454
FXUS61 KBUF 041421
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1021 AM EDT Fri Apr 4 2025

.SYNOPSIS...
High pressure over the Upper Great Lakes this morning will drift by
just to our north this afternoon. This will enable most areas to
experience partly to mostly sunny weather with notably less wind
than that from Thursday. Several waves of low pressure will then
move out of the Ohio valley during the weekend to support a soaking
rain. The bulk of this will fall late tonight into early Sunday with
many areas picking up at least an inch to an inch and a half of
rainfall.

&&

.NEAR TERM /THROUGH SATURDAY/...
The dense cirrus deck from earlier this morning is thinning across
Western and Central NY, allowing for increasing amounts of sunshine
through the rest of the day. An area of stratocumulus has developed
across the North Country, but this should be temporary as the
shallow field of supporting low level moisture mixes out this
afternoon.

The area of high pressure will exit across New England tonight...
while the first of several low pressure waves will approach our
region from the Ohio valley. A 50 kt low level jet pushing to the
northeast ahead of the sfc wave will ride up and across a tightening
H925-70 baroclinic zone. The resulting isentropic lift will lead to
widespread rain over the western counties (mainly after midnight)
where rainfall will range from a tenth of an inch across the Finger
Lakes to as much as a half inch over Chautauqua county.

Saturday then promises to a rainy...miserable day...as the first
lobe of low pressure will cross our forecast area. The rainiest
portion of the day looks like it will be in the morning and again
later in the afternoon with a period of relatively dry weather
(spotty showers still poss) from late morning into the afternoon.
Confidence is low on the timing of this though...so listen to
updated forecasts and/or keep an eye on your local radar. This will
also be important in the afternoon when there will be a low risk for
thunderstorms. Forecast rainfall amounts on Saturday range from a
third of an inch across the North country to three quarters to as
much as an inch across Chautauqua and Cattaraugus counties.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
Deep mid-level troughing centered across the Great Lakes Saturday
night, will support a shortwave trough to round its base Sunday. As
such, a cold front will slide across New York State Saturday night,
with a series of surface lows to ride northeast along the boundary
and pulling the frontal boundary east towards the Atlantic
coastline. In addition to the exiting frontal boundary, cold air
will advect in behind the boundary, dropping 850mb temperatures from
+3C to -6C Sunday. As a result, exiting rain showers will transition
to a mix of rain and snow from west to east Sunday.

The drying and cooling trend will continue Sunday night not only
supporting clearing skies but also aiding temperatures to drop into
the 20s due to radiational cooling.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Deep troughing will remain overhead of the Great Lakes and Northeast
Monday through Thursday. Through this time a couple of shortwave
troughs will round the base of the trough. The first shortwave
passage will act to begin to drag the longwave trough east, however
it won`t be until the second shortwave trough where the upper level
pattern will begin to shift (though the strength of this shortwave
continues to remain uncertain, more on this in a short few).

With the first shortwave trough passage, a cold front will slide
east across New York State Monday and Monday night. By Monday,
temperatures at 850 will be around -10C, and further plunge towards -
15C by Monday night, supporting snow showers to drop southeast
across the region with the frontal passage, and a few lake enhanced
snow showers east/southeast of Lakes Erie and Ontario in its wake,
which will linger into Tuesday morning.

After a brief period of height rises and corresponding dry weather
Wednesday, the forecast becomes uncertain with the placement of the
next system due to the strength and timing of the next shortwave
trough.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR weather with light winds will be in place today.

While VFR conditions will persist through most of tonight...clouds
will lower and thicken ahead of an initial wave of low pressure that
will make is way out of the Ohio valley. The lowering cigs will
reach MVFR levels over the far western counties after 06z with the
cigs further lowering to IFR levels after 09z for the western
Southern Tier. The lowering cigs will be accompanied by increasingly
widespread rain.

There will also be the risk for low level wind shear across the
Southern Tier late tonight.

Outlook...

Saturday and Sunday...Restrictions likely in scattered to numerous
rain showers.
Monday...Restrictions possible in scattered rain/snow showers.
Tuesday...Restrictions from snow showers likely.

&&

.MARINE...
Light to gentle winds and negligible waves will be found throughout
the region today...as high pressure centered over the SOO this
morning will cross JUST to the north of Lake Ontario this afternoon.

The sfc high will exit via the St Lawrence valley tonight...while
the first of several waves of low pressure will approach the region
from the Ohio valley. This will prompt winds to become easterly and
freshen during the course of the night...especially across Lake
Ontario. While waves will build a bit...the offshore flow will
direct the most noticeable rises in Canadian waters.

Moderate east to southeast winds Saturday morning will veer all the
around to the southwest on Lake Erie by afternoon...and to the south
southwest while further strengthening on Lake Ontario. This will be
in response to the first area of low pressure passing over New York
state. These winds will be accompanied by periods of rain...mainly
in the morning and later in the day when thunderstorms will also be
possible. Conditions could require small craft advisories on eastern
Lake Ontario for the afternoon and evening.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

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