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Area forecast discussion 
National Weather Service Buffalo New York
941 am EST Sat Feb 13 2016

Synopsis...
the coldest airmass of the season will settle over the region this
weekend. Bitter cold air will combine with a noticeable wind to
produce dangerously cold wind chill values through at least Sunday
morning. The frigid airmass will also generate lake snows southeast
of both lakes...although fresh accumulations are not expected to be
significant. Temperatures will moderate next week.

&&

Near term /through tonight/...
the coldest air of this winter season will settle over western and
north central New York today. The frigid polar air will keep
temperatures today from zero to 5 below in most areas...and 10 to 15
below across the north country. Instability from the bitter cold air
over the wide Open Lakes will continue to generate widespread lake
snows southeast of the lakes.

The northwest flow will continue to generate lake effect snow south
and southeast of the lakes through the rest of today and tonight.
The northwest flow will produce a wide spray of lake effect snow
showers across most of western and central New York. While instability is
strong in such a cold airmass...the air is also very dry which will
limit accumulations. The airmass is also too cold for dendrites...
with very small snowflakes falling that are not too efficient at
accumulating. These two negatives will keep accumulations modest...
with advisory level accumulations expected southeast of the lakes.

The better accumulations will focus from eastern Monroe to Oswego
counties where fetch is a little longer. These areas may see 2-4
inches today and another 2-3 inches tonight in persistent bands. An
upstream connection to Lake Huron may also produce better
accumulations across the western southern tier in a few spots today
and this evening with 2-3 inches today and up to 2 inches tonight in
persistent bands.

The bitter temperatures today and tonight combined with persistent
northwest winds gusting to 30 miles per hour at times will produce dangerously
cold wind chill values from 25 below to 30 below...to as cold as 40
below across portions of the north country. Actual low temperatures
tonight will be around 5 below on the lake plains and 10 below
across the interior southern tier. The north country will be far
colder with no lake effect clouds or lake modification. Expect lows
of 20 to 25 below.

&&

Short term /Sunday through Tuesday night/...
on Sunday...Arctic high pressure draped over the region at the start
of the day will slowly drift eastward into eastern New York...with
modest warm advection developing on its backside. After a bitterly
cold start to the day when dangerously low temperatures and wind
chills will still be in place...this will allow temperatures to begin
to recover somewhat...though it will still be a frigid day overall.
Expect daytime highs to range from zero to five above across the
north country to the five to ten above range across most of the rest
of the region...with the Lake Erie shoreline perhaps seeing readings
break into the teens.

Precipitation-wise...the Arctic airmass will still allow for some
nuisance-type lake effect snow showers southeast of the lakes at the
start of the day...with these then gradually fading out while
lifting northward in response to gradual backing of the low-level
flow across our region. Expect any activity off Lake Erie to dissipate
across the Chautauqua ridge during the morning...while the Lake Ontario
les gradually diminishes to just a few spotty leftover snow showers
across Oswego County by the end of the day. Given the very dry
nature of the Arctic airmass...a capping inversion at around 3-4 kft...
and increasing amounts of shear below this...expect the lingering
lake effect snow showers to produce little more than a couple
additional inches of fluff. Outside of the diminishing lake effect...
conditions should primarily be dry with just some scattered flurries
expected.

Sunday night...largely dry and quiet weather can be expected with
any leftover snow showers east of Lake Ontario ending altogether
in the evening...and the next Pacific-origin trough remaining too
far to our west to bring anything more than a chance of light snow
to Chautauqua County by late in the night. Otherwise...increasing
cloud cover and continued warm advection out ahead of this next
system will result in evening lows ranging some 10 to 15 degrees
warmer than those of Saturday night...followed by slowly rising
temperatures overnight. At this point...it still appears that both
temperatures and wind chill values will remain safely above wind
chill headline criteria.

After that...our attention will turn back to the synoptic scale for
the remainder of this period...as the aforementioned Pacific-based
upper level trough slowly makes its way eastward across the eastern
half of the nation. This system will bring slowly increasing chances
for some light snow on Monday as it encroaches upon our region...
followed by somewhat better precipitation chances both Monday night and
Tuesday as a developing attendant surface wave lifts northeastward
either along or somewhere east of The Spine of the Appalachians. With
the various guidance packages continuing to show considerable spread
in the track of this system...for now have elected to stick very close
to our existing continuity of chance probability of precipitation across far western New
York and likely probability of precipitation across the rest of the area...which currently
lies closer to a model consensus system track. With respect to ptype...
expect the precipitation from this system to remain in the form of snow Monday
night...then change over to a rain/snow mix on Tuesday as boundary
layer temperatures warm above freezing...before going back over to
all snow Tuesday night.

As for temperatures...continued broad warm advection across our region
Monday through Tuesday will allow our temperatures to recover back to levels
much closer to normal /mid 20s-lower 30s/ on Monday...before readings
finally climb back above normal on Tuesday...when most areas should
experience highs in the middle to upper 30s. Meanwhile at night...lows
both Monday and Tuesday nights should range through the 20s.

&&

Long term /Wednesday through Friday/...
trailing Tuesday/S system...a weak clipper system or surface trough
looks to cross the Great Lakes bringing a shot of colder air for
Wednesday. This will keep chances for snow in place...along with some
lake enhancement southeast of the lakes through midweek. Sub-freezing
temperatures are expected for Wednesday-Thursday with any lingering lake
enhanced snows tapering off by Thursday...followed by a potential
return to above normal temperatures late in the week as low pressure
tracks across the Great Lakes. This latter system will also bring
renewed precipitation chances to our region...with any precipitation likely
changing over from snow to rain as the atmospheric column warms.

&&

Aviation /15z Saturday through Wednesday/...
northwest flow will continue to produce widespread lake effect snow
showers across much of western and central New York today with areas of
IFR ceilings. The very cold air is resulting in tiny snowflakes which
greatly reduce visibility even in light snow. Ceilings will be mainly
MVFR with some IFR across higher terrain. This will continue tonight
before lake effect snow slowly diminishes on Sunday with IFR
becoming less common.

Outlook...
Sunday...a chance of IFR/MVFR in weakening lake effect
snow showers south of the lakes...otherwise MVFR/VFR.
Monday...VFR/MVFR with a chance of snow.
Tuesday...MVFR with rain and snow likely.
Wednesday...VFR/MVFR with a chance of snow.

&&

Marine...
a brisk flow of progressively colder Arctic air will continue across
the lower lakes region today...before gradually weakening tonight
and Sunday. This will result in a prolonged period of Small Craft
Advisory conditions that will last into either tonight or Sunday
dependent upon location.

An incoming frigid airmass will combine with brisk winds and will
result in heavy freezing spray on both lakes Erie and Ontario...for
which heavy freezing spray warnings will be in place.

&&

Climate...
an Arctic airmass will be dropping across our region...with near
record breaking cold lasting through the weekend. Below are some
climate stats and records regarding this weekend.

Buffalo:

Coldest temperatures last winter: -10f February 15th and 16th

Record low Saturday February 13th: -9f 1914
record low Sunday February 14th: -13f 1943

Record low maximum Saturday February 13th: 5f 1899
record low maximum Sunday February 14th: 5f 1979

Rochester:

Coldest temperatures last winter: -11f February 20th and 21st

Record low Saturday February 13th: -12f 1979
record low Sunday February 14th: -14f 1979

Record low maximum Saturday February 13th: 9f 1979
record low maximum Sunday February 14th: 6f 1979

Watertown:

Coldest temperatures last winter: -36f February 16th

Record low Saturday February 13th: -28f 1979
record low Sunday February 14th: -30f 1979

Record low maximum Saturday February 13th: 1f 1979
record low maximum Sunday February 14th: -1f 1979

&&

Buf watches/warnings/advisories...
New York...Lake effect Snow Advisory until 1 am EST Sunday for nyz002>006-
019-020-085.
Wind chill warning until 10 am EST Sunday for nyz001>008-
010>014-019>021-085.
Marine...heavy freezing spray warning until 7 am EST Sunday for lez040-
041.
Small Craft Advisory until 1 am EST Sunday for lez040-041.
Heavy freezing spray warning until 7 am EST Sunday
for loz042>045-062>065.
Small Craft Advisory until 1 am EST Sunday for loz042.
Small Craft Advisory until 1 PM EST Sunday for loz043>045.

&&

$$

Synopsis...tma
near term...Hitchcock/tma
short term...jjr
long term...jjr/Smith
aviation...Hitchcock/tma
marine...tma
climate...Thomas

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