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Area forecast discussion 
National Weather Service Buffalo New York
712 am EST Sat Dec 27 2014

Synopsis...
cloudy but dry and seasonably mild conditions will be found across
western and north central New York today as high pressure moves out
of the area. A low pressure system crossing from the central Great
Lakes to Quebec will swing a cold front across the region
tonight...bringing showers followed by much cooler temperatures on
Sunday. It will feel much more like middle-winter in the coming week as
Arctic high pressure builds across the Great Lakes with a potential
for lake effect snow late next week.

&&

Near term /through tonight/...
an abundance of low level moisture streaming north from the
Mississippi/Ohio valleys has made its way into the lower Great Lakes
on southerly flow. With satellite imagery showing plenty of this
moisture upstream...it will be a cloudy but seasonably mild day with
southerly flow pushing temperatures into the upper 40s with areas
along the lake plains cracking the 50 degree mark this afternoon
thanks to downsloping.

The aforementioned southerly flow will strengthen during the
afternoon and evening hours ahead of a low pressure system that will
tracking across the Soo and into Quebec tonight. As the low takes an
easterly path across Quebec tonight it will drag a cold front across
the lower Great Lakes and this will generate showers across the
forecast area overnight with most areas receiving around a tenth of
an inch or so of rainfall. Temperatures will stay quite mild as warm
air surges polewards ahead of the approaching front with upper 40s
prevailing through the evening hours before falling to the upper 30s
by daybreak as cold air advection kicks in behind the front.

&&

Short term /Sunday through Tuesday/...
a weak area of low pressure will shift east across southern Quebec
on Sunday with its associated cold front exiting east toward New
England. Any lingering showers Sunday morning will quickly end by
noon as high pressure ridging works across the lower Great Lakes
from an expansive Arctic high sliding south across the Canadian
rockies. Across the higher terrain some wet snow showers may mix in
with the rain before ending with no accumulation expected.
Increasingly colder and drier air will work across New York Sunday
afternoon with morning clouds becoming partly sunny. Cold advection
from a modified Arctic sourced airmass will keep temperatures
falling through the 30s during the day.

The remainder of the weather in this period will be controlled by the
Arctic surface high as it centers south across the western High
Plains. Surface ridging extending east from this high will remain over
the lower Great Lakes through Tuesday with flow veering from west to
north as the center of the high shifts south. This will keep our
area shielded from surface low crossing the southeast states on
Monday. 850mb temperatures across the lower Great Lakes will be cold
enough to support a lake response but the Arctic sourced flow into
our region will provide little synoptic moisture. Some upslope
clouds as the flow becomes northerly will be the only weather to
speak of outside of our temperatures falling to below normal by
Tuesday.

&&

Long term /Tuesday night through Friday/...
Tuesday night through Thursday night...the broad area of Arctic high
pressure centered over the Western Plains will slowly build east to
the East Coast...while broad/deep low pressure near Hudson Bay
slowly drifts eastward across northern Quebec. This pattern will
feed a general westerly flow of cold air across our region through
Wednesday then backing to southwest on Wednesday night and Thursday
as a surface trough associated with low pressure over Quebec crosses
the lower lakes.

Have continued with the broad areas of chance probability of precipitation downwind of lakes
Erie and Ontario...with the highest chances centered on Thursday
with a boost in synoptic lift and moisture with the surface trough.
Highest chances will be found east of Lake Ontario where moisture
might be a bit more favorable. Otherwise...it should just be cold
and dry outside of any lake effect areas.

By Friday...the center of the aforementioned surface high will slide
off the Atlantic coast while some semblance of the next surface low
begins to take shape over The Ark-la-tex. The ensuing warm advection
pattern under southwest flow should result in any lingering lake effect
quickly weakening and lifting northward.

Temperatures will average below normal right through Thursday
night...with highs in the 20s by day and lows in the teens to lower
20s at night...before readings moderate back to around seasonal
normals by next Friday.

&&

Aviation /12z Saturday through Wednesday/...
widespread stratocu has spread across the forecast area this morning
as a pool of low level moisture continues to surges northeastwards
out of the Mississippi/Ohio valleys. Skies will stay largely cloud
covered with ceilings generally hovering around 3000ft as the stratocu
promises to hang around much of the day ahead of an approaching cold
front. This front will cross the forecast area tonight...bringing
MVFR ceilings/visibilities in -shra with south winds veering westerly behind
the front. While there may be some improvement in ceilings across lower
elevations back into VFR range...upslope flow across higher terrain
may keep ceilings in MVFR through the end of the period.

Outlook...
Sunday through Tuesday...VFR/MVFR ceilings.
Wednesday...IFR in west-Southwest Lake effect -shra...MVFR/VFR elsewhere.

&&

Marine...
high pressure and tranquil conditions on the lakes this morning will
give way to southerly winds that will increase to 10 to 15 knots
this afternoon. Winds will continue to freshen and veer to the west
tonight as a cold front swings across the lakes. The ensuing cold
advection and increase in winds will generate Small-Craft Advisory
level winds and waves overnight and a new round of advisories is in
place to cover this frontal passage.

The higher waves will linger across the east end of Lake Ontario
through Sunday afternoon before subsiding as Arctic high pressure
begins to build across the lower Great Lakes. This will result in
relatively light northerly winds for the first part of the coming
week before winds back to the southwest again and strengthen again
ahead of another low dropping out of the Canadian Arctic. This will
potentially bring another round of small craft advisories by
Wednesday.

&&

Buf watches/warnings/advisories...
New York...none.
Marine...Small Craft Advisory from 10 PM this evening to 10 am EST
Sunday for lez040-041.
Small Craft Advisory from 3 am to 7 PM EST Sunday for
loz043-044.
Small Craft Advisory from midnight tonight to 1 PM EST
Sunday for loz042.
Small Craft Advisory from midnight tonight to 7 PM EST
Sunday for loz045.

&&

$$

Synopsis...wood
near term...wood
short term...Smith
long term...jjr/Smith
aviation...wood
marine...wood

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