899
FXUS61 KBGM 171145
AFDBGM

AREA FORECAST DISCUSSION
National Weather Service Binghamton NY
645 AM EST Sun Feb 17 2019

.SYNOPSIS...
High pressure will build into the area bringing dry weather
through this afternoon. Then, low pressure will move from Ohio
to the Atlantic coast bringing periods of snow to the area
tonight through Monday. There will also be some mixed precipitation
across northeast Pennsylvania and the New York southern tier.
Mainly dry weather aside from a few lake effect flurries Monday
night and Tuesday. Then, watching the next system which could
bring a wintry mix to the area once again midweek.

&&

.NEAR TERM /THROUGH MONDAY/...
430 AM Update...Main concerns in the near term will be a storm
system that will bring accumulating snow to the entire area, and
light ice to northeast PA and the NY southern tier starting this
evening through Monday. Winter weather advisory is now in effect
for just about the entire forecast area (except northern Oneida
County) this evening into Monday. See below for more details.

Today: Stubborn lake effect/upslope stratus clouds are
lingering over a good portion of the forecast area early this
morning. The NW flow completely weakens and turns southerly
after mid to late morning...so do believe the stubborn cloud
cover will quickly dissipate around this time. Should then see a
period of partly to mostly sunny skies late morning into the
early afternoon hours with just cirrus around. Mid level
clouds then move over the area mid to late afternoon from SW to
NE out ahead of the next weather system. After a chilly start it
will warm up to seasonable levels this afternoon, with highs in
the 30s. Light northeast winds this morning turn southeast,
less than 10 mph by afternoon. Any snow looks to hold off (even
in Steuben/Bradford counties) until after about 5 PM.

Tonight: A low pressure system moving through the upper Ohio
Valley will quickly spread snow over the region between about
5-6 PM in the west, and 9-10 PM in the east. An area of good mid
level warm air advection and frontogenesis will move through
between about 00-06z Monday, this along with some indications
for elevated instability (marginally negative EPV showing up in
the model guidance) support locally heavy burst of snow late
this evening across much of the area. Would not be surprise to
see snowfall rates, at least locally be close to 1 inch per hour
at times, as at least very briefly, bufkit soundings are showing
an omega bullseye collocated within the elevated snow growth
layer. This could all for very large, dendritic snow flakes to
form. Surface temperatures are forecast to be between 25-30
degrees during this time, so roads may quickly become snow
covered and slick. Convective allowing, near term models are
actually indicating convective looking reflectivities (with
ptype being snow) during this 00-06z timeframe tonight,
especially across the Twin Tiers and western Catskills. This
adds more confidence that embedded heavy snow burst could
certainly be an issue. The snow begins to mix with sleet across
the Wyoming Valley region of NE PA by late evening, then could
mix with light freezing rain or drizzle during the predawn
hours. The primary surface low makes it up into western PA, then
fades, transferring its energy to a developing coastal low
south of Long Island by 12z Monday. Model fields show a dry slot
at 700mb making it as far north as the NY/PA border or even the
southern tier. As we lose that mid level moisture for ice
crystal growth for a time late tonight, could even see freezing
drizzle mix in up to the I-86/Rte 17 corridor. Steady light snow
looks to continue north of Binghamton during the predawn hours,
as moisture and lift persist in this area. Snow amounts of 1 to
3 inches are forecast areawide by Monday morning, with the
higher end totals north of RTE 17, and especially across the
western Catskills, where up to 4 inches may fall by daybreak.
Light coatings of ice (< 0.10") possible south of RTE 17
corridor down into NE PA. Surface temperatures hold steady
overnight; in the mid to upper 20s for central NY, and in the
upper 20s to lower 30s for NE PA. Expect southeast winds 5 to 10 mph.

Monday: The remnants of the primary surface low`s circulation
slide right along the NY/PA during the morning hours. This setup
will keep ample snow showers or periods of snow going north of
the low track...with just scattered snow showers, freezing
drizzle or even rain showers south of the low across NE PA. This
wintry precipitation will likely impact the Monday morning
commute, with snow/ice covered and slick roads. Use caution and
plan some extra travel time. After the low passes by to the
east winds shift out of the NW, and increase, becoming gusty in
the afternoon (10-20 mph). Snow showers taper off and mostly
end from west to east by mid to late afternoon. The winter
weather advisory ends at 10 AM for much of NE PA, where
temperatures could rise above freezing...and the advisory ends
after 2 PM further north. Temperatures peak midday Monday, then
begin to fall by late afternoon back into the mid to upper 20s
in NY, and to around freezing in NE PA.

Additional snow amounts during the day Monday are forecast to
range from about 0.5 - 1.5" across Central NY, with a half inch
or less for our NE PA zones.

This will bring storm total snow to between 2-5 inches for the
northern tier of PA and just about all of central NY...with 1 to
3 inches of snow and light coatings of ice for the rest of NE
PA. Even though these amounts might be just below the typical
thresholds for a winter weather advisory, felt confident issuing
one considering the potential for ice (Twin tiers south) and
the fact that this storm system will be impacting the Monday
morning commute with snowy/icy untreated surfaces. Left out
northern Oneida county zone for now, as total amounts of 3-4
inches over a 18 hour period does not meet criteria here.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
320 am update...
Main concerns in the short term remain focused on the lingering lake
clouds and snow showers/flurries southeast of Lake Ontario Monday
night tapering off Tuesday afternoon, with quiet and continued cold
conditions through Tuesday night.

Broad cyclonic flow aloft in place Monday night as a weak embedded
short wave exits to the east and leaves in its wake a cold nwly flow
across Lake Ontario into central NY. A shallow mixed layer and
limited moisture will keep lake snow showers light Monday night into
Tuesday morning...roughly less than 1 inch of accumulation. Lake
clouds will likely have a tough time mixing out with the persistent
flow off the lake through most of the day. Mainly flurries in the
afternoon...becoming dry by the evening hours.

Temperatures will remain on the cool side with morning lows Tuesday
in the single digits and lower teens. By the afternoon on Tuesday
temperatures will only reach into the 20s...before falling back into
the single digits and teens Tuesday night.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
320 am update...
High pressure at the surface centered over the Northeast will be
shifting further to the ne as the next system approaches from the
sw. Rising heights aloft and the position of the surface low...over
nrn New England...as the precip shield moves in will be favorable
for a decent amt of virga with a wedge of dry, cooler air near the
surface getting dammed into central NY. Therefore, have delayed
the onset of precip Wed morning a bit. Should start out as
light snow with the warmer, above-freezing, air aloft not
expected into the area until Wed evening.

Will likely see light snow on and off through the day Wed with a
couple inches of accumulation possible. A nose of warm air aloft
will rotate newd from the mid-Atlantic region into New England and
allow for a period of a wintry mix Wed night/early Thursday morning.
The upper low will cut to the ne through the Great Lakes as a coastal
sfc low and a Great Lakes sfc low slowly converge into one as
the entire system progresses off the coast. At this time it
appears the majority of the moisture will remain to the south of
the forecast area. So, both snow and any wintry mix are
expected to be light through this event.

The bulk of the warm air will be over the region on Thursday with
the surface layer warming above freezing as well...likely getting
into the 40s for most of the area. Should see light rain throughout
the day before the change back to snow Thursday night. The air mass
should dry out fairly quickly, with only a brief window of nw
winds...so very minimal lake effect snow is expected into Friday
morning. High pressure looks to take hold of the area for a brief
period of time Friday and Friday night before the next upper low
cuts through the Great Lakes with more warm air and another threat
of a wintry mix by Saturday.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MVFR stratus is meandering around the area under a very weak NW
flow regime. Tough to forecast exactly where these lower cigs will
impact; but at this time current guidance keeps these 2-3k ft
agl cigs INVOF KITH, KBGM, KELM for a few more hours. These
clouds are forecast to slowly drift off to the south/southwest
and scatter out between 13-16z this morning. Otherwise, outside
of these stratus clouds it will be clear and VFR this morning
at KSYR, KRME and KAVP.

VFR conditions are then expected areawide late morning and into
this afternoon, before additional mid level clouds arrive from
the southwest late in the day. CIGS lower to MVFR or fuel
alternate and periods of snow move into the area from west to
east between 00-03z this evening. Then, Fuel alternate and
occasional IFR conditions persist at all taf sites after 03Z
Monday, through the end of the period. Some light sleet,
freezing rain or freezing drizzle could mix in at KELM, KBGM and
especially at KAVP early Monday morning. Snow accumulations of
2-4 inches are expected at all taf sites, except 1 to 2 inches
at KAVP.

Variable winds less than 5 kts this morning. Winds then turn
east-southeast this afternoon through tonight 5 to 10 kts.

Outlook...

Monday...MVFR/IFR Restrictions due to snow showers. Sleet and
perhaps some fzra or fzdz mixes in at KAVP, KELM & KBGM early in
the day.

Monday night...MVFR restrictions possible in CNY and VFR at AVP.

Tuesday into early Wednesday...VFR conditions possible.

Wednesday afternoon through Thursday...Restrictions likely in
snow, mixed precipitation or rain.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 6 PM this evening to 10 AM EST
     Monday for PAZ043-044-047-048-072.
     Winter Weather Advisory from 6 PM this evening to 2 PM EST
     Monday for PAZ038>040.
NY...Winter Weather Advisory from 9 PM this evening to 2 PM EST
     Monday for NYZ037-046-057-062.
     Winter Weather Advisory from 6 PM this evening to 2 PM EST
     Monday for NYZ015>018-022>025-036-044-045-055-056.

&&

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

NWS BGM Office Area Forecast Discussion