364
FXUS61 KBUF 141839
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
239 PM EDT Sun Jul 14 2024

.SYNOPSIS...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight...while also giving way to
the first in a series of disturbances that will bring a few showers
and thunderstorms to far western New York this afternoon...then to
the rest of the area tonight. Very warm and sultry conditions will
then follow for Monday and Tuesday along with periodic chances of
showers and thunderstorms. A cold front will then cross the area
between Tuesday night and Wednesday along with some more showers and
thunderstorms...with notably cooler and drier air then following in
its wake for the rest of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
The first in a series of convectively augmented shortwaves is
currently working across nearby southern Ontario...and is generating
a couple areas of convection that are lifting northeastward. The
first of these is line of showers and storms between Hamilton and
Georgian Bay...while the second is a smaller cluster of showers and
storms located near Erie Pennsylvania.

As we push through the rest of the afternoon this initial shortwave
will make its way across far western New York. Our current airmass
is notably drier and more stable compared to the source region of
the convection and is thus likely to take at least some toll on the
showers and storms as these try to push into our area...though given
current radar trends feel at least some of this activity will
survive the trip into our area. The greatest potential for this will
be across the western Southern Tier (and to a lesser extent) Niagara
county...and have upped both PoPs and thunder probabilities a bit
from continuity to account for this...with the best chances for any
thunder found across the Southern Tier. Otherwise it will be very
warm with most areas seeing highs between 85 and 90...and surface
dewpoints generally slowly rising through the 60s.

This first shortwave will push east across the rest of the area this
evening...with its associated convection continuing to weaken as it
pushes further east into progressively drier and more stable air. A
relative lull will then ensue...before one or more additional such
impulses arrive overnight in concert with increasing instability as
a warmer and increasingly moist airmass overspreads our region. This
will support the potential for at least some additional scattered
showers and storms overnight. Otherwise it will be notably more
uncomfortable than the last couple of nights...with surface
dewpoints climbing into the mid to upper 60s...and low temperatures
having trouble falling below the upper 60s and lower 70s in many
places.

On Monday at least one more convectively-augmented wave looks to
cross the region during the day...however the timing and placement
of this wave remains much in question at this time. Regardless...
this feature along with developing lake breeze boundaries should
help to generate at least some additional scattered showers and
thunderstorms...with this activity possibly becoming a bit more
numerous inland from the lakes during the afternoon...particularly
if the shortwave passage aligns with peak diurnal heating. With
PWATs up around 1.75 inches...any storms could produce locally heavy
downpours. Otherwise the sultry conditions will continue...as highs
of 85 to 90 will coupled with surface dewpoints near 70 degrees.
While this could briefly yield some apparent temperatures near 95
degrees across portions of the Finger Lakes...will hold off on any
heat advisories for now given the expected brief/marginal nature of
such readings...as well as the potential for convection to inhibit
apparent temps from actually getting that high.

&&

.SHORT TERM /MONDAY NIGHT 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 SUNDAY/...
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 /19Z SUNDAY THROUGH FRIDAY/...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight. This will allow the first in
a series of disturbances to cross far western New York this
afternoon along with a few weakening showers and thunderstorms. This
wave and its convection will then continue to push further east and
weaken as it crosses the rest of the area this evening. In general
conditions through this evening will remain VFR under increasing/
lowering clouds...with just a very low chance of restrictions in
convection across the Southern Tier.

Overnight and Tuesday additional such hard-to-time disturbances will
cross the area from west to east...and these in tandem with a
general increase in instability will support the potential for some
additional scattered showers and storms at times. This being said
conditions will continue to be predominantly VFR...with some MVFR
ceilings possible across the Southern Tier late tonight...and then
some brief/localized MVFR restrictions possible within any
convection during Monday.

Outlook...

Tuesday and Tuesday night...VFR/MVFR with scattered to numerous
showers and thunderstorms.

Wednesday...VFR/MVFR with a chance of showers and thunderstorms.

Thursday and Friday...VFR.

&&

.MARINE...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight. 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 across eastern Lake Erie
and western Lake Ontario this afternoon and evening...then in a more
general sense later overnight through Wednesday...with the potential
for locally higher winds and waves in and near any storms.

&&

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

&&

$$

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