Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 260807

Area Forecast Discussion
National Weather Service Buffalo NY
407 AM EDT Thu Apr 26 2018

Low pressure will move northeast from New England into the
Canadian Maritimes today. Lingering showers behind this system
will give way to drier weather from west to east today as high
pressure and drier air builds across the Lower Great Lakes. Two
more weak systems will then bring additional periods of rain
showers Friday and Saturday.


The main area of low pressure across New England will exit
northeast across the Canadian Maritimes today, as high pressure
and much drier air builds eastward from the Ohio Valley/Upper
Great Lakes into western New York. This will result in lingering
showers diminishing from west to east through the course of the
day, with the activity hanging on the longest east of Lake
Ontario due to the closer proximity of the low and lingering
upslope flow.

Following the departure of the showers, increasing subsidence and
drying should lead to partly to mostly sunny skies developing across
areas south of Lake Ontario during the late morning and afternoon
hours, with some breaks of sun reaching the North Country by late in
the day. Otherwise, a lingering pressure gradient will keep breezy
conditions in place, with afternoon highs expected to mostly range
through the 50s.

Dry weather is expected tonight, as there will be a brief break
before the next system arrives. Skies may briefly clear out and
temperatures will fall into the mid 30s to lower 40s.


Two areas of weak low pressure will approach the Northeast Friday,
the first one will track across the Great Lakes with an associated
cold front. The other, which is deeper of the two, will track from
southern VA to southern New England. Mid-high level clouds will
increase from the west and south Friday. Exiting high pressure
and dry air will keep the region mostly dry. The one exception
will be across the Southern Tier and Finger Lakes as rain brushes
the eastern side of the forecast area. As the cold front nears from
the west Friday, rain showers will form ahead of it. A shortwave
trough will also approach from the Ohio Valley and showers will
enter Western NY Friday evening. Rain showers will move to the north-
northeast, near the eastern Lake Ontario shoreline. Temperatures
will drop into the mid to upper 30s to low 40s Friday night.

The Great Lakes low and the coastal low will merge near, if not
overhead Saturday. Rain is expected to blossom as a cold front moves
through the eastern Great Lakes. An anomalously upper-level trough
will spin overhead through the end of the weekend. Cold air will
advect southward and multiple rounds of precipitation are through
Sunday night. Cold air advection, wrap-around moisture and lake
enhancement will lead to rain showers changing to snow showers late
Saturday night and into Sunday as temperatures drop to the
U20s/L30s. Rain and snow showers will taper off into Sunday night.


The anomalously cold upper-level trough will exit the region into
the Canadian Maritimes late Monday. Meanwhile, building 500mb
heights and an expansive surface high over the Tennessee Valley will
become centered along the Carolinas which will initiate a
strong warming trend across our region. The surface high along
the Carolinas will pump up a much warmer air mass into the Ohio
Valley and Great Lakes which will send high temperatures soaring
some +15- 20F degrees above climo by Wednesday with mid- upper
70s, even a few 80F readings. Late in the week, latest guidance
shows a potent shortwave dropping southeast out of Canada across
the Great lakes while several waves ride northeast along a
frontal boundary to our west. This will likely bring increasing
chances for showers Thursday and Friday. Otherwise, look for
relatively quite weather the first half of the week with dry
conditions and more like summer.


Low pressure over New England will lift into the Canadian Maritimes
today. In its wake, high pressure and much drier air will build
eastward into the region.

Wraparound moisture behind the low will maintain some lingering
showers and widespread IFR to MVFR ceilings across the region early
this morning, with the lowest conditions found immediately downwind
of the lakes and also across the higher terrain.

Conditions will gradually improve through the day today as the area
of high pressure builds eastward into our region and brings an end
to the showers followed by a west to east clearing trend, which will
result in flight conditions improving to VFR in most areas by the
end of the day. The one possible exception to this will be the
higher terrain east of Lake Ontario, where some MVFR cigs may linger
through sunset.

Friday and Saturday...Mainly VFR with a chance of showers.
Sunday...Mainly VFR with a chance of rain or snow showers east
of Lake Ontario.


Surface low pressure over New England with lift into the Canadian
Maritimes today, with westerly winds freshening in its wake. This
will lead to sufficient waves and winds on the southern and eastern
shores of Lake Ontario for Small Craft Advisories into tonight.
Lighter winds and waves are then expected through Friday, with waves
perhaps building again under westerly flow on Saturday.


MARINE...Small Craft Advisory until 8 PM EDT this evening for LOZ043.
         Small Craft Advisory until 5 PM EDT this afternoon for
         Small Craft Advisory until 11 PM EDT this evening for



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