369
FXUS61 KBUF 071934
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
334 PM EDT Mon Apr 7 2025

.SYNOPSIS...
A strong cold front will bring initial rain, changing to snow this
evening across our region. Temperatures tonight will fall back into
the upper teens to lower 20s tonight, and remain in the upper 20s
and lower 30s tomorrow...this as 1 to 2 inches of snow accumulates
on the hills east of Lake Erie, and 4 to 9 inches east of Lake
Ontario. Gusty west to northwest winds behind the front will be
strongest along the southern Lake Ontario shoreline tonight through
tomorrow.

&&

.NEAR TERM /THROUGH TUESDAY/...
A nice start to this period with a good deal of sunshine across the
region. However, upstream clouds are thickening ahead of a cold
front that is bearing down upon the Lower Great Lakes.

This cold front will advance across our region this evening with
initial rain showers changing to snow as temperatures fall to and
below freezing with the frontal passage. Road temperatures well
above freezing this afternoon thanks to the sunshine will delay any
freezing spots this evening, except for the elevated surfaces which
will cool faster tonight and could be found with slick spots.

This fast moving front will leave minimal snow accumulation across
the Lake Plain tonight. The higher upslope terrain of the Southern
Tier will fair better for snow accumulation, especially including
the light lake snow later tonight...where combined 1 to 2 inches
across the hill tops is likely.

East of Lake Ontario and within a slightly deeper moisture a burst
of snow tonight along the front will bring widespread inch or two of
snow across the region. After a brief lull later tonight in snow
east of Lake Ontario, and as another lobe of moisture returns along
with temperatures at 850 hPa falling to -12 to -14C we will
transition to lake effect and upslope snow east of Lake Ontario,
with moderate snow falling late tonight through tomorrow morning.
Could see snowfall rates briefly reach an inch per hour for this
region.

Rapid drying, and veering of winds to northwesterly over Lake Erie
will end any lake snows as they push southward into NW PA through
the midday hours Tuesday. East of Lake Ontario deeper moisture and a
colder airmass will maintain snow falling through the day. The lake
effect snows could become cellular through the daylight hours with
the diurnal effects of the stronger April sun.

It will also become windy behind this front later tonight and
through Tuesday. A west to northwest flow, along with a deep PV
intrusion...combined with increasing mixing heights tomorrow will
promote winds to gust to 50 mph along the southern Lake Ontario
shoreline. Will issue a wind advisory for the southern Lake Ontario
shoreline and through the Finger Lakes.

Elsewhere winds gusting 35 to 45 mph through the day. These winds
will create blowing snow east of Lake Ontario later tonight and
Tuesday and will add blowing snow to the eastern Lake Ontario
counties.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
The upper level trough will move east of the region Tuesday night
through Wednesday. A cold, westerly flow will maintain lake effect
snow showers southeast of Lake Ontario with an additional 1-2"
possible. It will be a cold night with lows in the teens to low 20s.
The core of the coldest air will move east of the region Wednesday,
850mb temperatures will average -8C across the region. Highs will
remain below normal, in the upper 30s to low 40s. Besides of few
lingering lake snows east of Lake Ontario Wednesday, dry conditions
are expected across the forecast area.

A series of shortwave troughs will move across the Mid-West and Ohio
Valley while a longwave trough digs south across the eastern CONUS
later in the work week. The first impulse and associated surface low
will move just to our west Wednesday night through Thursday. Snow
will move into western NY late Wednesday night into Thursday. The
low levels will be warming and surface temperatures will rise above
freezing across the lower elevations of far western NY Thursday
morning. Any snow will change to rain. This warming trend will
continue Thursday and snow will transition to all rain by Thursday
afternoon. Snow will linger across the higher terrain through the
afternoon. Highs will reach the 40s Thursday. Little to no snow
accumulation is expected.

The compact low will slowly move near Lake Ontario Thursday night. A
deformation zone may develop just west-northwest of the low and
potentially place steady rain across the Niagara Frontier to Lake
Ontario. Drier air will move into the rest of western NY and rain
will become light and showery. Due to uncertainty in potential
banding, there is low confidence in rainfall amounts. The current
forecast has storm total rainfall amounts (Thu-Thu night) of a
quarter to half inch in vicinity of Lake Ontario with less than a
quarter inch elsewhere.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
During this period the axis of deep and increasingly sharp longwave
troughing will slowly drift from the central Great Lakes and Ohio/
Tennessee Valleys on Friday to our region by sometime on Saturday...
the eastern seaboard on Sunday...and then out into the western
Atlantic Monday. On its eastern flank...an attendant broad
meridionially-oriented surface trough will similarly drift
eastward...with an incipient embedded weak surface wave over or just
south of our region at the start of Friday giving way to at least
one more subsequent wave lifting northward through the broader-scale
mean surface trough Friday night through Sunday.

This general pattern will keep unsettled conditions in place across
our region through at least the first half of the weekend. With the
medium range guidance continuing to exhibit some variance in the
number...strength...track...and timing of the secondary surface
wave(s)...there remains a fair amount of uncertainty in the degree
of precipitation chances our region could see Friday through
Saturday. With this in mind have leaned toward a mix of chance to
lower-end likely PoPs (30-60% probabilities) through Saturday...with
these peaking later Friday through the first part of Saturday when a
one of the surface waves looks to pivot a slug of richer Atlantic-
based moisture northward across our region. Given current thermal
profiles...virtually all of the pcpn looks as if it should fall in
the form of just plain rain.

Precipitation chances should then tend to gradually diminish from
west to east Saturday night through Sunday night as the whole system
translates eastward and is gradually replaced by high pressure and
drier air building eastward from the central Great Lakes and Ohio
Valley...with this potentially leading to a dry Sunday south of Lake
Ontario. Expect largely dry and uneventful conditions to then follow
for Sunday night...before another system approaches and potentially
brings renewed chances for some showers on Monday. Given the rather
poor model agreement on this next system`s track and forward
speed...have kept PoPs for Monday confined to just slight chance
(20% probability) for now...with a continuation of mainly dry
conditions more favored at this distant vantage point.

As for temperatures...these should continue to rebound through this
period...with near to slightly below normal readings Friday/Saturday
climbing back to above normal levels by next week Monday.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
For the 18Z TAFS VFR flight conditions are found and these
conditions will continue for about the next 6 hours, before
precipitation ahead of a strong cold front reaches the western TAF
sites. Initial precipitation will likely be plain rain showers, but
as temperatures cool along and behind the front, these showers will
mix with and change to snow...with visibilities briefly dropping to
IFR in the snow. East of Lake Ontario (KART) where the snow will
persist longer, a more extended period of IFR visibilities are
likely.

It will also become gusty behind the front later tonight and
tomorrow. Winds from the west to northwest wind direction will
likely be strongest along the southern Lake Ontario shoreline,
including KIAG and KROC where speeds may approach 40 knots later
tonight and through the day Tuesday. As winds establish a northwest
flow lake effect snow will become focused south and southeast of
Lake Ontario with cellular or broken bands of lake effect snow
intermittently impacting KROC to Oswego County.

Outlook...

Tuesday night...MVFR/IFR in light lake effect snow southeast of Lake
Ontario.

Wednesday...MVFR in diminishing lake effect snow SE of Lake Ontario
early. VFR/MVFR with a chance of snow showers late overnight.

Thursday through Saturday...MVFR/IFR in rain, with rain
becoming more intermittent Friday and Saturday.

&&

.MARINE...
A strong cold front will plow across the Lower Great Lakes this
evening with winds significantly strengthening while veering to the
west. Strong westerlies on Lake Erie will support high end small
craft advisories into the day Tuesday...while gale force winds can
be expected on Lake Ontario.

A brief period of SCA will also occur on the Saint Lawrence River
within southwest flow before the winds veer to westerly. The gale
force winds will start to subside on the western half of Lake
Ontario by midday Tuesday... while they will largely remain in place
(at least with gusts) for the rest of the lake for the vast majority
of the day.

Winds and waves will subside Tuesday night as an area of high
pressure works its way across the Lower Great Lakes. Moderate west
to southwest winds are forecast for much of Wednesday...with choppy
(but sub advisory) conditions expected over the eastern half of Lake
Ontario.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Wind Advisory from 1 AM to 6 PM EDT Tuesday for NYZ001>006-011-
     013-014.
     Winter Weather Advisory from 8 PM this evening to 6 PM EDT
     Tuesday for NYZ006>008.
MARINE...Small Craft Advisory until 5 PM EDT Tuesday for LEZ020.
         Small Craft Advisory until 11 PM EDT Tuesday for LEZ040-
         041.
         Small Craft Advisory from 11 PM this evening to 2 AM
         EDT Wednesday for LOZ030.
         Gale Warning from 11 PM this evening to 2 PM EDT Tuesday
         for LOZ042-062.
         Gale Warning from 11 PM this evening to 5 PM EDT Tuesday
         for LOZ043>045-063>065.
         Small Craft Advisory from 1 AM to 8 AM EDT Tuesday
         for SLZ022.

&&

$$

SYNOPSIS...Thomas
NEAR TERM...RSH
SHORT TERM...HSK
LONG TERM...JJR
AVIATION...Thomas
MARINE...RSH/Thomas