479
FXUS61 KBUF 300631
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
231 AM EDT Sun Jun 30 2024

.SYNOPSIS...
A cold front will push through the region this morning...and this
will usher in a notably less humid airmass that we can enjoy through
the state of the new work week. While there will be some leftover
showers and possible thunderstorms around today...the weather will
be appreciably nicer than that from Saturday. High pressure over the
Upper Mississippi valley today will then build across the region for
Monday and Tuesday. This will guarantee near perfect weather to
start the week.

&&

.NEAR TERM /THROUGH MONDAY/...
A very moist and unstable environment that is still in place early
this morning will support a few more showers and thunderstorms... then
in the wake of a passing cold front during the initial daylight hours
today...a drier more comfortable airmass will make its way into our
region. The frontal passage will help to keep some showers in the
forecast though through midday for many areas...especially east of Lake
Ontario.

Otherwise...the upcoming day will feature breezy conditions with an
increasingly comfortable airmass as Tds will drop from the 70s into the
upper 50s.

A secondary cold front will push south through our region Sunday night.
This will combine with a northerly upslope flow across a relatively
warm Lake Ontario to generate a fair amount of cloud cover across our
region...along with scattered nuisance showers east of Lake Ontario.

The pain of the unsettled weather for much of the weekend will give way
to absolutely gorgeous weather on Monday...as expansive high pressure
over the Upper Great Lakes in the morning will make its way across our
region during the afternoon and evening. Max temperatures Monday will
be within a few degrees of 70 with low humidity and wall to wall
sunshine.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Excellent weather will then be in place as we move into the first
day of July as a broad area of surface will be directly overhead
by Monday night before shifting off the New Jersey coast by
Tuesday evening. Monday night will again be on the cool side owed
to the clearer skies, with lows ranging from the upper 40s across
the interior hilltops to mid 50s near the lakeshores. Mid/high
clouds will increase through the day Tuesday out ahead of a warm
front lifting through the Ohio Valley. Temps at the sfc and aloft
will continue to warm on the western periphery of the surface
high Tuesday and Tuesday night, with temps topping out in the
upper 70s to low 80s and lows ranging in the 60s respectively.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Warmer, unsettled weather returns to the forecast as we move later
into the week. This comes as weak mid-level ridging shifts east of
the Great lakes Wednesday as is replaced with nearly zonal flow
aloft extending back toward the lower Midwest. Meanwhile, a
weakening mid-level trough will trudge east across James Bay from
northern Ontario to Quebec, causing several shortwave disturbances
to ripple through the overhead zonal flow, bringing on and off
chances for showers and thunderstorms through the end of the week.

The first of these opportunities for wet weather will arrive
Wednesday afternoon. A large surface low attendant to the trough
near James Bay will sag its elongated cold front southeastward
across Ontario Province and towards the eastern Great Lakes. Diurnal
convection will be possible during peak heating hours as the
forecast area sits within the system`s warm sector. A more
widespread round of showers and possibly a few additional
thunderstorms is expected Wednesday night as the front moves through
then stalls just south of the region, before the area dries out late
Wednesday night into Thursday morning.

Forecast uncertainty increases as we move further into Thursday and
towards the weekend. Long range guidance is in general agreement on
the stalled frontal boundary remaining to our south through
Independence Day, with an area of subsidence drying extending across
the forecast area from the upper Great Lakes. This being said, the
GFS is much further north with the placement of the boundary than
the ECMWF/CMCNH, both of which hint at some possible light diurnal
shower activity developing. This is reflected in the forecast as low-
end chances for showers (15-20%) in most areas Thursday afternoon
and evening, with slightly better chances (~30%) across the Southern
Tier in closer proximity to the boundary, where some thunderstorms
may be possible as well. Thereafter, a compact shortwave racing
across the Lower Great Lakes/Ohio Valley Thursday night will take
aim at the forecast area by Friday morning, followed by a larger
surface low which will move across the Great Lakes Saturday. As is
typical at this range, uncertainty is high in strength, timing, and
track of these systems which will also likely be influenced by how
they interact with the stalled boundary south of the area. Therefore
have stuck close to deterministic NBMs Chc PoPs Friday through
Saturday until details come into better focus.

For temperatures this period...Summer`s warmth will return to the
forecast area out ahead of the cold front Wednesday, with highs well
into the 80s likely in most areas. Temperatures cool a few degrees
with a bit less humidity by Thursday. Temperatures Friday will be
similar, likely cooling a bit more to the upper 70s/low 80s by
Saturday.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
Cigs of 2500 to 3500 feet will be found across much of the region
through the initial daylight hours. The risk for showers and
thunderstorms will persist during this time frame.

As we advance into the midday and afternoon...VFR conditions will be
found across the bulk of the region. The exception will be east of Lake
Ontario where some MVFR cigs could accompany leftover showers.

Cigs in many areas will drop to MVFR levels Sunday night...as a
secondary cold front will press through the region.

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.

&&

.MARINE...
A cold front will approach the region tonight...expect fresh to
strong westerlies in the wake of a front on Sunday. This will
likely lead to a fresh round of headlines for at least the
eastern half of Lake Ontario...while choppy conditions will be
found elsewhere.

Looking further ahead...high pressure drifting across the region Monday
and Tuesday will offer fine conditions for recreational boating with
generally light winds and negligible waves.

&&

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

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...PP
LONG TERM...PP
AVIATION...RSH
MARINE...AR/Apffel/RSH