Area Forecast Discussion Issued by NWS Buffalo, NY
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBUF 070909
AFDBUF
Area Forecast Discussion
National Weather Service Buffalo NY
509 AM EDT Wed Jun 7 2023
.SYNOPSIS...
A period of more unsettled weather continues with daily chances for
some showers and a few thunderstorms, with the best chances for
showers across the eastern portions of the region. Smoky skies with
haze and smoke from the wildfires across eastern Canada will likely
persist across the entire region through the end of the week. Cooler
than normal temperatures can be expected the rest of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
A few clouds are drifting south across Finger Lakes and there is
patchy fog along the Black River Valley. Leading edge of thickest
wildfire smoke plume is moving across the Niagara Frontier to the
eastern Lake Ontario region. Observations are reporting the "cloud
base" of this wildfire smoke plume of 2500-3000 ft. This is a very
low altitude smoke plume and it will not take much mixing to bring
dense smoke to the sfc through the morning. More details on expected
evolution of this smoke in a bit.
In the larger scale, the upper low that was over Nova Scotia on
Tuesday retrogrades into northern New England through tonight. Deep
moisture and widespread light rain that is occurring over eastern
Quebec and western New England figures to rotate west as well. By
late afternoon, widespread light showers with no thunder will begin
to move across the eastern Lake Ontario region. As this occurs a
sharper trough will swing westward and as a result those showers
will continue to try to expand westward across the Finger Lakes and
even toward Rochester this evening. Moisture not near as expansive
farther west than that, so through at least tonight, western NY will
be on the outside looking in for any rainfall. Yet, even where it
will rain in our area, rainfall amounts look pretty light (less than
0.25 inch) regardless. This is the sensible weather aspect of the
forecast. Now to the wildfire smoke that is becoming a bigger issue
as it is mixing to the sfc. NYS DEC has an Air Quality Alert for
most of our forecast area.
After a very dense plume of smoke moved to the sfc and impacted much
of our area on Tuesday, as mentioned another plume of thicker smoke
that has been shown by RAP/HRRR smoke models for a couple days is
beginning to arrive from the north. We have had a mix of haze and
smoke in the obs since yesterday with some spotters reporting vsby
down to less than 1 mile. As this point, until we see otherwise,
expect similar conditions today especially once even weak daytime
mixing begins so have included both haze and smoke for the
forecast with low visibility. Already starting to see vsby less
than 2 miles in parts of our area even before daybreak. Based on
obs upstream north of Lake Ontario and now along the south
shore of Lake Ontario, seems that we`ll be dealing with sky even
more opaque than Monday where the sun was barely visible at
times due to such thick and low altitude smoke. That smoke layer
is even lower today. As the trough alluded to earlier swings
westward across the eastern Lake Ontario region, the haze and
smoke should diminish there this evening and this is also
showing up in the modeled smoke forecasts, but otherwise the
haze and smoke in some shape or form will persist over the rest
of the area through tonight. High temps today with the shroud of
smoke will stay in the 60s. Normal highs are in the low to mid
70s. Lows tonight will be in the 40s though readings could drop
into the upper 30s again across Southern Tier and east of Lake
Ontario.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
Upper level low still spinning over northern New England to start
our Thursday, now looks to retrograde a bit further west during the
period, which will bring this feature a bit closer to our area than
previously forecast. Good news is this will bring better chances for
some much needed rainfall to our region during this timeframe.
Instability and moisture profiles look a bit better during this
time, so coverage of showers and thunderstorms should be somewhat
more expansive (and western extent) than previous days with portions
of the Southern Tier, Finger lakes, and North Country having a shot
at some much needed rainfall. This will be maximized during the
afternoon and early evening hours both Thursday and Friday during
max heating, with much lesser chances during the overnight hours. In
fact, Friday be the most active day in terms of shower and storm
coverage as activity is enhanced further owed to a potent shortwave
moving across the area during the peak heating hours. Areas across
western NY closer to the Lakes will see lesser chances for any
meaningful precipitation. That said, being that this will be mainly
convective activity, the higher rainfall amounts will mostly be
localized. Otherwise, with little change in our general wind flow
through the end of the period due to the upper low sitting over the
Northeast, smoke issues may still be a concern through the end of
the work week.
The core of the coolest air will move into the area Thursday,
resulting in the coolest day of the week ahead. Daytime highs will
be some 10-15 degrees below average, with temperatures struggling to
get out of the upper 50s across the inland higher terrain, with
lower to mid 60s elsewhere. Airmass modifies just a bit by Friday,
with highs mainly ranging through the 60s, which is still some 5-10
degrees below average.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
On Saturday, the persistent upper level low will finally depart off
to our east, with weak shortwave ridging briefly building in aloft
between this system and the next shortwave trough dropping from
central Canada to the upper Great Lakes. This will result in a drier
day for most areas, although areas from the Finger Lakes to the
North Country could still see a few more widely scattered showers as
one final shortwave impulse dives around the western periphery of
the departing upper low. Otherwise, we will see a warmer day with
rising heights/temperatures aloft allowing surface temps to climb
back to the low and mid 70s, with some upper 60s still found across
the higher terrain. Shortwave ridge over the area Saturday night
will provide a mainly dry night, with lows falling back to the upper
40s to mid 50s.
The guidance suite continues to suggest that the next aforementioned
shortwave trough diving south out of Ontario Province will close off
into yet another upper level low over the central/upper Great Lakes
between later Saturday night and Sunday, then continue to impact our
region through at least the first half of next week. Model guidance
has come into better agreement over past couple of runs on the
overall track of this system taking on a more easterly trajectory,
however there is still some discrepancy with respect to how quickly
this system meanders its` way to the east. Overall, this is good
news as this increases the chances of our area seeing some much
needed, more widespread rainfall. Capped PoPs in the high chance
range through the end of the period for now, mainly due to the
uncertainty in timing that still remains. Otherwise, temperatures
for this time frame look to be right around normal, with daily highs
mainly ranging through the 70s.-- End Changed Discussion --
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Smoke is the main concern for aviation. Widespread MVFR visibility
early this morning will lower to IFR over much of the area this
morning as the thickest plume of smoke moves through with even weak
daytime mixing. Slight improvement this afternoon back to mainly
MVFR. Based on multiple observations across the area, expect effective
"cloud" base of the smoke layer to be around 2-3kft much of the time
today.
In terms of weather, rain showers will move from east to west into
the eastern Lake Ontario region late this afternoon and settle
southward across the Finger Lakes later this evening and overnight.
Some showers could reach as far as western NY.
Outlook...
Thursday and Friday...Mainly VFR. Chance of showers each day.
Saturday...Mainly VFR.
Sunday...Mainly VFR. Chance of showers.
&&
.MARINE...
Mainly northerly component winds will prevail through the rest
of the week. At this time, conditions look to remain below Small
Craft Advisory thresholds, but it will be choppy at times with
waves peaking at 2-3 feet.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Apffel/TMA
NEAR TERM...JLA
SHORT TERM...JM
LONG TERM...JM
AVIATION...JLA
MARINE...Apffel/TMA