682
FXUS61 KBUF 152246
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
646 PM EDT Mon Jul 15 2024

.SYNOPSIS...
An unsettled pattern will continue through midweek...with
another round of strong thunderstorms possible Tuesday. A cold
front will sweep across the area midweek...with high pressure
building across our area in its wake and providing mainly
dry...cooler...and much less humid conditions for the second
half of the week.

&&

.NEAR TERM /THROUGH TUESDAY/...
Satellite imagery shows an MCV over Lake Ontario, with a line of
thunderstorms extending southeast of it across the Eastern Lake
Ontario region and into Central NY. The severe weather threat
associated with this will be ending soon as this line of storms
exits the area during the next hour or so. However, winds will
gust to 45 mph along the Lake Erie shoreline through 8 p.m. or
so.

The MCV will slide east of our region this evening...with associated
showers and storms quickly winding down from west to east in its
wake. Can`t rule out a few additional scattered showers or an
isolated storm overnight given the very warm and moist airmass,
however expect the bulk of the area to be largely dry following the
departure of today`s MCV. It will be another sultry night with lows
in the upper 60s to low 70s.

During Tuesday the longwave upper-level trough will remain well
upstream of the area over northwest Ontario. A weak low level trough
axis will linger in place from the Ohio Valley to New England, with
its position modulated by numerous rounds of convection and
associated composite outflow. This feature will serve as the conduit
for yet another convectively generated vorticity maxima/MCV that
will move east across our region Tuesday, with this feature
supporting another round of showers and thunderstorms that will
cross the area from west to east.

The 12z/15 suite of model guidance still suggests an earlier arrival
of this next wave compared to today`s...though this is just a little
bit slower than seen in last night`s guidance. Current timing takes
this feature across western NY between the morning/midday hours,
then the eastern Lake Ontario region/central New York early Tuesday
afternoon. The earlier arrival of forcing, clouds, and showers
relative to the diurnal cycle may act to limit potential instability
across far western New York...with areas further south and east
having a better opportunity for notable diurnal destabilization.
Deep layer shear is not particularly strong (only around 30 knots)
across western New York...however this looks to be greater with
increasing northeastward extent - with this especially the case
across the North Country where 0-6km bulk shear is currently
projected to be in the 40 to 50 knot range. As is typically the
case...the MCV will also likely bring a mesoscale region of enhanced
low/mid level shear, convergence, and ascent as it crosses the
region...thereby providing a more favorable environment for strong
to severe storms.

At this point strong damaging winds again appear likely to be the
primary severe weather threat...along with a secondary risk for
large hail. Additionally...the enhanced shear supplied by the MCV
will also support a low but nonzero risk for an isolated tornado or
two...with this risk likely greatest across the eastern Finger Lakes
and North Country where the environmental shear currently looks to
be highest.

In the wake of the MCV, a few more showers and thunderstorms may
develop along lake breeze driven convergence zones in the afternoon
and evening, mainly from the Southern Tier through the Finger Lakes
and Central NY. Increasing southwest flow off Lake Erie will likely
produce a stable lake shadow northeast of the lake with mainly dry
weather following the morning/midday convection.

Otherwise it will be very warm and humid again Tuesday, with highs
in the low 80s for Western NY and mid to upper 80s from the Genesee
Valley into Central NY. While apparent temperatures could briefly
tickle 95F from the Genesee Valley into Central NY, the brief/
marginal nature of these and the potential for clouds and convection
to keep temperatures a few degrees lower both preclude the need for
any Heat Advisories at this time.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
Longwave trough will gradually work through the Great Lakes
Tuesday night through Wednesday night, ending up in Quebec by
Thursday morning. One or more convectively augmented shortwaves
may cross NY/PA Tuesday night through Wednesday, supporting
ongoing chances of a few showers and thunderstorms at times.

Cold front will gradually settle southeast across the region
late Wednesday afternoon, with chances of showers and
thunderstorms ending from northwest to southeast late Wednesday
through Wednesday night with the frontal passage. Drier and less
humid air will arrive later Wednesday night in the wake of the
cold front.

High pressure will build in Thursday and Thursday night and
result in a period of drier, less humid, and somewhat cooler
weather. High temperatures Thursday in the 70s and lows Thursday
night in the 50s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
It`s looking like this will be a stretch of spectacular weather
across the region, with a broad ridge of high pressure building
across the region. A weak cold front will drop southward across the
region Sunday, but its passage should largely be rain-free with
possibly an isolated shower. Otherwise, there`s good model agreement
providing high confidence in rain-free weather. Temperatures will be
near normal with daytime highs averaging in the mid 70s to lower 80s
and nighttime lows mainly in the mid 50s to lower 60s.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A convective wave will push east of the area through this
evening...followed by a return to mainly VFR conditions for the
rest of the night. This being said...there could be a brief
period of lingering MVFR ceilings behind this wave...with
additional MVFR/IFR ceilings also possible across the Southern
Tier late tonight.

On Tuesday yet another convectively-driven wave will cross the area
from west to east during the morning and early afternoon hours. This
will support another round of showers and thunderstorms...with some
of the storms again potentially strong to severe...with this risk
greatest from the Finger Lakes eastward across the North Country. As
is the case today...strong wind gusts to 50 knots and large hail
will be the main severe weather threats. Otherwise brief periods of
MVFR/IFR will again be possible within any stronger/heavier showers
and storms.

In the wake of this second wave...a few more showers and storms and
localized MVFR restrictions may develop along lake breeze driven
convergence zones Tuesday afternoon and evening, mainly from the
Southern Tier through the Finger Lakes and Central NY. Meanwhile
conditions should tend to return to VFR further to the north and
west.

Outlook...

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

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

Thursday through Saturday...VFR.

&&

.MARINE...
In the wake of a passing disturbance, there will be a few hours
of strong southwest winds...resulting in a brief period of
small craft conditions on Lake Erie and the Upper Niagara River
through this evening.

Southwest flow will increase again late tonight through Tuesday,
producing more notable chop on both lakes, with a period of Small
Craft Advisory conditions appearing increasingly likely on Lake Erie
Tuesday following the passage of yet another disturbance. This
second disturbance will also likely generate a another round of
showers and storms across our region...with any stronger storms
again capable of strong wind gusts and locally higher waves.

Periodic chances for showers and thunderstorms will then continue
across eastern Lake Erie and Lake Ontario through Wednesday, with
the potential for locally higher winds and waves in and near any
storms.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Beach Hazards Statement until 11 PM EDT this evening for
     NYZ010-019-085.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LEZ020-
         040-041.

&&

$$

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