468
FXUS61 KBUF 251419
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1019 AM EDT Sat May 25 2024

.SYNOPSIS...
Showers and some gusty thunderstorms will be possible today in
response to a pair of fronts moving through the area. Weak high
pressure will then allow fair weather to return later tonight with
the finest weather of the weekend slated for Sunday. Looking at the
end of the long Memorial Day weekend...a complex storm system over
the Upper Great Lakes will support very unsettled weather for
Monday...including the potential for drenching thunderstorms.

&&

.NEAR TERM /THROUGH SUNDAY/...
Radar shows some showers and thunderstorms marching northeast which
will impact parts of Western NY this morning. These storms are in
association with a warm front moving northeast. Additional storms
will be possible this afternoon. The details...

Notably more humid air behind the warm front this morning will serve
as a breeding ground for more widespread and robust convection over
the western counties during the mid and late afternoon. PWAT values
will approach 1.5" with Td`s climbing to arnd 60 F. This moisture
rich environment will encourage convection to include torrential
downpours...and with bulk shear values forecast to be in the vcnty
of 25-30 kts...there could be some storms that could contain hail
and/or strong wind gusts. The greatest threat for strong
thunderstorms over the western counties will take place between 1
and 5 PM ahead of a cold front. These storms will then make their
way across the Eastern Lake Ontario counties between 5 and 8 PM.

By sunset...the strongest convection should be east of our area with
partial already taking place over the far western counties. The
residual showers will continue to end from west to east throughout
the evening. This clearing...coming on the heels of fairly
widespread convection...could lead to some late night fog and
stratus as we push into the wee hours of Sunday morning.

The nicest day of the three day weekend can then be expected on
Sunday...as a burgeoning shortwave ridge and corresponding weak sfc
high will move across the forecast area. While there may be some low
clouds around to start Sunday morning...all areas can fully
anticipate sun filled skies for the midday and afternoon. It should
be a fine day for outdoor activities with sunshine boosting
afternoon temperatures into the mid 70s to near 80.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
A shortwave trough over the Pacific Northwest this morning will
track southeast into the central Plains by Sunday morning. As the
trough tracks southeast, a sfc low will develop lee of the central
Rockies and center of the mid-Mississippi Valley by Sunday evening.
Out ahead of the sfc low and shortwave trough a warm front will push
north crossing the NY/PA line during the late evening and overnight
on Sunday night. As the front pushes north, showers along the front
will move into the forecast area (around Midnight), becoming better
organized as a shortwave trough tracks along the front. There is
still uncertainty among guidance for Sunday night as too how
organized the showers become, in part due to timing differences of
the warm front and the shortwave trough.

By Monday morning, the sfc low will be centered over lower Michigan,
and continue to track northeast, centering near the Georgian Bay by
Monday evening. The system will also start to occlude in the
process, becoming more vertically stacked with its mid-level low.
This will keep the region within the warm sector of the system for
Monday. Thunderstorms are also expected starting early Monday
morning, continuing through most of the day. This will be the result
of large scale forcing, increasing instability values of over 1,000
J/kg and bulk shear values of around or a little over 30 knots. An
influx of GOMEX moisture, combined with the large scale forcing and
forcing from a LLJ over the region will result showers that will
have some heavier rainfall rates. Increased potential for heavier
showers within thunderstorms expected as well. With the above
mentioned instability and shear values, the potential exists for at
least strong thunderstorms with gusty winds, with the Storm
Prediction Center placing much of the forecast area in a `Marginal
Risk` for Monday. The best potential for thunderstorms will be south
of Lake Ontario.

Monday night, steadier showers will track northeast and coverage of
the showers will become less through the night from west to east as
an occluded front pushes northeast and east into Canada & New
England. Some lingering/embedded thunderstorms will still be
possible through the first half of the night.

Widespread rainfall amounts for Sunday night through Monday night of
half to one inch is possible for most of the forecast area, with the
highest amounts expected for areas east of Lake Ontario. Localized
higher amounts are also possible due to thunderstorms as well.

Temperatures for Sunday and Monday night will be in the upper 50s to
mid 60s, with Monday night being the slightly cooler night behind
the passing front. Monday afternoon temperatures will be in the
upper 60s to near 80 from the higher terrain to the lower
elevations.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The departing vertically stacked system from earlier in the week
will continue to cause showers into the middle of the week as it
will take a few incoming troughs to finally push it out of the
region. There will also be a few passing cold fronts that pin wheel
around the system within the cyclonic flow. Showers should start to
taper off by the afternoon on Wednesday.

Mostly dry conditions expected from Wednesday night through the rest
of the week as a large area of high pressure and large ridge move
into the eastern half of the CONUS.

Temperatures will be below normal for most of the period, with
afternoon highs returning to near normal by Friday. Wednesday and
Thursday will be the coolest days with high temperatures around 5 to
10 degrees below normal.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
Showers and thunderstorms will be possible today as a pair fronts
cross the region. Best chance to see storms will occur after 18Z
this afternoon. Otherwise...VFR conditions can be expected outside
of these storms.

Tonight...convection from the afternoon storms will move out of the
area during the evening hours. While this will leave primarily VFR
conditions in place through 06z...clearing skies will lead to some
areas of fog and stratus that will result in fairly widespread MVFR
to IFR weather through daybreak Sunday.

Outlook...

Sunday...Improving to VFR.
Monday...Restrictions likely with showers and thunderstorms.
Tuesday and Wednesday...Restrictions possible with showers.

&&

.MARINE...
Winds across the Lower Great Lakes will become more variable
today...as a warm front will push through the region. This could
allow for some lake breeze circulations to develop. A few gusty
thunderstorms will be possible during the afternoon ahead of an
approaching cold front with the potential for locally higher winds
and waves.

With the cold frontal passage winds turn east-northeasterly
generally under 10 knots Sunday...as high pressure will briefly
build across the lower Great Lakes.

More notable winds will occur on Monday into Tuesday with increasing
southerly winds early Monday taking on a more west-southwesterly
component Monday afternoon into Tuesday. Winds could nudge into the
15 to 25 knots range with possible small craft headlines needed
during this time period. Scattered gusty thunderstorms will also be
possible Monday.

Boaters should continue to monitor the forecast, especially given
the holiday weekend which will likely increase boating activity.
This will especially be the case on Monday as conditions on the
lower Great Lakes will likely deteriorate.

&&

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

&&

$$

SYNOPSIS...AR/RSH
NEAR TERM...AR/RSH
SHORT TERM...SW
LONG TERM...SW
AVIATION...AR/RSH
MARINE...TMA