Forecast Discussion

Forecast Discussion for BUF NWS Office
000
FXUS61 KBUF 132020
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
320 PM EST Wed Nov 13 2019

.SYNOPSIS...
Light lake effect snow showers southeast of the lakes will end this
afternoon. A weak cold front will then cross the eastern Great Lakes
Thursday afternoon and evening, producing wet snow and rain showers
northeast of the lakes. A cold front will move south across the area
late Friday. This may produce a few light snow showers, and will
bring one last push of very cold air to start the weekend. A warming
trend will then begin Sunday through the first half of next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Lake effect snow showers continue to gradually weaken southeast of
the lakes. Off Lake Erie, a broad area of light snow showers across
the western Southern Tier will retract back over the lake through
mid afternoon, then move north and onshore along the Canadian
shoreline west of Point Abino late this afternoon. Off Lake Ontario,
multiple bands from Orleans and Monroe counties southeast into the
Finger Lakes, and also near Mexico Bay in Oswego County will weaken
and end by mid afternoon as boundary layer flow breaks down over the
lake with the passage of the surface ridge. Any additional snow
accumulations off Lakes Erie and Ontario will be less than an inch.

It will remain very cold this afternoon, with highs in the mid 20s
in most locations and teens across the higher terrain east of Lake
Ontario. Sunshine between the lake effect cloud bands will fade
behind increasing high clouds from west to east.

A warm front will move northeast across the eastern Great Lakes
tonight, spreading a wealth of mid/high clouds across our region.
The low levels remain quite dry, so any light precip that attempts
to develop aloft in the warm advection is not expected to reach the
ground. Temperatures will drop into the upper teens to lower 20s in
Western NY early this evening, and single digits to low teens east
of Lake Ontario. Ongoing warm advection will then allow temperatures
to warm overnight.

Thursday a mid level trough and associated weak surface cold front
will move from the central Great Lakes to the eastern Great Lakes by
late in the day. This system will be moisture starved, so from a
synoptic standpoint it will have little opportunity to produce much
precip. It will remain cold enough aloft to support some lake
enhancement however. Lake enhanced precip will develop first across
southern Ontario in SSW flow late tonight and Thursday morning. The
Lake Erie band will then move into the Niagara Frontier by
afternoon. The Lake Ontario band will move into Jefferson County by
mid to late afternoon. Temperatures aloft are quite cool still, so
the majority of this will be wet snow with the possible exception of
along the lakeshores where some rain may mix in. Accumulations will
be minimal however as surface temperatures warm above freezing, with
highs in the mid 30s across lower elevations. Winds may gust to 25-
30 mph northeast of the lakes Thursday as the pressure gradient
tightens ahead of the approaching cold front.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Thursday night a weak mid level trough and its attendant surface
trough over Southern Ontario will continue to deteriorate as they
push eastward and across our area. Given the rather weak nature of
this system...for the most part it will only produce some widely
scattered light rain and snow showers as it crosses our region...
with interior portions of the Southern Tier and Finger Lakes more
than likely to remain totally dry. The above said...temperatures
aloft will still remain sufficiently cold enough to support some
areas of lake enhancement northeast of Lakes Erie and Ontario...with
more numerous showers consequently affecting the Niagara Frontier
and Jefferson county...where forecast temperature profiles will
support mainly snow and possible fresh accumulations of an inch or
two away from the immediate lakeshores. Later on in the night...the
Lake Erie activity should tend to weaken and become more scattered
in tandem with warming aloft and a resultant lowering of the capping
inversion to around 3 kft.

On Friday yet another (and stronger) mid-level trough will pass by
to our north...with its attendant cold front pushing southward and
across our region. With very limited synoptic moisture and upper
level support...this second boundary will also only be capable of
generating some widely scattered rain and snow showers on its own...
though cold-enough temperatures aloft will still support some areas
of lake enhancement east of the lakes...with these drifting southward
over time as the low level flow gradually veers. Off Lake Erie a
relatively low cap of 3-4 kft will help to keep the lake enhancement
more limited than off of Lake Ontario...where a 2 kft-higher cap and
the longer westerly fetch across the lake should support more numerous
rain and snow showers. With only marginal temperature profiles in
place for rain vs. snow...any notable snowfall accumulations should
remain confined to the higher terrain...with the Tug Hill and western
Adirondack foothills possibly picking up fresh accums of an inch or
two. Otherwise...high temperatures will mostly range between 35 and
40 degrees.

Following the passage of this system...one last shot of much colder
but also rather dry air will build across our region for Friday
night and Saturday. The dry nature of the colder airmass and short
northwesterly to northeasterly fetch will help to confine any lake
response to some scattered snow showers and flurries southeast and
south of the lakes Friday night...with these followed by fair dry
weather Saturday and Saturday night as the surface ridge crests
across our region. Meanwhile temperatures will fall back to well
below average levels...with lows Friday and Saturday nights ranging
from the single digits across the North Country to the mid to upper
teens south of Lake Ontario...and highs on Saturday struggling to
get much above the mid to upper 20s south of Lake Ontario...and the
lower to mid 20s across the North Country.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
In the long term portion of the forecast...the core of the strong
surface high will slide eastward to northern New England and the
Canadian Maritimes on Sunday...where it will then remain in place
through Monday. With weaker ridging still extending all the way back
across our region through this time...we should experience continued
fair dry weather through Monday. With respect to temperatures...the
developing warm air advection pattern on the backside of the ridge
axis will result in a steady day-to-day warming trend...with highs
mainly in the upper 30s/lower 40s on Sunday mostly climbing into the
lower to mid 40s on Monday...save for the North Country which will
be a bit cooler both days.

By Tuesday the medium range guidance packages still suggest that
the aforementioned low level-ridging will give way to another broad
mid-level trough and its associated surface trough approaching from
the Upper Great Lakes. Increasing lift and moisture out ahead of
these features may provide the impetus for some scattered showers...
with the bulk of these likely falling in the form of plain rain
given the continued warm air advection pattern across our region.
Speaking of which...the latter will also help temperatures to
continue trending upward...with daytime highs reaching the mid to
upper 40s in most locations.

Finally...the mid level trough and surface trough should finish
crossing our region between Tuesday night and Wednesday...with
precipitation chances trending back downward following its passage.
Otherwise...weak to modest cool air advection on the backside of
of this system should help to temporarily halt or bring about a
slight reversal to the warming trend of the previous few days...
with highs mainly in the lower to middle 40s expected.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Light lake effect snow showers southeast of the lakes will end this
afternoon. Any lingering MVFR to IFR VSBY and CIGS in snow showers
will come to an end by 21Z Wed. Otherwise VFR will prevail between
the lake effect cloud bands.

A warm front will then move east across the area tonight, spreading
a wealth of mid level clouds across the area with VFR prevailing. A
cold front will then approach the area Thursday afternoon, and cross
the eastern Great Lakes Thursday evening. Lake effect showers of wet
snow and rain will develop northeast of the lakes by Thursday
afternoon with areas of MVFR/IFR VSBY and MVFR CIGS. Some of this
may impact KIAG, KBUF, and KART later in the afternoon.

Outlook...
Thursday night...MVFR/IFR in lake enhanced snow showers northeast of
the lakes, tapering off overnight. VFR outside of lake enhanced
showers.
Friday...A chance of lake effect snow showers east of the lakes with
local MVFR/IFR. Otherwise VFR.
Saturday through Monday...Mainly VFR.

&&

.MARINE...
A ridge of high pressure will cross the eastern Great Lakes this
afternoon and evening, providing a brief period of light winds. A
cold front will then approach the area Thursday, and cross the
eastern Great Lakes Thursday evening. Increasing southwest winds
ahead of the front will bring another round of Small Craft Advisory
conditions from late tonight on Lake Erie and the northeast end of
Lake Ontario. Small Craft conditions will likely continue at the
east end of both lakes through Friday.

&&

.CLIMATE...
A frigid airmass (for this time of year) will pass over the
region through Wednesday. The shot of sub arctic air will
support near-record to record cold temperatures. Below are the
record low maximum temperature and record low minimum
temperature for our three climate sites of Buffalo, Rochester
and Watertown for November 13th.

City.......Record Low Maximum (Year)...Record Low Minimum (Year)

Wednesday November 13

Buffalo..........24F (1911)............16F (1986)
Rochester........23F (1911)............17F (2013)
Watertown........24F (1983)............11F (1997)

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory from 1 AM Thursday to 4 PM EST Friday for
         LEZ040-041.
         Small Craft Advisory from 7 AM to 7 PM EST Thursday for
         LEZ020.
         Small Craft Advisory from 1 AM Thursday to 10 PM EST
         Friday for LOZ045.

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...Hitchcock
MARINE...Hitchcock
CLIMATE...Thomas/JJR

NWS BUF Office Area Forecast Discussion