278
FXUS61 KBUF 211836
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
236 PM EDT Tue May 21 2024

.SYNOPSIS...
Mid-summer warmth will continue this afternoon with well above
normal temperatures and elevated humidity levels. With the very warm
conditions and humidity it will also support some showers and
thunderstorm well inland from the lakes. A greater threat for
showers and storms arrives Wednesday as a cold front approaches the
region. Cooler more comfortable weather can be expected Thursday
into the first part of the Memorial Day weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
A couple areas to watch the rest of the afternoon and into the very
early part of the evening. Area of showers and thunderstorms
increasing ahead of convectively enhanced shortwave tracking across
Ontario/Quebec will develop into the Saint Lawrence Valley and
portions of the North Country inland from the lake breeze boundary
east of Watertown and Fulton. Some of this activity could be rather
robust, especially if storms can become more organized as they
move eastward into the area. Other area to watch will be
associated with growing cumulus field east of Lake Erie. Surface
based CAPES upwards of 1500 J/KG across the Southern Tier
through the Genesee Valley/Northern Finger Lakes. Shear profiles
do not look overly favorable, but some of the better developed
cells could produce some small hail.

The loss of diurnal heating will quickly end the convection early
this evening. The will leave a dry and mild night with overnight
lows in the 60s.

Active weather day expected Wednesday with the potential for strong
to severe thunderstorms. Ahead of approaching cold frontal boundary
an increasingly unstable environment will emerge, with surface
temperatures in the mid to upper 80s and surface dewpoints getting
into the mid to upper 60s. Surface based CAPES likely nearing 2000
j/kg during peak heating. Increasing shear profiles suggesting the
potential for damaging winds and hail, with even a small corridor of
enhanced low level helicity developing into southwest New York
possibly favoring a few rotating cells.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Closed mid-level low centered over the central portions of the
Ontario province will become vertically stacked by Wednesday night
with its surface low. As this low pressure system weakens, its
associated cold front draped southward across the lower Great Lakes
will continue to progress eastward across western and north central
NY. This being said heading into Wednesday night, showers and a few
thunderstorms will linger into the evening hours, though the
potential for severe thunderstorms will diminish shortly after
sunset due to the loss in diurnal heating and instability. The front
will then cross Wednesday night and continue to support showers
inland from the lakes. By Thursday morning the vast majority of
shower activity should be to the southeast of the area, as dry air
from the next incoming surface high advances east towards the area
resulting in dry conditions across the region.

As surface high pressure pushes east across the area Thursday
through Friday, associated subsidence will support dry weather
persist. Though dry, it will be `cooler` in the wake of the cold
front Thursday and Friday with highs ranging in the 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The next mid-level trough over the northern Plains/Upper Midwest
will support a surface low to push northeast across the eastern
Great Lakes into southern Canada Saturday. This will support a warm
front to advance towards the region ahead of the surface low,
resulting in an increase in shower potential Friday night and last
through Saturday night.

A brief interlude in shower activity for the Memorial Day weekend on
Sunday as high pressure slides east across the region.

Showers return late Sunday night and linger through Monday as
another upper level trough and associated surface low pushes across
the Ohio Valley towards the lower Great Lakes.

Temperatures for the period will be near normal with high
temperatures ranging in the low to upper 70s for most of the area
and cooler temperatures across the higher terrain.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Diurnal cu fields developing inland from the lakes this afternoon.
Uncertain on thunderstorm potential this afternoon and early
this evening. Scattered convection will develop ahead of
shortwave crossing north of Lake Ontario. Expanding cu field
from the Southern Tier into the Finger Lakes will also form some
convection. Given hi-res guidance keeping much of the
convection east and south of the area, confidence not high
enough to place a mention of TSRA in at KJHW, KROC and KART.
High confidence that lake shadowing will occur at KIAG and KBUF.

Any convection will die out quickly this evening leaving
widespread VFR conditions, with enough southerly graident flow
in the boundary layer to make it difficult for fog formation.

Outlook...

Wednesday...VFR/MVFR. Showers and thunderstorms likely.
Thursday...Mainly VFR. A chance of showers.
Friday...Mainly VFR.
Saturday...Restrictions possible. A chance of showers and
thunderstorms.
Sunday...Mainly VFR. A chance of showers and thunderstorms.

&&

.MARINE...
South winds will continue up to 15 knots through tonight as a
cold front to our west begins to approach the eastern Great
Lakes, with conditions remaining below small craft levels.

Low pressure will send a cold front into the eastern Great
Lakes on Wednesday, but winds and waves look like they will
remain below small craft conditions for the rest of the week.

&&

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

&&

$$

SYNOPSIS...AR/TMA
NEAR TERM...TMA
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...TMA
MARINE...AR/TMA