-- Discussion containing changed information from previous version are highlighted. --
468
FXUS61 KBUF 210842
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
442 AM EDT Fri Jun 21 2024

.SYNOPSIS...
While it will still be uncomfortably warm and humid through this
weekend...a frontal boundary oscillating back and forth over our
region will support enough cloud cover and some thunderstorm
activity to suppress the dangerously high heat indices.
Unfortunately...the daily thunderstorms will carry the risk of
torrential downpours and even severe weather. Notably cooler and
more comfortable conditions can then be expected next
week...especially during the latter half.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Muggy and mild start (dwpts in the 60s) and temps in the
mid/upper 60s to low 70s.

A weak slow moving frontal boundary will slowly drop southeast into
and through the area today. While there will be some measure of
showers and thunderstorms with this boundary, overall coverage
appears to be limited right now. That said...have placed the best
coverage (higher PoPs > 50%) across the S. Tier (closer to the NY/PA
line) and into the Genesee Valley/western Finger Lakes region. This
is supported by most Hi-res guidance. It is also highlighted by SPC
with a MRGL risk for severe storms. We should see most of the
activity today occur with peak heating. Given PW values of 1.5-1.7
inches and short MBE vectors torrential rain will be possible with
any of the stronger cells. Highs today (a few degrees cooler) will
be found in the 80s to near 90F in spots.

Tonight...most convection should slowly wane with the loss of
daytime heating. The weak east to west frontal boundary to our south
is also advertised to return back north as a warm front. We
could see a few showers or even a thunderstorm as it returns.
Otherwise...mild and muggy night with lows in the 60s to low
70s.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Heading into the weekend with zonal flow aloft, what was a stalled
surface front Friday night will have gradually shifted north as a
warm front by Saturday morning. A weak shortwave passing through
southern Canada, will cause the warm front to wiggle some throughout
the day Saturday and result in a few showers and thunderstorms with
its passage late Saturday morning through Saturday afternoon. The
best location for shower and storm activity will lie inland from the
lakes (across Allegany County and southeast of Lake Ontario). With
the warm front lying across the region and the North Country lying
to the north of the boundary, temperatures here will be on the
cooler side with highs in the mid to upper 70s. Otherwise, areas to
the south of the boundary will see highs in the upper 80s to low 90s.

The next upper level trough will begin to dive across the upper
Midwest Saturday night, causing associated low pressure to
strengthen across the central Great Lakes and lift the warm front
north of the region. This will place the area beneath the warm
sector, supporting ample warm moist air advection. Overall the
chances for showers and thunderstorms will continue throughout
Saturday night, with the best likelihood for activity lying across
the North Country due to its close proximity to the front.

The now 995mb surface low and associated trough will track to the
north of the area and result in a windy day Sunday, given the 850mb
winds ramp up to nearly 45 knots. Overall this will support the
passage of a strong cold front across the area, likely producing
thunderstorms with its passage. Organized convection featuring
damaging winds will also be possible due to the ample wind shear
across the region. With this cold frontal passage, the arrival time
will play an important role with convection. Model consensus
continues to support the front passing across WNY early enough to
hinder organized convection whereas the timing of the front passing
across central NY will support better organized convection.

The cold front will then slide to the east of the area Sunday night,
supporting lingering showers and thunderstorms to taper off from
west to east.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
To start off the new work week, a potent shortwave trough aloft will
did across New England Monday and bring increasing chances for
showers and a few thunderstorms across the North County with lower
chances elsewhere. After such a warm and humid week, it will be
notably cooler and drier Monday with highs in the 70s.

Brief upper level ridging will support surface high pressure to
slide across the region Monday night through Tuesday and bring the
return of dry weather. Though unlike this week, it will be much
cooler with highs in the low to mid 80s.

Another short trough will pass by well to the north Tuesday with an
associated cold front to move across the area Tuesday night and
Wednesday. Overall this will support warmer weather ahead of the
cold frontal passage with a chance for shower and thunderstorms. In
the wake of the front, surface high pressure will make a return in
addition to, cooler air will filter across the area.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
VFR across all terminals this morning. A weak frontal boundary will
sag south through the region today and potentially support some
showers and thunderstorms. This will mainly be the case for areas
south of Buffalo and Rochester during the midday and afternoon.

Tonight...mainly VFR but there may be some fog/low status across the
S. Tier at KJHW. Low confidence, so didn`t include it in the TAF.

Outlook...

Saturday...Mainly VFR. A chance for afternoon and evening
thunderstorms inland from the lakes.
Sunday...VFR/MVFR. Showers and thunderstorms likely.
Monday...Mainly VFR. A chance for afternoon and evening
thunderstorms inland from the lakes.
Tuesday...Mainly VFR conditions expected.
-- End Changed Discussion --

&&

.MARINE...
Light winds and minimal wave action is expected to continue across
the Lower lakes through Saturday. There will be a chance of afternoon
showers and thunderstorms which could produce gusty winds and higher
wave action each day.

A cold front will approach the region Sunday with increasing southwest
winds which may bring a period of SCAs to area lakes. Northerly
flow behind the front will then bring continued choppy conditions
to the lakes through Monday. High pressure builds in late Monday with
diminishing winds and waves for Tuesday.

&&

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

&&

$$

SYNOPSIS...AR/RSH
NEAR TERM...AR
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...AR
MARINE...AR