Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 192032

Area Forecast Discussion
National Weather Service Buffalo NY
432 PM EDT Mon Mar 19 2018

Surface high pressure over Canada will bringing an extended period
of dry weather to the region and below normal temperatures through
the end of the week.


Regional surface analysis shows 1034 surface high pressure over
Manitoba canada with it extending to the east and southeast across
the lower Great Lakes. Also, a weak cold front is positioned across
the Mason Dixon line (MD/PA) with a surface low pressure over
Oklahoma/Kansas. Otherwise, generally clear skies across the
forecast area and strong March sunshine making it feel rather nice
despite the below normal temperatures, 18Z observations 20s and
L30s. For the remainder of today, surface high pressure will
maintain fair and dry weather.

Tonight, surface high pressure will continue to build east and
southeast and become positioned near James Bay/Ontario Canada. With
surface high pressure influencing the forecast area and near zero
cloud cover it will be another cold night. Overnight, lows will dip
into the teens across Western New York, to near or below zero in the
North Country.

Tuesday, surface high pressure will be position over James
Bay/Ontario Canada and the aforementioned low pressure over
Oklahoma/Kansas will move into the Mid-Atlantic region. Latest
guidance packages continue to show this system remaining well to our
south with very little impact other than strengthening northeasterly
flow between the two features and the introduction of a fair amount
of cloud cover across Western New York. Again, highs will remain
below normal with temperatures peaking in the low/mid 30s areawide.


A closed 500 mb low centered near West Virginia on Tuesday night
will gradually slide eastward off the mid-Atlantic coast on
Wednesday. Meanwhile at the surface, a weak surface reflection will
re-develop into another coastal low along the eastern seaboard. This
low is forecast to track southeast of Cape Cod Wednesday and then
weaken as it moves into the Canadian Maritimes on Thursday.

There is still some spread in the guidance with a consensus of 12Z
guidance shifting perhaps slightly northward with this system. Even
so, it will have minimal impact on our area, with perhaps some light
snow just clipping the NY/PA border Tuesday night. Otherwise the
forecast period is expected to be dry. There is a risk if the system
backs closer to our region on Wednesday night and Thursday that
there may be some light lake enhanced snow showers, but it still
appears that the moisture will be too shallow to support any
precipitation. Instead, this will result in cloud cover south of
Lake Ontario.

There will be a cool northeasterly flow during this time, with this
most noticeable across the lake plains on Tuesday and Wednesday. This
will result in below normal temperatures, especially daytime highs
which will only be in the 30s during the period. Fairly persistent
winds and cloud cover will limit radiational cooling, but even
without it lows will generally range from the teens to mid 20s.


A strong area of Canadian high pressure will expand southward across
the Great Lakes region this period. This feature will bring mainly
dry conditions Friday and Saturday. Exceptions will possible light
upslope snow showers along the western foothills of the Adirondacks
early Friday, and possible flurries south of Lake Ontario Saturday

While the next storm system should remain well to our south (across
the lower Ohio Valley and towards VA/NC) Saturday night and Sunday,
isentropic lift cutting over the shallow colder air of the surface
high pressure may bring some light snow to near the state border
Saturday night and into Sunday morning.

This system will pass to our east Sunday, with dry air and sunshine
returning. How fast the high pressure scoots by to our east will
determine the next threat for precipitation. If the faster GFS
verifies, moisture returning on the back side of the surface high
may bring chances for light precipitation to WNY later Monday. The
slower ECMWF would maintain a dry day.

Temperatures will begin the period averaging below normal. Highs
Monday may reach into the lower 40s with a return southerly flow.


Surface high pressure will continue to build east-southeast and
become positioned near James Bay/Ontario Canada. VFR flight
conditions will prevail the rest of today through the entire TAF

Tuesday night through Saturday...Mainly VFR.


Surface high pressure will continue to build into the Lower Great
lakes with light northeast flow across the region today.

Tonight, low pressure over Oklahoma/kansas will move into the
Tennessee Valley while surface high pressure settling near James
Bay/ Ontario Canada. A tightening surface gradient between the two
features will prompt northeasterly flow to strengthen across the
region. A Small Craft Advisory(SCA) has been issued for lake Ontario
as waves and winds will reach SCA levels early Tuesday and remain
elevated through Wednesday. Lake Erie will see elevated winds but
will likely remain below SCA conditions.

Additionally, a significant portion of lake Erie from Ripley to the
Buffalo Harbor remains ice cover. With strengthening northeasterly
flow this ice pack will likely shift and break apart becoming a
hazard to anyone that might try to venture out onto the ice.


MARINE...Small Craft Advisory from 8 AM Tuesday to 5 AM EDT Thursday
         for LOZ043-044.
         Small Craft Advisory from 8 AM Tuesday to 8 PM EDT
         Wednesday for LOZ030-042.



LONG TERM...Thomas
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