022
FXUS61 KBUF 272105
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
505 PM EDT Thu Mar 27 2025

.SYNOPSIS...
High pressure will drift off the Mid-Atlantic coast this evening
into tonight. Meanwhile, a passing weak cold front will bring a
brief round of rain and snow showers to areas east of Lake Ontario
this evening, with a few widely scattered rain showers across the
Finger Lakes and western Southern Tier. Elongated low pressure will
then extend eastward across our area later Friday through the
weekend, bringing more widespread unsettled weather that will
feature periods of rain for most areas, and possibly some mixed
precipitation across the North Country. Expect a large north to
south spread in temperatures over the weekend owed to a wavy frontal
boundary draped across the area. This will be maximized on Saturday
with daytime highs near freezing toward the Saint Lawrence Valley,
and upper 60s to near 70 across the western Southern Tier.

&&

.NEAR TERM /THROUGH FRIDAY/...
High pressure that brought dry weather today will push slowly
off the Mid-Atlantic coast tonight. A weak cold front over the
central Great Lakes this evening will press southeast through
the lower Great Lakes tonight. The boundary does not have much
moisture to work with, so not expecting much more than some
scattered light rain showers across the Finger Lakes and western
Southern Tier. The exception will be across areas east of Lake
Ontario, specifically across the higher terrain, that may see a
coating to less than an inch of snow owed to the closer
proximity of the passing mid level shortwave combined with
upslope flow providing some better forcing. Otherwise, expect
breezy conditions through the first half of tonight ahead of the
approaching cold front, before Canadian high pressure ridges
south over the region bringing dry weather and diminishing winds
for the second half of tonight. Highs by late this afternoon
will mainly be in the 40s, with some upper 30s Tug Hill/western
Dacks. Fairly seasonable lows tonight with mid 20s to low 30s.

Narrow ridge of high pressure moves quickly east Friday, while a
large elongated area of low pressure moves from the northern Plains
into the upper Mississippi Valley. A strengthening LLJ will help
push an attendant warm front extending well east of the low toward
western NY from the southwest. This will bring increasing chances
for showers through Friday afternoon with Likely to CAT PoPs by late
in the day/early evening. across areas from the Genesee Valley
westward. Highs will range from the upper 30s to mid 40s east of
Lake Ontario, with upper 40s to mid 50s south of Lake Ontario.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A very unsettled and active pattern will develop over the weekend as
a WNW to ESE frontal zone develops over the Great Lakes and New
England, with the thermal gradient tightening with time. A series of
shortwaves will ripple down the frontal zone, with each one bringing
a period of enhanced ascent and precipitation. Strong and persistent
high pressure over Ontario and Quebec will also introduce low level
cold air, bringing the potential for significant freezing rain to
northern NY, and possibly a more brief window of freezing rain south
of Lake Ontario.

Friday night through Saturday, a persistent differential temperature
advection pattern will continue to tighten the thermal gradient
across the boundary and strengthen frontogensis, with a series of
weak frontal waves running down the boundary and enhancing ascent.
The strong frontogenetic forcing will support periods of rain,
especially from near the south shore of Lake Ontario northward.
Farther south on the warm side of the boundary, expect much lower
coverage of rain across the western Southern Tier. Across the North
Country, persistent low level northeast flow will lock into the
Saint Lawrence Valley. The initial wave of precipitation may contain
some snow Friday evening, after that, warming aloft will result in
periods of freezing rain Friday night through Saturday along the
Saint Lawrence River, and possibly as far south as about the NYS
Route 3 corridor from Watertown to Harrisville.

Saturday night through Sunday, the surface high to the north will
continue to strengthen, and likely force the low level frontal zone
to sag southward to near the NYS Thruway. This will bring the steady
precip a little farther south. Temperatures will drop across the
northern half of the area, and may drop enough to bring a period of
freezing rain to areas just south of Lake Ontario. The greatest
chance of this would be across Niagara, Orleans, and Monroe
counties. Meanwhile across the North Country, the risk of freezing
rain will continue, especially closer to the Saint Lawrence River.

Sunday night, surface low pressure will strengthen as it moves into
the central Great Lakes. Increasing southerly flow ahead of this low
will finally push the omnipresent frontal zone northward, with
temperatures rising significantly south of Lake Ontario and ending
the risk of freezing rain. The warm air will eventually make it into
the North Country as well overnight, changing the freezing rain to
rain.

This setup will present the risk for significant freezing rain
accumulation from southern Ontario into northern NY. The largest
risk area will be found north of our CWA, but there is a chance of
significant, impactful ice accumulation across northern Jefferson
County. If freezing rain materializes south of Lake Ontario, expect
amounts to be much lower, given the more brief time window and more
marginal temperature profiles.

There will be a stark contrast in temperatures this weekend, with
high bust potential at any given location depending on the exact
location of the frontal zone. Expect 30s to the north of the surface
front (and even some upper 20s near the Saint Lawrence River), and
60s to the south (and even 70s near the PA state line). The frontal
zone may drift north and south several times over the weekend, which
may result in several significant temperature swings for cities
along the NYS Thruway corridor.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Deepening surface low pressure sliding northeast across the Great
Lakes and into southern Quebec will drag its corresponding surface
cold front across the region Monday. Initially temperatures ahead of
the frontal passage Monday will be well above freezing with highs
peaking early in the day in the 50s. This being said, expect a swath
of rain to pass from west to east Monday. Behind the front,
temperatures will then drop to below freezing, supporting lingering
showers to change over to some snow.

Surface high pressure will then slide across the region Monday night
and Tuesday advecting in some dry air into the region. While
temperatures will tumble into the negative low teens Celsius at
850mb Monday night, the dry air overhead will limit any lake effect
response east/southeast of the lakes. As the center of high pressure
slides across the region Tuesday, expect dry weather to persist.

The next longwave trough will lift towards the Great Lakes Wednesday
through Thursday, introducing the next surface system to the area.
While the low confidence of the timing and track of the low, expect
temperatures to warm back up into the 50s/low 60s Wednesday and
Thursday with increasing chances for rain.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
Mainly VFR conditions expected through the 18Z TAF period. The
exception will be this evening as a weak relatively moisture-starved
cold front crosses the region. This may bring a brief period of low
VFR CIGS to the western Southern Tier, Finger Lakes region, and east
of Lake Ontario during this timeframe...with some MVFR CIGS possible
across the interior southern Tier and higher terrain east of Lake
Ontario. This boundary will also bring the chance for a few
scattered rain showers across the western Southern Tier and Finger
Lakes region, with some brief intermittent VSBY reductions in snow
showers possible east of Lake Ontario (mainly higher terrain).
Otherwise, expect some breezy southwest winds with gusts up to 20 to
30 knots ahead of the cold front through the first half of tonight.
Wedge of high pressure quickly builds in behind the frontal passage
bringing a return to widespread VFR conditions with winds veering
northwest/north and diminishing through the second half of tonight.

VFR conditions and light winds through at least Friday morning,
before flight conditions deteriorate from southwest to northeast
from midday Friday onward for areas south of Lake Ontario.

Outlook...

Friday afternoon...MVFR/IFR south of Lake Ontario with rain showers
becoming likely across far WNY by later Friday afternoon.
Friday night through Sunday...MVFR/IFR with periods of rain, with
mixed precipitation likely at times east of Lake Ontario.
Monday...VFR/MVFR with rain showers likely.
Tuesday...mainly VFR.

&&

.MARINE...
A cold frontal passage will bring another uptick in winds through
tonight, with a brief (6-12 hour) period of Small Craft Advisories
to account for this. These headlines will be followed by another
ridge of high pressure and a return to quieter conditions later
tonight and Friday morning, before freshening easterlies develop
across Lake Ontario Friday afternoon out ahead of an approaching
warm front. These may eventually require the issuance of another
Small Craft Advisory for southwestern portions of the Lake for later
Friday afternoon and Friday evening.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory from 8 PM Friday to 5 PM EDT Sunday
     for NYZ007.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LEZ020-
         040-041.
         Small Craft Advisory until 5 AM EDT Friday for LOZ042.
         Small Craft Advisory until 8 AM EDT Friday for LOZ043>045.

&&

$$

SYNOPSIS...JM/JJR
NEAR TERM...JM/HSK
SHORT TERM...Hitchcock
LONG TERM...EAJ
AVIATION...JM
MARINE...JM/JJR