172
FXUS61 KBUF 191840
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
240 PM EDT Sun May 19 2024

.SYNOPSIS...
Summer-like warmth is expected through mid-week. Mainly dry weather
is expected through Tuesday before chances for showers and
thunderstorms increase with the passage of a cold front Tuesday
night into Wednesday night. Cooler weather will follow the front
for the end of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
Mid level ridge and surface high pressure building into the region
will provide dry weather tonight. Likely will see another round
of fog tonight, although low level moisture looks to be a bit
less, probably keeping fog not as widespread or dense as last
night. It will be another mild night with lows in the mid to
upper 50s.

Summer-like warmth starts to build into the region Monday. Mid level
ridge remains over the area Monday as surface high pressure slides
to the east. For the most part Monday looks dry, but there is an
outside chance for a shower or storm on a lake breeze boundary
during peak heating. Temperatures about 10 to 15 degrees above
normal with most highs in the lower to mid 80s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Heading into Monday night in the upper levels of the atmosphere, a
large trough will be spread across the Rockies, while a ridge will
span across the eastern half of the United States. Meanwhile, within
the trough to the west, a shortwave trough will be in the midst
passing east across the Upper Great Lakes. Translating this pattern
down to the surface, the longwave trough aloft to the west will
support a surface low over the Central Plains with a cold front to
extend southward across the rest of the Plains, where it will
gradually traverse northeast throughout the first half of the week.
Additionally, the shortwave trough over the Upper Great Lakes Monday
night will support a surface low over northern Canada, placing its
weakening frontal boundary to the north of the region Monday night
through Tuesday, as surface high pressure elongated along the
Northeast`s Atlantic coastline remains strong to support primarily
dry warm weather. Given the surface pattern, a southeasterly breeze
Tuesday will support temperatures in the low to mid 80s with a few
locations across the southern Genesee Valley reaching 90.

As the surface low passes northeast across the upper Great Lakes
Tuesday night and Wednesday, an approaching cold front will support
showers and thunderstorms to pass across the area from west to east.
Speaking of thunderstorms, provided the favorable timing some storms
may have the potential of becoming well developed, as there will be
plenty of instability with CAPE values surge towards 2500-3000 J/kg
and lapse rates reach upwards of 8C/km, along with shear values of
+150 m^2/s^2. Showers and thunderstorms will then continue into
Wednesday night as the cold front passes across the area. Otherwise
expect another warm day Wednesday with highs surging into the low to
mid 80s across the higher terrain and the mid to upper 80s elsewhere.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The cold front should be in the process of exiting the region or
just to our east by Thursday morning. There may still be some
showers that linger behind the front on Thursday but should be
fairly limited coverage wise. Otherwise...it will be cooler Thursday
with highs in the low-mid 70s.

A secondary cold front is advertised to cross the region late
Thursday night or even early Friday which will deliver a second shot
of cooler air to the eastern Great Lakes. That said...the main
challenge will be how much cooler with H850 temperatures potentially
down to +4C to +7C. Guidance still shows anywhere from low-mid 60s
to low-mid 70s. Will lean on NBM guidance at this point which is
right in the middle with upper 60s to around 70F for daytime highs
on Friday. The cooler airmass rapidly modifies over the weekend with
a warming trend taking place across the region.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR conditions expected for this afternoon with sct-bkn030-050
inland from the lakes. There may be a stray shower toward the
upper Genesee Valley/Finger Lakes region late this afternoon,
but confidence in this is low.

Widespread VFR through the first half of tonight. There will be the
possibility for some fog once again for the second half of
tonight, however it is not expected to be as widespread or dense
as last night.

Outlook...
Monday and Tuesday...Mainly VFR.
Wednesday...VFR/MVFR. Showers and thunderstorms likely.
Thursday...Mainly VFR. A chance of showers.
Friday...Mainly VFR.

&&

.MARINE...
Not much airmass change over the lower Great Lakes tonight
which will keep the potential for more dense fog to develop. The
greatest chance of this looks to be across Lake Ontario.

Otherwise, light winds with minimal wave action expected on Lake
Erie and Lake Ontario through Monday.

South winds develop and begin to pick up by Tuesday as a cold front
near the eastern Great Lakes, but conditions will likely remain
below small craft levels. The next chance at small craft conditions
may materialize by midweek as low pressure sends a cold front into
the eastern Great Lakes.

&&

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

&&

$$

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