Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 232348

Area Forecast Discussion
National Weather Service Buffalo NY
748 PM EDT SAT JUL 23 2016

A few leftover showers and thunderstorms across the North Country
will end early this evening...with high pressure otherwise bringing
fair weather through the rest of the weekend. A stronger upper level
trough will then slowly cross the region Sunday night into Monday...
while producing some additional scattered showers and thunderstorms.
In the wake of a trailing cold front Monday evening...slightly cooler
temperatures will follow for midweek.


As of 740 pm...convection is in the process of dying out over the
North Country with its responsible shortwave now exiting to our
southeast...and should be pretty much finished by sunset.

Otherwise...fair weather will be the rule tonight as upper level
ridging upstream and surface high pressure moving overhead will
continue to exert their influence. The presence of noticeably drier
air in place will mean that temperatures should run around 5 degrees
cooler across the board. With light winds and clear skies tonight...
we could also see patchy valley fog developing in the Southern Tier.

The fair weather will continue through Sunday as high pressure
crosses the area. We will likely see an increase in mid and high
clouds from the west during the afternoon ahead of an approaching
upper level trough, but any associated convection should hold off
until later in the night Sunday night. Regarding temperatures, it
will be another hot summer`s day as 850mb temps climb back towards
+20C. Most areas should see readings in the upper 80s, with lower
90s in the Genesee valley and valleys of the Southern Tier, while
the North Country will run a little cooler in the wake of today`s
shortwave passage. Highs there should run in the lower 80s.


Sunday night into Monday, an upper level trough will track from
Ontario to Quebec just south of Hudson Bay while dragging a weakly
forced frontal boundary across the lower Great Lakes region during
the day Monday. Humidity will markedly increase Sunday night ahead
of the front, with dew points surging to the upper 60s and low 70s.
The combination of warm advection/moisture advection and persistent
southwesterly flow will make for an uncomfortable sleeping night
with lows only in the low to mid 70s. The axis of deepest moisture
and weak frontal forcing will cross the region in the early morning
hours Monday, ill timed for convection. Thus expect any upstream
convection coming out of the midwest and Ontario should be
dissipating by the time approaches our area. Thus expect only some
widely scattered to isolated shower and thunderstorm coverage across
the region.

The best moisture and forcing axis will shift toward our
southeast by the time diurnal destabilization is able to aid in
kicking off more numerous showers and thunderstorms. Afternoon lake
breeze boundaries across the inland Southern Tier and North Country
regions may help to initiate these afternoon storms, which will
quickly exit our area into central NY. This does not bode well for
the drought parched regions across western NY, including the Niagara
Frontier, which will likely receive little if any precipitation.
Otherwise, it will mainly be a dry hot and humid day on Monday with
some sun poking through by the afternoon and early evening before
sunset. Winds will also increase across western NY and the Niagara
Frontier with a synoptically supported strong southwesterly lake
breeze. An isolated shower or thunderstorm cannot be ruled out
along the southern Lake Ontario shoreline across Niagara County to
Monroe and Wayne counties with the enhanced lake breeze surface

High pressure will build across the region Tuesday into Wednesday,
with slightly cooler and less humid conditions on Tuesday before the
heat starts building back into the region on Wednesday. Highs
will be in the low to mid 80s Tuesday and the mid 80s to near 90 on
Wednesday. Large scale high pressure and subsidence will keep the
weather dry through mid-week.


The pattern has the potential to become at least a little more
active from late week into the first half of next weekend. The
expansive mid/upper level ridge which has dominated the central and
eastern CONUS will be knocked back as the longwave pattern buckles
across North America, with a western ridge and eastern trough
pattern becoming established by next weekend. The developing
longwave trough in the Great Lakes and Northeast states will be
carved out by several mid level shortwaves, each of which will bring
a period of large scale ascent and increased deep layer moisture to
our region.

Looking at the details, the first relatively weak trough will
approach the Great Lakes Thursday afternoon and evening. This system
may touch off a few widely scattered showers and thunderstorms with
sparse coverage. Models begin to diverge on the timing details of
the finer scale features by Friday and Saturday, but most
operational and ensemble guidance show a more significant mid level
trough and associated surface wave moving through the Ohio Valley
and eastern Great Lakes either Friday or Saturday, with a better
chance of somewhat more widespread showers and thunderstorms.

Temperatures will continue to run hot through Thursday, with 850mb
temps of around +18C supporting highs around 90 at lower elevations
away from the lakeshores. More clouds and showers will bring
temperatures back closer to average by Friday and Saturday.


As of 2340Z...convection is in the process of dying out over the
North Country with its responsible shortwave now exiting to our
southeast...and should be pretty much finished by sunset.

Otherwise...high pressure will keep VFR conditions in place through
tonight and Sunday...with just some increase in mid and high clouds
expected from west to east during Sunday. While some patchy valley
fog cannot be totally ruled out across the Southern Tier later on
tonight...the boundary layer could turn out to be just a little too
dry for this to form.

Sunday night... Mainly VFR with a chance of showers and thunderstorms
and associated brief MVFR/IFR.
Monday...Mainly VFR with scattered showers/thunderstorms and associated
brief MVFR/IFR.
Monday night...Mainly VFR with a chance of showers and thunderstorms
east of Lake Ontario in the evening.
Tuesday and Wednesday...VFR.
Thursday...Mainly VFR with a chance of showers and thunderstorms.


Generally quiet conditions should persist across Lakes Erie and
Ontario through Sunday...with local lake breezes developing Sunday
afternoon. A weak trough/cold front crossing the region will bring
a chance of showers and thunderstorms Sunday night and Monday.
Freshening southwesterlies out ahead of the front will likely bring
a period of advisory-worthy winds and waves to the eastern end of
Lake Erie Monday...before winds and waves diminish Monday night.
After that...we should see tranquil conditions return to the lakes
for much of the remaining week as a weak pressure gradient will
be in place across the region.





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