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549
FXUS61 KBUF 091043
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
643 AM EDT Thu May 9 2024

.SYNOPSIS...
High pressure will build in from the northwest providing mainly dry
weather through most of the day today, before shower chances
increase toward the Pennsylvania state line late this afternoon.
This will be the start of an unsettled weather pattern that will
impact the region for the end of the work week into this
weekend as a series of low pressure systems cross the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Cold advection today within northeast flow following a cold frontal
passage. Temperatures will be a bit below average with highs
ranging from the mid 50s to lower 60s. Some clearing occuring
across northwest portions of the area this morning, although low
level moisture behind the cold front producing plenty of low
cloud cover across the much of the region. There will be some
sunny periods this morning, before mid and high clouds work
overtop of the lower cloud cover to bring a general mostly
cloudy day. Despite the cloud cover, the day will be rain-free
through at least mid afternoon with increasing chances for
showers toward the NY/PA state line late in the day as a trough
approaches. The trough combined with some isentropic lift will
bring an increasing coverage of showers tonight, especially
south of the NYS Thruway. Coverage should be more scattered
north of the Thruway, with perhaps even dry conditions through
the night close to Lake Ontario.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
Zonal flow will transition to troughing across the eastern Great
Lakes region Friday into the weekend. A 500mb trough axis will swing
across the region while surface low pressure over central Appalachia
continues its transition to a coastal low off the Mid-Atlantic coast
Friday. The 850mb low will be displaced to the north with a thermal
gradient extending from western Pennsylvania to the southern New
Jersey coast. A deep easterly flow will continue to draw Atlantic
moisture into the northern Appalachian region while it interacts
with strong ascent from the incoming mid-level trough axis. Rain
showers across western NY Friday morning will pivot northward as
forcing and moisture shift further north ahead of the mid-level
trough axis. Rainfall amounts will range from less than 0.10 inches
from the Lake Erie shoreline to 0.50 inches across the Finger Lakes
region. Rainfall amounts will average 0.10 to 0.25 inches east of
Lake Ontario.

The mid level trough axis will be east of the forecast area Friday
night. Showers will come to an end across western NY while showers
continue along an inverted trough under diffulent flow from the
Finger Lakes region to north central NY. Rainfall amounts of up to
0.25 inches are possible in this location. There is a brief period
of ridging behind the trough and ahead of the next mid level trough
late Friday night. Showers will slowly end from west to east late
Friday night, however showers may persist east of Lake Ontario into
Saturday morning.

The next mid level trough will move overhead Saturday and solidify
troughing across the eastern Great Lakes region and Northeast
through the rest of the weekend. A weak area of low pressure will
track southwest of the region. The combination of moisture and an
upper level trough overhead will result in low chances for showers
Saturday morning. Peak heating and the potential for some clearing
will result in increasing chances for showers and a few
thunderstorms Saturday afternoon. Coverage of showers will decrease
Saturday night with mostly dry weather across the forecast area.

Cooler weather is likely Friday through Saturday night with high
temperatures below normal for mid-May.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
An amplified upper level trough will move across the Northeast
Sunday. It will move slow enough that showers will be possible
across the forecast area. There should be a brief period of ridging
before the next amplified upper level trough moves across the Great
Lakes region and Northeast into mid-week. An associated cold front
will likely approach the region with the chance for showers
increasing from northwest to southeast late Monday into Monday
night. The cold front may not move through the region until Tuesday
night into Wednesday resulting in a prolonged period of favorable
conditions for showers and possible thunderstorms through Wednesday.

High temperatures will steadily increase Sunday through Wednesday.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Weak high pressure will nose in from the northwest today, thus
with low level drier air working in, expect areas from the
Niagara Frontier (KBUF/KIAG) east and northeast to KROC and KART
to remain scattered this morning hours. Expect improvement to
low VFR at KJHW during the first part of this morning.

Widespread VFR is expected this afternoon with mid and upper
cloud decks, although there will be the chance for a few
scattered showers and MVFR CIGS to return across the western
Southern Tier (KJHW) after 21z.

Outlook...

Tonight and Friday...Mainly MVFR. Showers likely and MVFR
stratus.

Saturday through Monday...VFR/MVFR. A chance of showers.

&&

.MARINE...
A northeasterly flow will strengthen some today and tonight. This
will result in choppy conditions along the south shores of both
Lakes.

&&

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

&&

$$

SYNOPSIS...JM/TMA
NEAR TERM...TMA
SHORT TERM...HSK
LONG TERM...HSK
AVIATION...JM/TMA
MARINE...JM/TMA