382
FXUS61 KBUF 300749
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
349 AM EDT Mon Sep 30 2024

.SYNOPSIS...
Low pressure will drift slowly east through the Mid Atlantic
States through Tuesday as high pressure builds in from the
north. A cold front will cross the eastern Great Lakes Tuesday
night and early Wednesday with a period of showers. Temperatures
will continue to be above average through Tuesday before a
brief, one day cool down on Wednesday behind the cold front.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest nighttime microphysics satellite imagery showing areas
of fog and stratus early this morning. Not a large coverage at
this point of the morning, but will likely expand through
daybreak as a moist northeast flow and cooling continues. The
fog/stratus will gradually lift through midday leaving mainly a
coverage of mid and high clouds across the region for this
afternoon, with more of this cloud cover over southern portions
of the area. Despite the cloud cover, the day will be dry as
high pressure resides across New England. Temperatures will
continue to run solidly above normal with highs reaching the mid
70s for lower elevations and around 70 for higher terrain.

High pressure will continue just to our northeast tonight
maintaining dry weather. There will continue to be a coverage of
mid and high clouds with overnight lows mainly in the 50s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The eastern Great Lakes will start the period sandwiched between
several upper level features of note. A strong ridge of high
pressure will initially reside from New England and across the
Canadian Maritimes, as low pressure (and the remnants of Helene)
lingers over the Mid-Atlantic states. Meanwhile, a broad
longwave trough will be found over the Upper Midwest and western
Great Lakes. Through the day Tuesday and Tuesday night, this
trough will shift eastward, flattening with time and pushing the
other two upper level features along with it. This will result
in a cold frontal passage across the eastern Great Lakes late
Tuesday night into Wednesday morning, with an areawide round of
showers and brief cooldown.

While the aforementioned area of high pressure will keep the
forecast area mainly dry Tuesday, can`t rule out a few stray showers
in the Southern Tier through the early afternoon as moisture
circulating around the low over the Mid-Atlantic is advected
northward. This moisture advection will briefly deepen across WNY
ahead of the approaching cold front later Tuesday afternoon which
could touch off some light showers further north, though much more
widespread shower activity will come Tuesday night closer to the
front itself. This is expected to arrive on the fringes of WNY after
midnight, then slowly progress eastward through the pre-dawn hours,
being along or just east of the Genesee Valley by daybreak
Wednesday. While these showers could be a bit more impressive as
they approach the region from Ontario and a lingering thunderstorm
or two could possibly reach WNY, increasingly unfavorable upper
level jet dynamics as the parent trough flattens should cause precip
coverage and intensity to decrease through the night. Forecast basin
averaged rainfall totals through Wednesday morning range from just a
few hundredths of an inch in most areas to near 0.15" across far
western NY.

The main area of showers will trudge east across the Finger Lakes
and North Country through the day Wednesday. While much of WNY will
remain dry as surface high pressure quickly builds in the wake of
the front, this will extend east to the rest of the forecast area by
the late afternoon/early evening and persist through Wednesday
night.

As alluded to earlier...While Tuesday will be yet another warm day
featuring temps in the low/mid 70s across the Lake Plains and upper
60s elsewhere, the cold frontal passage will bring us closer to
normal for early October for Wednesday, with more of a range of 60s
across the area. Lows Tuesday night will be in the 50s, then dip
into the 40s across the region behind the front Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Moving later into the week, model consensus is initially in good
agreement on a large area of high pressure providing dry weather on
Thursday as it builds over our area from the west in the wake of the
cold frontal passage. A fairly fast zonal flow aloft will develop
across the CONUS which will drive systems from west to east fairly
quickly through next weekend, before the pattern potentially becomes
more amplified toward the tail end of the period. Back down at the
surface, this will take the high over our area Thursday and shove it
rapidly east to the New England coast by Friday morning. However,
this surface high will remain ridged back westward across New York
State through the end of the work week, which should provide mainly
dry weather through at least much of the day on Friday.

High pressure will then continue to press further east off the New
England coast, which will allow the next upper level trough and
associated surface cold front to approach our region from the upper
Great Lakes. As has been the case, the `Big Three` continue to
struggle with the exact timing and overall strength of this system.
Thus, the forecast package will remain similar to the previous with
SChc to low Chc PoPs to account for the cold frontal passage owed to
the continued uncertainty. At this point, shower activity associated
with the cold frontal passage should occur sometime between Friday
evening and Saturday morning depending on the timing of the system.
Another area of high pressure will then quickly build in from the
west bringing drier and cooler weather through much of the weekend,
before the next potential trough arrives late Sunday with renewed
chances for showers.

Otherwise, temperatures some 5-10 degrees above average Thursday and
Friday, will trend closer to average for next weekend with the
arrival and passage of the cold front.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
A mid level closed low will move slowly from the Ohio Valley towards
the central Appalachians today as surface high pressure builds in
from the north. A moist low level northeast flow this morning will
promote areas of low stratus and fog with ceiling and visibility
restrictions of IFR/LIFR. The lowest conditions are expected at KART
and KROC where skies cleared overnight. These conditions could also
reach KIAG and KBUF, but confidence at these sites is a bit
lower. The low conditions will improve by midday with mainly VFR
conditions expected by afternoon, with a coverage of mid and
high level cloudiness.

Outlook...

Tuesday...VFR.
Tuesday night...MVFR with showers likely.
Wednesday...Showers ending from west to east with a return to VFR
weather.
Thursday and Friday...VFR.

&&

.MARINE...
Northeast winds will continue to produce light to moderate chop
on Lake Erie southwest of Sturgeon Point, and on the western
portions of Lake Ontario today. Winds and waves will remain
below Small Craft Advisory criteria.

Winds will become southeasterly Tuesday, directing the greater wave
action into offshore and Canadian waters. A cold front will then
cross the lower Great Lakes Tuesday night and early Wednesday. This
will bring a brief period of elevated winds to the lakes, first out
of the south ahead of the front, and then northwest behind it. Winds
and waves may briefly approach Small Craft Advisory criteria.

&&

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

&&

$$

SYNOPSIS...Hitchcock/TMA
NEAR TERM...TMA
SHORT TERM...PP
LONG TERM...JM/PP
AVIATION...Hitchcock/TMA
MARINE...Hitchcock/TMA