NWS Forecast Discussion

000
FXUS61 KBGM 142249
AFDBGM

AREA FORECAST DISCUSSION
National Weather Service Binghamton NY
549 PM EST Fri Dec 14 2018

.SYNOPSIS...
A complex weather system will impact the region this weekend.
The first weaker wave of low pressure moves through tonight,
bringing a chance for light rain from the New York, Pennsylvania
border south. The next, stronger low moves through Saturday
night through Sunday night, bringing a possible wintry mix to
the area. Turning colder with snow showers early next week, then
drier and seasonable for midweek.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
300 PM Update...Partly to mostly cloudy around the region this
evening; still some patchy lingering fog/drizzle over our far
eastern zones, along with much cooler temperatures. Current
temperatures ranged from the the mid to upper 30s in parts of
the Poconos and western Catskills to 45-50 in the valleys along
and west of I-81. Temperatures will remain rather steady into
the evening hours as south winds continue between 5-15 mph.

Made adjustments to the PoPs/WX and QPF grids for tonight as
the latest near term mesoscale guidance continues to trend south
with the rain. Even in near term differences remain in just how
far north the rain actually makes it tonight. Tried to blend
the guidance and the previous forecast, which now caps PoPs
tonight at likely along and south of I-80 in NE PA...chance PoPs
for the rest of NE PA into Sullivan County NY...and now only a
slight chance of rain for the southern tier of NY (south of NY
17/I-86 corridor). QPF overnight was adjusted to show a tighter
gradient, and much lower amounts. Latest forecast guidance now
indicates one to two tenths south of I-84...with just a few
hundredths possible across the Twin tiers of NY/PA. It will
remain dry, but mostly cloudy for the rest of Central NY.
Temperatures stay mild, in the mid-30s to lower 40s. South winds
become variable late at night, less than 10 mph.

Model guidance has now come into better consensus that
much of the day Saturday will be dry as high pressure over
nearby southern Ontario will bring a dry northerly flow across
the region. Will carry just slight chance POPs for much of
northeast Pennsylvania and dry elsewhere. Could see some breaks
of sun at times in Central NY. Highs on Saturday will range in
the lower to middle 40s across central New York and mid to upper
40s in northeast Pennsylvania.

Saturday Night: The large upper level low that is currently over
the lower Mississippi Valley will advance into the Mid-Atlantic
states. The circulation around this low will begin to spread
moisture back north, toward our area later Saturday evening. A
surface high slides to the east over northern New England.
Latest model trends are that this high will provide just enough
cold air on a low level ENE flow for a wintry mix of precipitation
to develop overnight. There remains a good deal of uncertainty
with this system as well..such as exactly where the upper level
low tracks, how far north, and how heavy any precipitation is.
Also, thermal profiles are rather complicated, and for now
indicated a general mix of rain, freezing rain and sleet in the
grids for much of the area as this wave of precip moves north.
The best chance to see a wintry mix Saturday night appears to be
from the NY southern tier down into the northern tier of PA and
the Poconos. The precip may spread further north on Sunday; see
below for more details.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
Model trend continues to be colder for the departing mid
Atlantic low, bringing the possibility of some light mixed
precipitation for Sunday. There is still considerable
differences in the NAM/GFS/EURO but on average it looks like the
trend will be for the sounding to cool through the day
resulting in rain or freezing rain early Sunday transitioning
toward snow later in the day. At this time amounts look to be
fairly light but not insignificant to eventually Advisories may
be needed, especially for those places that see some freezing
rain.

System pulls out Sunday evening allowing the precipitation to
taper off followed by brief ridging. On Monday, cold front
crashes into the area followed by lake enhanced snow showers for
the remainder of the period.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
NW flow snow showers continue into early Tuesday, followed by
ridging to hold through the end of the period. Building upper
heights and a developing southerly flow on Wednesday will allow
temperatures to rise above normal for the mid week period. Dry
weather will prevail as well, although a complex system
developing over the southern U.S. may push some rain showers
into the NEPA zones right near the end of the long term.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...

VFR ceilings will fall into MVFR territory overnight. Expect
ceilings between 1200 and 2500 feet to develop between 06z and
11z as moisture trapped under an inversion produces a low cloud
deck.

The low ceilings will hold through early afternoon on Saturday,
then VFR conditions will return and last through sunset.

Winds will be light and variable overnight. On Saturday, winds
will be northerly at 4 to 8 knots.


Outlook...

Saturday evening through Sunday...Showers and associated
restrictions possible, especially southern tier down into
Northeast PA. Could see mixed precipitation as well. Lower
confidence.

Monday and Tuesday...Possible restrictions in snow showers,
especially NY terminals.

Wednesday...Likely VFR.

&&

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

&&

$$
SYNOPSIS...MJM
NEAR TERM...MJM
SHORT TERM...DGM
LONG TERM...DGM
AVIATION...DJP

NWS BGM Office Area Weather Forecast Discussion