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Area forecast discussion 
National Weather Service Buffalo New York
915 PM EDT Thu Oct 27 2016

low pressure will exit into the Saint Lawrence overnight, with
rain and possibly some wet snow showers lingering into Friday. A
ridge of high pressure will bring brief amounts of sunshine
Friday afternoon, before clouds increase Friday evening ahead of
the next storm system. This will bring a chance for rain Friday
night east of Lake Ontario, and Saturday across the entire region.


Near term /through Friday/...
low pressure across Lake Ontario late this evening will exit into
the St Lawrence overnight. Precipitation has tapered off
considerably through this evening, however there still are steady
showers across the Eastern Lake Ontario region. These will linger
through the evening hours, with a chance for some showers south
and east of the lakes as cooler air aloft moves in and increases
lake induced instability.

BUFKIT soundings show cloud tops marginally cold enough for
dendritic snow growth across much of western New York. As a
result, expect mainly drizzle or light rain showers. Fortunately
temperatures are and should remain just above freezing in these

Moisture will be deeper across the Eastern Lake Ontario region
which is closer to the departing mid/upper level low. Surface temperatures
across the Eastern Lake Ontario region have risen significantly in
a gusty southeast flow this evening. As cooler air builds behind
the low later tonight lake enhanced rain showers may change back
to snow across higher terrain, but little accumulation is
expected. This still may result in some slick spots.

Tomorrow the initial surface low over the slv will weaken, while a
secondary surface low develops near southern New England. While
precipitation will largely be ended over wny, there may be a few
lingering areas of precipitation east of Lake Ontario through the
morning hours.

A narrow ridge of high pressure will advance towards the region
tomorrow afternoon. Once this ridge arrives we should see a rapid
decrease in cloud cover, with sunshine spreading eastward across
the County Warning Area. Despite this sunshine, we will still remain chilly with
highs only in the mid to upper 40s.


Short term /Friday night through Monday/...
the axis of the north-south surface ridge across the lower Great
Lakes will slide eastward Friday night. Southwesterly low level jet
increases to 45 to 55 knots by Saturday morning as shortwave energy
races across southern Canada, laying a sharp baroclinic zone across
the upper Midwest/northern Great Lakes and southern Ontario. The
increasing warm advection and moisture out ahead of this system will
bring increasing chances for showers to the north country towards
Saturday morning, while the remainder of the region will remain dry.
The warm air advection and increasing southwest flow will result in
a non-diurnal temperature trend for most areas, with this most
pronounced across the lake plains of western New York where
overnight temperatures should warm into at least the lower to mid
50s by daybreak Saturday.

Saturday, latest models look to be just a tad bit slower with the
southward movement of the cold front. Nonetheless, it looks like the
boundary will ease through the area late in the day and Saturday
night. Increasing moisture and frontal lift will generate scattered
to numerous showers across the region, with the greatest rain
potential across the north country. A breezy to windy day is
expected day as the pressure gradient tightens across our region in
advance of the cold front and as the 45 to 55 knot low level jet
translates eastward across the area. Momentum Transfer scheme off
model soundings suggesting that we will not be able to tap into all
of this wind aloft with low levels rather stable, but still could be
looking at wind gusts in the 40 to 45 mph range, especially downwind
of the lakes. Likely not looking at much in the way of sunshine, but
still should be a rather mild late October day with most high
temperatures in the lower to mid 60s across western New York, with
rain holding the north country back in the 50s.

The southward progression of the front will likely be slowed further
Saturday night into early Sunday as a wave of low pressure ripples
eastward along it. This will likely keep widespread showers across
the region Saturday night into at least Sunday morning. The greatest
rain potential across the western New York and The Finger lakes.

The rainfall potential will diminish by Sunday afternoon as the
front drop south of the region. High pressure building into the
region behind the front will bring clearing skies Sunday night with
a good amount of sunshine expected for Monday. A gradually cooling
air mass will bring temperatures back closer to normal for Sunday
and Monday with most highs in the upper 40s to mid 50s.


Long term /Monday night through Thursday/...
the beginning of this forecast period will be dominated by broad
upper-level ridging that will build from the Mississippi Valley to
the eastern Seaboard...and its corresponding areas of surface-based
high pressure. These features will provide our region with a return
to warmer temperatures and largely dry weather. The ridged pattern
will get knocked down by a cold front Wednesday night through
Thursday. Expect a rainy period during the slow passage of this cold
front, as the surface and mid level flow will be along the front,
slowing its passage and allowing a longer and more persistent supply
of moisture.

Light south winds will provide warmer air and downsloping conditions
on Monday night, thus overnight low temps will be limited to the
lower to mid 40s, persistent south to southwest winds will hold
Tuesday night's lows to the upper 40s to lower 50s, and Wednesday
night will stay 10 degrees above normal with lows in the lower to
mid 40s. High temperatures will be in the mid to upper 60s, with
lower 60s east of Lake Ontario. Wednesday and Thursday will also be
mild for early November as high temps reach the upper 50s to lower
60s on Wednesday and the lower to mid 50s on Thursday, during the


Aviation /01z Friday through Tuesday/...
low pressure across Eastern Lake Ontario will track near Art late
this evening, and then up the St Lawrence Valley. Following what
happened in buf/iag...expect conditions to lower to IFR at Art
where winds will shift erratically due to the close proximity to
the low. Meanwhile IFR conditions at buf/iag are likely to
improve gradually as the northwesterly flow advects slightly
drier boundary layer air. Roc may briefly lower to IFR late this
evening, before following an improving trend as well. As is
climatologically favored, jhw should remain IFR the longest,
probably lasting most of the night.

Clouds will gradually lift and scatter on Friday, as drier air
builds in behind in with a narrow ridge. Morning mfvr/IFR
conditions should rather abruptly giveway to VFR conditions by
Friday afternoon.


Saturday...VFR/MVFR with scattered to numerous showers
Sunday...mainly VFR with a chance of showers.
Monday and Tuesday...VFR.


will not make any changes to the small craft advisories that are in
place across the eastern Great Lakes. As the surface low tracks
into the St. Lawrence Valley overnight, winds will be gusty near
the surface low and shift abruptly.

A narrow ridge of high pressure will cross the lakes tomorrow and
this will allow for Small Craft Advisory to end through the afternoon and overnight
time period on the lakes. However this will only be a lull, as
another storm system passing just to the north of Lake Ontario will
again freshen the winds on the eastern Great Lakes that will likely
bring another round of Small Craft Advisory late Friday night and into the weekend on
the lakes.


Buf watches/warnings/advisories...
New York...none.
Marine...Small Craft Advisory until 2 PM EDT Friday for lez040-041.
Small Craft Advisory until 11 am EDT Friday for
Small Craft Advisory until 8 PM EDT Friday for loz043-044.
Small Craft Advisory until 5 PM EDT Friday for loz042-045.



near term...apffel/Thomas
short term...tma
long term...wch

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