Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 212356

Area Forecast Discussion
National Weather Service Buffalo NY
756 PM EDT Wed Mar 21 2018

High pressure centered over northern Ontario will maintain dry and
chilly weather through the end of the week. Temperatures will then
finally climb back to more normal levels by early next week as
persistent deep troughing over the Northeast moves off the east


A Nor`easter will continue to strengthen while passing by to the
southeast of Long Island and Cape Cod tonight. While we will remain
well removed from this system`s precipitation shield and therefore
dry...we will still remain subject to some cloud cover. Initially...
this will be just in the form of some cirrus this evening...before
a northerly upslope flow and/or lake influences lead to the eventual
development of some lower clouds during the overnight hours. Given
the very dry current nature of our current airmass...have continued
to push the onset of the lower clouds back from continuity.
Otherwise...we can expect low temperatures primarily in the lower
to mid 20s.

On Thursday the Nor`easter will track into the Canadian Maritimes.
With this system remaining well away from our region we can expect
another dry day...with a mostly cloudy start to the day giving way
to some partial sunshine across the lake plains with daytime mixing.
Meanwhile...mostly cloudy skies should continue to prevail across
the higher terrain given a continued northwesterly upslope flow.
Otherwise temps will remain notably below normal...with highs mostly
ranging in the lower to mid 30s once again.


Overall there is above average model agreement during the period,
with differences among model guidance limited for our area. On
Thursday night a weak mid level circulation will move from near
Georgian Bay southeastward across Lake Ontario. Once this reaches
the area late Thursday night it will result in both colder
temperatures aloft (-11C at 850mb) and deeper moisture. This should
be just cold enough for cloud tops to reach the dendritic crystal
growth zone. Thursday evening should stay dry, then expect some
light lake/upslope enhanced snow showers to develop south and east
of Lake Ontario late Thursday night and during the day Friday.

Model consensus has this mid level system to New Jersey by late
Friday, with deep layer moisture diminishing late in the day Friday.
Temperatures aloft may still support lake enhanced clouds, but
probably will not be deep enough for anything more than flurries
Friday night. Canadian high pressure will then ridge southward into
the region heading into the weekend. This will result in dry weather
Saturday, with some lingering lake enhanced clouds south of Lake

Temperatures will continue to be below normal with highs averaging
in the lower to mid 30s and lows ranging from the teens to mid 20s.
The coldest low temperatures will likely be across the Southern Tier
valleys and in Lewis county.


Quiet and cool conditions will start this period as a broad and dry
area of high pressure presses southward from Canada and across the
Eastern Great Lakes region. This surface high will be squeezed
between a storm system passing by to our south and east, and a
developing storm system over the Plains. Strong subsidence will
bring a prolonged period of clear skies starting Sunday afternoon
behind a shortwave dropping across northern NY/NE...and persisting
through Monday night and into Tuesday.

Through the day Tuesday we will see mid and high level clouds build
across the region as moisture increases behind the surface high
pressure and a shortwave from the Plains approaches. There is still
uncertainty to the track of the shortwave, but there will be chances
for mainly rain showers Tuesday night and into Wednesday.

Additionally, a light southerly flow behind the surface high will
bring a taste of early Spring Tuesday and into Wednesday. While we
will likely remain cool Monday with little mixing under the surface
high, Tuesday and Wednesday should feature afternoons that have
temperatures rising to or above normal. This would place maximum
temperatures in the upper 40s to lower 50s for the region.


Widespread VFR conditions under just some cirrus this evening are
expected to lower into the upper MVFR/low VFR ranges overnight and
early Thursday as some lower clouds develop due to a combination of
lake influences and orographic enhancement. Renewed diurnal influences
on Thursday will then result in ceilings trending back to VFR levels
over time...though some MVFR cigs may linger through the day across
the highest terrain.

Thursday night through Friday night...Mainly VFR. A
chance of Lake Effect snow south/southeast of Lake Ontario Thursday
night and Friday.
Saturday through Monday...VFR.


Low pressure will move slowly northeastward offshore of the New
England coast tonight and Thursday. The pressure gradient between
this system and strong high pressure over northern Ontario will
continue to produce moderate northeasterly/northerly winds on Lake
Ontario into this evening...with the winds then gradually diminishing
overnight and early Thursday. Small Craft Advisories thus remain in
effect as outlined below to cover any lingering advisory-worthy
winds and waves.


MARINE...Small Craft Advisory until 8 AM EDT Thursday for LOZ043-044.
         Small Craft Advisory until 5 AM EDT Thursday for LOZ042.



LONG TERM...Thomas
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