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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBUF 140135
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
935 PM EDT Sat Apr 13 2024

.SYNOPSIS...
Deep low pressure will continue withdrawing northward across
northern Quebec through this evening. This will allow winds to
slowly diminish from west to east. High pressure will then cross the
area tonight and bring a BRIEF interlude of dry weather and lighter
winds...before a compact and fast-moving area of low pressure
crosses the area on Sunday. This will result in another round of
widespread showers along with a few thunderstorms. In the wake of
this system...high pressure will build in Sunday night and bring a
return to drier weather that will then last through Tuesday.

&&

.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
In the wake of a large stacked storm over eastern Canada...a
narrow/transient area of high pressure will bring a brief period
of mainly drier weather and lighter winds through the first
half to two thirds of the night before quickly sliding off to
our east later on tonight. At the same time a fast-moving and
compact area of low pressure will be dropping across the Upper
Great Lakes...with its attendant warm front snaking its way
southeastward to Lake Ontario and far western New York by later
on in the night. This latter system will bring a northwest to
southeast increase in cloud cover after midnight...and
eventually a chance of showers to western New York late.
Meanwhile lows will range from the mid to upper 30s in most
areas to around 40 across the Niagara Frontier and along the
Lake Erie shore.

On Sunday...the compact area of low pressure will quickly dive
southeastward across Lake Ontario and New York State...while in the
process bringing a couple rounds of fairly widespread showers. The
first of these will be warm frontal in nature and will focus across
Lake Ontario and adjoining areas during the morning...followed by a
second round along the trailing cold front during the afternoon and
evening. With this second round there looks to be enough weak
instability available to also present the possibility for a few
thunderstorms across western New York...with the greatest potential
for these found across the western Southern Tier. Given the amount
of shear in place...cannot rule out an isolated stronger storm or
two with gusty winds across the Southern Tier Sunday afternoon in
line with the Marginal Risk portrayed in the new SPC Day 2
convective outlook. That being said...the main severe threat with
this system still looks to remain confined to our south in tandem
with the main reservoir of instability. Otherwise...it will be a
milder day with highs ranging from the upper 40s/lower 50s east of
Lake Ontario to the lower to mid 60s across the Southern Tier.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
A shortwave trough will round the base of the longwave trough spread
across the Northeast Sunday night into Monday. This feature will
support a surface low overhead of southern New England, with its
attendant cold front draped just south of the New York/Pennsylvania
state line. Heading into Sunday night, ongoing showers and
thunderstorms associated with the cold front will continue to push
south following the frontal passage. Thus, expect the chances for
showers to diminish throughout the night. With the lack of support
from diurnal effects, expect thunderstorm chances to decrease as
well shortly after sunset.

Meanwhile, mid-level ridging overhead of the upper Midwest Sunday
night will push overhead of the lower Great Lakes by Tuesday night.
As a result, surface high pressure will spread across the Great
Lakes Monday through Tuesday supporting a couple of days of dry
weather for the start of the new work week. Temperatures will
gradually warm during this time, with highs by Tuesday warming up to
range in the 60s. A few locations along the valleys across the
Southern Tier may climb up towards 70.

The next vigorous southern stream mid-level trough will be lying
over the Central Plains Tuesday night, where it will support another
area of surface low pressure overhead of the southern Nebraska. An
attendant warm front to the surface low will sprawl eastward across
the central Mississippi Valley into the Ohio Valley. Meanwhile, just
upstream over the southern portions of the Canadian Rockies the
northern stream trough will lie. As both of these mid-level features
advance east and phase, a complex surface system will lie across the
Upper Mid-West by Wednesday morning, before it advances eastward
across the Great Lakes. Overall, Tuesday night expect increasing
chances for rain showers. By Wednesday morning another round of
soaking rain will be sliding east across the region from west to
east.

&&

.LONG TERM /THURSDAY THROUGH FRIDAY/...
With the now phased mid-level northern and southern stream trough
spread across the upper Midwest Thursday, expect the aforementioned
surface low spread across the Great Lakes to rotate its cold front
across the region Thursday. This will keep the chances for showers
to continue throughout the day Thursday.

The now large mid-level trough will span across the Great Lakes
region into the Northeast Friday into the weekend. This being said,
model guidance continues to remain differed with the strength and
broadness of the mid-level trough. Regardless, with the general
troughing pattern in place, active weather will continue throughout
the end of the work week into the weekend. Additionally, cold air
will begin to filter into the region late in the week which may turn
rain to snow across a few locations of the higher terrain of the
Southern Tier and eastern Lake Ontario regions.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Narrow/transient high pressure and drier air will continue to build
eastward across the area through this evening. General dry/VFR
conditions will be in place until late tonight...when a warm front
attendant to compact low pressure over the Upper Great Lakes will
bring a chance of showers/MVFR ceilings to far western New York.

On Sunday...the compact area of low pressure will quickly dive
southeastward across Lake Ontario and New York State...bringing
increasingly widespread showers...and possibly also a few afternoon
thunderstorms to areas south of Lake Ontario...with the greatest
potential for the latter found across the Southern Tier. As for
flight conditions...these will tend to deteriorate back to MVFR.

Outlook...

Sunday night...Improvement to VFR with leftover showers ending.
Monday...Mainly VFR.
Tuesday...Mainly VFR with a chance of showers Tuesday night.
Wednesday and Thursday...MVFR/VFR with showers likely.

&&

.MARINE...
-- Changed Discussion --
High pressure will pass over the Lower Great Lakes ahead of a warm
front overnight. The weakening sfc pressure gradient will continue
to allow winds and waves to subside. All of the gale warning
headlines have been discontinued as a result...with the small craft
advisories on Lake Erie and west of Hamlin Beach on Lake Ontario
being discontinued as well. New small craft advisories though are in
effect for the eastern two thirds of Lake Ontario into Sunday
morning.

As weak low pressure passes over the region on Sunday...moderate to
fresh southerlies will be found on Lake Ontario while fresh to
occasionally strong southwesterlies will be experienced on Lake
Erie. While waves are currently forecast to remain below SCA
criteria on Lake Erie Sunday afternoon...it should certainly become
choppy.

Gentle winds are then anticipated for Sunday night throughout the
region.
-- End Changed Discussion --

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NY...None.
MARINE...Small Craft Advisory until 11 AM EDT Sunday for LOZ043>045.
-- End Changed Discussion --

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...JJR
MARINE...RSH