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Area forecast discussion 
National Weather Service Binghamton New York
822 PM EDT Friday Oct 31 2014

Synopsis...
an upper level disturbance will move through our vicinity tonight
through Saturday...bringing spotty rain showers. As colder air
descends upon the region Saturday night into Sunday
morning...lingering rain showers will change to snow showers or
flurries for some parts of the area while diminishing.

&&

Near term /through Saturday/...
645 PM update... forecast in fine shape. Only tweek was to lower probability of precipitation
just a bit in the near term across the central southern tier and western Finger
Lakes where -shra are having a difficult time spreading eastward. Previous
below...

4 PM update...
still a stripe of sunshine from Scranton through Delhi for a time
this afternoon...but remainder of area has increasing clouds
especially in the upper levels. It will spread across the region
into this evening. Actual precipitation will be quite spotty
however.

Very sharp upper trough is now digging through western Great
Lakes...en Route to cutting off upper low while crossing southern
Appalachians tonight...and at the NC-SC coastline by 18z Saturday.
500mb heights will be extremely anomalous...5 to 6 Standard
deviations below normal in the Carolinas...yet also far enough
removed from our region to have only peripheral impact. We will still
get the upper trough and gradual cold air advection and
clouds...but lack of dynamics aloft and focusing features near the
surface will make associated shower activity light and
spotty...with amounts on the order of only a few hundredths of an
inch. The only exception will be some potential enhancement in the
Poconos-Wyoming Valley areas due to brief easterly jet as low
develops overnight.

For tonight...isentropic lift ahead of digging trough/cutting off
low will remain over western PA/NY...keeping some light shower
chances mainly in the central southern tier to western-central
Finger Lakes this evening. Then overnight...minor frontogenesis-
convergence in the middle levels over our region as cyclogenesis
ensues at the surface well offshore the midatlantic coast. In
effect...a 700mb pseudo-front will lose definition over our
area as middle level flow backs from southeasterly to northeasterly.
A better likelihood of rain Wyoming Valley to Poconos during brief
juxtaposition of transitory easterly jet /Atlantic moisture
contribution/ and middle level lift 09z-12z Sat.

With exception of Wyoming Valley-Poconos...overall though lack of
jet support...and the diminishing to eventually elimination of
isentropic uplift...will continue to make synoptic precipitation
rather spotty across our region overnight through Saturday. Cold
air advection through the daytime hours Saturday will also be
quite minor...and not yet enough to generate lake response.
Atmospheric column nor surface temperatures appear cold enough
tonight into Saturday for snow to mix in except perhaps highest
elevations of the western Catskills /and even that is iffy-
spotty/.

Lows tonight middle 30s to near 40...then temperatures not moving much
on Saturday with highs mainly in the 40s.

&&

Short term /Saturday night through Monday/...
350 PM update...
due northerly flow will very gradually back northwesterly Saturday
night into Sunday...while being pretty brisk due to the tight
pressure gradient between the deep Nova Scotia-bound low...and the
Ohio Valley high. This will mean a very limited fetch for Great
Lakes moisture...despite cold enough 850mb temperatures for a lake
response /well below zero celsius/. That along with very dry air
mass advecting into the region...dewpoints crashing through the
20s Sunday...will mean only a small amount of lake effect snow showers
at best. Before that...still some synoptic moisture which with
cold air advection will allow lingering rain showers to change to
snow showers or flurries while diminishing. Snow accumulations
where they occur will be meager and mainly limited to higher
terrain areas in The Finger lakes region as well as the western
Catskills.

Cyclonic pressure gradient Sunday will push gusts into 25-35 miles per hour
range...which along with temperatures only in upper 30s to low
40s will feel quite cold. Dryness of air mass will also allow
clouds to scatter out fairly quickly Sunday afternoon.

High pressure ridge then builds in Sunday night to Monday for a
period of dry weather. Lows in the 20s to near 30 Sunday night...but
some moderation in temperatures Monday /upper 40s-low 50s/ due to
warm air advection.

&&

Long term /Monday night through Friday/...
a ridge of high pressure building out of the southeastern U.S.
Will provide milder temperatures and fair weather at the start of
the long term period.

A cold front swinging out of Ontario and the
Great Lakes region will bring a chance of showers for Tuesday and
Wednesday.

After the mild start, temperatures will average slightly below
normal for the remainder of the extended forecast period.

&&

Aviation /00z Saturday through Wednesday/...
updated at 8 PM... showers over Elm and points west will slowly
work east toward ith bgm syr and ith overnight. Conditions will be
mainly VFR under these showers but ceilings could fall as low as 2-3
kft in heavier showers resulting in brief MVFR conditions. A few
scattered showers may linger on Saturday but most of the time will
be dry with ceilings ranging from 3 to 5 kft.

Winds will be east-northeast at less than 10 kts tonight becoming
north and increasing to 10 to 15 kts by late Saturday.

Outlook...

Sat night...occasional restrictions are possible in rain/snow showers.

Sun-Tue...VFR.

&&

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

&&

$$
Synopsis...mdp
near term...mdp
short term...mdp
long term...djp
aviation...djp/mse

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