the w/sw...which will lift any
lingering lake effect rain showers to the north and leave a
mostly dry day across the region. The air mass will be fairly
cold though...with highs only into the upper 40s and lower 50s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A weak trough will move ewd across ern Canada Tuesday night and
brush a weak cold front along the Finger Lakes and into the wrn
Mohawk Valley after midnight. A few rain showers may spread into
this area...but the bulk of the precip associated with the next
upper trough will not be until after 12Z Wednesday.

It will be turning much colder, windy and potentially wintry
for Wednesday night. First accumulating snowfall possible for
some locations Wednesday night into Thursday. Highs will be in
the 40s, with overnight lows in the mid-20s to lower 30s
Wednesday night.

Wednesday: Surface cold front pushes through during the morning
hours, with steady or slowly falling temperatures by afternoon.
We`ll have a chance of showers as the front/trough moves through.
Cold air advection increases as 850mb temps fall to around -4C
by late afternoon and the main upper level trough axis
approaches. WNW winds increase between 10-20 mph, with gusts
25-35 mph expected in the afternoon. As lake induced
instability increases the precipitation will transition to lake
effect rain showers under a 285-295 degree flow. Looks like most
locations should stay all rain for ptype during the daylight hours.

Wednesday night: Favorable conditions for early season lake
effect precipitation continue. The flow veers to WNW (290),
then NW (310-320) toward Thursday AM. Strong cold air advection
continues with 850mb temps falling to -7 to -10C over the area.
With average Lake Ontario surface temps around +13C, this will
give lake delta Ts around 20-22C. With 700mb temps around -20C,
lake delta Ts of 30-33C are expected. This can be described as
extreme lake induced instability, with potential CAPE values up
to 800 J/kg indicated by the BUFKIT NAM soundings for a time
late Wednesday evening. The overall flow looks well aligned
through the boundary layer, with lake equilibrium levels up to
around 12K ft AGL or 700mb. The entire layer below 700mb is also
fairly well saturated, with strong Omega indicated in the
850-900mb layer. The best snow growth is above this layer,
generally in the 700-800mb layer. All in all, the set up is
looking favorable for moderate to occasionally heavy lake effect
showers during this time period. Would not be completely
surprised to see a few lightning strikes around Wednesday
evening as well. The main question now will be when/if the rain
will transition over to wet snow. At this time, best indications
are that the rain will begin to mix with wet snow in the hills
S/SE of Syracuse shortly after sunset Wednesday evening. Then,
after midnight the precip should be mainly in the form of snow
as the band slides south into the Finger Lakes and Susquehanna
region of Central NY. The last places to change over to snow
will likely be the lower elevations along the Finger Lakes and
immediate Syracuse metro area (on the Lake Plain). As far as any
accumulations: at this point the best chance to see a light
accumulation of a coating to perhaps 2 inches, looks to be
across the higher elevations south of Syracuse and into the
northern portions of the Susquehanna region in Central NY.
However, could see some very light accumulations over the higher
terrain all the way to the NY southern tier and western
Catskills. Any accumulations would be generally on colder,
elevated surfaces such as grass and trees. Will mention in the
HWO for now, as this could be the first (early season)
accumulating snowfall.

Thursday: Lingering lake effect snow showers on a 315-320 flow
in the early morning hours will be across the Finger Lakes down
into the Southern Tier of NY. Heights begin to rise and the flow
should gradually back, becoming WNW by midday as weak warm air
advection takes hold. Could see another dusting to 1" of snow
over the higher elevations in Central NY early in the morning.
Despite the weak warm air advection temperatures aloft remain
cold, and surface temps only reach the 40s by afternoon. This
should be just enough warming that any lingering light showers
transition over to rain in the afternoon. NW winds remain breezy,
10-20 mph.

Thursday night and Friday: will be dry under brief upper level
ridging and surface high pressure in the mid Atlantic region.
Highs on Friday will rebound nicely into the middle to upper 50s
under a moderating southwest flow.

Friday night/Saturday: The next cold front approaches the area
late Friday night then passes through on Saturday. Will continue
to show likely POPs on Saturday across the north and chance for
the central and southern locations. Highs on Saturday will be
in the lower to middle 50s.

Saturday through Monday: A low pressure system moving into eastern
Canada drags a cold front through the area, with rain showers
becoming more likely for the daytime hours of Saturday. This starts
to taper off Saturday evening as the front moves southeast of the
area. However, any lingering showers may begin to mix in with some
snow Saturday night into Sunday, particularly for our northernmost
and higher-elevation spots. Some lake enhancement is also possible
overnight into Sunday as winds shift to the N/NW. Mainly lake-effect
rain showers continue into Sunday, changing over to snow and a
rain/snow mix overnight into Monday. Our best chance at any real dry
period would be Monday afternoon, with winds shifting to the SW
ahead of the next system and ending any lake effect showers. Expect
temps in the upper 40s/low 50s Saturday afternoon before colder air
works in for Sunday and Monday. Morning lows Sunday and Monday are
expected to be in the 30s and even upper 20s, with highs mainly in
the low/mid 40s.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Breezy and drier air is flowing into the region late this evening in
the wake of a cold front. Strong subsidence behind front is allowing
very strong gusts to reach the surface in vicinty of KSYR at 03Z and
suspect similar gusts of 30-40kt possible at KSYR and KRME between
04Z-06Z. Elsewhere, gusts in the 20-25kt range will be more common
across the region between 03Z-08Z. Expect diminishing winds late
tonight, as a ridge of high pressure builds in from the west.

Generally vfr conditions are expected across the region this
morning. However, moisture flowing off of Lk Ontario could bring a
few rain showers and mvfr cigs to KRME after about 09Z Tuesday.

Can`t rule out tempo mvfr cigs in vicinity of KRME through late
Tuesday morning. Otherwise, models support a high confidence of
widespread vfr conditions Tuesday.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...

NWS BGM Office Area Weather Forecast Discussion