958
FXUS61 KBUF 291921
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
321 PM EDT Wed May 29 2024

.SYNOPSIS...
A weak cold front crossing the Lower Lakes today, bringing scattered
showers mainly across the Southern Tier this afternoon. Drier
weather returns tonight into Thursday but it will remain on the cool
side. Dry weather continues Friday, with a warming trend as we head
into the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
A compact shortwave embedded within the broader long wave trough,
which can clearly be seen on GOES-16 IR channel and co-located with
the showers and thunderstorms over OH/PA line, will pass to our
south today. Meanwhile...a secondary front dropping south through
the region in concert with this shortwave will aid in the
development of some more storms this afternoon. The HRRR and various
other hi-res guidance suggest that the greatest coverage of storms
will be found across the Souther Tier. Instability of 250 to 500
J/KG of MUCAPE and decent mid level lapse rates will support some
thunder within the stronger cells. The stronger cells will be
capable of producing brief heavy down pours.

Otherwise...with a cooling airmass to the tune of +3C to +5C aloft,
despite sunshine returning by this afternoon, highs will only manage
to climb into the 60s near 70F today.

Tonight...we should see skies quickly clear this evening close to
sunset. Good radiational cooling anticipated with some valley fog in
the typical locales. The main concern will be the chilly airmass in
place over the region. With light winds we might see some `frost` in
the colder wind sheltered spots by sunrise Thursday. Lows will range
from the 40s to the upper 30s across the forecast area.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Fantastic stretch of weather on the way as we cap off the month of
May and transition into June this period.

To start, deep positively tilted troughing over the Northeast will
slide towards and away from the East Coast Thursday night into
Friday morning. In its immediate wake, stout high pressure ridging
at all levels will build across the central Great Lakes and Ohio
Valley. A cool airmass lagging behind the trough axis (850H temps
around 5C) combined with increasing subsidence drying will lead to a
rather chilly night for portions of the area. While lows will range
in the 40s for most areas, temps will likely dip into the upper and
possibly mid 30s across the interior Southern Tier, as well as up
across the Tug Hill and Western Adirondacks. Not out of the question
some patchy frost develops in these areas as well.

Fair, dry, and warmer weather will then be the story Friday through
Saturday as the high pressure ridge crests over and eventually east
of the Great Lakes. Friday will feature mostly sunny skies, though
there could be some mid/high clouds encroaching on the western
horizon Saturday as a warm front moves into the region. Highs Friday
will be in the upper 60s to low 70s, with more of a range of 70s
across the region Saturday. Low humidity can be expected both days
as there should be decent mixing of the dry low level airmass.

Two weakly couples shortwaves, one across northern Ontario Province
and another down across the Ohio Valley, will translate eastward in
tandem Saturday night. This system will further weaken as it runs up
against the ridge of high pressure over the Northeast, though a
diffuse cold frontal boundary will likely reach Western NY late
Saturday night. Shower chances with this feature remain low (15-25%)
as there remains some uncertainty in the exact timing, the depth of
the moisture ahead of the boundary and how much the southern
shortwave weakens before arriving. This being said, areas from the
Genesee Valley eastward are still nigh on guaranteed another rain-
free night, albeit under cloudier skies. Temps Saturday night will
be notably warmer compared to the previous nights in the 50s to low
60s across the area.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
High pressure ridging will remain anchored off the Southeast Coast
through the first half of the week as several low pressure
disturbances take aim at the eastern Great Lakes. This will lead to
a period of weather punctuated by warming temperatures to above
normal readings, as well as on and off chances for showers and
thunderstorms.

The first of these low pressure waves will be in the process of
weakening as it crosses through western NY and Pennsylvania as we
open the period Sunday. While the bulk of the day is expected to be
rain-free, showers and potentially a few thunderstorms will be
possible across the region as it moves through, especially across
the Southern Tier and western Finger Lakes. Mainly dry weather
across the region Sunday night through Monday night as upper level
ridging is briefly reestablished over the eastern Great Lakes,
though a few additional showers may develop across the Southern
Tier. The overall longwave pattern across the eastern CONUS becomes
fairly uncertain moving into Tuesday, though deeper GOMEX based
moisture is expected to begin advecting into the region ahead of
several upper level disturbances moving through the otherwise zonal
flow aloft. This will lead to more widespread chances for wet
weather Tuesday and Wednesday, though the finer details remain
uncertain at this time.

In contrast to the precipitation chances, confidence is much higher
in temperatures averaging above normal as we move further into the
first week of June. While temps Sunday should still range in the
70s, readings in the 80s will become increasingly common through
Wednesday, while overnight lows warm each night well into the 60s.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR for most terminals this afternoon. Showers will continue across
the Southern Tier which will potentially produce MVFR to IFR Cigs
and lower Vsbys at times at KJHW.

Tonight...VFR with valley fog developing overnight which may impact
KJHW.

Outlook...

Thursday through Saturday...VFR.
Sunday...Mainly VFR with a slight chance for showers.
Monday...Mainly VFR with a slight chance for a shower across the
Southern Tier.


 &&

.MARINE...
Light northerly flow will bring some modest chop to the lakes
through tonight into Thursday.

Winds will back to westerly later Thursday...and then eventually
become light and variable Friday into the weekend as the surface
high crests over the Lakes.

&&

.MARINE...
Light northerly flow on the Lakes today and into Thursday morning,
with a modest chop along the south shorelines of the Lakes.

Winds will back to westerly later Thursday...and eventually become
light and variable by Saturday morning as the surface high crests
over the Lakes.

&&

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

&&

$$

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