Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
103 PM EST Wednesday Dec 4 2013
a warm front will then edge northward later today with milder air
spreading across the region. After spotty rain showers and patchy
drizzle tonight...Thursday will be the warmest day of the week. A
cold front passing Thursday night will bring in colder temperatures
into the weekend. Rain developing Thursday afternoon and evening...may
turn into a mix Friday...then to potential accumulating snow by
Near term /through tonight/...
930 am update...continual adjustment to the very near term grids
was needed today as batches precipitation continues to generate
across north central New York within a zone of shallow to moderate
isentropic lift ahead of surface front. The atmosphere between the
12z radiosonde observation reports from aly and buf suggest profiles conducive to
rain...and sure enough we are seeing mainly liquid forms of precipitation
at the surface. Unfortunately clearing and radiative conditions
from last night have not been alleviated and the cold air remains locked
into our northern and eastern counties with areas of freezing rain
and drizzle being reported as these batches of precipitation move
through. Fortunately...radar returns are mostly light and temperatures
are only marginally cold so this should be only a short term
issue...and probably not much of one.
Beyond the next few hours...weak riding aloft takes hold and the
afternoon should be mainly quiet and milder. Warm air moving over
cold and/or snowy ground will still mean rather dank conditions
for upstate New York...although times of sunshine are possible. Best
chance for sunshine lays across nepa this morning...although that
may turn less optimistic this afternoon with middle level clouds
Early morning discussion...
at 415 am...as with prior nights...chasing a trace to a hundredth
of an inch precipitation...and patchy fog. Our region is at the
weak Point of a surface ridge...between high pressure centers
offshore the midatlantic coast and well to our northwest in
Canada. That division Marks the surface warm front that is
basically developing over US. Warm air advection has yielded
increasing moisture aloft and very light precipitation currently
extending across the Ontario peninsula and into western New York.
Flurries or sprinkles are shown in upstream observations...with
temperatures near freezing yet trending up soon after any
precipitation. Initial virga is now becoming flurries/sprinkles in
central southern tier New York...shifting northeast across much of
central New York through early-middle morning. We will be keeping a
close eye on temperatures as this very light activity moves
through...with the expectation that upon arrival temperatures will
edge above freezing as has occurred upstream. Weather grids
include slight chance of freezing rain where needed.
After that...quiet with temperatures mainly 40s areawide this
afternoon. By this evening...moist southeasterly low level flow will
cause some drizzle to show up in higher terrain of nepa and
Catskills this evening...and small chance of showers areawide
overnight as waves pass through upper flow that becomes west-southwest. Little
to no jet support tonight...and moisture for the most part remains
shallow...so only expecting light amounts of rain where spotty
showers occur. Temperatures will be too mild /mainly upper 30s to
low 40s/ for anything else except rain as precipitation type.
However...we will have to see if cold air damming could surprise
with near freezing temperatures for eastern fringes of
Delaware-Otsego-Oneida counties...not considering it likely at this
point but something to watch.
Short term /Thursday through Saturday/...
425 am update...
surging warm air advection continues into Thursday resulting in
widespread 50s for highs. Plenty of clouds but the moisture will
be shallow. Spotty drizzle or a couple showers around...but
overall a lull in precipitation initially with lack of deeper
moisture. However...by middle afternoon Onward...approaching cold
front will be accompanied by strengthening and moisture-laden
southwesterly jet...so rain should break out for at least twin
tiers to Catskills and points southeast Thursday afternoon-
evening. Less certainty for northern Finger Lakes to Syracuse...but
overall chances still pretty good.
For Thursday night through Friday night...the overall theme is
gradual cold air advection and several waves of precipitation running
up along the front as it slowly drags through. Looks fairly
complicated since models agree that shallow surface cold front
will likely make it through before 12z Friday...but relatively
warmer air aloft will be slower to progress. Late Thursday
night/early Friday...undercutting cold air could result in not
only mixing with snow...but perhaps also some light freezing
rain/sleet. Mix potential in central New York initially...but spreading
across remainder of the area by late Friday. Models disagree on
pace of cooling for thermal profiles...which of course is the
devil in the details for eventual precipitation types and amounts.
Late Friday into Friday night...good model consensus on a final
wave of precipitation passing through as accumulating snow. At this
point at least 1-3 inches probable...perhaps some higher amounts.
Advisory level /4 inches or more/ not out of the question.
Again...amounts less certain towards lake plain-New York thruway
zones...with chances better south and east.
Long term /Saturday night through Tuesday/...
continuity prevails with the medium range...with shortwave and surface low ejecting
out of the central U.S. Trough into the gtlakes by 12z Monday. After this
time we're likely to see some lake response in the wrly flow
behind this system. Initial indications are for a wintery mix of precipitation
on Sun night...transitioning to -shra by Monday. Started with wpc
guidance but tweeked clouds/probability of precipitation a bit towards middle week due to potnl
Aviation /18z Wednesday through Monday/...
skies across the forecast area this afternoon have become mostly sunny...with
patchy hi-end MVFR vsby's due to haze. Conditions are expeceted to
deteriorate this evening as br forms locally...with a stratus deck
moving northward tonight in dvlpng southeasterly flow. Conditions could go below alt
mins later tonight especially at ith/bgm late. We have the stratus working
into NE PA/southern tier in the 02-05z time frame. At syr...believe
MVFR conditons will be met by vsby's as ceilings likely to remain above
MVFR in this flow. Widespread MVFR/IFR expeceted to continue on Thursday. Best
chance for scattered -shra through 18z Thursday will be late in the period but main
restictions this forecast period will be due to br/fog and ceilings. Winds this
afternoon l&v...becmg southeasterly overnight 10 kts with gusts to 20 kts primarily
on the hilltops...persisting into Thursday.
Thursday night to Friday night...IFR/MVFR in rain and mixed precipitation.
Sat.Sat night...scattered MVFR central New York....primarily syr/rme.
Sun ngt/Mon...widespread IFR/MVFR in rain and mixed precipitation.