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000
FXUS61 KBUF 112338
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
738 PM EDT Thu Apr 11 2024

.SYNOPSIS...
Deep low pressure will cross the central Great Lakes tonight through
early Friday before reaching Quebec late Friday night and Saturday.
This system will continue to produce periods of soaking rainfall and
a few scattered thunderstorms through Friday. The rain will mix with
or change to wet snow later Friday night and early Saturday before
ending from west to east later Saturday. Some minor, slush
accumulations are possible across the high terrain late Friday night
and Saturday morning. It will also be quite windy much of the time
tonight through Saturday.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
A strong southern stream trough over the Tennessee Valley and a
strong northern stream trough over the upper Mississippi Valley are
in the process of phasing this evening, and this will result in a
deep full latitude longwave trough that advances slowly east across
the Great Lakes and eastern US through the end of the week. Deep
southerly flow ahead of the digging trough will continue to
transport copious moisture northward into the eastern Great Lakes
through early Friday. Strong large scale forcing will continue, with
strongly diffluent mid/upper level flow and a coupled upper level
jet structure supporting organized deep ascent through early Friday.
The most organized rain will be focused by low level forcing from a
series of warm frontal segments and shortwaves through tonight, then
a cold front on Friday.

Precipitation Details...

Rain will move northeast and weaken by late this evening, but
numerous spokes of vorticity ejecting out of the strong upstream
trough along with height falls and ongoing strong moisture transport
and convergence ahead of the surface low will support additional
periods of rain overnight through Friday morning. One more band of
moderate to heavy showers will enter Western NY late tonight, then
cross the rest of the area from southwest to northeast through the
first half of Friday as the cold front surges northeast across the
area. Enough instability may develop to support some isolated
thunder again along the front, especially east of Lake Ontario.

Expect another relative lull in rainfall following the passage of
the front as a brief dry slot works east across the area. This will
be followed by more widespread rain moving back into Western NY later
in the day as the wrap around/comma head moisture and forcing arrive
on the rear flank of the system.

Friday night, the mid level closed low will move east across
southern Ontario, with deep wrap around moisture and cyclonic flow
supporting a continuation of widespread rain. A cold pool aloft will
arrive overnight, and the boundary layer will continue to cool. This
will allow some wet snow to mix in overnight, first across higher
elevations and then possibly some lower elevations by late Friday
night. The highest terrain of the Southern Tier, western Finger
Lakes, and Tug Hill Plateau may change to all wet snow with a few
inches possible late Friday night through Saturday morning.

Wind Details...

This system will also produce an extended period of gusty winds
across the region. A strong southeasterly low level jet will
propagate across the eastern Great Lakes through tonight. This will
support widespread 30-40 mph gusts tonight across the entire region,
with local 45+ mph gusts in a few downslope areas. The best chance
of higher 50+ mph downslope wind gusts will be found along the
north/northwest slopes of the Tug Hill Plateau where the strongest
low level jet and most favorable low level stability profiles are
found for downslope acceleration. A Wind Advisory remains in effect
for Jefferson and Lewis counties.

A cold front will arrive in Western NY very late tonight, then move
northeast across the rest of the area Friday. Southwest winds will
increase along and behind the cold front, especially northeast of
Lake Erie. Expect gusts of 40-45 mph Friday across the Niagara
Frontier including Buffalo. Relatively poor low level lapse rates
should prevent gusts from reaching advisory criteria for an extended
period of time, but it will be close.

Winds become more westerly Friday night behind a secondary cold
front, with steepening lapse rates supporting widespread 35-45 mph
gusts. There is a chance a few areas may reach wind advisory
criteria gusts, especially near the lakeshores and across higher
terrain.

Temperature Details...

Temperatures will stay mild tonight, in the 50s or even low 60s.

A strong cold front will reach Western NY very late tonight or early
Friday morning, with temperatures falling quickly into the 40s.
Temperatures will hold steady or slowly fall in Western NY through
the day Friday, with falling temperatures for the rest of the area.
Temperatures will drop into the 30s Friday night areawide, with
upper 30s lakeshores and low to mid 30s higher terrain.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A mix of rain and snow (wet snow mainly above 900 ft) early Saturday
morning will slowly decrease in coverage from west to east as we
progress though the day. While there will be some snow fall,
elevation dependent, additional accumulations of under an inch is
all that is expected for the highest points. It will also continue
to be quite breezy with sustained WNW winds of 15 to 25 mph gusting
up to 40 mph at times. Highs will range from the upper 30s to low
40s east of Lake Ontario with mid and upper 40s near 50F elsewhere.

A brief lull between systems will occur Saturday night with dry
weather expected areawide for much of the night. Lows will be found
in the 30s to low 40s.

A fast moving shortwave and sfc reflection dropping through the
Great Lakes Sunday will then introduce chances for showers or even a
thunderstorm. The best shot at see a thunderstorm will be found
across the S. Tier with in the warm sector and along an advertised
tightening H850 thermal gradient across the region. BUFKIT profiles
do show MUCAPE values of 200-500 J/kg across the S. Tier to the
NY/PA line. Otherwise...a wide range of temps will be found across
the forecast area. Highs will peak in the 40s/50s east of Lake
Ontario with solid 50s to even low 60s across western New York.

The weak low quickly departs by Sunday evening with surface high
pressure building in across the region. A cooler air mass will be in
the process of filtering into the eastern Great Lakes with H850
temps falling down to -2C to -3C by Monday morning. Lows will
generally be found in the 40s with a few colder spots east of Lake
Ontario.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Another round of weak surface-based ridging will slide across our
area Monday and Monday night and bring another period of mainly dry
weather. This ridge will then slide off to our east on Tuesday...
while giving way to a sprawling cutter-type low that will lumber its
way from the central Plains states to near James Bay through the
rest of the period. This next system will usher in warmer and more
unsettled weather that will feature frequent opportunities for
showers from Tuesday afternoon through Thursday...though there will
also likely be some drier periods interspersed. In addition...
diurnal instability may also support the potential for a few
thunderstorms across far southwestern New York Tuesday afternoon and
early evening...then again south of Lake Ontario both Wednesday and
Thursday afternoons/evenings.

With respect to temperatures...these should average out a solid 5 to
10 degrees above normal Monday and Monday night...before trending
even more strongly above normal for Tuesday through Thursday as the
aforementioned cutter low spreads even warmer air across our region.
During the latter three days of the period...it currently appears
that highs will range from the mid-upper 60s east of Lake Ontario to
the 70s across much of western New York.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Through Friday...additional periods of rain will continue across the
region as low pressure passes just west of the area, and a trailing
cold front moves east across the Lower Great Lakes. Expect areas
of MVFR/IFR CIGS through Friday with some reduction in VSBY as well
in areas of heavier rainfall. There may be a chance of a few
isolated thunderstorms along the advancing cold front, mainly east
of Lake Ontario from mid morning through early afternoon. Again,
coverage of thunder looks to be sparse.

Finally, it will be quite windy through the period with gusts of 25-
35 knots common through Friday. A few gusts may approach or exceed
40 knots tonight in downslope areas, and then over and northeast of
Lake Erie on Friday.

Outlook...

Friday night...MVFR/IFR with rain, mixing with or changing to wet
snow overnight. Windy.
Saturday...MVFR/IFR early with rain and wet snow, gradually
improving to VFR from west to east in the afternoon. Windy.
Sunday...VFR/MVFR with a chance of showers and possibly a
thunderstorm.
Monday...Mainly VFR.
Tuesday...Mainly VFR with a chance of showers late.

&&

.MARINE...
Southeast winds will continue to increase this evening, producing
Small Craft Advisory conditions on the east half of Lake Ontario
where winds are strongest. The wind is generally offshore, so larger
wave action will be on the Canadian shoreline.

A cold front will sweep east across the Lower Great Lakes late
tonight and Friday. Winds will become southwest and increase, first
on Lake Erie by late tonight, and then on Lake Ontario from west to
east on Friday. This will produce a period of high end Small Craft
Advisory conditions leading into the weekend.

Winds will increase further on Lake Ontario late Friday night
through Saturday, when a period of gales is likely. With this in
mind, issued a Gale Watch for Lake Ontario for this period. Highest
confidence in gales for a longer period of time is on the east half
of the lake, but the west half may get close as well for a shorter
duration.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Wind Advisory until 5 AM EDT Friday for NYZ007-008.
MARINE...Small Craft Advisory from 6 AM Friday to 2 AM EDT Sunday for
         LEZ020.
         Small Craft Advisory from 2 AM Friday to 11 PM EDT
         Saturday for LEZ040-041.
         Gale Watch from late Friday night through Saturday
         afternoon for LOZ042-062.
         Small Craft Advisory until 8 AM EDT Friday for LOZ043-044.
         Gale Watch from late Friday night through Saturday evening
         for LOZ043>045-063>065.
         Small Craft Advisory until 1 AM EDT Saturday for LOZ045.

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...AR
LONG TERM...JJR
AVIATION...Hitchcock
MARINE...Hitchcock