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417
FXUS61 KBUF 031916
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
316 PM EDT Fri May 3 2024

.SYNOPSIS...
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High pressure will settle over the New England coast this evening,
supporting mainly dry and warm conditions through late this
afternoon. Meanwhile, a weakening cold front will approach from the
west late this afternoon before stalling out and falling apart over
far western NY. This will bring an uptick in shower and isolated
thunderstorm activity to far western NY very late this afternoon
into tonight, with mainly dry weather continuing from the Finger
Lakes east. Shower chances steadily decrease later tonight into
Saturday with just scattered showers and dry time built in. A slow
moving cold front will then pass across the area Saturday night
through Sunday bringing the next round of more widespread showers
and possibly a few rumbles of thunder. High pressure then returns
Monday, allowing for a dry start to the new work week.
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&&

.NEAR TERM /THROUGH SATURDAY/...
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Surface high pressure will settle over the New England coast this
evening, all the while the upper level ridge axis remains in place
over eastern NY. This has and should continue to keep shower
activity over Ontario Province just to our west through the
afternoon. Warm this afternoon with temperatures in the 70s across
the vast majority of the region with a few low 80s possible across
far WNY and the traditional warmer spots of the Genesee Valley.
Local lake breeze circulations will be in place through late
afternoon/early evening making areas along and near the lakeshores
cooler, particularly the southcentral and southwestern Lake Ontario
shoreline and well along and just inland of Lake Erie.

With the aforementioned upper level ridge axis over eastern NY,
southwesterly flow will advect in deeper moisture late this
afternoon into this evening. A weakening occluded front will slowly
approach from the west, then stall and wash out across far western
NY through the first half of tonight. However, as what`s left of
this boundary interacts with the increasing moisture and instability
associated with daytime, some showers and a few thunderstorms will
be possible across far western NY late this afternoon into the
evening. The best focus will lie along the lake breeze boundary
inland from Lake Erie, south of the Buffalo Metro.

Occluded boundary will stall over far western NY before falling
apart during the overnight. This will lend to a decreasing threat
for showers through the overnight, with areas east of the Finger
Lakes possibly remaining dry through the night. It will be mild with
lows mainly in the 50s.

With very little forcing in place for Saturday, expecting just
scattered showers, especially during the morning hours with a good
deal of dry time built in through the day. Next stronger cold front
will approach from the west late Saturday, while next wave moves
north from the Ohio Valley. This will help to displace the upper
level ridge east over New England, thus opening the door for the
next surge of moisture and lift to move over the area with chances
for showers increasing from south to north late in the day into the
evening. Highs will be mainly in the 60s.
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&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
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The mid-level ridge axis over the forecast area through Saturday
afternoon will push east toward New England Saturday night. In its
wake, a shortwave trough will track northeast out of the OH/TN
Valleys toward WNY. As the trough approaches, shower coverage will
increase significantly from south to north through the later portion
of Saturday evening and overnight. An influx of moisture with the
trough will also help showers expand over the region. There still
remains some uncertainty with track of shortwave trough and moisture
over the forecast area with some models placing the higher rainfall
amounts over WNY and other guidance more to the east toward CNY.

An incoming cold front on Sunday morning will increase forcing over
the area, prolonging and expanding the potential for showers through
at least the afternoon hours. Still uncertainty with how quickly the
cold front tracks through the region among guidance as well with
some guidance prolonging the showers through most of the day and
into the evening on Sunday. Overall though the later portion of
Saturday evening through at least the early afternoon on Sunday
looks to be soggy for most of the forecast area. The more organized
showers on Sunday should be mainly across the eastern third of the
area by the late afternoon, with some lingering/scattered showers
across the rest of the area.

With the large scale trough just north of the region still, along
with lingering synoptic moisture, scattered showers will linger
through most of Sunday night. Drier air moving into the area along a
zonal flow will start to scatter out any remaining showers from west
to east through the late night.

Rainfall amounts of a quarter of an inch to half an inch is
expected, with some higher amounts possible as well. Current
thinking is the higher qpf amounts will be along the south shore of
Lake Ontario east to the north country. Still plenty of uncertainty
with higher qpf placement among guidance still.

A ridge building into the region will result in drier weather for
Monday through Monday night across the entire area. Clearing skies
on Monday will result in increasing sunshine from northwest to
southeast through the day. Clouds will linger the longest near the
NY/PA line as a disturbance tracks south of the area.

Temperatures on Sunday will be in the low 50s for the higher terrain
east of Lake Ontario to the mid and upper 60s for the lower
elevations south of Lake Ontario. For Monday, temperatures warm to
the mid 60s to mid 70s from the higher terrain to lower elevations
respectively.
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&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
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A sprawling mid and upper level low will start out this period over
the northern Rockies and Upper Plains states on Tuesday...then will
slowly drift eastward across the northern half of the CONUS through
the remainder of the work week. This being said...the medium range
guidance continues to exhibit considerable differences in the
strength and rate of eastward progression of this low...and
consequently also in the strength/timing of a number of shortwave
impulses ejecting eastward from this system and across our region.

With the above in mind...forecast confidence in associated
precipitation potential/timing  remains fairly low particularly from
about Wednesday onward...and as such have undercut blended guidance
a bit in an attempt to better reflect this uncertainty. In general
this system should bring more unsettled weather with frequent
opportunities for showers and perhaps a few thunderstorms during the
middle and latter portions of next week...though likely also with
some drier periods interspersed.

As for temperatures...these will continue to average some 5-10
degrees above normal through this period.
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&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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High pressure settling over the New England coast by this evening
will continue to support VFR flight conditions. Expect some
thickening and lowering mid level cloud decks across western NY
through late afternoon ahead of a weakening occluded front slowly
approaching from the west. Despite the increasing cloud cover, VFR
conditions will persist.

The weakening cold front will slowly move toward the area late this
afternoon, with some showers and a possible rumble of thunder across
far western NY late this afternoon into the evening with VFR
conditions remaining intact outside of any shower activity, where
brief MVFR VSBY may be possible.

Showers become likely across far western NY through the first half
of tonight, with just a chance of showers from the Finger Lakes
east. A few thunderstorms will also be possible, especially across
western NY. Shower chances then slowly decrease through the second
half of tonight. Otherwise, flight conditions will slowly
deteriorate with MVFR CIGS developing across the Southern Tier
(KJHW) by late evening, then advancing northward across the Niagara
Frontier (KBUF/KIAG) through the second half of the overnight, with
mainly VFR conditions expected from the Genesee Valley eastward.
Brief MVFR VSBY possible in showers.

Just some scattered light showers expected for the first half of
Saturday with MVFR CIGS continuing across the Southern Tier (KJHW).
KBUF/KIAG should improve to low VFR by late morning/midday, with VFR
flight conditions expected to continue from KROC east.


Outlook...

Saturday night and Sunday...VFR/MVFR with showers likely and
possible thunderstorms.

Monday...VFR.

Tuesday and Wednesday...VFR/MVFR. Chance of showers with a slight
chance of thunderstorms.
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&&

.MARINE...
Mainly weak pressure gradients are expected to persist into this
weekend across the lower Great Lakes supporting winds to generally
remain below 15 knots. Expect this to bring some choppy waters at
times, however conditions will remain below headline criteria,
especially with an offshore flow developing tonight then persisting
through the weekend, keeping the highest waves over Canadian waters
for Saturday and Sunday. While quiet weather continues for the end
of the work week, a few showers and thunderstorms will be possible
tonight through Sunday. High pressure will build across the area for
the start of the new work week providing mainly gentle breezes with
no more than some light chop expected through Tuesday.

&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...SW
LONG TERM...JJR
AVIATION...JM
MARINE...JM