545
FXUS61 KBUF 042317
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
717 PM EDT Sat Apr 4 2026

.WHAT HAS CHANGED...
Wind Advisory issued for Jefferson and Lewis counties for localized
downslope wind gusts of around 50 mph tonight.

&&

.KEY MESSAGES...
1) Showers and scattered thunderstorms will move from west to east
across the area tonight, with localized strong wind gusts and heavy
rainfall possible.

2) Localized strong downslope winds tonight across the North Country.

3) Much cooler with gusty winds and scattered showers Sunday.

4) Well below normal temperatures and snow at times for Sunday night
through Tuesday.

&&

.DISCUSSION...
KEY MESSAGE 1...Showers and scattered thunderstorms will move from
west to east across the area tonight, with localized strong wind
gusts and heavy rainfall possible.

A warm front will continue to move northeast across the area through
the rest of the afternoon, reaching northeast NY by early this
evening. A few showers will continue along and ahead of the
advancing warm front, reaching the eastern Lake Ontario region mid
to late afternoon. Farther west, modest instability will develop in
the expanding warm sector across Western NY and the Finger Lakes,
but a layer of warm air in the mid levels and lack of forcing for
ascent or low level foci will keep any convection isolated, or
possibly non-existent in the warm sector this afternoon and early
evening.

The main focus will continue to be tonight as a strong cold front
moves east across the eastern Great Lakes. Thermal and wind field
analysis suggests the cold front will come through in two segments,
with the focus for strong to severe convective potential along the
first boundary. Diurnal timing is less than ideal, with the line of
convection expected to enter Western NY during the mid to late
evening, reaching the Genesee Valley by around or shortly after
midnight. The limited surface based instability that develops will
be on the wane, and may prove to limit the severe weather potential.
Wind fields and shear are impressive, with a narrow axis of 50-70
knots of mid level flow along and just ahead of the cold front.

Given the strong shear environment and strong forcing, a narrow,
shallow band of convection may persist into the late evening despite
the limited instability, with any convective line segments
supporting the potential for localized strong wind gusts across
Western NY. Overnight, instability will diminish further, with a
lowering risk of convective winds with eastern extent.

The advancing cold front will be situated in the favorable right
entrance region of an upper level jet streak, with upper level
divergence atop the strong frontal zone supporting a wide band of
moderate rain along the front, which will last for 4-6 hours at any
one location as it moves east across the area tonight. Any embedded
convection will produce embedded downpours. PWAT values briefly
surge to 1.25" or better, which is close to 3 standard deviations
above average for early April.

Expect rainfall amounts to average 0.50" to 0.75" in most areas,
with more localized amounts of around 1.0" to 1.25" possible in any
embedded convection. These amounts will produce some minor ponding
of water in poor drainage areas and some within bank rises on area
creeks and rivers, but should not be enough to result in significant
flood issues.

KEY MESSAGE 2...Localized strong downslope winds tonight across the
North Country.

A strong low level jet will propagate across the area tonight, with
a brief window of 60-70 knots near the top of the boundary layer.
For most of the area, stability will not be favorable for mixing of
strong winds to the surface (outside of convection), or for
downslope winds across Western NY.

The setup across the North Country will be much more favorable for
downslope winds, with forecast BUFKIT soundings suggesting a more
stable inversion layer near the top of the Tug Hill Plateau and
western Adirondacks. This layer of ridgetop stability will likely
support localized strong downslope wind gusts along the north slopes
of the Tug Hill Plateau, the Black River Valley, and near the
northwest slopes of the Adirondack Plateau. Expect gusts to peak for
a few hours just ahead of the rain, with gusts to around 50 mph. A
Wind Advisory has been issued for tonight in Jefferson and Lewis
counties.

KEY MESSAGE 3...Much cooler with gusty winds and scattered showers
Sunday.

Strong cold advection will develop late tonight through Sunday in
the wake of the departing cold front. A few scattered showers will
develop, especially in the afternoon as lapse rates steepen with
cold air aloft and modest boundary layer heating. DPVA will increase
ahead of an incoming shortwave later in the afternoon. The most
persistent showers will likely focus on a lake breeze convergence
zone stretching from the Niagara Peninsula eastward in a band just
north of the NYS Thruway during the afternoon and early evening.

Precipitation type will be mostly rain for lower elevations,
although some wet snow, graupel, or even small hail may mix in
within any heavier showers. The higher terrain will have a better
chance of going over to snow later in the day as temps aloft
continue to cool.

It will be quite windy areawide Sunday with 30-40 knots of wind in
the post-frontal boundary layer. This will translate into surface
gusts in the 25-35 mph range, and as high as 40-45 mph in the
typically windier locations northeast of Lake Erie and Lake Ontario.

KEY MESSAGE 4...Well below normal temperatures and snow at times for
Sunday night through Tuesday.

A cold front crossing the area tonight will bring cooler than normal
temperatures to the region for the Sunday night through Tuesday
night time period. Another cold front and associated sfc low will
track across the area Monday evening. This will bring a reinforcing
cold airmass to the region through Tuesday night. Afternoon
temperatures on Monday will be in the mid 30s to mid 40s for the
entire area, which will be around 10 degrees cooler than normal. On
Tuesday, afternoon temperatures will only reach the upper 20s to mid
30s, around 15 degrees below normal for most areas.

A large scale troughing pattern will be in place during this time,
resulting in an active period. The combination of the cold
temperatures aloft and passing sfc lows and embedded shortwave
troughs crossing the area will result in periods of showers, with
widespread, upslope and lake enhanced/effect all possible. A passing
shortwave trough, combined with upsloping will cause rain and snow
to continue into Sunday night. As the night progresses, any
precipitation that falls in the form of rain will slowly mix with
and then change to snow as temperatures cool through the night. Snow
amounts for Sunday night will be limited to and inch or two over the
higher terrain with only a coating for the lower elevations
expected.

Another shortwave trough and sfc low will cross the area Monday into
Monday night, precipitation will remain mostly as rain or a
rain/snow mix during the daytime hours on Monday, with the greatest
chance for more snow across the higher terrain. Once again, any rain
will mix with and then change to snow Monday night as temperatures
cool. A cold front associated with this sfc low will also cross the
area Monday night, cooling temperatures aloft to -12C by early
Tuesday morning. With a northerly flow over Lake Ontario, lingering
synoptic moisture, the cold temperatures and a trough aloft, lake
enhanced snow south of Lake Ontario will linger through the night
and into the start of the morning on Tuesday. Snow amounts on Monday
into Monday night in the 1 to 3 inch range will be possible for
areas north of I90 toward the south shore of Lake Ontario, and for
the higher terrain of the Western Southern Tier where upsloping will
continue. For the lower elevations and areas farther away from the
lakes, up to an inch of snow will be possible.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions prevail across the region this evening in the wake of
a warm frontal passage earlier in the day. However, conditions will
deteriorate in the next few hours as a strong cold front pushes east
across the region. Strong ascent and a plume of deep moisture will
support a wide band of rain along the front, supporting a period of
rain for 4-6 hours as any one location. Despite the front`s arrival
will be after sunset, and therefore instability will be waning, a
few thunderstorms may be along the leading edge of the rain where
some locally strong winds gusts and heavy downpours will be
possible. The chance for thunder will continue to diminish
overnight, especially for the eastern portions of the region. With
the front, ceilings will tumble to MVFR/IFR along and behind the
front.

The last of the rain associated with the cold front will exit the
eastern Lake Ontario region by mid morning on Sunday. A few showers
may linger behind the front, with the best coverage occuring during
the afternoon and evening. The most persistent showers will focus
along the lake breeze convergence zone from the Niagara peninsula
eastward along/just north of the NYS Thruway. Precipitation will
mainly fall in the form of rain, though a few wet snowflakes or
small hail may mix in with heavier showers possible across the
higher terrain. Ceilings will remain a mix of MVFR/IFR.
Additionally, it will be quite windy Sunday with gusts ranging from
20 to 30 knots areawide and up to 35 knots northeast of Lakes Erie
and Ontario.

Outlook...

Sunday night through Tuesday...MVFR/VFR with a chance of snow
showers...with IFR possible in areas of lake effect snow showers
east/southeast of the lakes.

Wednesday...VFR.

Thursday...Mainly VFR with a chance of showers late.

&&

.MARINE...
Moderate to strong easterly flow on Lake Ontario will continue to
produce Small Craft Advisory conditions on the west half of Lake
Ontario through early this evening before winds become south and
briefly diminish.

A cold front will then move east across the lower Great Lakes
tonight. South winds will increase on Lake Ontario just ahead of the
cold front, especially at the east end of the lake where sustained
winds may briefly approach 30 knots. Winds will becoming southwest
behind the cold front late tonight through Sunday and increase
again, with a period of Small Craft Advisory conditions on Lake Erie
and Lake Ontario, along with the Niagara River and Saint Lawrence
River. Winds will remain elevated on Lake Ontario through Sunday
night before diminishing Monday.

&&

.HYDROLOGY...
A Flood Advisory remains in effect for the Salmon River in
northern Oswego County. High flows will continue as water is
released from the Salmon River Reservoir due to runoff from
recent heavy rain and snowmelt. The water expected water levels
will not produce any significant flooding, but will continue to
produce minor flooding in low lying areas along the creek and
create dangerous currents. Fisherman should avoid the river
until flows subside.

A cold front will cross the area tonight, producing another
round of soaking rainfall. The rain will result in minor ponding
of water in poor drainage areas and within-bank rises on area
creeks and rivers, but is not expected to be enough to produce
any more impactful flooding.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Wind Advisory until 4 AM EDT Sunday for NYZ007-008.
MARINE...Small Craft Advisory from 8 AM to 10 PM EDT Sunday for LEZ020-
         040-041.
         Small Craft Advisory from 8 AM to 10 PM EDT Sunday
         for LOZ030.
         Small Craft Advisory until 4 AM EDT Monday for LOZ042.
         Small Craft Advisory until 10 AM EDT Monday for LOZ043.
         Small Craft Advisory until 10 AM EDT Monday for LOZ044-045.
         Small Craft Advisory from 11 AM to 10 PM EDT Sunday
         for SLZ022-024.

&&

$$

DISCUSSION...Hitchcock/SW
AVIATION...EAJ
MARINE...Hitchcock
HYDROLOGY...Hitchcock