977
FXUS61 KBUF 031058
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
658 AM EDT Thu Jul 3 2025

.SYNOPSIS...
A cold front moving through from the north will bring scattered
showers and thunderstorms to the region at times through this
afternoon. An area of high pressure will then bring dry and
comfortable weather tonight through Independence Day. Heat and
humidity will then build over the weekend, with more unsettled
weather early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Water vapor satellite imagery this morning indicates an upper level
closed low churning over western Quebec. This trough will gradually
sink further southward into the province through tonight, with its
cold front coming through in pieces to bring periods of scattered
showers and thunderstorms to the region. Confidence remains low in
overall convective evolution including coverage and timing of
storms, though the primary concern for stronger storms still looks
to be from about mid morning through early afternoon as SBCAPE
values build to 1000-1500J/kg and a cyclonically curved upper level
jet streak on the backside of the trough moves in from the west,
bringing effective shear values to 35-40kts. This could allow a few
storms to develop stronger outflow winds or large hail, particularly
in the corridor from the interior Southern Tier to the southern Tug
Hill region across the Finger Lakes. SPC has maintained a Marginal
Risk (level 1 of 5) in this region for the day, expanding it a
just bit further westward overnight. The main trough axis and
localized lake breeze convergence could also allow for a few
thunderstorms across the Niagara Frontier during this timeframe,
though deep shear values here look to be much lower with a
corresponding lower severe risk.

The the loss of daytime heating and passage of the primary cold
front, any scattered thunderstorms will come to an end by this
evening with quieter and cooler weather then expected to last
through tonight.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Expansive surface-based ridging will settle directly across our area
on Friday...and this coupled with rising heights aloft will result
in simply spectacular weather for the Independence Day holiday.
Attendant subsidence and drier air will result in plentiful
sunshine...with temperatures/humidity levels also rather comfortable
(850 mb temps of +9C to +13C supporting highs in the mid-upper
70s...and surface dewpoints only running in the lower-mid 50s). The
axis of the surface ridge will then only slowly drift southeastward
Friday night...allowing for continued fair/dry and comfortable
weather.

During the rest of this period the surface ridge will then drift
further southeastward and off the mid-Atlantic coastline...while the
axis of broad upper level ridging crests across our region aloft.
The increasing southwesterly flow on the backside of the departing
surface ridge will help to pump warmer and at least somewhat more
humid air back into our region...with highs on Saturday reaching
into the mid-upper 80s in many areas...along with surface dewpoints
climbing back into the lower half of the 60s. Coupled with daytime
heating and a developing lake breeze boundary...cannot completely
rule out an isolated shower/storm popping up southeast of Lake Erie
Saturday afternoon...though dry weather should otherwise continue to
prevail.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
On Sunday deep-layer ridging will remain anchored across the mid-
Atlantic states...while a low-amplitude trough digs across the Upper
Great Lakes. At the surface...an elongated/wavy frontal boundary
across southern Ontario/Quebec will only slowly edge southward as
its western periphery becomes more "wavy" in response to the
approach of the above trough...resulting in the front remaining to
our north through the day. In turn...this should result in another
largely dry day...though again cannot completely rule out some
isolated afternoon convection across Niagara/Orleans counties and
northern portions of the North Country...which will lie closest to
the slowly approaching boundary. The bigger story will be the very
warm to hot and humid conditions...which could result in portions of
the Niagara Frontier/Finger Lakes flirting with or reaching low-end
Heat Advisory Criteria.

After that...gradually amplifying (but still rather broad) troughing
over eastern Canada will encourage the frontal boundary to slowly
push southeast as a cold front and cross our region sometime during
the Sunday night-Monday night time frame...with this feature
bringing renewed chances for convection as it makes its way through
our region. Following its passage...somewhat cooler and drier air
should then filter back across our region through the balance of
this period...resulting in a return to generally drier weather along
with temperatures near early July normals.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
An upper level low over Quebec will slowly drift southward through
tonight. A cold front tied to this feature will move through in
pieces and bring periods of convection to the region through this
afternoon. VFR weather will prevail outside of any convection,
though within localized MVFR/IFR vsbys will be possible at times.

Confidence in evolution of showers and thunderstorms remains low
through this afternoon. PROB30 groups continue to be used to cover
the potential for thunderstorms at the TAF sites during the windows
when chances are expected to be greatest for individual sites.

With the arrival of drier air and loss of daytime heating this
evening, any leftover thunderstorm activity will likely taper off by
00z with mainly VFR continuing to prevail through tonight. Southern
Tier valley fog is expected to develop overnight which could bring
IFR or lower vsbys to KJHW.

Outlook...

Friday through Sunday...VFR.

Sunday night through Monday...Chance of showers and thunderstorms
with MVFR restrictions possible.

&&

.MARINE...
Westerly winds today will maintain a light chop on the waters as a
cold front moves through. Widely scattered thunderstorms will be
possible on both lakes at times through the afternoon.

High pressure will then build across the Lower Lakes region tonight
and Friday. Winds will shift northerly overnight behind the front
with wave action gradually diminishing in the second half of the
night. Generally light winds and minimal waves then expected for the
Independence Day holiday.

&&

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

&&

$$

SYNOPSIS...JJR/PP
NEAR TERM...PP
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...PP
MARINE...JJR/PP