-- Discussion containing changed information from previous version are highlighted. --
846
FXUS61 KBUF 151414
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1014 AM EDT Sat Jun 15 2024

.SYNOPSIS...
High pressure moving in from the upper Great Lakes will supply us
with fantastic weather for the weekend. Oppressive heat and humidity
will then DOMINATE our weather next week with dangerously high
apparent temperatures, peaking in the upper 90s to low 100s Tuesday
and Wednesday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
High pressure building into the region will bring mainly sunny skies
today. Diurnal cumulus have developed across the higher terrain of
the Southern Tier, Finger Lakes, and east of Lake Ontario. These
will continue through early afternoon, then tend to mix out later in
the afternoon as the limited low level moisture is depleted by
ongoing diurnal mixing. Temperatures will be on the cooler side of
normal with most highs in the upper 60s to lower 70s.

Mainly clear skies tonight along with light winds will allow
temperatures to drop into the mid 40s to lower 50s.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
High pressure will bring fair weather Sunday to our region. Low
PWATS and southeast flow will keep dewpoints on the comfortable
side, with dewpoints around 50 through the day.

A shortwave cresting a mid level ridge will bring potential for a
few showers to Lake Ontario and points eastward late Sunday night,
with activity ending east of Lake Ontario early Monday with the
passing of the shortwave aloft.

Monday the surface pressure gradient will increase with the passing
of the shortwave aloft, with a bit of a southerly breeze in the 20
mph range. While not a great magnitude, this southerly flow behind
the departed surface high will increase moisture advection through
the day.

Monday will have a noticeable increase in moisture, with dewpoints
rising into the 60s, some 15 to 20 degrees warmer than Sunday. This
combined with surface temperatures in the mid 80s to around 90F will
bring apparent temperatures in the afternoon into the mid 90s.

The increase in temperature and moisture will create plenty of low
level instability. However aloft a 700/500 hPa ridge axis will be
increasing through the day, likely to prevent most if not all
towering cumulus from becoming full thunderstorms.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
...Dangerous Heat Wave To Impact The Region Next Week...

A very strong 500mb ridge will anchor itself across much of the
eastern CONUS and western Atlantic through much of the week, which
will dominate the sensible weather across the eastern Great Lakes.
NAEFS ensemble guidance continues to indicate this ridge will be of
anomalous strength with 500mb heights and 850mb temperatures in the
99th percentile, if not exceeding the maximum climatological values
for the Northeast through Thursday. Deep anticyclonic flow around
the resultant Bermuda High will cause hot, humid air to surge across
the eastern CONUS. Given the strong signal from nearly all available
long range guidance packages, confidence is high in a prolonged
stretch of oppressive summer heat and humidity lasting through much
of the week.

Not much change to previous forecast packages with daytime highs
solidly in 90s Tuesday through Thursday. Highest temps will be in
the interior valleys, while cooler temps will be found immediately
along the lakeshores and immediately northeast of both lakes
(including Downtown Buffalo) as a persistent southwest flow advects
cooler marine air off the lakes. Have leaned more towards the ECMWF,
Canadian and ICON models for temperatures as the GEFS/GFS seems to
have too much convection/clouds given the strength of the 500 hPa
ridge.

Tuesday and Wednesday still seem like the peak days of excessive
heat and humidity with low 100s possible in interior valleys. 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.

An upper level trough over south-central Canada will move east
through the end of the week. The approaching trough will begin to
suppress the strong ridge over the eastern Great Lakes region
Wednesday night. Based on the NAEFS, 850mb temperatures will begin
to fall into the upper teens Thursday through Friday, HOWEVER this
may only result in a few degrees difference from Tuesday and
Wednesday, continuing the heat wave across the forecast area. For
context, daytime highs average the upper 70s for Buffalo, Rochester,
and Watertown during the days of June 18-21. Record high
temperatures and record warm minimum temperatures are possible this
period, and the climate section below lists such records for
Buffalo, Rochester and Watertown.

Little relief is expected overnight with overnight lows in the upper
60s to mid 70s within a muggy airmass.

Otherwise...The primary forecast uncertainty through much of next
week continues to be the potential for convection. Daytime surface
based instability will greatly be present each afternoon with
dewpoints climbing into the upper 60s and low 70s although the
strong ridge should preclude much of the diurnal convective
potential with strong capping expected to be in place for Tuesday
and Wednesday. A shortwave driving through this ridge Thursday could
bring an isolated shower or thunderstorm Thursday or slightly
better, on Friday.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
High pressure will build overhead through tonight, providing
dry weather with VFR flight conditions and light winds through
the end of the TAF period.

Outlook...

Sunday through Monday...VFR.
Tuesday through Wednesday...VFR, but a slight chance for afternoon
thunderstorms inland from the lakes.

&&

.MARINE...
Conditions will remain below headline criteria through the weekend,
although there may be a few periods with some light to moderate
chop, especially on eastern Lake Ontario this morning, then western
Lake Ontario Sunday afternoon.

&&

.CLIMATE...
A prolonged period of heat is expected for our region, starting
Monday June 17th. Below are record high temperatures for our three
main climate sites:

...Buffalo...

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

...June 17........94/1994............73/2006
...June 18........95/1994............73/2006
...June 19........90/2001............73/1919
...June 20........92/1995............73/2012


...Rochester...

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

...June 17........94/1994............70/1994
...June 18........97/1957............72/2018
...June 19........95/2001............72/1919
...June 20........95/1953............72/1923


...Watertown...

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

...June 17........89/1994............68/1949
...June 18........91/1957............70/1992
...June 19........91/2007............70/1949
...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...None.
MARINE...None.

&&

$$

SYNOPSIS...JM/RSH/TMA
NEAR TERM...Hitchcock/TMA
SHORT TERM...Thomas
LONG TERM...HSK/PP/Thomas
AVIATION...JM/TMA
MARINE...JM/TMA
CLIMATE...Thomas