Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 270818

Area Forecast Discussion
National Weather Service Buffalo NY
418 AM EDT Fri Apr 27 2018

High pressure across our region will shift east today, maintaining
fair dry weather through most of the day. A pair of weak low
pressure systems will bring opportunities for rain showers tonight
and Saturday, before a shot of colder air leads to chances for some
rain and wet snow showers Saturday night and Sunday. The return to
colder conditions will be short-lived however, as much warmer
weather returns for next week.


The surface ridge currently across the region will slide eastward
and off the Atlantic coastline today. We will continue to see dry
weather prevail for much of the day today, as we will remain in
between a compact, but potent upper shortwave and associated
surface low lifting northeast from the Mid-Atlantic states into
New England and an approaching upper trough/cold front from the
upper Great Lakes. A stray shower or two is possible along our
southeastern periphery during the mid to late afternoon as some
very weak instability develops along the western fringes of the
east coast wave, and then some additional scattered showers
becoming possible across the Southern Tier late in the day,
again with the development of some very weak instability and the
approach of the upper level trough and cold front. There should
be enough sunshine, especially early in the day to get
temperatures into the 60s away from any lake influences, with
areas immediately east and northeast of the lakes running a bit

Better forcing eventually arrives tonight with the incoming upper
level trough and cold front, bringing some scattered showers. A
stronger PV anomaly currently digging into northern Minnesota
will likely bring the best potential for rain late tonight,
especially to western portions of the area.


A closed upper level low will be the main driver for the upcoming
cold snap this weekend. As an upper level ridge amplifies across the
Rockies, the upper level low will deepen and dig into the Ohio
Valley Saturday. At the surface, low pressure will be across New
England with a cold front stretching southward into the Carolinas
while high pressure moves into the Northern Plains. Cold air
advection will increase Saturday with 850mb temperatures falling to -
3 to -5 deg C.

Multiple rounds of rain and snow showers will pass through the
eastern Great Lakes this weekend as the upper level low spins
overhead. A cold front will pass through the region Saturday and
light rain showers are expected. Cold, northwest flow will begin to
produce lake enhancement southeast of the lakes Saturday night as
temperatures drop into the low to mid 30s with higher elevations
dropping to the U20s/L30s. The upper level trough axis will also
move across the eastern Great Lakes Saturday night and rain or
showers will be possible across the forecast area. The combination
of wrap around moisture, lake enhancement and instability from
the upper level low will bring the chance of rain or snow
showers across Western NY Sunday - Sunday night. Light snowfall
accumulation is possible across the higher terrain Saturday
night and Sunday night when temperatures are the coldest. Best
chance will be across the Southern Tier/Boston Hills and Tug
Hill Plateau region.

The upper level ridge will move eastward across the Great Lakes
Monday. Northwest flow will continue however warm air advection will
increase aloft. Subsidence will build into the region from west to
east and dry conditions are expected into Monday night. High
temperatures will rebound into the U50s/L60s.


The closed upper-level low will slowly open up and exit the region
off into the Canadian Maritimes Monday. In its place, building 500mb
heights and surface ridging along the Carolinas will begin a rapid
warming trend with dry conditions for the Lower Great Lakes that
will last through Midweek. However, before that can happen look
for one last chilly start with temperatures in the 20s and low
30s early Monday morning. Temperatures will then begin to
rebound with highs climbing into the L60s with U50s across
higher terrain for Monday. Additional warming will occur through
midweek with highs climbing +15-20F degrees above climo with
mid-upper 70s, even a few 80F readings by Wednesday. Wednesday
night, a frontal boundary will approach Western New York from
the west bringing increasing chances for showers for our region.
This frontal boundary will then serve as a guide for several
waves to ride northeast into and across our region with
additional chances for precipitation through the end of the


The surface ridge across the region will slide to the east today and
and off the Atlantic coastline, however mainly dry weather and VFR
conditions should still prevail through the bulk of the day, as
we will be in between one shortwave lifting northeastward from
the Mid-Atlantic region into eastern New York/New England, and
a second and larger upper level trough and associated cold
front pushing eastward across the upper Great Lakes. Any
diurnally driven scattered showers will be limited to interior
portions of the Finger Lakes and North Country from about mid
afternoon onward, and across the Southern Tier late in the day.

Tonight and Saturday...Mainly VFR with scattered to occasionally
more numerous rain showers.
Saturday night and Sunday...VFR/MVFR with a chance of rain and
snow showers.
Monday and Tuesday...VFR.


High pressure will be across the lower Great Lakes through today.
Light winds and minimal wave action is expected through tonight.

Low pressure will track across the northwestern periphery of the
lakes tonight through Saturday night. This will freshen west-
southwest winds Saturday and Saturday night. Winds/waves may
increase enough to bring marginal small craft conditions by
Saturday afternoon and Saturday night.

Winds will veer to west-northwesterly by Sunday and Monday with
marginal small craft conditions continuing, especially along
Lake Ontario.





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