-- Discussion containing changed information from previous version are highlighted. --
584
FXUS61 KBUF 261435
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1035 AM EDT Wed Jun 26 2024

.SYNOPSIS...
Warm and mild again today with a better chance of showers and some
thunderstorms, especially in the Southern Tier in the afternoon.
Cooler and less humid conditions expected Thursday and Friday.
Active weather returns Saturday as a cold front crosses the region.
Dry weather return Sunday as high pressure builds in for the start
of the new work week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A weak cold frontal boundary will slow its forward progression
and stall out in the vicinity of the NY/PA line this afternoon.
This boundary is advertised to serve as the focal point for
convection by this afternoon. The coverage of thunderstorms and
northern extend for severe weather will greatly depend on the
position of this frontal boundary. That said...guidance continue
to suggest that a convectively enhanced wave will track along
this boundary this afternoon, along with a shortwave dropping
out of the central Great Lakes. These two feature could
potentially enhance the severe weather potential. Sufficient
shear looks to be present too, especially along the Southern
Tier, which lines up with the Marginal/Slight Risk for severe
storms issued by SPC in the Convective Outlook. Last but not
least...PW values jump up to 1.5 to 1.75 inches this afternoon
and any of the stronger cells could produce very heavy rainfall.


Overall...the greatest risk still remains across the Southern Tier
which lies closer to the track of the passing frontal wave. Outside
of the shower and thunderstorm chances, expect another day of temps
in the upper 70s to low 80s.

Tonight...showers and thunderstorm will decrease in coverage from
west to east. Northerly upslope flow and residual low-level moisture
behind the front will `likely` combine to keep much of the forecast
area blanked in a low stratus overnight. We even could see some fog
for areas that see precipitation. Outside of that...lows will be
found in the 50s to low 60s.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
A secondary cold front will finish sliding across our area
Thursday morning...with its weak nature and accompanying shallow
moisture field likely keeping this feature from generating much
more than some widely scattered showers in the process. The
best overall probabilities for these still look to be across the
North Country where some chance PoPs remain in place...while
slight chance to negligible PoPs have been indicated for areas
further south and west. In the wake of the secondary front...
another shortwave will dive across Southern Ontario and Saint
Lawrence Valley Thursday afternoon and evening...and this in
tandem with some weak diurnally- driven instability could lead
to a few more widely scattered showers across the North Country.
Otherwise generally dry and uneventful weather will prevail
during Thursday...with early morning low clouds giving way to
increasing amounts of sunshine as high pressure and cooler/drier
air builds in behind the secondary cold front. The incoming
cooler airmass will also lead to pleasant temperatures and
humidity levels...with highs mostly ranging from the upper 60s
across the higher terrain to the lower 70s elsewhere...and
surface dewpoints falling through the 50s.

Expansive Canadian high pressure will then build directly overhead
Thursday night...before drifting east into New England on Friday.
This will provide us with fair dry weather to close out the work
week. Excellent conditions for radiational cooling will allow
Thursday night`s lows to settle into the mid-upper 40s across the
interior Southern Tier/North Country and to the lower-mid 50s
elsewhere...with a developing southeasterly return flow on the
backside of the departing ridge then allowing highs to recover to
the mid 70s across the North Country and the upper 70s-lower 80s
elsewhere on Friday. At the same time humidity levels will remain
rather comfortable...as surface dewpoints will remain confined to
the upper 40s to mid 50s.

As we move through Friday night...a mid-level trough and associated
surface low will make its way across the northern Plains and Upper
Mississippi Valley. In the process...this system will push its
attendant warm front into western New York...with this boundary and
a lead shortwave impulse both helping to bring increasing chances
for showers and perhaps a few thunderstorms from west to east.
Otherwise an increasing southerly flow of warmer air will result in
a much warmer night than the one before...with lows ranging from the
lower to mid 60s across the North Country to around 70 along the
Lake Erie shoreline.

Saturday and Saturday night the mid level trough will make its way
across the Great Lakes and Ontario Province...with its attendant
surface low consolidating as it makes its way from Lake Superior to
central Quebec. As the low makes its way northeastward...it should
finish pushing its warm front across our area Saturday morning...
before swinging a pre-cold frontal trough into our area Saturday
afternoon/evening...followed by an initial trailing cold front later
Saturday night.

The deepening/strengthening southerly flow out ahead of this system
will send a plume of deep subtropical moisture across our region
during Saturday...with precipitable water values surging to around
or perhaps even a little over 2 inches. With daytime heating of this
subtropical airmass and the approach of the pre-frontal trough...
fairly widespread showers and scattered thunderstorms will develop
as we push through the course of Saturday...with these peaking in
coverage during the afternoon and early evening hours. Instability
currently only looks weak to modest which should help to greatly
limit any potential for strong to severe storms...however the
moisture-rich airmass will support the potential for torrential
downpours and locally heavy rainfall. Following the passage of the
pre-frontal trough...PWAT values then appear to drop off rather
sharply from west to east Saturday night...which should result in a
commensurate decrease in pcpn coverage and intensity out ahead of
the approaching cold front. Otherwise this period will be warm and
very humid...with highs in the upper 70s to mid 80s Saturday
followed by lows largely in the mid-upper 60s Saturday night.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
On Sunday the surface low will slide into the Canadian Maritimes...
with its initial cold front crossing our area during the morning...
followed by the passage of the main mid-level trough axis and an
associated weaker secondary boundary later Sunday/Sunday night. The
passage of these features will support the potential for some
additional scattered showers and (during Sunday) a couple more
isolated storms. Otherwise this period will be drier and more
comfortable than Saturday as drier and cooler air overspreads our
region...with surface dewpoints falling back into the 50s...and
daytime highs in the mid 70s to lower 80s Sunday giving way to lows
in the lower to mid 50s Sunday night.

After that...fair dry weather is expected for the remainder of the
period as large surface high pressure drifts from the western Great
Lakes to New England. Pleasant temperatures (upper 60s-lower 70s) on
the cool side of the ridge Monday will give way to warmer readings
in the upper 70s/lower 80s on Tuesday as a southerly return flow of
warmer air develops on its backside...though humidity levels should
remain comfortable.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Frontal boundary will stall across the region this afternoon, a wave
riding along this feature will then bring increasing chances for
showers and thunderstorms after 18z. Chances will be greatest in the
Southern Tier (KJHW) which may see periodic impacts at terminals
(MVFR to IFR). Confidence remains lower in shower and thunderstorm
coverage north of the S. Tier. Outside of the areas of
precipitation, VFR will prevail through the day.

Tonight...shower and storms will decrease in coverage but stratus and
fog may bring about MVFR-IFR Cigs and lower vsbys. This will
especially be the case across the higher terrain of the S. tier and
east of Lake Ontario.

Outlook...

Thursday and Friday...Mainly VFR.
Saturday...Localized restrictions with shower likely and a chance of
thunderstorms.
Sunday...Mainly VFR.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Light winds and wave action expected this afternoon, but there will
be increasing chances of showers and thunderstorms. Some storms
could produce strong winds and locally higher waves on Lake Erie.

A period of light, variable winds across the lakes will precede
increasing northwesterly winds behind a cold front tonight, though
winds and waves are expected to remain below SCA criteria.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...AR/TMA
NEAR TERM...AR/TMA
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...AR/TMA
MARINE...AR/TMA