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665
FXUS61 KBUF 172219
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
619 PM EDT Fri May 17 2024

.SYNOPSIS...
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A trough of low pressure will slowly cross the area through tonight,
bringing a soaking rainfall to much of the region along with the
chance for a few thunderstorms. A few showers may linger into
Saturday before high pressure then builds across the area Sunday
bringing a dry finish to the weekend. Above normal temperatures will
continue for the end of the work week into this weekend.
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&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Currently an area of showers is tracking east across the region,
with steady showers filling in just east of Rochester. The back edge
of the showers is moving east toward far WNY and the eastern portion
of Lake Erie. Additional, but more scattered showers over NE OH & NW
PA will move into SW NY behind the steadier showers.

The area of showers and thunderstorms will move into the Finger
Lakes region and central NY this evening. A strong surface ridge
along the east coast will halt forward progression and lead to
weakening of showers and any storms tonight. Low-level moisture will
remain pooled across the region overnight and patchy fog is likely
across western NY. If clouds decide to clear overnight, fog could
become more widespread and dense in some locations. Mild tonight
with lows in the upper 50s to low 60s.

Little change in MSLP Saturday. Surface high pressure remains along
the east coast with variable winds across the forecast area. Ridging
will build into the forecast area as the shortwave trough moves into
the Capitol Region Saturday. Daytime heating and low level moisture
will likely lead to diurnal showers and an isolated thunderstorm,
mainly across interior western NY or along a lake breeze boundary.
Highs will reach the low to mid 70s. Saturday night will begin a
period of dry and warm weather across western and north central NY.
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&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Little change in MSLP Saturday. Surface high pressure remains along
the east coast with variable winds across the forecast area. Ridging
will build into the forecast area as the shortwave trough moves into
the Capitol Region Saturday. Daytime heating and low level moisture
will likely lead to diurnal showers and an isolated thunderstorm,
mainly across interior western NY or along a lake breeze boundary.
Highs will reach the low to mid 70s.

Saturday night will begin a period of dry and warm weather
across western and north central NY.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
A high amplitude upper level ridge will be entrenched along the
spine of the Appalachians and into New England to start the period.
With the ridge axis centered along the eastern side of the CWA, the
surface high pressure center itself will slowly wander from being
centered over the western end of Lake Erie on Monday toward the east
coast on Tuesday. As a result of the gradual progression, weak
southerly (or even southeasterly) flow on Monday afternoon will to a
stronger southwesterly flow on Tuesday and Wednesday. With the
eastward slumping of the surface ridge and increasing momentum off
the deck from Monday through Wednesday, surface to 850 hPa mixing
should increase and allow for strong afternoon run ups in
temperatures with interior sections from the Genesee Valley eastward
easily jumping into the mid 80s while even most of the lakeshores
approach 80F during this interlude as select guidance has 850 hPa
temperatures running up to +16 to +18C. The only places in the CWA
that may reach their thermal apex on Monday rather than Tuesday or
Wednesday seem to be the Niagara Frontier and the Watertown areas,
where the south/southeasterly flow would keep any lake-influenced
air out of the picture. With stronger southwesterly flow on Tuesday
and Wednesday, these areas may hold back a few degrees relative to
their more interior peer locations.

While all will seem bright and sultry early next week, don`t dare be
fooled that summer is here as things go way off the tracks shortly
thereafter. A massive pattern shift looks to be in store for the
second half of next week. The semi-resident ridge will slide off the
east coast with an upstream closed 500 hPa low ever-so-slowly
ejecting from the Rockies toward the upper Great Lakes. Several
successive short-wave troughs with associated reinforcing shots of
cooler air will push through the region beyond Wednesday as a
result. This will lead to steadily increasing chances of showers
with temperatures falling back substantially from where we will have
been by that juncture. In fact, while the forecast features a
consensus of wildly disparate guidance numbers by the end of next
week and the upcoming Memorial Day holiday weekend, there are
several fairly reliable pieces of guidance in the mix that would
suggest some drastically colder conditions will be in the mix by
that time. Evidence of this can be gleaned from the +4C at 850 hPa
on the ECMWF and +3C on the Canadian global by Sunday, as well as
the -3C on the GFS Friday morning. While each of these numbers by
themselves doesn`t mean a whole lot, when we approach the Friday
through Sunday period as a whole, it would certainly tend to lean
toward the belief that a portion of it is likely to be significantly
colder than we have been accustomed to.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
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Weather conditions will be impactful for aviation across western NY
through Saturday morning. A surface ridge will maintain VFR and
mostly dry conditions east of Lake Ontario including KART during
this period.

A moist airmass will result in heavy downpours and result in
MVFR/IFR conditions across western NY this evening. At this time,
confidence is low to add TS into any TAF but will amend if needed.
Flight conditions will likely fluctuate through this evening as
showers continue and moisture begins to pool at the surface.
Overall, flight conditions will become IFR/LIFR overnight across
western NY. Fog is a concern especially for locations where clouds
clear out overnight. As previously stated, VFR conditions will
persist east of Lake Ontario including KART overnight.

Flight conditions will slowly improve Saturday morning and IFR
conditions may persist until late morning. Showers will develop away
from the lakeshores but also along lake breeze boundaries. This may
impact the TAF sites across western NY. Mostly dry and VFR
conditions will continue at KART.

Outlook...

Sunday through Tuesday...Mainly VFR. An isolated shower Tuesday on
Lake Erie lake breeze.

Wednesday...MVFR/IFR possible. There is a low to medium chance of
showers and thunderstorms.
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&&

.MARINE...
A weak pressure gradient will continue the generally light winds
through this weekend into the start of next week. A light offshore
southeasterly flow will increase some today as a weak trough of low
pressure slowly crosses the Lake. Following the passage of the weak
system, winds will remain light through Tuesday. The next system
will be a stronger cold front that will cross the Lake toward mid
week bringing the next notable increase in winds and waves.

&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...HSK/SW
SHORT TERM...HSK
LONG TERM...Fries
AVIATION...HSK
MARINE...JM