759
FXUS61 KBUF 161817
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
217 PM EDT Mon Jun 16 2025

.SYNOPSIS...
Canadian high pressure will maintain quiet weather through tonight.
A series of low pressure systems will lift a stalled boundary to our
south back northwards as a warm front Tuesday, opening the door to
warmer air and unsettled weather through midweek. On and off chances
for showers and thunderstorms through the weekend before more
substantial heat and humidity builds early next week.

&&

.NEAR TERM /THROUGH TUESDAY/...
Two distinct areas of sfc high pressure, one retreating into the
northwestern Atlantic and another quickly shifting east across
Quebec, will continue to suppress more active weather across our
region through tonight. A weak inverted trough lingering over the
region between these features and a stalled frontal boundary over the
Ohio Valley will lead to a wealth of stratus and patchy strato-cu
through the rest of the day with a few scattered showers at
times. Low to moderate confidence in overall coverage though
best chances for any measurable precip will lie across the
Niagara Frontier and Lewis/eastern Jefferson counties. Temps
will top out in the mid/upper 70s for most areas, cooler across
the interior Southern Tier.

A shortwave trough rippling across the stalled boundary will cause
it to lift further northward as a warm front tonight. After some
partial clearing, this will likely cause the thicker cloud cover to
fill back in. A few showers may creep over the NY/PA border or up
through the Finger Lakes overnight.

The warm front will further encroach on the region Tuesday as high
pressure further loosens its stabilizing influence. This will bump
daytime temps up a few degrees though main impact will be expanding
chances for showers expanding across the region. Greatest chance for
a few scattered thunderstorms will be across WNY in the afternoon,
with minimal instability east of the Finger Lakes.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
A shortwave trough responsible for pushing the stalled boundary
northward and producing showers and thunderstorms Tuesday, will
slide east of the area. The exiting shortwave trough combined with
the loss of diurnal instability will support shower and thunderstorm
coverage to begin to diminish Tuesday evening, however a secondary
shortwave trough passing across northern Ontario/Quebec will edge a
weakening cool front into our area from the northwest resulting in
the possibility in a few showers throughout the night. Additionally,
a few rumbles of thunder may be possible, though the instability
will be on the tamer side.

The phasing of the aforementioned shortwaves will support a deeper
longwave trough to carve out across the Great Lakes and result in a
strengthening surface wave of low pressure. As this feature lifts
northeast from the Upper Midwest to Quebec, a pair of fronts will
slide across the area Wednesday through Thursday. Initially a warm
front will lift north across the area Wednesday afternoon,
supporting a warm humid airmass to advect across the area. The
combination of strong diurnal heating and ample moisture will
produce scattered showers and storms. Then, a strong southwesterly
low level jet will move into the area, along with a prefrontal
trough and eventual cold front late Wednesday night into Thursday
morning, renewing the potential for showers and thunderstorms. The
combination of PWAT values around 1.75 inches (amounts well over 90%
of the daily mean) and a wind direction parallel to the front, would
support heavy rainfall, as supported by WPC`s Day 4 marginal risk
for excessive rainfall. In regards for severe thunderstorms, the
better low level lapse rates, and shear will lie across the northern
Finer Lakes eastward, and therefore a few stronger storms can`t be
ruled out.

While convection will gradually diminish Thursday night a few
showers may linger across the area through Friday as the longwave
trough axis crosses the area. Additionally, cooler air will advect
across the area in the wake of the trough axis Friday/Friday night.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
The next stout upper level ridge will slide across the Gulf States
Saturday before amplifying northeastward Sunday and into the start
of the next work week. This upper level feature will bring steady
increasing heat and humidity into the region for the weekend and
into the start of new work week. However, an ill-timed shortwave
ridge-runner will support the possibility for a few rounds of
showers and thunderstorms Saturday through Sunday before surface
high pressure then dominates overhead for Monday. As alluded to
previously, the combination of 500 mb heights building to near 600dm
over the Ohio Valley and lower Great Lakes would support very hot
and humid conditions with heat index values climbing well into the
90s by Monday.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
An inverted trough extending across the eastern Great Lakes region
with lingering low-level moisture will maintain stratocu with low
VFR to MVFR cigs. A few showers are possible across the Niagara
Frontier through about 23z.

Partial clearing expected through the first half of tonight outside
of the Southern Tier. After about 06z, lower cigs will begin to
expand back northward as a warm front moves towards the region from
the Ohio Valley. Variable cigs between low VFR (Niagara Frontier)
and LIFR (Southern Tier) expected by 12z. A few showers could move
over the NY/PA border and into the Southern Tier overnight.

Tuesday, the warm front will move further into the region. Cigs will
likely be mainly MVFR through the morning north of the Southern
Tier, which may hold onto IFR into the early afternoon. Showers and
thunderstorms are expected to develop in the afternoon, mainly
across WNY though coverage will be greatest in the Southern Tier.
More notable improvement to VFR expected from KIAG to KROC after 18z.

Outlook...

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

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

Saturday...Mainly VFR. Increasing chances for showers and
thunderstorms.

&&

.MARINE...
Minimal wave action and light to modest winds on the lakes through
tonight as Canadian high pressure shifts into the northwestern
Atlantic.

A more potent low pressure system will track from the Upper Great
Lakes tonight 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...PP
NEAR TERM...PP
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...PP
MARINE...PP