069
FXUS61 KBUF 202141
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
541 PM EDT Thu Jun 20 2024

.SYNOPSIS...
While it will still be uncomfortably warm and humid through this
weekend...a frontal boundary oscillating back and forth over our
region will support enough cloud cover and thunderstorm activity to
suppress the dangerously high heat indices. Unfortunately...the
daily thunderstorms will carry the risk of torrential downpours and
even severe weather. Notably cooler and more comfortable conditions
can then be expected next week...especially during the latter half.

&&

.NEAR TERM /THROUGH FRIDAY/...
An anomalously strong 598dm ridge stretching from the Ohio valley to
the Mid Atlantic coast will maintain very warm and muggy sub tropical
conditions (PWAT values nr 1.75" and Tds in 70s) across the region
to end this work week...but the good news is that it will slowly
weaken and retrograde to the Lower Mississippi valley by the start
of the weekend. This will signal a gradual change to more comfortable
conditions...particularly next week.

In the process though...we will have to contend with bouts of robust
thunderstorm activity that will include torrential downpours and
potentially severe weather.

As of late this afternoon/early evening...lake shadows east-northeast
of both lakes are still maintaining fair dry weather for most of the
largely populated areas. There are scattered storms across parts of
the Srn Tier where the greatest instability is found...but the more
immediate concern is the organized strong convection crossing southern
Ontario into the Thousand Islands/St Lawrence valley area. This is
associated with the second of two residual MCVs and likely carry the
greatest risk for impactful convection. You can see the cyclonic
rotation in this area of storms both in VSB and radar imagery. By 7-8
PM...this area of convection will be east of our area.

Our attention will then turn to the west where strong storms in the mid
western states environment between Hamilton and London, OT, will be
approaching the IAG Frontier. This activity should weaken...both due to
the present lake breeze and also due to the gradual lessening of the
diurnal influences to the instability. Most of the CAMs are suggesting
the same...but will still have the potential for storms over the IAG
Frontier as we transition past sunset.

Otherwise...as we move through tonight...a weak slow moving frontal
boundary will slowly drop southeast into the area. This will result in
a continued for showers and thunderstorms. The warm and humid airmass
will continue to support thunderstorms with the frontal boundary
continuing to weaken...providing only minimal relief...mainly north of
where it stalls. Temperatures tonight will be in the upper 60s to low
70s for most of the area. This will only be a few degrees lower than
the stuffy conditions of the past several nights.

Friday, showers and thunderstorms will continue with the frontal
boundary stalled over the area from west to east. A few showers and
storms in the morning should increase in coverage some as daytime
heating increases instability. Guidance is a bit split on coverage
of showers and how heavy some of the showers will get, but the best
coverage for showers will once again be in the afternoon with the
daytime heating, that is generally agreed on among guidance. Friday
afternoon highs in the low to upper 80s will be coolest to warmest
from the north to the south with the frontal boundary draped west to
east over the area.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Friday night, the stalled front across the area will begin to slowly
push north as a warm front late in the night and into the early
Saturday morning. Can`t rule out a stray shower or thunderstorm but
for the most part there should be a break in precipitation Friday
night.

Most models show a weak shortwave passing by to the north which
would cause the front to meander a bit during the day Saturday. The
North Country should stay on the cool side of the boundary. The
shortwave is likely to generate some showers with its passage, but
there`s a lower risk of thunderstorms in the North Country. For the
Western NY, a lot depends on the timing of the shortwave with lower
chances for showers and thunderstorms if it passes in the morning
and greater chances if it`s in the afternoon. High temperatures will
range from the upper 80s near the Pennsylvania border to the upper
70s in the North Country.

Strengthening low pressure tracking across the central Great Lakes
will lift the front back to the north, putting the entire forecast
area in the warm sector. The warm and moist air mass will support
small chances for showers and thunderstorms across Western NY with
showers and storms likely across the North Country which will be
closer to the boundary and any disturbances that track along it.

A 995mb surface low and robust shortwave tracking to our north will
result in a windy day on Sunday with 850mb winds increasing to about
45 knots. This will push a strong cold front across the area which
is likely to produce some thunderstorms with its passage. There will
be ample wind shear in place to support organized convection with
damaging winds possible. Timing will be key, with model consensus
bringing the front through slightly earlier than ideal to produce
storms in far Western NY, with greater risks for storms closer to
Central NY. But this could change in future model runs. Even without
convection it will be windy across the Niagara Frontier where wind
gusts of 45 mph can be expected.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A cold front will slide east of our area Sunday night, with
lingering showers and thunderstorms tapering off from west to east.
This will be followed by a potent shortwave which will dig across
northern New England on Monday. This will bring increasing chances
for showers and a few thunderstorms across the North Country with
low chances elsewhere which will be further from the disturbance. It
will also be notably cooler and less humid with highs on Monday only
in the 70s.

High pressure will move across the region Monday night and Tuesday,
resulting in rain free and cooler weather. Another shortwave will
pass by well to the north Tuesday with an associated cold front
moving across the area Tuesday night or Wednesday. This will bring
warmer weather ahead of the cold front with a chance of showers and
possibly a thunderstorm. The cold front will then usher in cooler
weather for Thursday. By Thursday highs should only be in the upper
60s to lower 70s. Did hedge below model guidance for high temps
given the cool air mass and recent warm weather included in bias
correction.

&&

.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
Tonight...VFR conditions outside of showers and storms. Once again
there will be the potential for some fog in the river valleys of the
S. Tier.

Friday, showers and thunderstorm potential remains across much of
the area, especially inland form the lakes and during the afternoon
hours. Mainly VFR conditions except in showers/storms that may cause
reductions to VSBYs at times.

Outlook...

Saturday...Mainly VFR, but a chance for mainly afternoon
and evening thunderstorms inland from the lakes.
Sunday...VFR/MVFR. Showers and thunderstorms likely.
Monday...Mainly VFR, but a chance for afternoon and evening
thunderstorms inland from the lakes.
Tuesday...Mainly VFR conditions expected.

&&

.MARINE...
A generally quiet period is expected for the lower Great Lakes
through the rest of the week and into the first half of the weekend
as a large upper-level ridge remains across the eastern CONUS,
resulting in a lighter surface flow. Only concern will be in the
afternoon and early evening hours as showers and thunderstorms could
produce briefly higher wind gusts and waves.

Increasing winds on Sunday will bring the next potential for Small
Craft Advisory conditions for both lakes.

&&

.CLIMATE...
The heat will continue today. Below are record high
temperatures for our three main climate sites:

...Buffalo...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 20........92/1995............73/2012


...Rochester...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 20........95/1953............72/1923


...Watertown...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 20........90/1971............71/2012

Temperature records for Buffalo and Rochester date back to 1871.
Temperature records for Watertown date back to 1949.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory until 8 PM EDT this evening for NYZ001>008-
     010>014-019>021-085.
MARINE...None.

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH/SW
SHORT TERM...Apffel
LONG TERM...Apffel
AVIATION...AR/SW
MARINE...AR/SW
CLIMATE...Thomas/TMA