-- Discussion containing changed information from previous version are highlighted. --
136
FXUS61 KBUF 150513
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
113 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 /THROUGH TONIGHT/...
Tonight, expansive high pressure centered over the upper Great Lakes
will slowly drift to the southeast towards our region. Other than
some patchy areas of clouds, this scenario will promote moonlit
skies tonight with temperatures dipping to below normal levels. Mins
will range from the low to 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 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 /05Z SATURDAY THROUGH WEDNESDAY/...
Widespread VFR flight conditions will remain in place overnight,
with just some patchy areas of low level VFR clouds.

High pressure will build overhead on Saturday, providing dry weather
with VFR flight conditions and light winds through the end of 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...
Northwesterly winds behind a cold front late this evening will
generally remain below 15 knots while veering more northerly
overnight. 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 later tonight into
Saturday morning, then western Lake Ontario Sunday afternoon.

&&

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

&&

$$

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