Forecast Discussion for BUF NWS Office
000
FXUS61 KBUF 190939
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
539 AM EDT Tue Mar 19 2024

.SYNOPSIS...
An elevated frontal boundary will help to produce some widespread
snow across the region today with most areas receiving a coating to
an inch or two of non impactful snow. Lake enhancement could lend to
somewhat higher amounts east of both lakes. While the snow showers
will taper off tonight...a frontal passage Wednesday morning will
lead the charge of reinforcing cold air. This will promote at least
scattered snow showers throughout the day while setting the stage
for pure lake effect snow showers Wednesday night and Thursday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
A sub 1000mb sfc low in the vcnty of Lake Superior at daybreak will
slowly drift east during the course of today. In the process...an
elevated warm front will make its way across our forecast area along
with a swath of deeper moisture. Frontogenetic lift associated with
the elevated boundary should be enough to generate fairly widespread
snow showers during the course of the day...esp east/northeast of
the lakes where pure lake effect will give way to synoptic forcing
and act as an enhancing feature due to H85 temps `warming` to -8c.
This will effectively eliminate the lake induced instability.

Snowfall amounts today will generally range from one to two
inches...although higher amounts of up to four inches will be found
near and south of the Tug Hill. Amounts will be most insignificant
(an inch or less) over the Finger Lakes region. Otherwise...today
will continue to feature below normal temperatures peaking in the
low to mid 30s...while a modest 35 knot low level jet will support
widespread wind gusts of at least 30 mph.

While a deep cyclonic flow of chilly air will maintain a wealth of
clouds over the region tonight...enough weak warm advection should
have taken place with the aforementioned elevated warm front to
preclude pure lake effect east/northeast of the lakes. There will be
some lake and orographically enhanced areas of light snow though
that could accumulate as much as three inches in the vcnty of the
Tug Hill. Temperatures tonight will settle to within a few degrees
of 30.

On Wednesday...a 120kt H25 jet will accompany a robust shortwave
that will drive the next cold front through our forecast area. This
will easily support scattered to likely pops for snow showers
throughout the region with orographics pushing the pops to
categorical levels in the vcnty of the Tug Hill. Fresh daytime snow
accumulations will generally range from an inch or two...but amounts
should reach three inches or so for the higher terrain of the Srn
Tier and east of Lk Ontario. While relatively warm sfc`s should aid
in limiting the impact of the snow on area roadways...there could be
a burst of snow with the front that would quickly lead to a slushy
coating.

Speaking of which...a 40kt LLJ and a 10kft deep layer of very steep
lapse (9-10 deg c/km) rates that will accompany the front could set
the stage for a squall line of heavy snow during the frontal passage
between mid morning and early afternoon. This set up will also
promote a windy afternoon throughout the region...especially over
the western counties where winds could gust to 40 mph. If you will
be traveling during the aforementioned window...be wary of a 15
minute burst of snow that will not only SIGNIFICANTLY reduce the
visibility but could also lead to a glaze of ice.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Strong mid level shortwave and associated surface low will move from
far southern Quebec into New England Wednesday night, before moving
east of Maine by late Thursday. Strong cold air advection ensues
Wednesday night in the wake of a surface cold frontal passage
earlier on Wednesday. This will allow widespread snow shower
activity to become more upslope and lake effect dominant Wednesday
night. Temperatures aloft will certainly support a lake response as
850Ts take a nose dive, getting down to -15C to -18C overnight. A
westerly flow will place lake effect snow bands east of the Lakes
initially, before flow veers northwesterly sending lake bands
southeast of the Lakes. Winds will be quite strong with some blowing
snow possible as lows bottom out in the mid teens to low 20s.
Equilibrium levels around 10kft Wednesday evening will slowly drop
through the night to around 5-6kft by Thursday morning as drier air
slowly works in aloft from the west. Despite a lowering cap,
possible upstream lake connections and a DGZ that remains fully in
play will allow LE snow to continue into Thursday morning, before
drier air and subsidence along with early spring sun angle win out
with the last of the lingering lake effect snow showers tapering off
through Thursday afternoon. Snowfall amounts from Wednesday night
through Thursday will be 2-4" on the Tug Hill, 1-3" southeast of Lake
Ontario and across the higher terrain east of Lake Erie, especially
the Chautauqua Ridge. Little to no accumulation expected elsewhere.
Otherwise, Thursday will feel much more like mid-January as opposed
to the start of spring with daytime highs mainly in the mid to upper
20s, struggling to reach 20F across the Tug Hill and western Dacks
(some 15-20 degrees below average). Strong northwest winds will
lower wind chill values down into the single digits and even below
zero Tug Hill/western Dacks by late Wednesday night, with wind chill
readings still only in the single digits and teens by Thursday
afternoon.

Surface high pressure will bring mainly dry conditions Thursday
night as it slides directly overhead, while also providing good
radiational cooling conditions as surface winds decouple along with
clearing skies, especially away from any lingering lake clouds. This
will set us up for a cold night with teens for lows area wide, with
single digits Tug Hill/western Dacks. This will also be a night
where those traditional cold spots may tank, especially if there is
fresh snow cover.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Deep upper level low lifts out on Friday, while surface high
pressure shifts east with a south to southeast low level return flow
setting up bringing some warmer air north toward our region. Jet
stream will remain active with the northern and southern stream
branches trying to phase toward the tail end of the work week into
the start of the weekend. Models continue to struggle with phasing
of the two branches, with a partial phasing of the two jets looking
like the worst case scenario at this point. GFS continues to be the
most aggressive with the phasing of the two jets. If phasing of the
northern and southern branch did occur, it would have the potential
to develop a strong synoptic system that could develop over or east
of our area depending on timing. Either way, it appears likely that
a slug of precipitation will impact our region sometime in this
window, with p-type highly dependent on how this system develops.

High pressure brings dry weather for the second half of the weekend.
As we start the new work week, a system ejecting out of the Rockies
will approach from the west, while another system tries to get its
act together while moving northward along the East Coast. High
pressure wedged in between these two systems may remain close enough
to keep dry weather going into Monday, however with a decent amount
of discrepancy at this time range, will follow closer to ensemble
guidance with slight to low chance PoPs in the forecast for now.

Below average temperatures through the weekend...will quickly jump
back the near or even a bit above average for the start of the new
work week.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
Widespread cigs arnd 3500ft will accompany some light snow during
the remaining pre dawn hours...although MVFR conditions in steadier
lake snows will be found southeast of Lake Ontario...impacting sites
such as KJHW.

After daybreak...an elevated frontal boundary will support
deteriorating conditions with MVFR cigs and snow that will reduce
vsbys to 2-4SM. This will be accompanied by winds that increase to
include wind gusts of 30-35 knots.

The fairly widespread snow will taper off late today and early this
evening...while cigs should improve to VFR levels. The exception
will likely be across the Srn Tier and east of Lk Ontario where MVFR
cigs should persist.

Outlook...

Wednesday...Occasional lake effect snow showers with local/brief IFR
conditions. MVFR/VFR outside of lake effect.
Thursday...MVFR/VFR with a chance of snow showers and associated
brief/local IFR.
Friday...Mainly VFR with increasing chances for snow showers.
Friday night through Saturday...MVFR with chances for snow showers.

&&

.MARINE...
A tight sfc pressure gradient between relatively deep low pressure
to our north and high pressure centered over the Lower Mississippi
valley will support widespread small craft advisories throughout the
region today. This includes the Upper IAG River and Buffalo
Harbor with a freshly issued SCA in this package.

While winds will drop off a bit tonight...moderate to fresh breezes
will keep conditions choppy enough to warrant extending many of the
SCAs through the night up to when a widespread gale watch will go
into effect Wednesday afternoon.

The gale watch for Wednesday is a result of a 40kt low level jet
that will accompany the passage of...and persist for several hours
afterward...a strong cold front.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory from 11 AM this morning to 11 PM EDT this
         evening for LEZ020.
         Small Craft Advisory until 11 AM EDT Thursday for LEZ040-
         041.
         Small Craft Advisory until 2 PM EDT Wednesday for
         LOZ042>045.
         Gale Watch from Wednesday afternoon through late Wednesday
         night for LOZ042>045-062>065.

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JM
LONG TERM...JM
AVIATION...RSH
MARINE...RSH

NWS BUF Office Area Forecast Discussion