585
FXUS61 KBUF 131742
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
142 PM EDT Thu Jun 13 2024

.SYNOPSIS...
A cold front will slowly sag through the region tonight while likely
generating some showers and possible thunderstorms into Friday
morning. A fresh Canadian airmass and expansive high pressure in its
wake will guarantee fair but cool weather to start the weekend...and
this will be followed up by simply gorgeous weather on Sunday. Mid
summer heat and humidity will then build across our region for much
of next week with apparent temperatures in  most areas soaring to
between 95 and 100.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
Delightful weather will be in place for the remainder of the
afternoon...as sun filled skies will be accompanied by widespread
temperatures in the low to mid 80s.

A cold front over the Upper Great Lakes this evening will slowly
settle to the south during the course of the night...crossing our
forecast area between midnight and early Friday morning. The front
will generate some showers and possible thunderstorms in the
process. While the timing of the cold frontal passage will not be
conducive to support strong convection...we can expect basin average
rainfall amounts that will range from a tenth to a quarter inch.
Any organized convection will have the potential to produce
localized amounts of a half to up to one inch.

Some leftover showers will be possible Friday morning...mainly south
of Buffalo and Rochester...as the aforementioned cold front will
continue its slow push into Pennsylvania. Clearing skies from north
to south will then take place during the midday and afternoon. This
should leave pleasant conditions for most areas for the latter
portion of the day. It will be cooler with max temperatures in the
70s.

Expansive high pressure over the Upper Great Lakes Friday evening
will slowly drift southeast during the course of the overnight. This
will guarantee fair dry weather with temperatures falling into the
50s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
A strong area of high pressure at all levels will build back
across the Great Lakes in the wake of the trough on Saturday. 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 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 THURSDAY/...
...Headline Worthy Summer Heat Expected This Period...

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 oppressive 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 low 70s, which will
cause overall heat indicies in the afternoon to climb into the mid
90s to lower 100s.

It will not only be the impressive level of oppressive midday and
afternoon heat to contend with, but the cumulative impacts of only
having the mercury settle to near 70 for the overnights (Monday
night and beyond), thereby extremely limiting any relief.

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 /18Z THURSDAY THROUGH TUESDAY/...
VFR conditions will be in place through this evening. The only
potential issue will be gusty sfc winds today. Winds of 15 to 25
knots will be fairly common though until about sunset...with some
gusts to 30 knots for the IAG Frontier (KIAG and KBUF).

A slow moving cold front will press through the region later tonight
and early Friday. While VFR flight rules are forecast to persist...
the front will support at least scattered shower and thunderstorm
activity. The exception will be across the Southern Tier where MVFR
to IFR cigs will be likely between about daybreak and midday Friday.

Outlook...

Friday night through Tuesday...VFR.

&&

.MARINE...
A cold front will move across the lower Great Lakes late tonight and
early Friday. Southwest winds will increase ahead of the front
today, 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
NEAR TERM...RSH
SHORT TERM...PP
LONG TERM...PP/RSH
AVIATION...RSH
MARINE...AR/RSH/TMA