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512
FXUS61 KBUF 301846
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
246 PM EDT Sun Jun 30 2024

.SYNOPSIS...
Notably less humid airmass will pour into the Lower Lakes today,
with a few showers possible this afternoon...especially east of Lake
Ontario. High pressure over the Upper Mississippi valley will then
build east tonight and overhead on Monday. This will guarantee near
perfect weather to start the week. The next chance of showers and
storms arrives Wednesday with the next cold front.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
Strong cold air advection behind the front is bringing in a
drier and much cooler airmass to the Lower Lakes. Dwpts have
already fallen into the 50s behind the front in many spots. As
advertised mercury levels are also dropping this afternoon.
This is something that is quite unusual during the warm
season...let alone for the end of June when the sun
angle/intensity is at its peak. Furthermore...we are seeing some
lake induced clouds this afternoon off Lake Erie. This
shouldn`t be much of a surprise given how cool the core aloft is
of +6C to +7C @ 850mb.

Otherwise...a few showers will be possible this afternoon but
nothing like we saw yesterday or last night.

Tonight...a secondary cold front will push south through our region
with some nuisance showers early on and mainly east of Lake Ontario.
Given northerly flow and a relatively warm Lake Ontario we will also
see a fair amount of cloudiness across our region. Cool night
expected with lows in the 40s to 50s.

High pressure over the Upper Great Lakes will make its way across
our region Monday during the afternoon and evening. Max temperatures
Monday will be within a few degrees of 70 with low humidity and wall
to wall sunshine. Little chance Monday night with quiet dry weather
as high pressure moves through the region. Lows will be found in the
upper 40s in the cooler locales to low to mid 50s elsewhere.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
A large expanse of surface high pressure underneath a stout mid-
level ridge will lie across central NY to open the period Tuesday.
Dry weather will persist through Tuesday night as the ridge slowly
shifts towards and away from the New England coast. The onset of
warm advection on the backside of the surface high will allow high
temperatures Tuesday in the upper 70s to low 80s. Dewpoints will
also rise a few degrees though should remain in comfortable
territory, generally averaging in the 50s. Deepening southerly flow
Tuesday night will lead to rather warm overnight low temperatures,
especially across the Lake Plains where temps will only dip into the
upper 60s.

Unsettled weather returns later Wednesday and into Wednesday night
as a robust mid-level trough and attendant surface low track from
northern Ontario to Quebec across Hudson Bay. This will initially
cause warm front to lift out of the Ohio Valley and into the
forecast area Wednesday morning, before the system`s cold front sags
southeast through the region Wednesday night. While the initial
frontal passage in the morning is expected to be dry, moisture
advection into the warm sector behind it will allow for increasing
chances for showers and thunderstorms later in the afternoon and
into the evening, particularly from the Genesee Valley westward. Mid-
range guidance indicates PWATs approaching 2" ahead of the cold
front Wednesday afternoon which could support some locally heavy
downpours, especially in the western Southern Tier where instability
is expected to be greater. Otherwise, it will be a rather sultry day
as the increasing moisture will also lead to muggier dewpoints
values in the mid to upper 60s, while high temps climb WELL into the
80s in most areas. The typical warm spots across the interior
valleys such as Dansville may even breach the 90 degree mark
Wednesday afternoon.

The cold front will make its way through the eastern Great Lakes
Wednesday night before it runs up against the strong offshore ridge,
causing it to stall out across Pennsylvania. Broad scale ascent
along a ribbon of deeper moisture will allow for a round of
widespread showers and a few storms just out ahead of the cold front
Wednesday night, mainly in the first half of the night. Weak surface
high pressure and subsidence drying should allow much of western NY
to begin drying out in the second half of the night, though lower-
end chances for showers will otherwise linger through the pre-dawn
hours as the front`s momentum slows over the region. Temperatures
Wednesday night will likely depend on the exact timing of the front,
though it is expected to be rather muggy with mid 60s to low 70s for
overnight lows.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
-- Changed Discussion --
A secondary shortwave trough will round the base of the longwave
trough Thursday, pulling longwave pattern east across the lower
Great Lakes and New England Thursday night.The exiting shortwave
will support the cold front to finish sliding southeast across the
area Thursday, ushering in a cooler and less humid airmass into the
region. Thursday will take on a drying trend with just a few
scattered showers and thunderstorms heading into the afternoon.
Temperatures for the holiday will feature highs in the low to mid
80s.

As the longwave trough pull east across the lower Great Lakes and
New England Thursday night placing zonal flow across the area, the
now stalled cold front to the south of the area. While the area will
remain mostly dry, a few showers and thunderstorms can`t be ruled
out, especially along and near the New York/Pennsylvania state line.

Zonal flow Friday will give way to the next trough diving across the
Great Lakes through the weekend, it is this point the the forecast
the model guidance begins to diverge with the timing and positioning
of the next shortwave and corresponding cold front for Friday night
through Sunday. With this in mind, have chances for showers and
thunderstorms lasting throughout the weekend with the better chances
for the weekend being Saturday, but time will tell being this far
out.
-- End Changed Discussion --

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Low VFR to MVFR cigs will be found across area terminals for much of
the day behind the cold front. A few showers will also be possible.

A secondary cold front will push through tonight. This will lead to
most areas experiencing MVFR cigs. That said...a few terminals
across the higher terrain might also see IFR cigs overnight.

Outlook...

Monday through Tuesday...VFR.
Wednesday...VFR/MVFR with showers and thunderstorms likely.
Thursday...Mainly VFR with a chance of a shower or thunderstorm
across the western Southern Tier.
Friday... Mainly VFR with a chance of a shower or thunderstorm.

&&

.MARINE...
Moderate to strong west to northwest winds behind the front is
producing small craft conditions on both lakes. Small craft
advisories have been put in place through all of this evening.

The fresh to strong westerlies will persist into tonight before
approaching high pressure encourages winds and waves to subside late
tonight and Monday.

Nearly ideal conditons for recreational boating can then be expected
for Monday and Tuesday...as high pressure will cross the region.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Beach Hazards Statement until 11 PM EDT this evening for
     NYZ002.
     Beach Hazards Statement until 2 AM EDT Monday for NYZ003>006.
     Beach Hazards Statement until 8 PM EDT this evening for NYZ007.
MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ040-
         041.
         Small Craft Advisory until 11 PM EDT this evening for
         LOZ042.
         Small Craft Advisory until 2 AM EDT Monday for LOZ043-044.
         Small Craft Advisory until 8 PM EDT this evening for
         LOZ045.

&&

$$

SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...PP
LONG TERM...EAJ
AVIATION...AR
MARINE...AR