Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 170818

Area Forecast Discussion
National Weather Service Buffalo NY
418 AM EDT Mon Oct 17 2016

A cold front will weaken and stall across the area this morning with
low clouds, fog, and drizzle. The front will then move back north as
a warm front this afternoon with a few scattered showers, and
possibly some thunderstorms. Temperatures will remain well above
normal through the first half of the week with warmth peaking on
Tuesday, then much cooler weather arrives again late in the week.


A cold front will cross Lake Ontario and stall close to the south
shore of the lake today. This will become a region of convergence
for low level moisture, resulting in low clouds, fog and drizzle
early this morning.

The foggy and drizzly conditions will improve by mid day as a strong
mid level trough moves into the Upper Midwest, enhancing the
southwesterly flow and moving the front back to the northeast as a
warm front. This front may produce a few scattered showers, with an
isolated thunderstorm also possible in the afternoon as modest
instability develops. High temperatures today will be well above
normal, with highs in the upper 60s to lower 70s in most areas.

It will remain very warm tonight with a breezy SSW wind maintaining
warm advection into the area and some downslope winds across the
lake plains. Any lingering showers along the warm front will pass
across the North Country and into the St. Lawrence valley while
other areas should be dry. Lows will mainly be in the lower to mid
60s with a very un-autumnal feel.


Tuesday will be unseasonable mild within deep warm sector as the
core of low level thermal axis shifts eastward into the region.
Temperatures across the Genesee Valley and Finger Lakes region
likely to top 80 degrees. Flow off the lakes will likely keep
downwind areas a bit cooler. This probably will keep Buffalo from
reaching the record high of 82, but the record high of 83 degrees in
Rochester appears be in jeopardy.

Gusty winds remain a concern downwind of the lakes, across the
Niagara Frontier and Saint Lawrence Valley. Southwesterly low level
jet will increase to 45 to 50 knots in advance of an approaching
cold front. A strong low deepening to around 980 mb is forecast to
track across Ontario into Quebec. This is not a favorable track to
reach high wind criteria in our area, however there should be ample
sunshine and mixing for wind gusts to approach 50 mph.

A cold front will drop across the region on Tuesday night then tend
to stall to the south of the area Wednesday, as high pressure noses
in from the west. Model consensus still supports a narrow ribbon of
likely probabilities along the front Tuesday night.

The area should dry out for a time Wednesday into Wednesday night,
before the stalled frontal boundary gradually works its way back
northward towards our region as a warm front later Wednesday night.
This should bring an increasing chance of showers toward Thursday
morning, especially across western New York.


It appears increasingly likely that the week will end on a wet note
across Western and North-Central New York, as the area will be
underneath a region of enhanced lift brought about by strong DPVA
associated with a deep upper level trough approaching the region,
and a favorable location underneath the right entrance region of a
130+kt upper level jet. Resultant development of surface low
pressure across the Lower Great Lakes along with ongoing
frontogenesis and ample moisture should set the stage for a
widespread rain event across the forecast area for Thursday into
Friday as the surface low moves along the boundary, with a general 1-
2 inches possible across the forecast area.

The upper level trough is still progged to swing across the forecast
area Friday night into Saturday. While heavier precip will taper off
as the main lift departs to the east, expect a few lingering showers
as the upper level trough moves overhead. Once the trough moves
through and cool westerly flow becomes better aligned vertically,
expect lake effect showers to develop east of the lakes. The 12Z
ECMWF drops 850mb temps to around -2C across the North Country on
Saturday, suggesting a potential for a few wet snowflakes mixing in
Saturday night...however the GFS is 2-3 degrees warmer, so will
stick with rain showers for now.

Speaking of temperatures, after an exceptionally warm stretch
earlier in the week, temperatures will fall back to near normal
during the period as extensive cloud cover and rainfall will
mitigate the effects of warm advection on Thursday, when highs will
range from the upper 50s in the north to the mid 60s along the PA
border. As the stalled frontal boundary over the area shifts east on
Friday, cooler air will filter into the region and highs will run in
the mid to upper 50s. Lows will return to the upper 30s to lower 40s
Friday night as the cold air in the core of the upper level trough
moves overhead, with highs on Saturday only topping out in the low
to mid 50s. Westerly flow off of the relatively warm lakes and cloud
cover associated with lake effect will moderate temperatures Friday
and Saturday night, with lows in the lower 40s near the lakes with
upper 30s across the cooler spots of the Southern Tier and North


A surface front across southern Ontario overnight will stall near
the south shore of Lake Ontario by early Monday morning.
Scattered showers will develop along the frontal boundary, along
with areas of drizzle. This will bring widespread IFR CIGS overnight
into Monday morning, along with some patchy fog which will produce
MVFR and IFR VSBY. The low stratus and fog will likely impact the
busy morning push period at all the TAF sites, with at least a low
potential of conditions approaching airfield minimums at times.

The low stratus and fog will slowly improve during the late morning
and early afternoon with most areas becoming MVFR. The stalled front
will begin to move back northeast across the area as a warm front,
producing a few widely scattered showers.


Tuesday night...Mainly VFR with a chance of showers.
Thursday and Friday...Areas of MVFR with a chance of showers.


As a cold front settles south of the lake, easterly winds will
produce choppy conditions on the west half of Lake Ontario today,
before the front moves back north as a warm front tonight. Southwest
winds will then increase late tonight and Tuesday as a strong area
of low pressure moves from Lake Superior to western Quebec. This
will bring the next round of Small Craft Advisory conditions to
Lake Erie and western Lake Ontario late tonight into Tuesday.


MARINE...Small Craft Advisory from 5 AM to 5 PM EDT Tuesday for LEZ040-
         Small Craft Advisory from 8 AM to 8 PM EDT Tuesday
         for LOZ042.



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