Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 150758

Area Forecast Discussion
National Weather Service Buffalo NY
358 AM EDT Thu Mar 15 2018

A trough will cross the region later this afternoon and tonight,
producing scattered to numerous snow showers across the area with
spotty minor accumulations. The snow will finally come to an end
from west to east on Friday as high pressure and drier air build
into the region. Dry weather will continue through the weekend, but
temperatures will remain below average.


Radar imagery showing steady snow continuing east of Lake Ontario
early this morning. This snow will quickly taper off by daybreak as
deeper moisture and ascent move away from the region. Otherwise the
rest of the area will be mainly dry through the morning hours with
areas of mid level clouds.

This afternoon and evening a mid level shortwave and associated
surface trough will cross the region, bringing deeper moisture, weak
large scale ascent, and increasing low level convergence. From a
synoptic scale standpoint, this will bring a general increase in
scattered snow showers during the afternoon and evening, aided by
boundary layer mixing from the higher March sun angle. Ongoing WNW
upslope flow will also support more numerous snow showers this
afternoon across the higher terrain east of Lakes Erie and Ontario.
In addition, mesoscale model guidance suggests a well defined
convergence zone will develop this afternoon and evening from near
Buffalo and Niagara Falls extending southeast across Wyoming and
northern Allegany counties. This appears to be in response to
positive feedback from the synoptic scale trough and mesoscale
convergence between veering winds over Western NY and stubborn WSW
flow channeling down Lake Erie.

The afformentioned convergence zone should support a good
concentration of snow showers later this afternoon and evening
across Western NY, centered on a line from near Buffalo into
Southern Erie/Wyoming counties and the Southern Tier. This may
produce an inch or so of accumulation for the Buffalo Metro area,
and 2-4 inches locally for the higher terrain of the Boston Hills
and western Wyoming county, mainly this evening when the sun begins
to set, allowing snow to accumulate more efficiently. The rest of
the area can expect a spotty coating to an inch through the
afternoon and evening.

Overnight the convergence zone will break down, and diurnally driven
snow showers will come to an end. Cold advection behind the trough
axis will bring a little better setup for lake effect snow showers
overnight, with equilibrium levels rising to around 7K feet. Expect
snow showers to become most conentrated across the Chautauqua Ridge
off Lake Erie with some help from Lake Huron, and across Wayne and
northern Cayuga counties off Lake Ontario. Both these areas may see
another inch or two overnight, with locally up to 3 inches in the
most persistent bands. Mesoscale model guidance also suggests a
Georgian Bay band may develop across the Niagara Frontier overnight,
which may produce local accumulations of around an inch about
halfway between Buffalo and Rochester. Outside of these areas,
scattered snow showers will produce a spotty dusting.

Temperatures will remain well below normal. Expect highs in the mid
30s today on the lake plains, and around 30 on the hills. Lows will
drop into the low to mid 20s on the lake plains tonight, with teens
across the interior.


Mainly tranquil and cool weather expected for the weekend as
Canadian high pressure builds across the region.

Friday night a few light lingering lake/upslope enhanced snow shower
or flurries south and east of the lakes will diminish with dry air
and subsidence overspreading the region. Temperatures will remain
cool northwesterly flow in place ahead of the surface high building
into the region. This will keep night time lows in the teens over
the higher terrain, and around the 20 degree mark in the lake
plains. The coolest night will likely be Saturday night across WNY
and Sunday night for the North Country as the surface high crests
the region providing the best chance of prime radiational cooling
conditions. Daytime highs will range from the upper 20s in the North
Country to the mid 30s in WNY each day. A few isolated snow showers
are possible Saturday morning across the North Country as a mid-
level wave dropping south across New England drags a weak surface
boundary through across the region.


A surface low will advance east from the Midwest and potentially
brings a chance of precipitation to our area Tuesday and Wednesday.
However, uncertainty remains high with this next system with respect
to track and its intensity. The suite of global models (GFS/GEM/EC)
and their ensembles remain steadfast in tracking a deepening low
pressure system south of the forecast area during this time frame,
however there remains large run-to-run inconsistency in the track.
With such high uncertainty, have maintained chance POPs through the
end of this period.

Temperatures likely will remain below climo as we head towards the
latter half of March. For this time of year highs should be in the
lower 40s and climb towards the upper 40s by the end of the Month.


Steady light to moderate snow will continue to produce IFR east of
Lake Ontario through the pre-dawn hours before quickly tapering off
this morning. Otherwise the rest of the area will be VFR through the
morning hours with areas of mid level clouds crossing the region.

Snow showers will increase again this afternoon across Western NY
with IFR VSBY and MVFR CIGS expanding in coverage. These snow
showers will become more common during the late afternoon and
evening cross the rest of the area as a trough crosses the region.
The snow showers are likely to be cellular in nature with the
stronger March sun, leading to frequent and sudden changes in VSBY.
The cellular snow showers will continue into this evening before
evolving into lake effect snow showers southeast of the lakes
overnight, with areas of IFR continuing.


Friday...Areas of IFR with snow showers southeast of the lakes in
the morning, improving to mainly VFR during the afternoon. Saturday
through Monday...VFR.


Moderate northwest winds will continue on Lake Erie today through
Friday night as strong low pressure moves slowly away from the
region and into the Canadian Maritimes. This will maintain Small
Craft Advisory conditions through Saturday morning before high
pressure brings diminishing winds Saturday afternoon.

On Lake Erie, winds have temporarily diminished early this morning,
but will increase again this afternoon with Small Craft Advisory
level winds then continuing through Friday afternoon.


NY...Winter Storm Warning until 8 AM EDT this morning for
MARINE...Small Craft Advisory until 8 PM EDT Friday for LEZ040-041.
         Small Craft Advisory until 2 PM EDT Saturday for
         Small Craft Advisory until 8 AM EDT Saturday for LOZ042.



NEAR TERM...Hitchcock
LONG TERM...Church
MARINE...Hitchcock is the U.S. government's official web portal to all federal, state and local government web resources and services.