000
FXUS61 KBUF 301506
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1006 AM EST Thu Nov 30 2023

.SYNOPSIS...
Weak high pressure builds in briefly today bringing dry and warmer
weather through the first half of tonight. A series of low pressure
systems will then bring several rounds of unsettled weather to the
region from Friday right through the start of the new work week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Weak high pressure builds across the region today resulting in
mainly sunny skies. Stubborn lake clouds northeast of Lake Ontario
will continue to break up from southwest to northeast this
morning, with mainly sunny skies eventually developing here as
well. It will breezy again today, however continued weak warm
air advection will give temperatures a boost with highs mid to
upper 40s lower elevations and mainly upper 30s across the
higher terrain.

Dry and breezy conditions to start off tonight. A cold front
trailing a weak area of low pressure moving through central Quebec
will slowly approach the region overnight. Although much of the
region will remain dry, the front may get close enough and with some
help from the Lakes may see a few showers develop from the Niagara
Frontier to the eastern Lake Ontario region during the second half
of the overnight. Otherwise, a mild night on tap by the start of
meteorological winter standards with lows only bottoming out in the
mid to upper 30s.

Our weather deteriorates on Friday as southern stream system rides
along the aforementioned boundary bringing a steady (mainly) rain to
our region. Perhaps some wet flakes mixing in on the hilltops, but
not expected to amount to much of anything. Plenty of moisture with
this system, however it is a quick mover which will help limit
rainfall amounts, with average basin rainfall of 0.25"-0.40" during
the day. High temperatures will be mainly in the low to mid 40s with
some mid and upper 30s across the higher terrain, coolest Tug Hill
and western Dacks where a few wet flakes will be possible.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A low amplitude...Pacific based flow over the country at the start
of this period will amplify during the course of the weekend. This
will GUARANTEE above normal temperatures for our forecast area...
especially Saturday night and Sunday when the mercury will average a
solid 5 to 10 degrees above normal. The milder than normal weather
to start the month of December will be accompanied by fairly
unsettled conditions though. Fortunately for most of us...this will
translate into the bulk of the expected pcpn falling in liquid form.
The details...

As we open this period Friday evening...a robust shortwave will be
in the process of exiting our region via the Adirondacks and New
England. Widespread mixed pcpn east of Lake Ontario at that time
will taper off to showers during the overnight. A second shortwave
will quickly follow in its wake though...and this feature will be
accompanied by a weak sfc reflection that will approach from the the
Lower Ohio valley. A modest 35-40 kt LLJ ahead of the sfc low will
ride up and over a well defined baroclinic zone that will result in
fairly deep frontogenetic forcing. This will support fairly
widespread rain showers or even a period of steady rain over the
western counties as we push through the wee hours of Saturday
morning.

After daybreak Saturday...the weak sfc low and attendant mid level
shortwave will pass over the forecast area by early afternoon. The
aforementioned frontogenetic forcing will continue to support
widespread showers...but this activity will wane during the course
of the afternoon as mid level drying and the onset of subsidence
will build across the region. We can expect fairly mild weather
though...as afternoon temperatures should range from the lower 40s
across the North country to between 45 and 50 over the western
counties.

While there may a few leftover showers over the Eastern Lake Ontario
region Saturday night...the passing crest of a broad mid level ridge
should be able to keep the bulk of the region pcpn free.

Conditions will then deteriorate on Sunday...as a loosely organized
southern stream storm system will make its way across the Ohio
valley to the Mid Atlantic states. While there is a fair amount of
uncertainty to the track of this system with the GFS actually
tracking it to our northwest and most other packages pushing it by
to our south...there is fairly high confidence that it will be too
`warm` aloft to support anything other than liquid pcpn. The bulk of
the pcpn will fall during the second half of Sunday into Sunday
evening.

Notably colder air will work its way back across our region in the
wake of the system late Sunday night. If the GFS scenario works
out...it could become quite breezy with gusts approaching 40 mph.
Will half step this with the more southern solution (which is
favored) for now. Otherwise...the pcpn will gradually taper off
overnight with some snow mixing in. A couple inches of accumulation
cannot be ruled our east of Lake Erie and especially over the
Eastern Lake Ontario region.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A phasing of the two jets during this time frame will result in
general troughiness over the Great Lakes region...while a burgeoning
ridge will become established over the western conus. This should
allow our temperatures to settle to near...or just a bit below
normal.

In regards to pcpn...a cyclonic flow of chilly air (H85 ~ -7c)
Monday and Monday night will support scattered mixed rain and snow
showers over the bulk of the forecast area with likely pops found
east/southeast of both lakes. Problematic snow accumulations are not
anticipated.

A shortwave ridge and a narrow wedge of sfc high pressure will cross
the region on Tuesday. Mid level dry air and a low subsidence
inversion associated with this synoptic set up will limit any
nuisance shower activity...even southeast of both lakes.

A weak cold front is forecast to cross the Lower Great Lakes Tuesday
night or Wednesday with additional snow shower activity...although
moisture should be limited.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Lingering low VFR CIGS at KART will completely erode by 17z.
Otherwise, widespread VFR with only passing cirrus level clouds
through this afternoon and evening. SSW/SW winds gusting 20-30 knots
from late this morning on at all terminals.

VFR to start this evening. A cold front will then approach from the
northwest tonight, with low VFR/MVFR CIGS moving back in from NW to
SE second half of tonight. Strong LLJ off the deck this evening, but
winds should continue to mix enough to mitigate true LLWS conditions
through the first half of tonight, before the stronger winds aloft
exit east later tonight as surface winds come down as well.

Outlook...

Friday...Mainly VFR/MVFR with rain showers.
Saturday...Restrictions likely in widespread rain and possible fog.
Sunday and Monday...Restrictions possible in scattered to numerous
rain showers, possibly mixed with snow for higher terrain.

&&

.MARINE...
Strong southwest flow will continue to keep winds and waves above
headline criteria through early Friday morning, with Small Craft
Advisories in effect for all but the lower Niagara River and Saint
Lawrence River at this time. Southwest winds will ramp back up today
for the upper Niagara River and Buffalo Harbor for which a Small
Craft Advisory is in effect for this morning through the first half
of tonight.

Winds and waves subside Friday into the weekend with conditions
expected to remain below Small Craft Advisory criteria.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 1 AM EST Friday for LEZ020-040-041.
         Small Craft Advisory until 1 AM EST Friday for
         LOZ042>045.

&&

$$

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