-- Discussion containing changed information from previous version are highlighted. --
342
FXUS61 KBUF 261859
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
259 PM EDT Wed Jun 26 2024

.SYNOPSIS...
-- Changed Discussion --
Showers and thunderstorms will impact the area through this evening.
Severe storms along with locally heavy rainfall possible across the
western Southern Tier. Cooler and less humid conditions expected
Thursday and Friday. Active weather returns Saturday as a cold front
crosses the region. Dry weather return Sunday as high pressure
builds in for the start of the new work week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
A diffuse boundary setup across the western Southern Tier will be
the focus for numerous thunderstorms into early this evening.
Mesoanalysis this afternoon showing the better instability and shear
profiles reside just to the south of the New York border.
Nonetheless, the potential exist for some strong to severe storms to
make to shift northwards into the western Southern Tier through this
afternoon. Although the threat for strong to damaging wind gusts
exists with the thunderstorms, a bigger concern will be the
potential for training convection with the potential for very heavy
rainfall and flash flooding. This could especially be the case along
and south of I-86. Farther to the north, across the remainder
of the region the expectation is for an increase in showers and
possible thunderstorms into this evening as a cold front to the
northwest start to push onto the region. Instability and shear
parameters are far from favorable, therefore no severe weather
is expected, but some heavier downpours are possible within a
very moist environment.

Shower and thunderstorm activity will decrease in coverage from west
to east tonight as the cold front crosses the area. Northerly flow
and residual low-level moisture behind the front should allow for
some lower stratus to develop overnight. Some fog is possible for
area which sees rainfall through this evening.

A secondary cold front will finish crossing the area Thursday
morning, bringing a few additional showers. A weak shortwave will
dive across southern Ontario and the Saint Lawrence valley Thursday
afternoon behind the passage of the front bringing the potential
for a few instability showers across the North Country. Otherwise
generally dry weather is expected Thursday, with early morning
low clouds giving way to increasing amounts of sunshine as high
pressure and cooler/drier air builds in. The incoming airmass
will also lead to cooler temperatures and lower humidity levels.
High temperatures ranging from the upper 60s across the higher
terrain to the lower 70s elsewhere with surface dewpoints
falling through the 50s.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
Surface high pressure will crest across our region Thursday night
through Friday evening, providing comfortable levels of humidity and
fair weather. Patchy fog is possible across SW NYS.

Behind the surface high deep southerly flow will transport moisture
northward, with Pwat values peaking near 2 inches by Saturday
afternoon.

Showers, first within isentropic lift along a warm front extending
across our region Friday night and Saturday morning will become more
numerous Saturday afternoon and evening within the deepening
moisture and passage of a subtle shortwave. The evening timing of
the pre-frontal trough, cloud cover holding instability back to
around 750 J/KG or less and poor mid level lapse rates under 6 C/KM
are not favorable for strong to severe storms. However, 0-6 km bulk
wind shear values 35 to 45 kts could aid in strength to the storm if
any taller storms can develop. In addition the very moist atmosphere
will allow for localized heavy rainfall to develop. Training cells
within a SW flow could bring localized ponding of water through
Saturday mid- overnight. Actual cold front will remain off to our
west through the night, leaving a still humid, warm atmosphere with
prospects for fog in place.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
On Sunday the surface low will slide across east-central Quebec to
the Gulf of Saint Lawrence with a mid level shortwave and its
associated initial cold front crossing our area during the morning.
This will be followed by the passage of the main mid-level trough
axis and an associated weaker secondary boundary later Sunday/Sunday
night. Of note with the second cold front will be the much cooler
airmass that gets ushered in behind it with 850Ts dropping back into
the mid single digits C. The passage of these features will support
the potential for some additional scattered showers into at least a
portion of Sunday night (especially eastern areas), and (during
Sunday) a couple more isolated storms. Otherwise high pressure
building in from the west will provide drier, cooler, and more
comfortable conditions with surface dewpoints falling back into the
mid 40s and 50s across the region, lasting through Tuesday. Daytime
highs will be in the mid to upper 70s Sunday and the upper 60s to
mid 70s on Monday. High pressure slides east of the area on Tuesday
with a southerly return flow boosting highs back up into the mid 70s
to low 80s, however very tolerable humidity levels will remain in
place for one more day. Comfortable overnight lows ranging through
the 50s Sunday night and Monday night.

Shower and thunderstorm chances start to ramp up again toward mid
week as the next frontal system approaches the area with a warm
frontal segment crossing the area, followed by another cold front.
Exact timing of these features will become better resolved as we get
closer in time. Also, expect a return to very warm and humid
conditions.
-- End Changed Discussion --

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
Diffuse boundary across the western Southern Tier this afternoon. A
wave riding along this feature will maintain numerous showers and
thunderstorms, some possible severe across the western Southern Tier
through around 23z. KJHW may see periodic impacts with IFR.
Confidence remains lower in shower and thunderstorm coverage north
of the S. Tier. Outside of the areas of precipitation, VFR will
prevail into this evening.

Shower and storm coverage will decrease tonight, but stratus and fog
may bring about MVFR-IFR Cigs and lower vsbys. This will especially
be the case across the higher terrain of the Southern Tier and east
of Lake Ontario.

Outlook...

Thursday and Friday...Mainly VFR.
Saturday...Localized restrictions with shower likely and a chance of
thunderstorms.
Sunday and Monday...Mainly VFR.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Light winds and wave action expected through this evening, but there
will be increasing chances of showers and thunderstorms. Some storms
could produce strong winds and locally higher waves on Lake Erie.

A period of light, variable winds across the lakes will precede
increasing northwesterly winds behind a cold front tonight, though
winds and waves are expected to remain below SCA criteria.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...AR/TMA
NEAR TERM...TMA
SHORT TERM...Thomas
LONG TERM...JM
AVIATION...AR/TMA
MARINE...AR/TMA