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Area forecast discussion 
National Weather Service Binghamton New York
331 PM EST Thursday Feb 11 2016

Synopsis...
lake effect snow showers will continue across central New York
with flurries across southern New York and northern Pennsylvania
into tonight. A period of mostly dry weather can be expected from
late tonight into Friday afternoon... then spotty light snow will
develop ahead of another cold front later Friday. The coldest air
of the season will arrive Friday night into Sunday with bitterly
cold temperatures and wind chills. The entire area will be below
zero by Saturday night and Sunday morning.

&&

Near term /until 6 am Friday morning/...
broken bands of lake effect snow oriented from around 290 degrees
continue to drift across the area this afternoon. The flow is
forecast to slowly shift to around 300 degrees through the middle
of this evening which should favor moving the snow bands slowly
southward during the next several hours. Based on this we believe
that there is still a good chance that some moderate snow will
reach the city of Syracuse late this afternoon or this evening.
Factors working against really heavy snow this evening include
that the dendritic snow growth continues to be confined to the
layer below 900 mb due to the very cold air mass in place. In
addition the gradual southward movement of the bands should keep
heavy snow from persisting at any one location for long. Based on
this we are expecting snow showers to continue across the warning
area through this evening with most places getting an additional 1
to 4 inches of snow. This snow will combine with blowing and
drifting to create hazardous travel conditions. Meanwhile farther
south bands of snow showers could still produce an inch or two of
additional snowfall through this evening from Cayuga and Seneca
counties down through Cortland and Otsego counties. We will allow
the advisory to continue in this area for a few more hours before
ending this evening. Things should quiet down overnight as the
flow shifts to more westerly and dryer air works in from the
west... with weakening bands shifting northward toward the East
Shore of Lake Ontario overnight.

&&

Short term /6 am Friday morning through Saturday night/...
Friday will start out quiet with mainly dry cold conditions across
the area. Some light snow may spread into central New York and
northern PA later Friday afternoon ahead of an Arctic cold front
approaching from the north. Snow showers and snow squalls will
accompany the passage of the Arctic front Friday evening with many
places picking up an inch or two of snow. Low level lapse rates
are forecast to exceed 8.0 degrees c per km Friday evening over
central New York and over 7.0 degrees c per km over northeast PA with
small amounts of cape. This will add to the convective nature of
the snow showers as they cross the area Friday evening with brief
periods of heavy snow possible.

The coldest air of the season will follow behind this front later
Friday night through Saturday. Models are still in good agreement
lowering 850 mb temperatures to between -30 and -32 over central
New York and northeast PA by late Saturday which is about as cold as we
ever see in this area. Based on this we are expecting temperatures
tofall to near zero in most places Saturday morning... holding
near zero through the day then falling below zero by middle to late
afternoon. These temperatures will be combined with 10 to 20 miles per hour
winds creating dangerous wind chills. We are going with a wind
chill watch for central New York for Saturday through Sunday morning...
and a watch for Saturday night through Sunday morning for
northeast PA where temperatures will not be quite as cold... but
still dangerously cold especially Saturday night. North-northwest flow will
bring some snow showers south of Lake Ontario and possibly
enhanced by The Finger lakes Saturday into Saturday night. However
amounts should not be heavy as dendritic snow growth potential
will be low due to the entire sounding being below -20 c.

&&

Long term /Sunday through Thursday/...
330 PM Thursday update...
we start off well subzero dawn Sunday. Winds will be
significantly less than Saturday...yet still enough to yield
dangerously low wind chills for at least the first half of the day
because it will take until late Sunday- Sunday night for high
pressure to actually build in. Lake moisture still trapped under
the developing subsidence inversion will also continue scattered
snow showers and flurries from Steuben County through The Finger
lakes to Syracuse regions...but with only light dry fluffy
accumulations. Highs will only be in the single digits to around
12 degrees.

Busy pattern comes together for Monday through Wednesday. Sharp
trough from this weekend lifts out...only for mean upper trough
positioning to retrograde slightly west as a new one digs into the
Great Lakes region. Phasing of northern and southern streams looks
likely to produce a low pressure system somewhere in the
southeast...which then deepens while heading northeast. With
retrograded trough...warmer air will be able to advect in as the
system approaches. The devil is in the details...and while the
models agree on existence of the system...they have been
inconsistent on its track and amount of warm air run-to-run and
model-to-model. One thing that appears missing is high pressure in
the northeast for anchoring the cold air...so the warmer trend in
latest guidance makes sense. All we can say at this point is a
fair amount of precipitation is looking probable especially Monday
night through Tuesday night...but precipitation type is very
questionable. Stay tuned.

&&

Aviation /21z Thursday through Tuesday/...
Lake effect bands with IFR to below alt mins for visible will
continue to impact ksyr and krme this afternoon...persisting into
evening for ksyr before lifting back briefly into krme late
tonight before ending. Blsn will also hamper visible this afternoon
until the west-northwest winds diminish this evening...and then back
southwesterly Friday morning /vrb to southeast krme/. Further
south...thinner bands will briefly visit the other New York
terminals...including intermittent IFR visible for kbgm through 20z
and MVFR visible for kith. Kavp and kelm will get flurries but likely
non-restricting. Except for the lingering ksyr-krme issues
mentioned Above...All terminals go VFR tonight through Friday
morning.

Outlook...

Friday aftn-ngt...VFR until strong Arctic front blasts through with
a probable low visible snow squall roughly 01z Sat northwest to 07z Sat southeast.

Sat...occasional restrictions from scattered -shsn and gusty winds/blsn.

Sat ngt-Sun...Lake effect scattered -shsn and associated brief
restrictions ksyr and perhaps kith-kelm.

Mon-Tue...restrictions in potential snow as an East Coast system
moves through...best chance Monday ngt-Tue.

&&

Bgm watches/warnings/advisories...
PA...wind chill watch from Saturday afternoon through Sunday
afternoon for paz038>040-043-044-047-048-072.
New York...Lake effect Snow Advisory until 7 PM EST this evening for
nyz016-017-044>046.
Wind chill watch from late Friday night through Sunday
afternoon for nyz009-015>018-022>025-036-037-044>046-
055>057.
Wind chill watch from Saturday afternoon through Sunday
afternoon for nyz062.
Lake effect snow warning until 4 am EST Friday for nyz009-018-
036-037.

&&

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

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