261
FXUS61 KBUF 140832
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
432 AM EDT Sun Jul 14 2024

.SYNOPSIS...
Surface high pressure will drift to the east coast today, with
sunshine giving way to increasing high clouds from west to east this
afternoon and evening. A few scattered showers may reach Western NY
by late afternoon, with the chance of a few showers spreading to the
rest of the area tonight. It will be very warm and muggy Monday
through Wednesday with a chance of a few showers and thunderstorms
at times. A cold front will then cross the area Wednesday and usher
in cooler and drier air for the second half of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Clear skies prevail across the region early this morning as high
pressure remains centered over the eastern Great Lakes. Patchy fog
across the Southern Tier valleys and east of Lake Ontario will burn
off shortly after daybreak.

Surface high pressure still over the region this morning will drift
to the eastern seaboard this afternoon. A broad mid level trough
with embedded convectively augmented shortwaves will move east
across the Great Lakes later today through tonight, bringing an
increase in large scale forcing for ascent across our region. The
leading shortwave will arrive in Western NY late this afternoon,
then move east to the eastern Lake Ontario region by late evening.
This feature will be moving into an antecedent dry airmass, with
associated showers likely diminishing in coverage and intensity as
they try to spread east across the area. There may be some thunder
upstream today, but the weakening nature of forcing and diminishing
instability with eastern extent will keep the thunder chances to a
minimum through this evening across our region.

Additional weak vorticity maxima will spread east into the region
overnight, along with modest instability, supporting the chance of a
few more scattered showers or an isolated thunderstorm with uneven
coverage.

It will be very warm today, with highs in the 85-90 degree range
across the lower elevations away from the immediate lakeshores.
Surface dewpoints will only slowly creep up, with no appreciable
heat index today. Tonight will be warm and increasingly muggy, with
lows in the lower 70s on the lake plains and mid to upper 60s for
cooler interior locations.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
This will be the most active period of the next seven days with
several rounds of showers and thunderstorms possible. It will remain
very warm to hot, with humidity levels rising back to very sticky or
even downright oppressive levels with some areas approaching Heat
Advisory criteria. In addition, there will also be at least limited
potential for a few severe storms that would be capable of producing
strong winds and heavy rainfall that could produce localized
flooding. Confidence is high that we will be in a very warm and
humid regime, however the pattern will become very convoluted during
the first half of the work week, which lowers confidence for any
severe/heavy rainfall potential across our area. The details...

There is the potential for several convectively augmented shortwaves
to cross the region during this period. The problem lies in just
that...these mesoscale features are not easily resolved by model
guidance, even the CAMs, which makes forecasting the impacts of such
elements very difficult with track, timing, and strength in
question. That said, a moisture-rich atmosphere combined with strong
diurnal heating will likely allow for shower and thunderstorm
development each afternoon, especially along and inland of lake
breeze circulations. This is where the importance of the
aforementioned convective shortwaves comes into play with regard to
severe potential; if one of these features moves across the area
during the time of peak heating, this will be the extra ingredient
that will increase our severe weather threat. Each shortwave will
produce at least scattered showers and thunderstorms no matter what
time it moves through, however in the absence of peak heating,
severe potential would be more limited. With regards to heat index
values, these features could also impact just how hot it may get if
they cross area during the daytime hours. One last puzzle piece to
throw in will be a cold front slowly sagging southeastward through
the central Great Lakes Tuesday with an associated pre-frontal
trough ahead of the main front possibly moving over the area Tuesday
afternoon, only further enhancing the chances for showers and
thunderstorms. Bulk shear values will also become more favorable on
Tuesday. Winds off the deck (LLJ) will also increase late Monday
night and Tuesday as well. Will at least partially mix some of these
winds to the surface Tuesday, which along with a tightening surface
pressure gradient will produce some gusty southwesterly breezes from
late Tuesday morning into the afternoon, especially northeast of the
Lakes. Bottom line...stay tuned for any updates to the forecast as
we get closer in time.

Otherwise, high temperatures will mainly range from the mid 80s to
near 90, however it will feel even warmer with dew points climbing
into the upper 60s and lower 70s Monday, with low to even mid 70s
possible by Tuesday. Expect very warm nights as well with upper 60s
to lower 70s both nights.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
On Wednesday the surface cold front will either make or complete its
passage across our area, with the medium range guidance packages
still exhibiting some minor differences in timing. This appears
mainly due to the potential for a wave of low pressure to move
northeastward along the boundary, which would slow its southeastward
progression. With this in mind, the exact timing of the front will
be key to determining how much severe potential remains on
Wednesday...with a slower passage allowing more time for diurnal
destabilization and therefore a greater risk for a few stronger to
severe storms, with the greatest threat along our southeastern
periphery. In contrast, a faster passage would likely preclude much
in the way of destabilization and consequently severe risk as the
boundary would be south and east of western and northcentral NY
prior to daytime heating. Given the uncertainty, for now have
maintained a mix of chance to low-end likely PoPs during Wednesday,
highest toward southeastern areas. As for temps, it will not be as
warm with highs on Wednesday generally ranging from the upper 70s to
lower 80s, and at least some decrease in humidity levels.

By Wednesday evening the main cold front should be well south and
east of our area, with a weaker secondary cold front then
potentially crossing our area later Wednesday night and Thursday.
Cannot rule out an additional few showers/isolated storm with this
second boundary as it crosses our region, especially on Thursday as
the axis of the main longwave trough crosses the area. Otherwise,
sprawling Canadian high pressure will gradually extend eastward
across the Great Lakes and Northeast through the rest of this period
and bring a return to cooler and more comfortable weather. Expect
surface dewpoints to fall into the 50s later Wednesday and remain
there through Saturday, while highs pull back to the lower to mid
70s Thursday, then only gradually climb back to the upper 70s to
lower 80s by Saturday.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
Surface high pressure will drift east across the eastern Great Lakes
through this morning, with clear skies and VFR in most locations.
Expect some patchy fog across the Southern Tier river valleys with
local IFR. This may impact KJHW for a few hours around daybreak.

High pressure will drift to the eastern seaboard by late today, with
an upstream trough crossing the Great Lakes. This will bring
increasing and lowering mid/high clouds through the afternoon, with
a few scattered light showers possible later this afternoon and
evening as the weakening remnants of upstream convection move into
the eastern Great Lakes. A few more scattered showers are possible
overnight with sparse coverage. VFR will prevail in most areas, with
a breeze reducing the chances of any fog overnight.

Outlook...

Monday through Tuesday...VFR to MVFR cigs with scattered showers and
thunderstorms.

Wednesday...Chance of showers and thunderstorms. Mainly VFR to
MVFR, with a chance of IFR or below in thunderstorms.

Thursday...VFR.

&&

.MARINE...
High pressure over the eastern Great Lakes this morning will drift
to the eastern seaboard this afternoon. Southwest winds will
increase into the 10-15 knot range tonight through Monday as the
high drifts off the east coast, enough to produce some chop on Lake
Erie and Lake Ontario. The southwest winds will increase further
Monday night through Tuesday, producing more notable chop on both
lakes.

There is a chance of a few thunderstorms at times Monday through
Wednesday, with the potential for locally higher winds and waves in
and near storms.

&&

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

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...JM
LONG TERM...JM/JJR
AVIATION...Hitchcock
MARINE...Hitchcock