397
FXUS61 KBUF 130758
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
358 AM EDT Thu Jun 13 2024

.SYNOPSIS...
High pressure moving off the East coast will provide us with fair
dry weather through Thursday. Temperatures will climb into the 80s
Thursday, then the passage of a cold front Thursday night will
support some showers and possible thunderstorms. Mid summer warmth
and humidity is guaranteed for early next week when apparent
temperatures will soar into the 90s.

&&

.NEAR TERM /THROUGH TONIGHT/...
The only thing of note overnight is some high clouds filtering
in from the upstream convection over Wisconsin.
Otherwise...quiet weather will dominate the overnight hours as
the axis of shortwave ridge crosses the region. It will not be
as cool...particularly over the western counties where mins of
55 to 60 (nr 50 Lewis co) will be some 7-10 deg higher than
those of the past few nights.

Thursday will be noticeably warmer...as sfc based ridging along the
East Coast will circulate H85 temps in the mid teens C across our
forecast area. This will combine with sunshine through high clouds
that will support afternoon temperatures in the low to mid 80s F.
The warm weather will be accompanied by a touch of humidity as well
with many areas experiencing Td`s close to 60.

A slow moving cold front will sag to the south through the area
during the course of Thursday night. This will likely lead to some
showers and possible thunderstorms...particularly east of both
lakes where basin average rainfall could be as high as a
quarter inch. Otherwise...basin average rainfall is forecast to
generally be a tenth of an inch or less.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Surface low pressure initially across eastern Quebec will shift
northeast into Labrador through the course of the day Friday. The
system`s elongated cold front will gradually sag southward through
the eastern Great Lakes as it does so, with the greatest threat for
showers and a few storms moving in tandem just out ahead of the
boundary. A lingering convective wave moving out of the Ohio Valley
will likely move into the region and ripple along the front Friday
morning, slowing its progress while causing a few moderate to
locally heavy showers and/or thunderstorms to blossom across
portions of the Southern Tier and western Finger Lakes region. While
the steadier shower activity should be mainly southeast of the
forecast area by the afternoon, diurnal heating and residual
moisture ahead of the system`s parent upper level trough axis could
cause a few additional lighter showers or an isolated thunderstorm
to redevelop across western NY. Chances for this look to be slightly
better up in the North Country where a weak secondary shortwave will
move through, though subtle differences in the timing of the upper
trough axis are noted among the latest 00z suite of guidance so will
shy away from higher PoPs at this juncture. Otherwise, the cold
front will knock daytime temperatures back to near normal values
Friday with highs in the low to mid 70s, a few readings in the 60s
across the hilltops.

A strong ridge of high pressure at all levels will build back across
the Great Lakes in the wake of the trough Friday night. The center
of the surface high should move directly overhead by Saturday night,
then shift east and migrate off the East Coast by the end of the day
Sunday. This will result in dry, tranquil weather across the
forecast area through the weekend with pleasant temperatures. Highs
Saturday will be on the cooler side mainly in the upper 60s to low
70s as the region remains within the post-frontal airmass. With the
onset of warm air advection on the backside of the high Sunday,
temps should top out in the upper 70s to low 80s with low humidity.
Nighttime lows Friday and Saturday night will be cool, dipping into
the 50s across the lower terrain and mid/upper 40s across the
interior of the Southern Tier and North Country.

While the weekend will feature superb weather for outdoor
activities...It will also present the perfect opportunity for
anyone who has yet to put in their AC units to finally do so
BEFORE the heat and humidity surges next week. More on that in
the long term section below.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
...Summer Heat To Impact The Region Next Week...

The longwave pattern across the CONUS next week will be dominated by
broad troughing west of the Rockies and an expansive ridge across
the east. This ridge is expected to become abnormally strong, with
overhead 500mb heights potentially climbing to near 600dm (2-3SD
above normal compared to climatology) by the middle of the week. The
resultant Bermuda High will anchor itself over the western Atlantic,
with deep anticyclonic flow around the high causing a warmer airmass
to surge across the eastern CONUS. 850H temps over the forecast area
within this airmass are expected to quickly reach or exceed +20C by
Monday and stay within this range through the remainder of the 7 day
forecast, and potentially beyond.

In terms of sensible weather, what this will translate to at the
surface will be a prolonged stretch of sultry summer heat and
humidity. Daytime temperatures Monday will feature widespread upper
80s and lower 90s, though remaining a bit cooler across the North
Country with low/mid 80s where a slightly cooler airmass will
linger. By Tuesday and Wednesday, widespread high temperatures in
the low to mid 90s are expected, hottest in the interior valleys and
coolest just northeast of both lakes (including the Buffalo area) as
a persistent southwest flow advects cooler marine air off the lakes.
This heat comes as dewpoints climb into the upper 60s and low 70s,
which will cause overall heat indicies in the afternoon to climb
into the mid and even upper 90s.

Muggy nights will offer little relief as sleeping temperatures will
quickly become very uncomfortable next week. While lows Sunday night
will range from the upper 50s to mid 60s, by Monday night and beyond
lows are not expected to dip below the 70s outside of the interior
hilltops of the Southern Tier and North Country.

While the added heat and humidity will also force a degree of
daytime instability next week and lead to some extent of diurnal
shower and storm development outside of the stable lake
shadows...There remains uncertainty in the position and orientation
of the upper ridge, as well as shortwave ripples expected to crest
over it, and the degree of the subsidence capping likely to be in
place on any given day. Thus PoP values remain low (15-20%) as
confidence is low in coverage and intensity of any potential
convection that develops or moves into the region next week.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Fine flying weather will remain across area TAF sites with VFR
overnight.

Sfc winds on Thursday will increase to 15 to 25 knots in most areas
with gusts over 30 knots possible at both KBUF and KIAG.

Outlook...

Thursday night and Friday...VFR/MVFR. Showers and thunderstorms
likely.
Friday night through Monday...VFR.

&&

.MARINE...
Light winds and minimal wave action on area lakes overnight.

A cold front will then move across the Lower Great Lakes late
Thursday night and early Friday. Southwest winds will increase ahead
of the front Thursday, with winds remaining elevated through Friday.
This will bring choppy conditions to both lakes. High pressure will
then build back across the waters with light winds and generally
favorable boating conditions during the weekend.

&&

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

&&

$$

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