409 
FXUS61 KBGM 161015
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
515 AM EST Fri Feb 16 2018

.SYNOPSIS...
Steadier rain, will taper off this morning, in the wake of a 
cold frontal passage. Colder air, will filter into the region 
today, then remain over the area this weekend. A fast moving 
storm system, will bring a period of snow to northeast 
Pennsylvania, the Catskills, and possibly the southern tier 
Saturday night, before exiting on Sunday. It appears that milder
weather, will settle in again, next week. 

&&

.NEAR TERM /THROUGH SATURDAY/...
445 am update... The back edge of the steadier rain is gradually
pushing southward early this morning, and is just about through
CNY. It will take longer for the rain to exit NEPA (perhaps not
until towards midday). 

As a surface low deepens off the east coast today, it will pull
colder, but also drier air down across the forecast area. This
drier air mass will mute the lake response from strong low-level
cold air advection. Thus, we only see maybe an inch or so of
accumulation over favored areas south and southeast of Lake
Ontario today into early this evening. 

Late tonight and Saturday morning, a dry period is foreseen,
under partly-mostly cloudy skies, as surface ridging temporarily
builds across the region. 

Light snow may begin to overspread our far southern zone late in
the afternoon, as forced ascent and deeper moisture associated
with a southern stream surface system, and northern stream 
upper system, start to move in.  

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
415 AM Update...
High confidence in a several hour period of snow occurring 
Saturday night as a system moves through the region, but there
is still a fair amount of model spread for the amounts. Best
potential still appears to be over the Poconos to Catskills, but
at least a light snow is likely to occur over Northeast PA/most
if not all of Central NY.

Models have consolidated on idea that precipitation will extend
well inland of the actual coastal low track. Though that 
southern stream low will develop and track offshore, an inverted
trough connected to it, will pass across our area quickly
Saturday night. At the same time, the northern stream will
contain a well-marked negatively tilted upper wave. Ahead of the
wave we will be on the right entrance region of an upper jet,
then briefly in left exit region of another jet just behind the
wave. This will cause forced ascent including through the
dendritic growth layer aloft. These factors, especially upper
jet structure, increase confidence in precipitation occurring
well inland. The ECMWF has been the most stable model for
several runs now, whereas others have been inconsistent yet
finally converging towards this idea. 

Precipitation amounts however still remain in question; though
type is definitely all snow. Poconos-Catskills (Pike-Sullivan 
counties specifically) have the best potential yet even there
model precipitation outputs range from only several hundredths
of an inch to a few tenths of an inch. Placing a bit more weight
on 00Z ECMWF/NAM type solution, at this time we are figuring on
3 to 5 quick-hitting inches in Poconos-Catskills Saturday 
night, especially first half of the night. There still remains 
some spread of course, to which just a slight shift in track
could result in only 2 to 3 inches in Poconos-Catskills, or as
high as 5 to 7 inches if things came together just right. For
the rest of Central NY-Northeast PA, a light coating of 1 to 3
inches appears most likely; lightest in Finger Lakes-Central 
Twin Tiers-NY Thruway Corridor. The steady snow will quickly
exit southwest to northeast between midnight-4 AM Sunday
morning.

Other than perhaps lingering lake-aided flurries in northern
Oneida County, Sunday will be dry with increasing sunshine and
melting of newfallen snow. This will be courtesy of high
pressure, the center of which will be passing across the Central
Appalachians to the Midatlantic Coast. Highs will be in the mid
30s to mid 40s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
245 PM Update...
No major changes to the overall thinking regarding the pattern 
evolution for the upcoming week with a broad trough becoming 
established over the West and a stout ridge building along the 
East Coast. Looking for a substantial warm up after we get past
Sunday. 

Low pressure lifting out of the Midwest on Monday will spread 
warm frontal rains into the area by afternoon. Models are in 
good agreement with this idea, although latest GFS is slightly 
behind the EC/GGEM. Will go with the slightly faster solution in
an isentropic lift situation. Then, deep southwesterly flow 
aloft sets up through the middle of the week which will push 
temperatures well above average. We have temperatures 
approaching 60 in many areas Tuesday with expectations that a 
stationary frontal boundary will set up just to our north. The 
position of this front is all over the spread of model guidance 
for Weds-Thurs. There is a bit better consensus among the GFS/EC
that the boundary could move south of us by Thursday with high 
pressure taking control, but the GGEM keeps it stalled over 
CNY/NEPA. Either way, we are planning for a series of weak waves
to form along this front and thus a semblance of chance-likely 
PoPs will continue Weds-Thurs.

With the snow cover expected to melt away, along with a series
of rain events in the offing in the next 5-7 days, the risk of 
minor river flooding will be on the increase.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
Below alternate-near field minimum restrictions are common early
this morning in rain and fog. As the rain gradually pushes to
the south, and the fog lifts a bit later this morning,
conditions should ultimately improve to fuel alternate or MVFR
at most sites, and perhaps back to VFR at KAVP by early
afternoon.

Surface winds mostly 5 kt or less early this morning, will
become gusty (up to 20-25 kt) out of the NW by midday.

Outlook... 

Saturday...Mainly VFR.

Saturday night...Restrictions in snow possible, mainly across 
southern NY and NEPA.

Sunday...VFR.

Monday and Tuesday...Restrictions possible in showers.

&&

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

&&

$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...MDP
LONG TERM...JAB
AVIATION...MLJ/RRM