826
FXUS61 KBUF 142121
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
521 PM EDT Fri Jun 14 2024

.SYNOPSIS...
A weak cold front could touch off a shower or two across the North
Country through the early evening hours, otherwise 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 /THROUGH SATURDAY NIGHT/...
Delightful weather with a mix of sun and clouds through early
evening, although a weak cold front sagging south from the Ottawa
Valley will support a few passing showers across the North country,
with the outside chance for an isolated thunderstorm.

Tonight, expansive high pressure centered over the upper Great Lakes
will slowly drift to the southeast towards our region. While some
clouds wil be found across the North Country to start, this scenario
will promote moonlit skies tonight with temperatures dipping to
below normal levels. Mins will range from the mid 50s in most areas
to the mid and upper 40s across much of the Southern Tier and also
across Lewis County.

The large area of high pressure will move directly over our region
Saturday and Saturday night. This will support mainly clear skies,
although it will be on the cool side of normal with Saturday
afternoon temperatures only in the 60s to near 70. Mins Saturday
night will be lower than to those of tonight for much of the area.

Enjoy this pleasant weather that will be in place through this
weekend, before dangerously oppressive heat and humidity takes hold
for much of next week.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Broad mid-level ridging centered across the Great Lakes Sunday will
continue its eastward progression into the eastern Great Lakes
through Monday. Meanwhile within the ridging, a shortwave trough
will ride the top of the ridge Sunday and Monday well to the north
of the region. While this shortwave trough indicates some active
weather Sunday night through Monday, its placement well to the north
should keep any activity outside of the area. This being said, have
slight chances for showers and thunderstorms Monday afternoon.

Outside of this, deep southerly flow will advect in warmth and
moisture from the Gulf of Mexico initiating the heat wave for the
middle portion of the week. Highs Sunday will topple off in the low
to mid 70s across the North Country and upper 70s to low 80s
elsewhere. Monday will be warmer with highs in the mid to upper 80s
across most of the region, however across the climatologically
warmer places in the Genesee Valley a few low to mid 90 readings
will be possible. These 90 degree readings along with the humidity
will create heat index values to range in the mid to upper 90s.

&&

.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. 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.

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

Otherwise...The primary forecast uncertainty through much of next
week continues to be the potential for convection. Daytime surface
based instability will 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. Given the low confidence in shower
and storm timing and coverage, PoPs values remain on the low side
(15-30%) through Thursday.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
While a weak secondary cold front could touch off a shower across
the North Country through the early evening hours, dry weather with
widespread VFR conditions and generally light winds can be
expected through the TAF period.

Outlook...

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

&&

.MARINE...
Westerly winds behind a cold front will generally remain below 15
knots through early evening, before veering more northerly tonight.
Conditions will remain below headline criteria through the weekend,
although there may be brief periods with some light to moderate
chop, especially on Lake Ontario.

&&

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

&&

$$

SYNOPSIS...JM/RSH
NEAR TERM...JM/RSH
SHORT TERM...EAJ
LONG TERM...HSK/PP
AVIATION...JM/RSH
MARINE...JM