689
FXUS61 KBUF 230542
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1242 AM EST Sat Nov 23 2024

.SYNOPSIS...
Low pressure will continue to spin over the Northeast US through
tonight, with areas of rain this evening across Western NY tapering
off to scattered showers overnight. Some wet snow may continue to
mix in across high terrain, with little or no additional
accumulation. A few leftover rain and wet snow showers will continue
Saturday through early Sunday before high pressure builds in and
brings a return to mainly dry weather by late Sunday.

&&

.NEAR TERM /THROUGH TODAY/...
Stacked low pressure across eastern Pennsylvania this evening will
complete a cyclonic loop and move offshore of New Jersey overnight,
before giving way to another secondary triple point low near the
Canadian Maritimes Saturday. This will maintain a moist cyclonic
flow aloft during the period and a risk for periodic precipitation.

Large scale lift associated with the warm conveyor of the cyclone
continues to weaken and shrink, with shower activity across the
region becoming increasingly scattered. Expect more of a lull in
precipitation for most areas late tonight, although the NNE upslope
flow and limited lake instability may continue to produce a few
spotty showers. Precipitation type will be mainly rain in most
areas, although some wet snow may continue to mix in across the
highest elevations, above 1700 feet MSL. Any additional accumulation
will be minimal.

Saturday will start mainly dry with just a few spotty, light
showers. A mid level shortwave will then cross the area in the
afternoon and combine with the limited lake instability to bring
increasing coverage of showers from west to east from late morning
through the afternoon. Precipitation type will be mainly rain even
across the high terrain by this time as the boundary layer continues
to warm.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
Cool NW flow will continue to support some measure of
lake/upslope precipitation Saturday night behind the departed
mid-level low. A shortwave dropping southeast through this NW
flow is advertised to bring a re-enforcing shot of colder air
overnight nudging H850 T`s down to -5C/-7C as we move into
Sunday. While this normally would help or support lake
effect...drier air working in at the mid-levels will limit its
potential. Therefore...have lowered POPs and added drizzle given
the lack of moisture extending through the DGZ. Lingering
precipitation Sunday morning will then begin to dissipate and
drier conditions will take hold by late in the afternoon. After
that...weak high pressure takes over and mid-levels begin to
warm rapidly Sunday night.

Monday...it looks like it will remain dry for much of the day and
mild ahead of an area of low pressure taking shape over the Mid-
Mississippi Valley. Monday night...given that guidance shows the low
passing to our west across Michigan this will keep the eastern Great
Lakes firmly in the warm-sector. No p-type concerns at the
moment with precipitation all in the liquid form.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Next upper level trough will dive southeast across the Great Lakes
Tuesday, supporting a deepening Colorado low to advance northeast
across the central/lower Great Lakes. Overall this will support a
pair of fronts to cross the area, supporting daytime rain and a mix
of rain and snow at night. Should note that, breezy to blustery
conditions will be possible with this low pressure system, but it
will highly depend on the track of the surface low. If the low
tracks northeast across the central Great Lakes, expect a windier
forecast. As of right now, model consensus has the low tracking
overhead and kept windy conditions at bay for now.

By Tuesday night the trough will have deepened into an upper level
low, where the low will then lift northeast across New England into
the Canadian maritimes by Thursday, and place zonal flow across the
area. Overall a surface low pressure will slide northeast into New
England while surface high pressure pushes into the area in its
wake. A weak shortwave will pivot the exiting upper level low
helping provide some moisture and advect colder air (temperatures
drop to -6C at 850mb) in northwest flow. This will result in lake
effect precipitation southeast of both lakes. Temperatures will
drastically cool to support snow Tuesday night through Wednesday.
Surface high pressure will push east across New York State Thursday
supporting a dry start for the Thanksgiving holiday.

The next upper level trough will dive southeast across much of the
CONUS Thursday night and linger across the Great Lakes and New
England for the end of the week and into the next week. This will be
the first shot of lasting cold air this season. The next surface low
will be advancing east/east-northeast across southeast brushing the
southern portions of New York State, producing some rain and snow
showers. This low will then lift northeast along the Atlantic
coastline returning chances for some lake effect showers
southeast of the lakes Friday.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Low pressure will continue to spin across the Northeast US
overnight. Scattered shower activity will persist though expect
coverage to decrease through the pre-dawn hours. Some wet snow
may continue to mix in across the high terrain at times. VSBYs
will improve to mainly VFR overnight. Widespread MVFR CIGS will
continue, with areas of IFR mainly across higher terrain.

Saturday, it will be mainly dry early with nothing more than a few
spotty, light rain/wet snow showers. A mid level trough will then
cross the area in the afternoon and combine with some lake
instability to bring increasing coverage of showers advancing from
west to east across the area. This will be mainly rain as
temperatures warm, with spotty MVFR VSBY in the steadier showers.
Fairly widespread MVFR CIGS will continue through the day, with some
higher elevation IFR.

Outlook...

Saturday night...VFR/MVFR with rain or wet snow showers across
higher terrain.

Sunday...VFR/MVFR with a chance of a rain or snow shower.

Monday...VFR/MVFR with a chance of rain during the afternoon and
evening.

Tuesday...MVFR with rain and snow showers likely.

Wednesday...VFR/MVFR with a chance of rain or snow showers.

&&

.MARINE...
A moderately deep surface low NY across southern New England will
support Small Craft headlines on Lake Ontario as outlined below.

Winds will gradually diminish later tonight with Small craft
Advisory conditions coming to an end. The lull in winds will not
last long, with increasing northwest winds Saturday bringing another
round of Small Craft Advisory conditions to both lakes. A ridge
will then briefly build across the waters Sunday night.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 1 AM EST early this morning for
         LEZ040-041.
         Small Craft Advisory until 1 AM EST early this
         morning for LOZ030-045.
         Small Craft Advisory until 4 AM EST early this morning for
         LOZ042>044.

&&

$$

SYNOPSIS...Apffel/Hitchcock
NEAR TERM...Apffel/Hitchcock/PP
SHORT TERM...AR
LONG TERM...EAJ
AVIATION...Hitchcock/PP
MARINE...Apffel/Hitchcock/PP