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Area forecast discussion 
National Weather Service Binghamton New York
635 PM EST sun Dec 21 2014

Synopsis...
clouds and cool air will continue over the area into Monday as
moisture remains trapped under an upper level area of high
pressure. A low developing over the northern Midwest in
combination with a low moving up the East Coast will bring a
period of mixed precipitation followed by mostly rain into
midweek.

&&

Near term /through Monday/...
no one can say the bgm/S reputation for clouds is undeserved after
this stretch of overcast weather. Area of clearing over the northern Finger Lakes and
along the lake plain quickly filled in as heating bubbled up adtnl
moisture into a new SC deck. While some of the models insist that
drier air will begin to clear the area this evening into Monday...
stubbornly strong inversion remains in place...and with light winds and no
mixing...see little to break up the clouds in place. Also...Sat images
show a solid deck all the way back into eern Ohio this after. When
winds fnly do develop Monday morning...they/re from the southeast potentially adding
moisture to the sndg. So...have gone against model guidance and gone
with experience and consistency and continued the clouds through the near
term.

Temperatures ended up staying below guidance forecast today as the stubborn clouds
did not allow any heating as anticipated by MOS. Expect little diurnal change
overnight with the clouds. For Monday...some weak warm air advection does occur with the
southeasterly flow so have gone nearer guidance forecast. Some light precipitation may develop
over the southeastern zones on Monday as a weak WV passes by to the south.
Temperatures marginal so have gone with mixed precipitation which blended well with
surrounding offices.

&&

Short term /Monday night through Friday afternoon/...
300 PM EST update... a large storm system is expected to impact New York
and PA starting late Monday night/Tuesday morning and may linger
through late Thursday night...

Many uncertainties still exist with this storm. But...
synoptically... guidance has a good agreement on the track of the
upper low. Guidance also seems to have a good idea of the overall
progression of the surface low and it moving towards the northeast.

Late Monday night the potent upper level trough will dig southward
along and slightly east of the Rocky Mountains and generate
cyclogenesis over the eastern portions of Kansas and NE. This surface low
will then track NE towards the central Great Lakes region. By Tuesday
morning a strong vorticity maxima will round the base of the upper
trough over far S Texas generating a secondary surface low/surface trough over
east la. As this occurs... the main surface low over the north will become
occluded.

The upper trough will start to shift east Tuesday night. As the trough
shifts east the secondary surface low/trough will merge with the
primary system. This system will track northeast towards our County Warning Area and
bring the chance for precipitation starting late Monday night
lasting through the forecast period.

As this system starts to generate precipitation... expect the precipitation to
start out as a wintry mix and mainly over the eastern portions of
the County Warning Area. This is due to warm air advection and isentrophic lift ahead the
occluded front. Precipitation will slowly shift to the north and west. A strong
low level jet will become established over the County Warning Area late Tuesday morning/afternoon
resulting in strong warm air advection and gusty winds over the region. By Tuesday
afternoon the warm air advection will dominate the region and all precipitation will
fall as rain. Rain is then expected to continue to fall through
Wednesday night. The rain is expected to be heavy at times as precipitable water
values are well above normal.

The colder attendant with this system will start to push into the
region Thursday morning. Winds are expected to be fairly gusty behind
the frontal passage. This system will not have very cold air with it due it
where it originated. It is a Pacific airmass not an Arctic.
Thus... temperatures will not drop dramatically Post frontal.

Behind this system some lake effect showers may develop.
Accumulations are not expected at this time to be heavy.

&&

Long term /Friday evening through Sunday/...
cold fnt swings through Friday night and returns the area to more typical
early winter weather. Continued cold air advection will gradually lower temperatures through the period
incrsg the chance of le snow showers. Sheared flow inintially bhd
the fnt will limit the amount of le...while the deeper cold air aits
to just beyond the period late sun and early Monday.

Temperatures will average near normal through the period.

&&

Aviation /00z Monday through Friday/...
persistent stratus deck will remain across all taf sites in
central New York and northeast PA. Ceilings will average between 1500 and
2500 feet through the forecast period. It is possible that ceilings pop up
to MVFR at kelm Monday PM. Otherwise solid MVFR ceiling through 00z Tuesday.

Winds will be light north this evening and shift to southeast at 5 knots
or so by Monday.

Outlook...

Monday night...mainly MVFR ceiling.

Tuesday to Thursday...restrictions with developing light mixed
precipitation Monday night-early Tuesday...then periods of rain Tuesday-
Thursday.

Friday...VFR.

&&

Bgm watches/warnings/advisories...
PA...none.
New York...none.

&&

$$
Synopsis...dgm
near term...dgm
short term...kah
long term...dgm
aviation...djn

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