-- Discussion containing changed information from previous version are highlighted. --
706
FXUS61 KBUF 111837
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
237 PM EDT Tue Jun 11 2024

.SYNOPSIS...
Extensive cloud cover across the region will gradually erode
through this evening. High pressure will build across the
region, bringing dry weather which will last tonight through
most of Thursday. A cold front will bring another round of
showers and scattered thunderstorms Thursday night through a
portion of Friday.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
A deep mid level trough will continue to move slowly east
across New England tonight. A moist cyclonic flow on the
western flank of the trough will persist across the eastern
Great Lakes this afternoon. As this trough moves further away,
the cloud cover will gradually erode through this evening.
Mostly cloudy and cool weather early this afternoon, with some
warming where the sun breaks out late afternoon and evening.
Afternoon temperatures will be well below normal, only topping
out 60 to 65F.

High pressure will build over the eastern Great Lakes tonight.
This will clear out the low clouds, although some mid-level
clouds will enter Western NY late tonight. The clearing will
allow some patchy fog to develop in the Southern Tier river
valleys overnight. Light winds will also allow for good
radiational cooling when skies are clear, with lows ranging from
the mid 40s to lower 50s.

Surface high pressure will build across the region Wednesday and
Wednesday night, resulting in dry weather. A band of mid-level
clouds will move from west to east across the area Wednesday,
but outside of this skies will be mostly clear. It`ll also be
warmer during the day Wednesday, with highs in the lower to mid
70s. This is near normal for mid-June.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
-- Changed Discussion --
On Thursday our area will be situated within the deepening
southwesterly flow in between high pressure anchored off the east
coast...and a mid-level trough/associated area of low pressure
sliding across the Upper Lakes and central Ontario Province to
western Quebec. While the cold front associated with this system
will remain well to our west through the day...a weak leading
shortwave impulse and warm frontal segment out ahead of this system
will slide across our region. This may bring some widely scattered
showers/isolated thunderstorms during the afternoon...with the
greatest chances of these found across the counties bordering Lake
Ontario where the best combination of moisture...lift...and
instability will come into play. Outside of these the day will just
be dry...notably warmer...and increasingly breezy as the
southwesterly flow across our region ramps up. Highs will mostly
range in the lower to mid 80s...with the warmest readings (upper
80s) found near Dansville...and the coolest temps immediately
northeast of Lake Erie due to the stiffening southwesterly breeze
off that lake...which may gust to 30-35 mph at times.

Thursday night and very early Friday the core of the mid-level
trough and the attendant surface low will eject northeastward across
Quebec Province...while pivoting its trailing cold front across our
region. In the spatial and temporal senses the best overall chances
for any associated showers and embedded storms will lie near Lake
Ontario and across the North Country Thursday evening...with this
potential then fading through the rest of the night and with
increasing southeastward extent as instability wanes and the frontal
boundary becomes increasingly estranged from its departing mid-level
support. Otherwise...lows will largely be in the lower to mid 60s.

On Friday the main cold front will slide off to our southeast...
with high pressure and drier air building eastward into our region
in its wake. With the guidance continuing to trend toward the above
happening more quickly...any convection associated with the front
should be faster to exit our region during the morning...leaving
behind a largely dry afternoon. The one possible exception to this
will be across the North Country and Saint Lawrence Valley...where
the approach and passage of a secondary shortwave trough/weak cold
front could produce a few more widely scattered showers and storms
during the afternoon and early evening. Otherwise the cooler and
drier airmass building in behind the front will result in highs
ranging through the 70s.

The increasingly expansive surface ridge will then strengthen as it
builds across our region Friday night...bringing an end to any
spotty convection across the North Country and leading to a quiet
and tranquil night otherwise. With good radiational cooling
conditions in place...lows will settle back into the upper 40s
across the North Country and interior of the Southern Tier...and
into the lower to mid 50s elsewhere.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
-- Changed Discussion --
Upper level trough responsible for the cooler weather earlier this
week will exit the Northeast Saturday, while ridging will advance
and build east across the Great lakes Sunday through Tuesday. While
the ridge builds east across the region, a short wave trough will
ripple across the top of the ridge Monday.

Overall with the exiting trough followed by the ridge building east,
surface high pressure centered over the Great Lakes Saturday morning
will slide southeast towards the Atlantic Coast by Monday morning.
While this pattern will support dry weather throughout the weekend,
it will also support warm and moist Gulf of Mexico air to filter in
across the area supporting temperatures to surge above normal for
mid June.

The aforementioned shortwave trough rippling across the top of the
ridge across the Great Lakes, will support a surface low well to the
north across northern Ontario and Quebec. Extending southward from
the low will be a pair of fronts to slide east across the eastern
Great Lakes. This far out, timing and placement continues to be in
question and therefore have slight chance to low end chance for
showers and afternoon thunderstorms Monday afternoon through
Tuesday. Despite the frontal passages, temperatures will continue to
be above average.
-- End Changed Discussion --

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
A mid level low across New England will maintain a cool and
cyclonic flow aloft here, resulting in some lingering MVFR
stratus. This cloud cover will continue to erode this afternoon
as the mid level low moves further away.

Mainly VFR flight conditions by this evening as surface high
pressure builds in. Some river valley fog may impact KJHW
tonight, depending on how long it clears. After the stratus
clear out, there will be a band of mid level clouds which moves
across the area from west to east late tonight into Wednesday.
VFR flight conditions on Wednesday.

Outlook...

Wednesday night and Thursday...VFR.

Thursday night and Friday...VFR/MVFR. Showers and thunderstorms
likely.

Friday night through Sunday...VFR.

&&

.MARINE...
High pressure will build across the Eastern Great Lakes,
resulting in light winds which will last through Wednesday
night.

A cold front will then move across the eastern Great Lakes late
Thursday night and early Friday. Southwest winds will increase ahead
of the front Thursday, 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...Apffel/Hitchcock
NEAR TERM...Apffel/Hitchcock
SHORT TERM...EAJ
LONG TERM...JJR
AVIATION...Apffel
MARINE...Apffel