867
FXUS61 KBUF 191816
AFDBUF

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

.SYNOPSIS...
High pressure across our region will generally keep fair dry weather
in place through at least the beginning of the new work week. More
notable will be the summer like heat that we can look forward to, as
the mercury in most areas will climb WELL into the 80s for the
Monday through Wednesday timeframe.

&&

.NEAR TERM /THROUGH MONDAY/...
Amplifying mid and upper level ridge overhead will provide mainly
dry weather today. There will be an outside chance for some
diurnally driven scattered showers and possibly an isolated rumble
of thunder across the Genesee Valley/Finger Lakes region with a
lingering weak surface convergent boundary in place there. High
temperatures should climb into the mid to upper 70s, some 5 to 10
degrees above normal.

High pressure will provide dry weather tonight. Although low level
moisture looks to be a bit less tonight, there may still be enough
to produce some areas of fog again overnight, mainly south of Lake
Ontario. However, it is not expected to be as widespread or dense as
last night. Another mild night with lows in the mid to upper 50s.

&&

.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 /18Z SUNDAY THROUGH FRIDAY/...
VFR conditions expected for this afternoon with sct-bkn030-050
inland from the lakes. There may be a stray shower or rumble of
thunder toward the upper Genesee Valley/Finger Lakes region during
the 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 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 and thunderstorms.

&&

.MARINE...
A highly saturated airmass and weak flow will continue across the
lower Great Lakes allowing for some patchy fog and stratus to remain
over the lower Great lakes this afternoon, especially Lake Ontario.
Conditions have however improved enough on Lake Ontario to drop the
dense fog advisory there.

The same airmass will remain over the lower Great Lakes tonight into
Monday morning which may allow 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 the
Lakes 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 through
the Lakes.

&&

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

&&

$$

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