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000
FXUS61 KBUF 240551
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
151 AM EDT Wed Apr 24 2024

.SYNOPSIS...
A cold front will push away to our southeast on Wednesday...but for
many areas...leftover clouds and showers will linger into the early
afternoon. An expansive area of Canadian high pressure will then
assure us of fair dry weather Thursday and Friday. While some
showers will be likely this weekend...the majority of the time will
be rainfree. Looking further down the road...we can look forward to
a summer-like warm up Sunday and Monday with the mercury surging
well into the 70s and even a few spots in the 80s.

&&

.NEAR TERM /THROUGH THURSDAY/...
A sharp mid level trough will advance east across the Great Lakes
overnight, providing a period of large scale ascent as DPVA and
height falls overspread the region. A weak wave of low pressure will
move northeast over the eastern Great Lakes overnight, with
associated low level flow adjustments aiding in low/mid level
convergence and deformation across the area, supporting several
hours of widespread rainfall.

Radar imagery showing fairly widespread light rain across most of
the region late this evening. Rainfall intensity is quite light
across most of the region, with lingering low level dry air still
allowing plenty of sub-cloud evaporation. The most widespread rain
will fall across Western NY through the first half of the night,
followed by a brief break in organized rain late tonight. East of
Lake Ontario, the most widespread rain will fall from late evening
through the overnight.

Wavy cold front moves into northern portions of the area early
Wednesday morning, then will push southeast across the remainder of
the area through the morning hours. The cold front will bring
another round of showers to the region Wednesday morning, aided by
weak lake induced instability and increasing northerly upslope flow.

Decent CAA in the wake of the front will cause temperatures to fall
from the 40s into the 30s for most areas. Enough moisture will
linger briefly in the colder air that precipitation may end as a few
wet snowflakes across higher terrain (especially east of Lake
Ontario) before rapidly tapering off from north to south from late
morning through mid afternoon. May be able to squeeze out a slushy
coating across the Tug Hill Plateau and western foothills of the
Adirondacks around late morning just before the precipitation ends.

Skies should then rapidly clear from north to south through the
afternoon as much drier air builds in, with sunshine likely
returning, especially across northern portions of the area. It will
be a very chilly day with many area remaining in the 30s to low 40s
after peaking in the low to mid 40s to start the day.

A large Canadian sfc high over the Upper Great Lakes Wednesday
evening will gradually expand across the whole Great Lakes region
overnight and Thursday. This will guarantee fair dry weather
throughout the region...although temperatures will be solidly BELOW
normal. Mins tonight will be in the 20s away from the immediate lake
shores with highs on Thursday only ranging from the Upper 40s to
lower 50s. These readings will average some 10 degrees below typical
late April levels.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
High pressure centered over New England Thursday night will push
off the coast on Friday. This will support fair dry weather
through the first half of Friday night.

A surface warm front will advance northeastward towards the
Lower Great Lakes late Friday night/early Saturday morning. This
feature should generate some scattered rain showers over the far
western counties late Friday night while dry weather should
persist east of Rochester.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The main story for the weekend and early next week will be the
strong warmup, as well as on and off chances for showers and
thunderstorms.

On Saturday, a sfc-700mb ridge of high pressure will be well east of
the region over New England, while the upper level ridge lags behind
to the west. This will allow a warm front associated with a low over
the upper Midwest to move out of the Ohio Valley and across the
forecast area through the day. Isentropic lift on this wing of warm
advection will bring a swath of rain showers to the region west to
east. Shower coverage will be highest across WNY in the morning,
before this batch of precip then slowly falls apart as it traverses
eastward, becoming further detached from its parent low and running
up against the strong ridge over New England. Temps should be
similar to those seen on Friday, generally ranging from the upper
50s to the low/mid 60s.

The more pronounced warming trend will come starting Saturday night
as the broad low to the west weakens and slides across the upper
Great Lakes to Canada. This will cause the overhead upper level
ridge to flatten and perhaps allow a few additional showers/tstorms
to cross into the region overnight. Thereafter, the synoptic pattern
will eventually evolve into something resembling an Omega block,
with a stubborn ridge of high pressure across the eastern CONUS
flanked by waves of low pressure on the lee side of the Rocky
Mountains and a closed low across the northwestern Atlantic. Strong
anticyclonic flow around the sfc high off the East Coast will begin
to circulate much warmer air across much of the eastern CONUS
including the Great Lakes through the remainder of the weekend and
into early next week. At this range...it appears low temps Saturday
night should range in the 50s, closer to normal daytime highs for
late April. Thereafter Sunday and especially Monday will be the
warmest days we have seen in quite a while with temps climbing well
into the 70s in many areas, possibly even low 80s across the typical
warmer spots across the interior Genesee Valley. A cold front should
then bring temps back down a few degrees Tuesday, though still
remaining warm the 60s and low 70s.

While this synoptic pattern lends high confidence in temperatures
averaging well above climatological norms, confidence in chances for
additional showers and thunderstorms after Saturday remains low. The
main uncertainty stems from how the closed low over the Atlantic
evolves, as well as the strength/timing of the additional waves of
low pressure to the west cresting over the ridge. In general expect
shower and thunderstorm chances to roughly follow the diurnal
heating trend, being greatest in the afternoon and early evening
hours each day, with plenty of dry time mixed in. More widespread
showers should arrive with the front on Tuesday though PoPs are
mainly in Chc range as uncertainty in the timing of the front
remains low.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A wave of low pressure will move across the Lower great Lakes
through daybreak, producing periods of rain. Cigs will deteriorate
to MVFR to IFR levels in the process.

Fairly widespread IFR cigs will be in place along with leftover rain
or wet snow showers Wednesday morning. The cigs will clear from the
north during the midday and afternoon...leaving VFR weather for the
latter portion of the day.

Winds during the day Wednesday will become northerly in the wake of
the aforementioned front...occasionally gusting to 30 knots at
times.

Outlook...

Wednesday night through Friday...VFR.
Saturday...VFR/MVFR. A chance of showers.
Sunday...Mainly VFR. A chance of showers.

&&

.MARINE...
A wavy cold front will slowly pass through the region overnight
through early Wednesday morning. While winds and waves will briefly
subside in the process (especially on Lake Ontario), a notable but
short-lived increase in northerly winds can be expected on
Wednesday. While the fetch will not be overly favorable for
significant wave increases, a brief period of moderate northerlies
will still generate Small Craft Advisory conditions on Lake Ontario,
and very choppy conditions on Lake Erie.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory from 7 AM this morning to 5 PM EDT this
         afternoon for LOZ042-045.
         Small Craft Advisory from 7 AM this morning to 8 PM EDT
         this evening for LOZ043-044.

&&

$$

SYNOPSIS...RSH
NEAR TERM...Hitchcock/JM
SHORT TERM...EAJ/RSH
LONG TERM...PP
AVIATION...RSH
MARINE...Hitchcock/JM/RSH