Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 260206

Area Forecast Discussion
National Weather Service Buffalo NY
1006 PM EDT Sat Mar 25 2017

A frontal boundary will remain draped across Pennsylvania through
tonight...before slowly lifting back north across the region as a
warm front Sunday and Monday. Several disturbances sliding along
this boundary will bring frequent rounds of precipitation through
the rest of the weekend and early next week...with cooler temperatures
prevailing north of the boundary and milder temperatures found to
its south.


Overnight...the frontal boundary to our south will begin to
lift back northward as a warm front. Modest warm air advection
out in advance of this feature will allow for increasing chances
of some spotty light precipitation from southwest to northeast
through the overnight hours...for which chance PoPs remain in play
as confidence in measurable precipitation at any given location
remains low. Expected thermal profiles suggest that this should
primarily fall in the form of plain rain...though a little freezing
rain cannot be totally ruled out late tonight or Sunday morning
across the Eastern Lake Ontario region...which could ultimately
require another winter weather headline if the precipitation
becomes widespread enough/well enough developed.

With respect to temperatures...expect nighttime lows to generally
fall before midnight across most areas south of Lake Ontario...with
readings then rising through the balance of the night as the frontal
boundary lifts back into our region. The exception to this will be
across the North Country...where clearing skies should allow for
decent radiational cooling and a more typical nocturnal temperature
trend...with overnight lows falling into the lower to mid 20s.

As we move through the day Sunday...the precipitation should briefly
wane for a time south of Lake Ontario within the burgeoning warm
sector. Closed/occluded low in the plains expected to finally open
up and advance up into the western Ohio Valley/lower Great Lakes
during the day. This will bring a northward bulge of warmer air back
up into western New York while opening up a feed of Gulf moisture into
the Great Lakes, which will in turn spread rain back into the region
during the late afternoon and early evening hours. Temperatures in the
west will approach or potentially exceed 60 degrees....particularly if
any breaks of sunshine are realized.


A large low pressure system than has been meandering through the
central plains over the last couple of days will finally eject
northeastward across the Great Lakes region Sunday night and Monday,
as it rejoins the mean mid-latitude flow. In the process, increased
moisture advection will bring Gulf of Mexico sourced air into the
region with ample synoptic forcing as the cold front and vorticity
advection ahead of the upper level low approach the area Sunday
night into Monday morning. This will bring an area of widespread
showers across the forecast area, and will maintain categorical PoPs
for that time period. By Monday mid-day and afternoon, height rises
behind the trough passage and drier low-level air will end the
widespread rain showers in favor of just some widely scattered
showers and lingering cloudiness. With respect to temperatures,
Sunday night will remain mild with downslope flow and warm advection
ahead of the wave, with lows ranging from the low 40s in the North
Country to around 50 in western NY. By Monday, the airmass in the
wake of this largely cut-off low pressure system will not be much of
a contrast to the day prior, as better mixing and 850 mb temps to
around +5C will result in highs in the upper 40s in the North
Country to the low 60s in the Genesee Valley and northern Finger

Monday afternoon through much of Monday night will remain dry in the
wake of the initial trough passage, but then by Tuesday morning a
trailing open wave will cross the region. Global models remain
conflicted in the exact track of the wave and where the best forcing
will coalesce. Overall there has been a bit of a southward trend,
which increased the northeasterly flow and push of cooler air into
the region for Tuesday. Thus have lower temperatures some for
Tuesday with highs in the 40s to low 50s. Showers will accompany
this wave, but their coverage across the region will be guided by
the track of the wave, with a more southerly track favoring a drier


The very lengthy period of unsettled weather will finally come to an
end by Wednesday as a mid level trough digs southeast across Quebec
and forces the frontal zone well south of our area. This will bring
an end to any lingering showers by Wednesday morning, but will also
deliver another push of cooler air into our region. The GFS is far
colder Wednesday than the ECMWF or GEM with its more amplified and
southerly trough position. Have followed the ECMWF/GEM consensus
with temperatures a little milder than the GFS would suggest, but
still on the cool side with highs in the 40s.

Surface high pressure will build across Quebec Wednesday night and
Thursday with a ridge extending down into the eastern Great Lakes
and New England. This will provide a continuation of dry and cool
weather with highs in the 40s again Thursday and lows Wednesday
night and Thursday night in the upper 20s to lower 30s for most.

Model guidance diverges significantly by Friday and Saturday. The
GFS continues to suppress the next system well south of our area
with the moisture and forcing moving through the southeast states.
The ECMWF and Canadian GEM meanwhile are vastly different, taking a
surface low through the central Great Lakes. Have continued to lean
towards the ECMWF/GEM consensus for this period with rain chances
increasing again later Friday through Saturday. Temperatures will
begin to rebound if this farther north low track verifies, with
highs back in the 50s by Saturday.


A stalled out frontal boundary to our south will lift back north
as a warm front overnight and Sunday. This front will produce some
spotty light precipitation as it pushes northward...most of which
should fall in the form of plain rain...though a little freezing rain
will be possible across the Eastern Lake Ontario region (including
KART) late tonight and Sunday morning. As we move through the day
Sunday...the precipitation should briefly wane for a time south of
Lake Ontario within the burgeoning warm sector...before rain chances
return to far western New York late in the TAF period.

In terms of flight conditions...areas south of Lake Ontario will
experience a general mix of IFR/MVFR tonight...with some brief
clearing/VFR conditions possible early this evening along and
inland from the south shore of Lake Ontario. Meanwhile areas
east of Lake Ontario should see improvement to VFR this evening
as skies gradually clear from north to south...with general VFR
conditions then prevailing in this area through the balance of
the night. As we move through Sunday the warm front will lift
across our region...with flight conditions deteriorating to MVFR/
IFR east of Lake Ontario...and improving to MVFR/VFR in the
burgeoning warm sector south of Lake Ontario.

Sunday night through Tuesday...MVFR/IFR cigs with periods of rain.
Wednesday and Thursday...VFR.


A stiff northeasterly to easterly flow on the cool side of a frontal
boundary will require small craft headlines along the south shore of
Lake Ontario through Sunday evening. Winds and waves will briefly be
at marginal advisory levels on Lake Erie southwest of Dunkirk late
this evening...before subsiding overnight.

After this, expect a benign pattern for the first half of next week
resulting in modest winds with any headlines unlikely.


MARINE...Small Craft Advisory until 2 AM EDT Sunday for LEZ040.
         Small Craft Advisory until 11 PM EDT Sunday for



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