944
FXUS61 KBUF 220015
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
815 PM EDT Thu Aug 21 2025

.SYNOPSIS...
Clouds will continue to slowly break up from north to south across
areas south of Lake Ontario through this evening. Otherwise, high
pressure will bring fair weather Friday into the start the weekend,
with a cold front bringing the return of showers and thunderstorms
Saturday night into Sunday. Much cooler air will arrive to start the
new work week in the wake of the cold front with scattered rain
showers and periods of lake effect rain showers.

&&

.NEAR TERM /THROUGH FRIDAY/...
Low cloud deck continuing to slowly clear from the north. The higher
terrain of the western Southern Tier will be the last to clear.
Other than mainly river valley fog across the Southern Tier later
tonight into the first part of Friday morning, high pressure
building into our region will yield mainly clear skies tonight and
mainly sunny skies Friday. With clearing skies and light winds
tonight, undercut guidance a bit for low temperatures, with low to
mid 50s for most areas and upper 40s for some of the higher terrain.
After a cool start to the day, good diurnal mixing will allow a
warming airmass aloft to mix down during the afternoon boosting
highs back into the upper 70s and lower 80s, however humidity levels
will generally remain comfortable.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Friday night and Saturday surface high pressure will drift out
across New England and into the western Atlantic...while a deepening
upper level trough and its attendant surface low make their way from
northwestern Ontario to near James Bay...while becoming increasingly
vertically stacked over time. Out ahead of this...broad upper-level
ridging will amplify over our region Friday night...before slowly
drifting east to New England Saturday. This will result in fair dry
weather prevailing through Friday night and likely for most of
Saturday...with some isolated to widely scattered convection
becoming possible across WNY late Saturday afternoon/early Saturday
evening with diurnal heating of our gradually warming and moistening
airmass. Otherwise temperatures and humidity levels will remain
comfortable Friday night...before giving way to highs in the lower
to mid 80s and moderate humidity (Td`s climbing into the lower-mid
60s) during Saturday.

Saturday night and Sunday the broad...vertically-stacked low will
slowly meander around the southern portion of James Bay...while
slowly pivoting its trailing cold front and leading prefrontal
trough eastward and eventually across our region. As these features
interact with and lift our antecedent warm and moderately humid
airmass...these will help to generate some scattered to numerous
showers and thunderstorms. Current multimodel consensus suggests that
the coverage of these will peak across far western New York Saturday
night and across our eastern zones between later Saturday night and
Sunday...with the overall timing of these a bit faster than seen at
this time yesterday. The above said...it should be noted that some
differences still persist with respect to the amount of waviness
that develops along the cold front...and consequently its eventual
timing. The slower that the front pushes through our area...the
larger the window for diurnal destabilization will be on Sunday...
and if this is large enough there could still be at least some risk
for a few stronger to marginally severe storms given the presence of
35-45 knots of deep-layer environmental shear. At this juncture...
the best chances of such appear to lie across our far eastern
zones...however this will again depend upon the eventual timing of
the front.

Sunday night...general subsidence in the wake of the front and dry
slotting aloft should bring about a diminishing trend to any
showers/storms across our far eastern zones...with a few spotty lake
effect showers then becoming possible downwind of the lakes
overnight as progressively cooler air works in aloft. Speaking of
which...the latter will also allow overnight lows to drop back to
the mid to upper 50s in most areas...with some lower 50s across the
higher terrain of the Southern Tier/North Country.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Anomalously deep...full-latitude upper level troughing will
consolidate its grip across eastern North America on Monday as
another vigorous shortwave rounds its base...then will remain in
place through Tuesday night...before gradually weakening and
broadening later Wednesday into Thursday. This feature will deliver
a shot of the coolest air we`ve seen in a while (850 mb temps
falling into the middle single digits above zero) Tuesday and
Wednesday. This will not only result in temperatures falling to
solidly below normal levels during the first half of next week...but
will also translate into unsettled conditions through at least
Tuesday night...with some lake effect rain showers downwind of the
lakes each night/morning...and more general diurnally-driven
scattered showers and isolated thunderstorms following each
afternoon/early evening.

With blended guidance again unable to adequately resolve the lake
effect shower potential this far out in advance...have manually
inserted some higher PoPs to account for this Monday night/Tuesday
morning (50% chance) and again Tuesday night/Wednesday (30%-20%
chances respectively). By later Wednesday...increasing low-level
ridging and the onset of gradual warming aloft should bring about a
trend toward drier weather...with dry conditions and highs largely
back in the 70s expected on Thursday.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR has return to all terminal expect KJHW as the low cloud deck
continues to slowly from north to south. KJHW will remain with MVFR
ceilings until around 04z.

Aside from mainly Southern Tier valley fog late tonight into the
start of Friday morning (possibly impacting KJHW), expect widespread
VFR conditions and light winds overnight and Friday as high pressure
builds across western and northcentral NY.


Outlook...

Friday night through Saturday...VFR.

Saturday night and Sunday...MVFR/VFR. Rain showers likely with a
chance of thunderstorms.

Monday and Tuesday...Mainly VFR with a chance of showers and
embedded thunder afternoons/early evenings. MVFR in lake effect rain
showers overnights into the mornings downwind of the Lakes.

&&

.MARINE...
Northeasterlies will continue to slowly weaken tonight as as a weak
area of surface high pressure builds across the lower Great Lakes.
This has allow the small craft headlines to fall off.

Weak gradient flow Friday becomes southerly Saturday, then increases
some Saturday night ahead of a cold front that will cross the Lakes
late Saturday night into Sunday.

&&

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

&&

$$

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