826
FXUS61 KBUF 051744
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
144 PM EDT Sat Jul 5 2025

.SYNOPSIS...
Heat and humidity will grace the forecast area again with its
presence throughout the rest of the weekend as high pressure drifts
east off of the Mid-Atlantic coast. A few scattered showers may
develop across the inland portions of the western Southern Tier this
afternoon, otherwise dry weather will prevail elsewhere through much
of Sunday. A cold front`s arrival Monday will not only bring
widespread chances for showers and thunderstorms but also cooler and
less humid conditions.

&&

.NEAR TERM /THROUGH SUNDAY/...
Surface high pressure centered on the Mid-Atlantic coastline this
afternoon will shift further east as the axis of a surface ridge
traverses from the Great Lakes towards New England. Meanwhile,  a
warm front on the northwestern periphery of the high will continue
to move in tandem across Ontario and Quebec this afternoon. While
this has caused south/southwesterly flow to return the area this
afternoon, it has also advected in a warm and humid airmass,
supporting temperatures well into 80s. The introduction of the
marginally unstable air mass combined with the lake breeze
boundaries setting up may spark a few scattered showers and isolated
thunderstorms across the western Southern Tier later this afternoon.

Loss of diurnal instability this evening will result in the showers
and isolated thunderstorms to peter out with dry weather returning
and prevailing throughout the overnight hours. Otherwise, southerly
flow will persist as the pressure gradient between the wave of low
pressure sliding into the central Great Lakes and the exiting surface
high, all leading to little relief in humidity tonight, supporting
lows in the 70s.

The axis of the flattening mid-level ridge will then slide east
across the Northeast Sunday, while multiple partially phasing
shortwave troughs ripple across the provinces of Ontario and Quebec.
Associated surface high pressure with the aforementioned ridge will
support dry weather to mainly prevail. Additionally, 850 mb
temperatures will warm to around +20C Sunday, resulting in surface
high temperatures well into the upper 80s to low 90s, with a few mid
90s possible across the warmer spots of the Genesee Valleys. Cooler
temperatures will lie along the shorelines of both lakes and a few
miles inland due to the lake breeze. With humidity levels creeping
up, head indices across the Lake Plains, Genesee Valley and into the
Finger Lakes will climb up above Heat Advisory criteria, thus a Heat
Advisory is in effect Sunday from late morning (11AM) into the
evening (8PM).

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Sunday night through Monday night broad upper troughing over eastern
Canada will gradually amplify as shortwave energy ripples through
it, which will in turn encourage an approaching frontal
boundary to gradually push southeast as a cold front. This may
result in some isolated to widely scattered convection
developing across the northwestern half of the area Sunday
night, with better chances for showers/storms then following
areawide on Monday as the front pushes through our
region, before diminishing from NW-SE in the wake of the front
Monday night. While wind profiles are not all that strong and
thus are not particularly favorable for strong to severe
storms, the combination of the mostly unidirectional flow and
PWATs of 1.5 to 2 inches could pose a risk for locally heavy
rainfall and localized flooding should any areas of training
cells materialize. Otherwise humidity levels (dewpoints of
around 70F) will peak on Monday, lending a very sticky feel to
the air in spite of temps that should be some 5-7 degrees cooler
than Sunday. Cooler and less humid air will then gradually
filter in behind the cold front Monday night.

A weak sfc high will move into the region for late Monday night
through the rest of the period. This will result in mainly dry
conditions for the bulk of the forecast area for the rest of the
period from late Monday night onward. However, mid level zonal flow
combined with a weak passing shortwave trough and afternoon heating
on Tuesday will bring the potential for showers and thunderstorms to
portions of the Southern Tier and Finger Lakes. Temperatures for
Tuesday along with humidity levels will lower some from Monday`s
values, with highs in the mid 70s to low 80s for most areas and Td
values in the lower to mid 60s.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
This period will be dominated by persistent broad upper-level
troughing across the Great Lakes and Northeast. Currently Wednesday
appears to be on the drier side for the most part, with just
some limited afternoon convection possible across the Southern
Tier/interior Finger Lakes, with this due to the combination of
diurnal heating/a developing lake breeze boundary Wednesday.
Somewhat better and more general chances for convection may then
return for Thursday into the first half of Friday in tandem
with a couple shortwave passages. Another approaching frontal
boundary from the west will start to increase the potential for
showers/storms for Saturday as well, though the guidance
unsurprisingly continues to struggle with the details for most
of the long term period at this distant vantage point. With that
in mind, the chance PoPs advertised by blended guidance look
fine for now. Otherwise, temps during this period will average
out near to slightly above normal for this time of year.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Mainly VFR conditions prevail this afternoon as high pressure
centered over the Mid-Atlantic coast line extends east into the
eastern Great Lakes. A passing warm front on the northwestern fringe
of the surface high, will introduce a marginally unstable air mass
to the area, mainly across the western Southern Tier (between KJHW
to KELZ), supporting a few scattered showers and isolated
thunderstorms this afternoon and into this evening. Within these
showers and thunderstorms expect localized MVFR/IFR conditions
mainly due to restrictions to visibility.

Convection will then diminish with the loss of diurnal heating
shortly after 00Z, with dry weather returning and prevailing
through out the remainder of the night.

Mainly VFR conditions will then last throughout Sunday as the
aforementioned high pressure exits east. Daytime mixing combined
with a low level jet overhead will support southwest winds to mix
down, especially across the Niagara Frontier and the Saint Lawrence
Valley, thus impacting KBUF, KIAG, and KART

Outlook...

Sunday night and Monday...A chance of showers and thunderstorms with
MVFR restrictions possible.

Tuesday and Wednesday...Mainly VFR.

Thursday...A chance of showers and thunderstorms with MVFR
restrictions possible.

&&

.MARINE...
Expansive surface high pressure will continue to settle well off the
Mid-Atlantic coast through this evening, resulting in light winds
and minimal wave action to prevail.

Southwest winds will begin to increase tonight into Sunday as the
pressure gradient tightens between the offshore high and an upstream
cold front moving into the central Great Lakes. Wave action will
become choppy though likely remain below SCA criteria. Winds look to
be marginally high enough that headlines may eventually be needed
across some of the nearshore waters, particularly on Lake Erie,
Niagara River, and western end of Lake Ontario.

While the cold front won`t cross the region until closer to Monday
evening, winds will subside by Sunday evening and remain below SCA
criteria through much of next week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory from 11 AM to 8 PM EDT Sunday for NYZ001>006-011-
     013-014.
MARINE...None.

&&

$$

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