863
FXUS61 KBUF 160840
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
440 AM EDT Mon Jun 16 2025

.SYNOPSIS...
Canadian high pressure will keep mostly dry and comfortable weather
in place today. A series of low pressure systems will lift a
stalled boundary to our south back northwards as a warm front
Tuesday, bringing warmer and increasingly unsettled conditions
through midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
A stalled frontal boundary will remain across the Ohio Valley and
Mid-Atlantic states. With the boundary and better moisture to
our south, mainly dry weather is expected today. There could be
a few stray showers that develop during peak heating, but
overall confidence in placement of these showers is low.
Seasonable temperatures in the mid to upper 70s.

A shortwave trough will move east across the Ohio Valley tonight
which will start to lift the boundary to our south northward as
a warm front. The first half of the night looks to be dry, but
some showers north of the boundary should start to work into the
Southern Tier after midnight.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
The next shortwave trough will move east across the Ohio Valley and
Lower Great Lakes on Tuesday, and as it does so will encourage the
frontal boundary that has been stalled out to our south for some
time now to finally start making its return back northward. Weak to
modest warm advection/isentropic upglide out ahead of this feature
will spread increasing moisture and lift across our area, which in
turn will result in a general southwest-northeast increase in shower
potential as we push through the day. This will particularly be the
case during the afternoon hours, when destabilization from diurnal
heating will come into play and could also lead to a few thunder-
storms, especially from the Finger Lakes westward. At this point
shower coverage continues to look to be on the scattered side across
northwestern areas, with somewhat better coverage possible across
interior sections. The highest coverage will likely lie across the
Southern Tier and interior Finger Lakes, which will lie closer to
the encroaching warm front, and thus where convection may be a bit
more numerous.

As we move into Tuesday night, the shortwave trough will slide off
to our east. Coupled with nocturnal stabilization, this will lead to
a general decrease in convective coverage Tuesday evening. That
said, with the aforementioned warm front temporarily stalling out on
our southwestern doorstep, and a second northern stream shortwave
trough over northern Ontario/Quebec trying to edge a weakening cool
front into our area from the northwest, a few more showers will
remain possible through the night. Can`t rule out a stray rumble of
thunder, but instability looks meager.

What will also be rather noticeable Tuesday and Tuesday night will
be the arrival of a notably more humid air across our region, with
surface dewpoints rising into the mid to upper 60s during the day
Tuesday, then remaining in this general vicinity Tuesday night. As
such, Tuesday will have a much more muggy and summer-like feel than
Monday in spite of similar high temperatures, with the more humid
airmass then keeping lows from falling much below the mid to upper
60s Tuesday night.

Pushing into the midweek period, a phasing shortwave pattern will
carve out a deeper longwave trough across the Great Lakes Wednesday
through Thursday, with a strengthening wave of surface low pressure
and piece of shortwave energy ahead of this main trough tracking
northeastward from the upper Midwest to Quebec. This will help to
finally lift the warm front through our area sometime between
Wednesday afternoon and the first half of Wednesday night, with a
downright sultry mid-summer airmass (surface dewpoints of near 70F
and 850 mb temps in the mid to upper teens) overspreading our area
in its wake. Strong diurnal heating combined with ample moisture
will produce scattered showers and storms, especially from midday
through early evening on Wednesday. Stout southwesterly low level
jet is then expected to move into the area sometime Wednesday night,
bringing renewed potential for more widespread showers and
thunderstorms, with additional convection likely on Thursday
attendant to the system`s trailing pre-frontal trough and cold
front. While the exact details and timing of all this remains murky
at this range, the general setup may be supportive of heavy rainfall
and more robust convection should all parameters come into favorable
alignment. Additionally, there may also be a scenario usually
reserved more for the cool season, where at least a brief period of
stronger winds may be possible in the cool advection behind the cold
front. The main area of low pressure will be deepening as it crosses
northwest of our area, and though is forecast to be above 990 mb,
the strong winds off the deck may be present in the CAA regime. Want
to stress, there is still a fair amount of disagreement amongst
various guidance packages, thus confidence in how this will all play
out remains low. As we get closer in time and into the hi-res/CAMs
time window, finer details should start to become more clear.
Needless to say, this is a time frame that will need to be closely
watched over the coming days.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
As we move into the long term portion of the forecast, convection
should tend to quickly wane in the wake of the cold front Thursday
night, though a few showers/isolated storms could linger into Friday
in association with the passage of the supporting upper level trough
axis. Otherwise it will briefly turn cooler with much more
comfortable humidity levels to end the work week, before burgeoning
upper level ridging amplifies across the southeastern states
northward into the upper Great Lakes this weekend. While this will
bring steadily increasing heat and humidity back into our region
through the weekend (especially for Sunday), along with ill-timed
convective shortwave ridge-runner type systems possibly bringing
bouts of showers and thunderstorms; confidence is growing heading
into next week (beyond Day 7) as medium range guidance
consensus is fairly well-aligned at this distance in time that
strong upper level high/ridge (500 mb heights approaching 600
decameters) builds right over the Ohio Valley and Lower Great
Lakes region for the first part of next week. Just from a
pattern recognition standpoint, if this comes to fruition,
expect a very hot and humid time period possibly reaching
dangerous levels. Stay tuned.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
A frontal boundary will remain across the lower Ohio Valley and
southern Mid-Atlantic region. Lower stratus will continue across the
southern Half of the area this morning with MVFR conditions and
local IFR across the interior Southern Tier. Some patchy fog
expected through about 13z, which may sneak into KJHW for a
time.

MVFR/low-end VFR conditions will continue across the region today.
Diurnal cu is likely in the afternoon and may result in a isolated
shower across the Niagara Frontier, after 18z.

Outlook...

Tonight...Mainly VFR. Chance of showers with lowering cigs across
the Southern Tier late.

Tuesday...Mainly VFR with a chance of showers and thunderstorms,
especially southern portions of the area.

Wednesday and Thursday...VFR/MVFR with showers and thunderstorms
likely.

Friday...Mainly VFR. A chance of showers and thunderstorms,
mainly east of KROC.

&&

.MARINE...
Canadian high pressure will shift across Quebec to the northwestern
Atlantic through Monday as several weak waves of low pressure ripple
along a stalled frontal boundary across the Ohio Valley. This will
result in light to modest northeasterly breezes across the lakes and
minimal wave action across the nearshore waters.

The high will move further out to sea as a more potent low pressure
system tracks from the Upper Great Lakes Monday night to southern
James Bay by Tuesday evening. This will cause winds to initially
shift southeasterly before turning south/southwesterly through
Wednesday, though SCA conditons are not expected. Choppier
conditions will likely form Thursday as a more potent system and
associated cold front move across the lakes.

&&

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

&&

$$

SYNOPSIS...HSK/PP/TMA
NEAR TERM...TMA
SHORT TERM...JM/JJR
LONG TERM...JM/JJR
AVIATION...HSK/PP/TMA
MARINE...PP