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000
FXUS61 KBUF 220822
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
422 AM EDT Mon Apr 22 2024

.SYNOPSIS...
High pressure nosing northeast from the Ohio valley will supply us
with a nice start to the work week...guaranteeing ample sunshine
with the mercury rebounding some 5 to degrees higher than those from
Sunday. The fair dry weather will last through at least the first
half of Tuesday...then a slow moving cold front will produce a
general soaking...quarter to a half inch of rain Tuesday night into
Wednesday morning. Dry weather will return for Thursday and Friday.

&&

.NEAR TERM /THROUGH TUESDAY/...
A weak cold front slipped through the region overnight...and while
it produced very little actual weather...there will be just enough
cold air in its wake to keep todays temperatures below normal.
Despite a wealth of sunshine courtesy of high pressure over the Ohio
valley...the mercury today will only climb into the low to mid 50s
across the western counties...and into the upper 40s to near 50
across the North country. These values will average about 5 degrees
below normal values.

Fair dry weather will remain in place tonight...as a flat mid level
ridge will cross the region while its corresponding sfc high will
drift off the coast.

Conditions will gradually deteriorate on Tuesday though..as GOMEX
moisture taking a circuitous route out of the southern plains and
Ohio valley will stream into our area ahead of a developing storm
system over the Upper Great Lakes. While much of Tuesday will be
rainfree...clouds will thicken during the course of the midday with
showers developing from west to east by the end of the day. The
inconsequential showers will develop in the vcnty of a pre frontal
sfc trough while more widespread steady rain will hold off until
after sunset. The silver lining in this scenario though will be that
a deepening southerly flow will support warmer weather...as the
mercury is expected to reach into the low to mid 60s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A positively-tilted mid-level trough will slide from the central
Great Lakes to New York State Tuesday night...then on to New England
during Wednesday. In the process...this system will push its
attendant and rather elongated/wavy surface low across our area
later Tuesday night...with this system then quickly departing off
the New England coastline Wednesday.

On the front flank of this system...lead shortwave energy entering
our region from the Ohio Valley will act in concert with a modest
low level jet and leading prefrontal trough to bring increasingly
widespread showers into our region from southwest to northeast
Tuesday evening. The showers will then evolve into a 3-6 hour period
of steadier moderate rainfall during the late evening and early
overnight hours as the wavy cold front approaches and a coupled
upper level jet structure develops aloft...with these two features
helping to more strongly lift the plume of GOMEX-based moisture that
will be in place across our region.

Very late Tuesday night and Wednesday morning the main cold front
will then slice through our region from northwest to southeast...
bringing some additional showers and perhaps even a few embedded
thunderstorms given the presence of some weak instability during
this time frame. Following the cold frontal passage...much colder
and progressively drier air will then flood across our region during
Wednesday as Canadian high pressure begins to rapidly build in
behind the departing frontal boundary. While some discrepancies
persist with respect to exactly how cold our airmass will get...the
expected degree of cold advection should be enough (when coupled
with plentiful cloud cover and lingering pcpn) to support a non-
diurnal temperature trend Wednesday morning. This should result in
widespread readings ranging through the 40s at the start of the day
falling back to the mid to upper 30s in most areas...save for
perhaps interior portions of the Finger Lakes and areas near the
NY/PA border. As we push through the afternoon...further drying and
the re-introduction of at least some partial sunshine will then help
to slow or temporarily reverse this trend...with this particularly
true across our northwestern periphery where temps may actually
recover into the lower to mid 40s for a time.

Given the expected trends in temperature profiles during Wednesday
there will be at least some potential for rain showers to mix with
and/or changeover to wet snow before ending. That stated...this
changeover looks to get off to a slower start than previously
thought...and will also be in a race against the pcpn tapering off
rather quickly from northwest to southeast as the surface high and
much drier air/subsidence rapidly build in behind the departing cold
front. With this in mind expect the potential window for wet snow to
be limited and fairly narrow...with this and the high late April sun
angle helping to largely confine any spotty minor accumulations to
our higher terrain.

Wednesday night the core of the Canadian surface high will settle
directly across New York State...with largely clear skies...light
winds...and the chilly airmass allowing temps to tumble into the mid
to upper 20s areawide...and possibly even to the lower 20s across
interior sections of the Southern Tier and North Country.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
On Thursday the strong surface high will remain draped across our
region...then will slowly drift east across New England on Friday as
upper level ridging builds in aloft. This will result in two days of
fair dry weather to close out the work week...along with a day-to-
day warming trend owing first to some modest diurnal airmass
modification on Thursday...and then a developing south-southeasterly
return flow of milder air on the backside of the departing surface
ridge on Friday. This will allow highs to climb back to the upper
40s to mid 50s Thursday...and then into the lower to mid 60s
Friday...when a SSE downslope flow may even help to push readings
along the Lake Erie shoreline into the upper 60s from roughly
Dunkirk southwestward.

As we move into the weekend...an initial weakening cutter-type
system will lift northeastward across the Upper Great Lakes Saturday
before sliding across Quebec on Sunday...with a second such system
then developing across the Mississippi Valley during Sunday. The
initial low will help to push its attendant surface warm front
across our region during Saturday/Saturday night along with at least
some scattered showers...with these perhaps becoming a bit more
numerous and featuring some embedded thunder for a time across far
western New York. The weakening system will then keep a general
chance of showers in place as it slides by to our north on
Sunday...though both its weaker nature and the nose of building
ridging aloft should result in a somewhat lowered potential for
these from the day before. Otherwise the trend toward warmer
temperatures should continue as progressively warmer air continues
to overspread our region aloft...with fairly widespread highs in the
mid to upper 60s Saturday likely to be followed by readings
peaking in the upper 60s to lower 70s on Sunday.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR conditions will be in place through the TAF period.

Outlook...

Tuesday...Mainly VFR. A chance of showers later in the afternoon.
Tuesday night into Wednesday...MVFR to IFR cigs with rain.
Thursday and Friday...VFR.

&&

.MARINE...
High pressure nosing across the Lower Great Lakes from the Ohio
valley will support generally light winds and negligible waves
through early tonight. During the course of the overnight...
southerly winds will freshen somewhat...as the aforementioned sfc
high moves off the East coast.

Fresh southerlies Tuesday morning will become southwesterly in the
afternoon. While will lead to choppy conditions on portions of Lake
Erie and western Lake Ontario...the highest wave action will be in
Canadian waters. This should minimize the potential for any small
craft advisories.

A slow moving frontal boundary will cross the Lower Great Lakes
Tuesday night. Moderate to fresh southwesterlies are expected with
waves remaining below small craft advisory criteria.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH