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Area forecast discussion 
National Weather Service Binghamton New York
1023 PM EST Sat Dec 27 2014

Synopsis...
a cold front will pass through New York and PA with rain showers overnight
into Sunday morning. This front will bring cooler weather for
Monday and Tuesday...with dry conditions other than a chance for
light lake effect snow showers in parts of central New York Monday.

&&

Near term /through Sunday/...
1015 PM update...
very mild night continues...as evidenced by the 53 degree reading
in Syracuse and even 54 to our north on Watertown. Some locations
that decoupled earlier in the evening with temporary lack of cloud
cover...have had clouds and winds return with temperatures
bouncing back up. Elmira went from calm and 35 degrees at
8pm...to 46 degrees at 10pm with a southwest wind at 7 kts.
Thickening clouds and persistent southwest wind will keep temperatures
from going down for most of night...until frontal passage forces
cold air advection Sunday morning...and thus many places actually
creeping cooler during the day. Forecast updated to keep up with
these fine details. Mainly virga so far as expected...primary rain
times listed below still look good.

730 PM update...
was able to continue trend of delaying onset of rain showers
overnight. A few sprinkles could run out ahead...but appears that
timing for bulk of rain will be midnight-6am in central New
York...to 3am-9am twin tiers...to 5am-11am Wyoming Valley-Poconos-
Sullivan County New York. Trends in hi res models are also catching up
to the milder reality /with slower cooling when it does
occur/...and so temperatures were adjusted accordingly. As
mentioned below...bleak prospects for the rain to end as a wet
snow. The end result looks like one to two tenths of and inch of
chilly rain for large majority of the area...closer to a quarter
inch in Oneida County. No snow accumulation...most places not even
a single flake.

Previous discussion...
a storm system moving across the Great Lakes will bring rain
showers to our forecast area tonight. A cold front will dip in from the
northwest, arriving around midnight.

Forecast quantitative precipitation forecast values are between 0.10 and 0.15 inches. Atmosphere
remains very mild with temperatures above freezing all the way up to 8000
feet at 8z, and through 2500-3000 feet by 12z once the cooler air
deepens.

The odds appear less favorable for a rain to snow changeover after
the front moves through.

As the cold front dips southeastward through the afternoon, the
rain will come to an end from northwest to southeast. Much drier air follows in
the wake of the front. Temperatures will return to near seasonable
norms, as -8c to -11c 925mb airmass bleeds into the forecast area.

&&

Short term /Sunday night through Tuesday/...
quiet weather is forecast for the short term period. There is a
slight chance for lake effect snow showers due to persistent
280-300 lake flow through early Tuesday. However instability
leaves a lot to be desired, and the atmosphere is rather dry.
Stuck to slight chance for the les activity and added a tenth or
two of snowfall each period.

&&

Long term /Tuesday night through Saturday/...
grnl westerly flow through much of the extended period will keep gnrly dry
conds...although some le snows possible in the far north and far west
sections of the forecast area. Various waves/ripples in the flow will
occasionally enhance or change locations of...the snow showers. Temperatures really
not all that cold for the beginning of winter...but cold enough for
snow when precipitation does fall. Changes begin on Friday when a more important
system develops in response to a broad deepening of the trough over the upper
Midwest and corresponding ridging over the western Atlantic. This will
allow warmer air...and deeper moisture to arrive in the area for the
end of the period. Significant run to run and model to model dfrncs
at this time leads to cnsrbl uncertainty in the forecast. Will simply go with
chance probability of precipitation and a rain or snow forecast as the position and amount of warm air advection
still very uncertain.

For the daily forecast itself...gnrly flwd HPC guidance once again but
also tweeked it toward the colder GFS MOS which allowed for better
collaboration and consistency in the forecast.

&&

Aviation /03z Sunday through Thursday/...
00z update...
cold front set to drop through the area overnight into early
Sunday morning. VFR for now with increasing clouds...and light
S to south-southwest winds /except easterly local valley wind krme/. Along
with development of light showers with only minor visible restrictions
if any...we are expecting ceilings lower into MVFR starting around 05z
krme...06z ksyr- kith...07z kelm- kbgm...and 11z kavp. Winds to
also veer from SW to west-northwest with frontal passage. Except kelm-
kavp...fuel alt feq MVFR level likely to be reached for a time
behind the front into Sunday morning. Model soundings suggest that
low level moisture combined favorable wind direction and should
cause brief IFR ceiling for krme with frontal passage 09z-12z. Not as
likely at other terminals...thus not in taf...but not totally out
of the question kbgm-kith. Forecasting improvement to VFR 18z-
20z...but with northwest winds around 8-12 kts at that time...would not
surprise ME to see MVFR ceiling linger longer for some of the New York
terminals.

Outlook...

Sun ngt/Mon...VFR.

Tue/Wed/Thu...brief restrictions possible at times for krme/ksyr due
to lake effect -shsn. Otrws...VFR is expected.

&&

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

&&

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

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