643
FXUS61 KBUF 141911
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
311 PM EDT Sun Jul 14 2024

.SYNOPSIS...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight...while also giving way to
the first in a series of disturbances that will bring a few showers
and thunderstorms to far western New York this afternoon...then to
the rest of the area tonight. Very warm and sultry conditions will
then follow for Monday and Tuesday along with periodic chances of
showers and thunderstorms. A cold front will then cross the area
between Tuesday night and Wednesday along with some more showers and
thunderstorms...with notably cooler and drier air then following in
its wake for the rest of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
The first in a series of convectively augmented shortwaves is
currently working across nearby southern Ontario...and is generating
a couple areas of convection that are lifting northeastward. The
first of these is line of showers and storms between Hamilton and
Georgian Bay...while the second is a smaller cluster of showers and
storms located near Erie Pennsylvania.

As we push through the rest of the afternoon this initial shortwave
will make its way across far western New York. Our current airmass
is notably drier and more stable compared to the source region of
the convection and is thus likely to take at least some toll on the
showers and storms as these try to push into our area...though given
current radar trends feel at least some of this activity will
survive the trip into our area. The greatest potential for this will
be across the western Southern Tier (and to a lesser extent) Niagara
county...and have upped both PoPs and thunder probabilities a bit
from continuity to account for this...with the best chances for any
thunder found across the Southern Tier. Otherwise it will be very
warm with most areas seeing highs between 85 and 90...and surface
dewpoints generally slowly rising through the 60s.

This first shortwave will push east across the rest of the area this
evening...with its associated convection continuing to weaken as it
pushes further east into progressively drier and more stable air. A
relative lull will then ensue...before one or more additional such
impulses arrive overnight in concert with increasing instability as
a warmer and increasingly moist airmass overspreads our region. This
will support the potential for at least some additional scattered
showers and storms overnight. Otherwise it will be notably more
uncomfortable than the last couple of nights...with surface
dewpoints climbing into the mid to upper 60s...and low temperatures
having trouble falling below the upper 60s and lower 70s in many
places.

On Monday at least one more convectively-augmented wave looks to
cross the region during the day...however the timing and placement
of this wave remains much in question at this time. Regardless...
this feature along with developing lake breeze boundaries should
help to generate at least some additional scattered showers and
thunderstorms...with this activity possibly becoming a bit more
numerous inland from the lakes during the afternoon...particularly
if the shortwave passage aligns with peak diurnal heating. With
PWATs up around 1.75 inches...any storms could produce locally heavy
downpours. Otherwise the sultry conditions will continue...as highs
of 85 to 90 will coupled with surface dewpoints near 70 degrees.
While this could briefly yield some apparent temperatures near 95
degrees across portions of the Finger Lakes...will hold off on any
heat advisories for now given the expected brief/marginal nature of
such readings...as well as the potential for convection to inhibit
apparent temps from actually getting that high.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Ensemble members show zonal, mid-level flow across the eastern Great
Lakes region Monday night through the first part of Tuesday night. A
westerly, 500mb flow will increase during this time as a sharp mid-
level trough moves south from James Bay. Mid-level winds will begin
to back to the southwest ahead of this trough late Tuesday night
with a 50kt winds at 500mb across the forecast area by Wednesday
afternoon. The trough maintains a positive tilt as it slides across
the Great Lakes region Wednesday night. Deterministic models
including CAMs show the potential for convectively induced shortwave
troughs to trigger convection at times Monday night through
Wednesday. A cold front will move through the forecast area
Wednesday bringing a switch to cooler and drier weather.

Warm and muggy weather is expected Monday night with low
temperatures in the low 70s and dewpoints in the upper 60s to low
70s. A southerly wind will increase through the overnight hours and
should preclude widespread fog development, however patchy fog is
possible in sheltered valleys. Previous day convection will be
exiting the forecast area Monday evening with mostly quiet weather
the rest of the night. A convectively induced shortwave trough will
approach the region Tuesday morning. Convection may still be ongoing
in the warm and humid airmass so chances for showers and
thunderstorms will increase across the far west late Monday night
into Tuesday morning. This impulse will move across the forecast
area late Tuesday morning through Tuesday afternoon. There is some
question as to how much surface based instability will form due to
cloud cover, however PWATS will be increasing with dewpoints in the
low 70s. Temperatures will rise into the low to mid 80s, with mid to
upper 80s across the Finger Lakes region into central NY.
Instability will likely rise over 1000 J/kg and thunderstorms are
expected to increase in coverage. The wind field ahead of an
approaching mid-level trough will be increasing, however shear
remains weak to marginal. Wet microbursts are possible with an
isolated threat of severe storms. Showers and thunderstorms may also
form across the Niagara Peninsula and enter Niagara county Tuesday
afternoon through Tuesday evening. Any thunderstorms are capable of
heavy downpours and localized flooding. At this time,
thunderstorm coverage is expected to be isolated to scattered
across the forecast area with low confidence that flooding would
occur in any particular place. Regarding heat, heat index
values may reach the mid 90s in the Finger Lakes region. Cloud
cover and rain could play a role in temperatures through the
afternoon. While we have heat indices in the mid 90s in this
area right now, confidence is not there to issue a Heat
Advisory.

A cold front will approach the region Tuesday night. Previous
afternoon, showers and thunderstorms will move east of the forecast
area Tuesday evening, while another round of showers and
thunderstorms may move into the forecast area from the west or the
south overnight. Confidence is low where and when showers and
thunderstorms will be and kept low to medium chances overnight. The
cold front will enter the forecast area Wednesday morning. Model
consensus shows the cold front entering the forecast area Wednesday
morning. As the front moves east, drier and more stable air will
move into the region from the west. Showers and thunderstorms will
become likely ahead of the cold front but due to the timing of the
cold front, the more favorable conditions will be far inland before
they move out of the forecast area. Mostly dry weather is expected
Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Sprawling Canadian high pressure will gradually extend eastward
across the Great Lakes and Northeast through the period and
bring a return to cooler and more comfortable weather. Expect
surface dewpoints to fall into the 50s later Wednesday and
remain there through Saturday, while highs pull back to the
lower to mid 70s Thursday, then only gradually climb back to the
upper 70s to lower 80s by Saturday.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight. This will allow the first in
a series of disturbances to cross far western New York this
afternoon along with a few weakening showers and thunderstorms. This
wave and its convection will then continue to push further east and
weaken as it crosses the rest of the area this evening. In general
conditions through this evening will remain VFR under increasing/
lowering clouds...with just a very low chance of restrictions in
convection across the Southern Tier.

Overnight and Tuesday additional such hard-to-time disturbances will
cross the area from west to east...and these in tandem with a
general increase in instability will support the potential for some
additional scattered showers and storms at times. This being said
conditions will continue to be predominantly VFR...with some MVFR
ceilings possible across the Southern Tier late tonight...and then
some brief/localized MVFR restrictions possible within any
convection during Monday.

Outlook...

Tuesday and Tuesday night...VFR/MVFR with scattered to numerous
showers and thunderstorms.

Wednesday...VFR/MVFR with a chance of showers and thunderstorms.

Thursday and Friday...VFR.

&&

.MARINE...
High pressure over eastern New York and New England will drift to
the Atlantic coastline through tonight. Southwest winds will
increase into the 10-15 knot range tonight through Monday as the
high drifts off the east coast, enough to produce some chop on Lake
Erie and Lake Ontario. The southwest winds will increase further
Monday night through Tuesday, producing more notable chop on both
lakes.

There is a chance of a few thunderstorms across eastern Lake Erie
and western Lake Ontario this afternoon and evening...then in a more
general sense later overnight through Wednesday...with the potential
for locally higher winds and waves in and near any storms.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...HSK
LONG TERM...JM/JJR
AVIATION...JJR
MARINE...Hitchcock/JJR