Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 281901

Area Forecast Discussion
National Weather Service Buffalo NY
301 PM EDT Tue Mar 28 2017

Low clouds and patchy fog will linger into tonight with light
northerly winds. High pressure building south across the Great Lakes
will allow clouds to slowly erode on Wednesday with mainly clear
skies expected by Wednesday night. Our next storm system will bring
rain later Thursday into Friday. Temperatures will run near to
slightly above normal through Friday.


Surface analysis this afternoon shows a weak cold front pushing into
eastern NY with expansive arctic sourced high pressure centered over
Manitoba. This high is building south across the upper and central
Great Lakes behind the front. Radars showing all rain showers have
now exited east of the forecast area with the front. A lingering
moist airmass and northerly winds off the lakes continue to support
the widespread low clouds and patches of fog across the area. The
northerly flow will continue through tonight as the high pressure
noses across our region with clouds and patchy fog lingering as
moisture becomes trapped beneath a subsidence inversion.

On Wednesday, surface ridging will continue to build over western
and central New York. Clouds will be slow to erode with northerly
winds but drier air from the north should eventually bring some slow
clearing through the afternoon. The northerly winds will keep
temperatures nearly steady of slowly falling through the remainder
of the afternoon. Tonight, the lingering clouds will keep most of
western NY and the Finger Lakes just above freezing, though some
pockets of freezing or below temperatures could be found in the
colder valleys of the western Southern Tier. Most areas east of Lake
Ontario will dip to the lower 30s and upper 20s.


While dry pleasant weather will be featured at the start of this
period...a closed low currently over the Desert Southwest will play
a big role in supplying our region with another soaking rain during
the latter portion of the week. As a side note...this same system
will be directly responsible for widespread severe weather across
Texas and the Lower Mississippi Valley in the days leading up to our
rain event. The details...

Expansive high pressure centered over northern Quebec will nose to
the south across our forecast area Wednesday night. This will
produce fair chilly weather across our region with nothing more than
some cirrus obscuring an otherwise star filled sky. Temperatures
will be very close to typical late March levels...with lows ranging
from the low to mid 20s across the North Country to between 25 and
30 elsewhere.

The axis of a mid level ridge will pass overhead on Thursday...while
a closed low over the central Plains will open up and move east.
This will push an area of strong warm advection to the northeast...
where a tightening H925-70 baroclinic zone will make its way to the
Lower Great Lakes. Warmer and increasingly more moist air will push
up and over this burgeoning warm that some rain showers
will become possible over the western counties during the afternoon.
Otherwise...lowering and thickening clouds can be expected over our
region during the course of Thursday with temperatures climbing to
between 50 (Srn Tier) and the mid 40s (North Country).

The aforementioned mid level low will move across the Lower Ohio
Valley Thursday night while attempting to phase with northern stream
energy over the Upper Great Lakes. A 40 kt low level jet ahead of
these mid level features will pump increasing moisture across our
region...with a wide open connection to the GOMEX encouraging PWAT
values to climb to around an inch (wrn counties). The low level jet
will push the moisture rich low level air up and over a fairly
strong warm frontal boundary...producing several hours of steady and
occasionally heavy rain across our region. The rain could start off
as wet snow or a mix of rain and snow across parts of the eastern
Lake Ontario region...and in particular across Lewis County. At
first glance of the synoptic pattern (and strength of warm
front)...would think that there would be the potential for a
thunderstorm or two. Model soundings do not suggest steep enough
lapse rates aloft without significant elevated CAPE...
will keep the mention of thunder out of the package. Have raised pops
to 90 over the western counties and to likely over the North

On Friday...the tight baroclinic zone will push north across Lake
Ontario and the North Country. While this is where the steadiest...
most widespread rain will be found...rain and drizzle will stay in
place across the western counties in the vcnty of a stacked trough.
Will use cat pops across all of the forecast area. Any mixed pcpn at
the start of the day over the North Country will change to just rain
by late morning.

The complex system responsible for the all of the unsettled weather
will push to our east Friday night. While the bulk of the associated
lift and mid level moisture will be removed...there will still be
the chance for some leftover showers...especially along and east of
the axis of the sfc trough...which will be aligned over the Genesee
Valley for the first half of the night. Again...some of this pcpn
could change to a wintry mix late.


There is high confidence that this will be a relatively mild a progressive ridge will make its way across the eastern
half of the country. This ridge will also keep the bulk of the
period rainfree. The tranquil weather will come to an end though by
Monday night and the next southern stream system will
lift northeast out of the Lower Mississippi Valley. The details...

A storm system exiting off the East Coast will support some leftover
nuisance showers across the region Saturday morning. In its wake...
expansive high pressure centered over Hudson Bay will build south
across the Lower Great Lakes Saturday afternoon through Monday. This
will promote fair dry weather. While high temperatures will
generally be in the 40s on Saturday...the mercury will climb into
the 50s for Sunday and Monday.

Monday night and Tuesday...low pressure over the Lower Mississippi
Valley is forecast to push north towards the Lower Great Lakes. Most
of the ensemble members of the GEFS along with the operational
ECMWF track the broad low to our west within a negatively tilted
trough...which will once again set up a scenario where we experience
another round of rain.


A mix of MVFR and IFR cigs in low clouds with patchy IFR vis in fog
will continue this afternoon and into tonight. This is brought on as
high pressure building across the Great Lakes traps low level
moisture below an inversion with northerly winds off the lakes.

Most sites will improve to or hold at MVFR cigs through much of
Wednesday with no change in the above mentioned pattern. ART
has the best chance of improving to VFR.


Wednesday night and Thursday...VFR.
Thursday night into Saturday...MVFR/IFR with occasional rain showers.
Sunday...some improvement to VFR possible.


Light northerly winds will increase some tonight through Wednesday
as strong Canadian high pressure builds across the Great
Lakes...however winds and waves are expected to remain below
advisory levels. Winds will turn easterly Thursday and Friday as our
next storm system passes south of the Great Lakes. Winds will
approach 15-20 knots but higher waves should remain in Canadian





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