National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBUF 282049
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
449 PM EDT Wed Oct 28 2020

.SYNOPSIS...
High pressure will support a brief period of dry weather tonight
into early Thursday morning. A storm system will then pass well to
our south Thursday and Thursday night. This storm will produce
another round of widespread rain, especially along and south of the
Thruway. The rain will mix with some wet snow later Thursday night
and Friday morning, with minor accumulations possible across the
higher terrain of the Southern Tier. Strong high pressure will bring
a return to dry weather Friday night and Saturday.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
A weak bubble of high pressure will remain over Ohio and PA
tonight, and this will provide a brief break of dry weather for most
of our region. Any temporary clearing through the first half of
tonight will be short lived as clouds stream northward again ahead
of the next system. Still cannot rule out a few isolated light
rain/wet snow showers east of Lake Ontario overnight as lingering
shallow lake instability interacts with a weak passing trough. Lows
will drop into the upper 30s to lower 40s in most locations, with
mid 30s for the North Country.

Thursday and Thursday night...the remnants of Zeta will quickly
become extra-tropical and become involved with a mid-latitude
frontal zone. The remnant surface low of Zeta will race from just
south of the Ohio Valley Thursday morning to off the Jersey Shore by
late Thursday evening. Meanwhile the baroclinic frontal zone north
of Zeta and its associated frontogenesis, deformation, and strong
upper level jet dynamics will force a large shield of stratiform
precipitation to the north of the track of Zeta. A mid level trough
and associated DPVA will cross the eastern Great Lakes Thursday
evening, with the added forcing marking the time of most widespread
precipitation across our area.

Looking at the details, the entire region should still be dry at
daybreak Thursday. Rain will then overspread the Southern Tier by
mid to late morning, then spreading north to near the NYS Thruway
corridor during the afternoon. The northern edge of the
precipitation shield will likely have a very sharp cutoff given the
low level dry air being fed into the region by increasing northeast
flow from strengthening high pressure to our north. The most
widespread precipitation will occur Thursday evening with an added
boost of forcing from the passing mid level trough, and also due to
an increase in lake enhancement from northeast flow off Lake Ontario
as cold air begins to deepen and lake induced equilibrium levels
rise. The synoptic precipitation will then taper off from northwest
to southeast late Thursday night as the system moves well offshore
of southern New England.

Precipitation type will be all rain through early Thursday evening.
Colder air surface and aloft will feed into NY during the latter
stages of the event, allowing the rain to mix with, and change to
wet snow. The changeover will likely occur first across the higher
terrain by late Thursday evening, then progress to lower elevations
by late Thursday night. Multi-model, multi-run consensus still
suggests minor accumulations will be highly elevation dependent,
with 1-2 inches expected across the higher terrain of Cattaraugus
and Allegany counties and possibly the Bristol Hills, with a coating
to an inch on the hills in surrounding counties. Farther north on
the lake plains, there may be a few wet snowflakes in the air late
Thursday night, but no accumulation is expected.

Friday all of the widespread synoptic scale precipitation will have
exited by daybreak. Cold northwest flow will still support scattered
lake effect snow showers through midday south of Lake Ontario and
Lake Erie, possibly mixed with some rain close to the lakes. This
may produce an additional light coating in a few spots over the
hills. High pressure will build towards the eastern Great Lakes
later in the afternoon, with rapidly lowering inversion heights
bringing an end to the brief, weak lake response. Friday will be
very cold, with highs only in the upper 30s on the lake plains and
low to mid 30s for higher terrain.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
An area of surface high pressure spanning across the Great Lakes
Friday night will continue to push east into the eastern Great Lakes
and eventually New England Sunday. With the high pressure overhead
of the region Friday night, dry conditions are expected. While
directly under the center of surface high pressure Friday night,
calm winds along with mostly clear skies will promote ample
radiational cooling causing Friday night to be the coldest night
thus far this season. Lows Friday will drop down into 20s across the
Lake Plains to upper teens along the higher terrain.

Dry chilly conditions continue Saturday and into Saturday night as
the area of surface high pressure continues to slide eastward into
New England and eventually exits the east coast. Temperatures
Saturday night will be warmer than Friday night as a tightening
pressure gradient from the next incoming system will cause winds to
freshen, and thus dampen the radiational cooling effect.

As alluded to previously, the next upper level trough and associated
surface features(low and cold front) is progged to cross the Great
Lakes Saturday night through Sunday. As such, the upper level trough
should sharpen late Sunday which will put the arrival and passage of
the surface cold front Sunday afternoon. That said, expect
increasing cloud cover and rain shower chances throughout the day on
Sunday.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Strong cold air advection will follow the passage of the cold front
Sunday night. This will mark a couple day stretch in the beginning
of next week of below normal temperatures as temperatures at 850mb
drop to around -12C. The cool air combined with west-northwest flow
and wrap around moisture from the system prior in the weekend will
result in a period of lake effect rain and snow showers southeast of
both lakes Sunday night and Monday.

A wave of low pressure and mid-level trough will pass across Canada
Monday afternoon and Tuesday. With this, a fresh batch of cold air
should arrive late Monday into Tuesday which will produce a few more
lake effect rain and snow showers east and southeast of the lakes.
Any leftover precip should come to an end by Tuesday afternoon and
mark a period of dry weather as a broad area of high pressure builds
over southeastern CONUS and nudges into the area. Warm air advection
with an increasing south-southwest flow Tuesday will help raise
temperatures back to near normal for Tuesday night and Wednesday.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
While MVFR cigs will linger across the Southern Tier til about
nightfall...general VFR weather will be found throughout the
region tonight. The VFR conditions may be accompanied by some
nuisance showers east of Lake Ontario.

Low pressure will then pass well south of the area Thursday. A large
shield of rain to the north of the low will overspread the Southern
Tier in the morning, then develop northward to near the south shore
of Lake Ontario by late afternoon. VSBY will deteriorate to MVFR in
the steadier rain. CIGS will also deteriorate through the day
Thursday, with widespread MVFR at lower elevations and IFR higher
terrain in the afternoon.

Outlook...

Thursday night...MVFR/IFR with rain, mixing with or changing to wet
snow.
Friday...MVFR/IFR with wet snow or rain showers tapering off in
the morning, improving to VFR/MVFR.
Saturday...VFR.
Sunday...VFR/MVFR with a chance of showers.
Sunday night and Monday...MVFR/IFR possible in lake effect rain
and snow showers southeast of the lakes.

&&

.MARINE...
High pressure will build south of the area this afternoon and
evening, allowing west to southwest winds to freshen. This will
support a round of Small Craft Advisory conditions on both Lake Erie
and Lake Ontario through this evening. Winds will then diminish
later tonight.

Low pressure will move from the Ohio Valley to off the northern Mid
Atlantic Thursday through early Friday. A period of stronger
northeast winds will develop on the eastern Great Lakes as a tight
pressure gradient develops between this low and high pressure
building into Ontario and Quebec. This will bring another round of
Small Craft Advisory conditions staring Thursday afternoon and
lasting through Friday morning on both lakes.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LEZ020-
         040-041.
         Small Craft Advisory until 5 AM EDT Thursday for
         LOZ043>045.
         Small Craft Advisory until midnight EDT tonight for LOZ042.

&&

$$

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