252
FXUS61 KBUF 131723
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
123 PM EDT Sat Jul 13 2024

.SYNOPSIS...
Surface high pressure will ridge across the region through
Sunday, resulting in mostly dry and fair weather during the
weekend. Additionally, expect warm and moderately humid weather
with highs ranging in the mid 80s to the low 90s. Active
weather will return Sunday night with a risk of showers and
thunderstorms lasting through Wednesday as a series of weak
disturbances moves through.

&&

.NEAR TERM /THROUGH SUNDAY/...
A broad ridge of high pressure will ridge across the region,
resulting in mainly rain free weather for the weekend. There`s a
slight chance of instability driven showers across the Western
Southern Tier and in Lewis County this afternoon. After this,
dry weather will prevail tonight and the vast majority of
Sunday. A mid-level trough will approach from the west late in
the day Sunday, possibly sparking a few showers or thunderstorms
across far Western NY just before sunset.

Otherwise, afternoon temperatures will be on the warm side this
weekend with highs in the mid to upper 80s on Sunday. Good
radiational cooling underneath the surface high tonight with
lows in the 60s and patchy fog possible in the Western Southern
Tier river valleys.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Expect some unsettled weather to start the new work week as model
consensus continues to key in on a couple of potential convectively
augmented shortwaves moving through the broad trough over the Great
Lakes and Northeast, which may cross the area on Sunday night and
Monday respectively bringing better chances for showers and
thunderstorms back into western and northcentral NY. Though the
track, timing, and strength of these features is typically difficult
to forecast, as mentioned above the bulk of the guidance packages is
in surprisingly decent agreement on said convective elements.
However, there is still a bit of disagreement on exact timing and
track. For these reasons, will cap PoPs in the high Chc range for
now. A more pronounced southwesterly flow will also set up on
Monday, along with diurnally driven lake breeze circulations. A very
warm and more humid air mass will be in place to start the new work
week, so would also expect at least some scattered afternoon/early
evening convection to fire along and inland of these boundaries as
well, but again exact location of said boundaries is still in
question.

A weak area of transient high pressure will try to nudge in across
the area Monday night, however with model guidance advertising yet
another convectively augmented shortwave right on its heels, will
keep SChc to low Chc PoPS for showers/storms in the forecast due to
the continued uncertainty in track and timing of these features.

Have high confidence in very warm and sticky conditions prevailing
during this period. Mid 80s to near 90 for highs on Monday will be
bookended by warm and sticky lows in the upper 60s to low 70s for
most both Sunday night and Monday night. Heat indices Monday will
likely be in the low 90s for the bulk of the lake plains, Genesee
Valley, and Finger Lakes region.

Low pressure will slide from east-central Ontario Province into west-
central Quebec Tuesday and Tuesday night. In the process the system
will send a prefrontal trough through our area Tuesday...then will
push its trailing cold front toward/into our region Tuesday night.
Timing of prefrontal trough Tuesday could produce a few feisty
storms with the aid of daytime heating, however shear profiles at
this time remain modest keeping more robust severe potential low.
Nocturnal approach/passage of the cold front will also keep severe
potential on the low side, although shear profiles do become more
favorable just ahead of the cold front, so can`t completely rule out
the chance for a nocturnal severe storm or two with a very moist and
unstable air mass in place. With PWATs climbing to the vicinity of 2
inches...there will again also be the potential for torrential
rainfall with any storms. Otherwise, it will be another very warm
and humid day Tuesday with highs a couple ticks higher than those
seen on Monday.

&&

.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 differences in timing. The exact timing of the
front will be key to determining how much severe potential will
exist during Wednesday...with a slower passage allowing for more
time for daytime destabilization and therefore a greater risk for a
few stronger to severe storms...with this greatest along our
southeastern periphery. In contrast...a faster passage would likely
preclude much in the way of destabilization and consequently severe
risk. Given the uncertainty...for now have maintained a mix of
chance to low-end likely PoPs during Wednesday. As for temps...highs
on Wednesday should generally range from the upper 70s to lower 80s.

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 completely rule out another couple showers with this second
boundary as it crosses our region...however given the time frame and
limited accompanying moisture will keep PoPs below the slight chance
threshold for now. 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 /17Z SATURDAY THROUGH WEDNESDAY/...
Widespread VFR flight conditions for the vast majority of the
18Z TAF cycle. few-sct cumulus this afternoon with cloud bases
around 4k feet. River valley fog is expected again tonight,
which may bring a period of IFR or lower conditions to the KJHW
terminal. Any fog will dissipate by mid-morning Sunday, with VFR
conditions through 00Z Monday. A slight chance of showers and
thunderstorms late Sunday afternoon across Western NY.

Outlook...

Sunday night 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 will continue to build east across the lower Great
Lakes this weekend, resulting in quiet conditions with light winds
and limited waves. A generally weak pressure gradient will
result in quiet conditions through Monday night, then winds
will pick up a bit on Tuesday in response to a trough of low
pressure.

&&

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

&&

$$

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