Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 251901

Area Forecast Discussion
National Weather Service Buffalo NY
301 PM EDT MON JUL 25 2016

Showers and thunderstorms will continue to end from west to east
late this afternoon as a cool front crosses the region. This will
usher in another period of fair and slightly less humid weather that
will persist through the midweek. Another, much weaker cold front
will slide south out of Canada Wednesday night into Thursday,
bringing a slight chance of showers and thunderstorms, however
nothing that is expected to put a dent in the current drought


Convection has largely cleared the forecast area this afternoon,
with mainly  trailing stratiform still moving through the western
Finger Lakes and portions of the North Country. Meanwhile, sunny
skies are lurking just upstream, along a cold frontal boundary
pushing across Southern Ontario. The clearing is poised to move
into Western NY later this afternoon.

The cold front will cross the forecast area this early this evening.
Convection ahead of the front will push off to the east and out of
the forecast area. While temperatures will cool slightly behind the
front, upstream dewpoints will remain in the lower 60s, and with
clearing skies and winds becoming light, we will see the potential
for patchy fog across lower lying areas, particularly those areas
that see substantial rainfall today. Temperatures will fall into the
60s overnight.

The upper level trough will complete its transition across the
forecast area overnight and will be replaced by low-amplitude upper
level ridging and surface high pressure across the Lower Great
Lakes. This should yield plenty of sunshine across the area with
highs in the low to mid 80s, with 70s along the lakeshores. With
slightly lower dewpoints in the upper 50s to lower 60s advecting in
behind the front, it should also feel nominally more comfortable


There should not be much weather to contend with during this a low amplitude flow will be found along the length of
the Canadian border. While troughiness will characterize this
pattern over the Great Lakes region...a lack of baroclinicity and
low level forcing will mean that generally fair weather can be
anticipated. This despite the passage of a weak cold frontal
boundary. The day to day details...

High pressure centered over the Mid West will remain in control
across our forecast area Tuesday night. While light winds and clear
skies will encourage decent radiational cooling...we have not had a
fresh airmass change in a few the mercury is only forecast
to drop into the mid 60s across the lake plains while 50s will be
found across much of the Srn Tier.

A cold frontal boundary over the Upper Great Lakes will then slowly
push south across Southern Ontario during the day Wednesday...while
high pressure over the Mid West will gradually lose control of our
weather in the process. Nevertheless...fair weather will persist
across the region with H85 temps in the upper teens C supporting
afternoon readings in the upper 80s to near 90 for the lake plains
and in the valleys.

We can anticipate a weak frontal passage Wednesday night...but with
little forcing...will only raise pops to slgt chc while increasing
cloud cover. Temperatures overnight will be a few degrees higher
than the night before...but with dew points holding steady near should not be overly uncomfortable.

The frontal boundary will stall and wash out over Pennsylvania on
Thursday...while a ribbon of moisture in its wake will settle over
our forecast area. The bulk...if not all...of the day will be rain
free...but the passage of a shortwave in the northwest flow will be
enough to warrant low chc pops for the afternoon and evening. Since
a northeast low level flow will be in place in the wake of the
front with little instability...will only use a slgt chc for tstorms.

The various guidance packages remain out of step with each other as
we push into Thursday there is a `disagreement` as to
whether a wave will form along the west end of the aforementioned
frontal boundary. Will keep low chc pops in place for all but the
North Country. While there will be low confidence with these pops...
there is more certainty that clouds will remain in place...
especially over the western counties.


This period has the potential to be rather unsettled...or at least
more disorderly than what we have become accustomed to the past
couple months. The good news is that this would lead to some needed
rainfall for the region...but the bad news is that it would
adversely impact some peoples plans for the weekend.

Troughiness found over the Great Lakes region is forecast by some of
the ECMWF/GFS based ensembles to amplify somewhat...and this would
encourage waviness along a stalled frontal boundary over the Mid
West to evolve into an actual sfc low. Will use a compromise of the
HPC and ECMWF solutions...which favors such a sfc low development.
This feature is forecast to slowly track northeast across the Lower
Great Lakes during the course of the weekend while generating
scattered showers and possible thunderstorms in the process. Given
the low confidence of this forecast...will keep chc pops in place.


Showers and thunderstorms are in the process of exiting the forecast
area this afternoon and will continue to push east out of the
forecast area as a surface cold front approaches the region from the
west. The cold front will cross the forecast area around 00Z, with
any showers and thunderstorms pushing off to the east and out of the
forecast area as the front moves through. Gusty SW winds this
afternoon will give way to light winds behind the front tonight, and
with skies clearing, we will likely see the development of patchy
fog across low lying areas, particularly in the Southern Tier, that
will potentially generate IFR/LIFR conditions after 06Z. Fog may
also affect KIAG late tonight/early Tuesday morning. Fog should
clear out after 12Z, giving way to widespread VFR conditions on

Outlook... Tuesday Night and Wednesday...Mainly VFR.
Thursday...Mainly VFR with a chance of showers and thunderstorms.
Friday and Saturday...VFR/MVFR with a chance of showers and


Gusty southwest winds will continue to be an issue this afternoon on
Lake Erie ahead of an approaching cold front, and small craft
advisories remain in effect. Winds will diminish rapidly behind the
cold front, however westerly flow to around 15 knots on Lake Ontario
will generate moderate chop on the eastern end of the lake Tuesday,
though conditions should remain sub-advisory. After that, high
pressure will build across the Lower Great Lakes, with winds and
waves remaining generally tranquil through the remainder of the week.


NY...Beach Hazards Statement until 8 PM EDT this evening for NYZ010-
MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ020-



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