914
FXUS61 KBUF 061414
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1014 AM EDT Sun Oct 6 2024

.SYNOPSIS...
Gusty southerly winds within the warm sector of an approaching
system will bring temperatures well above normal today. A strong
cold front will track across the region late this afternoon and
evening, with strong to severe thunderstorms expected with its
passage. Cooling temperatures over the region through the middle of
the week will result in periods of showers and fall like conditions.
A return to drier and warmer than normal weather is expected for
late in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
...Strong to Severe Thunderstorms Possible This Afternoon and
Evening...

Vigorous upper trough arrives into the eastern Great Lakes this
afternoon with western New York emerging into the warm sector.
Robust warm air advection develops within the warm sector as a 40 to
45 knot low level jet focuses on the region, sending 850 mb
temperatures to 12-15C. This will send temperatures into the lower
to mid 70s for most areas, with some upper 70s possible across
western New York.

A strong cold front will arrive by late this afternoon with a narrow
corridor of dewpoints reaching into the 60s pooling ahead of the
front. Cooling aloft along with steepening mid-level lapse rates
will overlap modest boundary layer moisture to support an area of
moderate instability along and just ahead of the cold front. The
expectation is that a band of convection will develop along and just
ahead of the cold front entering western New york around 4 PM.
Strong wind fields aloft with nearly 50 knots of deep layer shear
will likely yield a narrow band of organized convection. Damaging
wind gusts will likely be the PRIMARY threat associated with the
strong wind fields aloft. Bufkit profiles showing sufficient low-
level hodograph curvature and SRH signals to suggest the potenial
for supercell development with an isolated tornado possible,
especially across southwest New York. SPC has much of the area in a
Marginal Risk for severe thunderstorms with a Slight Risk area
highlighted for all of far western New York.

The cold front will track east and out of the forecast area by the
mid/late evening tonight. As the line of showers and thunderstorms
tracks east, conditions become less favorable for strong/severe
storms with less instability and shear expected.

Tonight, guidance is starting to come into better agreement on the
shower potential behind the passing cold front and as the axis of
the potent trough moves through the region. The line of more
organized showers/storms will clear out by the late evening. After a
few hour break as some drier air briefly moves in, additional
showers will start to develop, mainly downwind of the lakes as
moisture increases some once again and as the trough axis crosses
over the area. Cooling temperatures aloft to the lower single digits
celsius by daybreak will also help support the lake response. Lows
tonight will be in the mid 40s to mid 50s.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
Several waves of shortwave energy will round the base of a stacked
low pressure system over James Bay Monday, causing the core of
the broad scale trough to deepen and slide southeastward to the
Canadian Maritimes by late Wednesday. This will effectively keep
the cool, cyclonic WNW flow pattern that emerged behind
Sunday`s cold front locked in across the eastern Great Lakes
through midweek. 850H temps will already be in the low single
digits by Monday morning, though the core of this cooler
Canadian airmass (850H temps near -3C) will likely not cross the
region until Wednesday night.

In stark contrast to the abnormally warm temperatures the region has
been contending with for some time, this pattern shift will ensure a
stretch of cooler, decidedly fall-like weather this period.
Temperatures Monday will be some 15-20F colder than Sunday with
highs only in the mid 50s to low 60s. Thereafter, a small day to day
cooling trend can be expected, with temps Wednesday afternoon likely
not escaping the 50s away from the lakeshores. Nighttime
temperatures will be quite cool in the low/mid 40s across the Lake
Plains and downright cold across the higher terrain areas, with a
range of 30s expected. Temperatures could even approach the freezing
mark across the Tug Hill/Western Adirondacks Wednesday night. Gentle
nighttime breezes and patchy cloud cover should help inhibit
widespread frost development, though it would still be wise for
though those living in the higher terrain areas and who have
sensitive outdoor vegetation to begin preparing for frost.

Of course, as is typical when cooler air flows across the Great
Lakes this time of year...We can also expect some extra clouds and
periodic lake enhanced rain showers downwind of the lakes Monday
through Wednesday night. The passing shortwave energy and steepening
lapse rates could carry showers outside the main lake effect areas
during the afternoon hours each day. Still a bit of an uncertain
forecast here in terms of overall rain potential and timing, as
synoptic moisture will be lacking and strong high pressure will be
slowly building across the western and central Great Lakes. As a
result, expect the higher chances for lake enhanced rain showers
to be east/southeast of Lake Ontario through Wednesday.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
A strong ridge of high pressure will build over the Great Lakes and
Ohio Valley by Thursday. This will finally displace the deep trough
and cooler airmass circulating over the Canadian Maritimes further
east, ending any lingering lake effect rain showers. Dry weather
will then last into Saturday as the main surface high slowly settles
to our south across the Southeast states. A weak shortwave moving
across Quebec will lead to low chances for showers across the North
Country by late Saturday.

While temperatures will continue to be solidly below normal through
Thursday with highs only in the 50s, the pattern is expected to
quickly trend back towards above normal temperatures by the weekend.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
While VFR weather will persist through mid afternoon, winds will
significantly freshen ahead of an approaching strong cold front.
Southerly winds could gust to 30 knots. By late afternoon, a line of
showers and strong to severe thunderstorms will start to push across
the western counties of the state. This convection could be
accompanied by short periods of MVFR conditions.

Tonight, MVFR early with showers/storms will improve to VFR from
west to east through the evening. Additional cloud cover and showers
developing during the later half of the night will cause flight
conditions to drop to or near MVFR at times, mainly downwind of the
lakes where lake clouds will develop.

Outlook...

Monday through Wednesday...VFR/MVFR with a chance of showers...
especially east/southeast of the lakes.

Thursday...Mainly VFR.

&&

.MARINE...
A warm front followed by a much stronger cold front will move
through the region today and this evening respectively. South winds
will increase 15-25 knots behind the initial warm front. Although
the higher wave action will be offshore wind speeds will be high
enough to warrant the issuance of a small craft advisory for the
Lake Erie nearshores through this afternoon.

The cold front will then shift winds to the west-northwest by
tonight and continuing through Monday, resulting in a continuation
of small craft headlines on Lake Erie and the likely need for
headlines on Lake Ontario.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 5 PM EDT Monday for LEZ040-041.

&&

$$

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