217
FXUS61 KBUF 121821
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
221 PM EDT Tue May 12 2026

.WHAT HAS CHANGED...
Minor changes to the forecast with this update.

&&

.KEY MESSAGES...
1) Return to wet and cool conditions for the middle to late portion
of the week.

2) A notable warming trend later this week will push temperatures
well above average into next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Return to wet and cool conditions for the middle to
late portion of the week.

A sfc low and potent shortwave trough over the Upper Great Lakes
today will slowly track southeast to SE Ontario by Wednesday
morning. The warm front associated with the system will start to
push rain showers into the region this evening and into tonight.
Strong forcing from the front and increased moisture will bring the
potential for moderate to heavy showers at times tonight, especially
near and east of Lake Ontario, closer to the triple point for the
system. Showers will expand east through the first half of the night
as the warm front crosses the area. Showers will linger across the
entire area for the rest of the night.

Wednesday, the sfc low will start to become vertically stacked with
its mid and upper level lows through the day on Wednesday,
developing an occluded front in the process. With the warm front
generally found from west to east across Lake Ontario, the most
persistent showers will continue over and east of Lake Ontario.
Showers south of Lake Ontario will scatter out during the morning to
some extent, but a pre-frontal trough, followed by the systems cold
front will track across the area from mid morning through the
afternoon hours. A few thunderstorms will also be possible during
the day on Wednesday, but instability ahead of the trough and
frontal passage will be limited. Showers along the trough and cold
front will have the potential to become heavy at times. Showers will
taper off from west to east during the late afternoon into the
evening on Wednesday. Guidance stalls the passing cold front just
east of the BUF forecast area, so showers for the Eastern Lake
Ontario area will linger the longest, into Thursday morning.

For Thursday, depending on where the cold front stalls, the chance
for showers will continue through the day east of Lake Ontario.
South of Lake Ontario, less organized showers will be possible for
most of the day as the mid/upper level low remains over the area and
as daytime heating increases instability with a cool airmass aloft.
Favorable upsloping areas will also have increased potential for
showers. Showers will taper off Thursday night, but a few showers
can`t be ruled out for Friday east of Lake Ontario.

Temperatures behind the passing cold front will cool once again for
later Wednesday through Thursday night. Afternoon highs will
approach 15 degrees below normal for Thursday, with values only
reaching the upper 40s to mid 50s. Areas to the east will be
slightly warmer, depending on where the cold front stalls.
Temperatures will start to warm on Friday, with continued warming
into the weekend, more on that below.

KEY MESSAGE 2...A notable warming trend later this week will push
temperatures well above average into next week.

The closed low aloft across the Northeast will eventually get pushed
out to sea by a flattening upper level ridge late this week. In its
wake, broad sfc-700mb ridging will expand across the Southeast which
will support a Bermuda High type pattern into next week. Resultant
deep S/SW flow across the East will advect a considerably warmer
airmass into the Great Lakes with 850mb temps near 0C Thursday
increasing to the teens by Saturday. This will translate to
seasonable to slightly cool surface temps Friday, then hedging
several degrees above average over the weekend with highs in the 70s
for most areas.

Moving into next week, a powerful southwesterly LLJ ahead of an
approaching cold front will cause the warmth to surge with models
largely suggesting 850mb temps peaking the upper teens across the
Great Lakes between Monday and Tuesday. If verified this would
likely cause afternoon surface temps into the 80s for most areas, at
least those south of Lake Ontario. Confidence is low in whether or
not this warmth will last into Tuesday due to uncertainty in the
timing of the cold front, as evidenced by very large NBM high temp
75th-25th percentile spread Tuesday of 15-20F.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR conditions are present this afternoon under mostly clear skies
as high pressure slides eastward to the New England coast. An
occluded frontal system will approach from the west tonight, leading
to the development of rain showers across WNY, and eventually MVFR
conditions as rain becomes steadier overnight and into tomorrow
morning. There is some potential for IFR across the southern tier
tomorrow morning during the peak of the rain for a few hours, but
will hold off on indicating this in the TAF for now. Elsewhere
ceilings should bottom out around 1200-1800 ft, and begin to
slightly lift/scatter by early tomorrow afternoon, but remain MVFR.

A 40-50 knot low level jet will cross the eastern Great Lakes early
tomorrow morning, which has the potential to result in low level
wind shear across Western NY, and then surface gusts 20-30 kts later
tomorrow.

Outlook...

Thursday through Thursday night...Areas of MVFR with showers likely
at times.

Friday...A chance of showers, mainly east of Lake Ontario. Areas of
MVFR CIGS early, improving to VFR.

Saturday and Sunday...Mainly VFR. Slight chance of showers.

&&

.MARINE...
Low pressure will move into the central Great Lakes tonight,
reaching the lower Great Lakes by tomorrow morning. Southeast winds
will ramp up ahead of this system later tonight through tomorrow,
likely bringing a period of Small Craft Advisory conditions to the
east end of Lake Ontario. Winds will become more southwesterly with
time later tomorrow, with a moderate chop on Lake Erie and Lake
Ontario. Lighter winds will return Thursday and Friday with a
weakening pressure gradient across the lower Great Lakes.

&&

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

&&

$$

DISCUSSION...PP/SW
AVIATION...SGK
MARINE...SGK