NWS Area Forecast Discussion

FXUS61 KBUF 031043

Area Forecast Discussion
National Weather Service Buffalo NY
643 AM EDT Tue Aug 3 2021

High pressure will keep mainly dry weather over the area through the
end of the week. Temperatures will trend warmer through the week.


Southern Tier valley fog in place with clear skies elsewhere early
this morning. The valley fog will dissipate by 8/9 am then mostly
sunny skies for the rest of the day as high pressure continues
to build in. Temperatures just a bit below normal with highs in
the mid to upper 70s.

Tonight, mainly clear skies and light winds will be favorable for
radiational cooling and allow for patchy valley fog to develop
after midnight.


Surface high pressure spanning from the lower Ohio Valley to
interior New England will remain in place through Thursday before
starting to slide east toward the Mid-Atlantic and New England
coastline Thursday night. Meanwhile perpetual troughing will
continue aloft across the eastern third of the CONUS. While dry
weather will prevail the majority of the time, increasing low level
moisture combined with the presence of the weak mid level trough and
embedded weak shortwaves will bring a chance of a few isolated
showers and thunderstorms both Wednesday and Thursday afternoon. The
best chance of this will be across the higher terrain and along lake
breeze boundaries where localized convergence may aid parcels in
breaching mid level capping.

Temperatures will continue a gradual day to day warming as the
airmass modifies and heights slowly build aloft. Highs Wednesday
will average around 80 for lower elevations, with mid to upper 70s
across higher terrain. Highs Thursday will reach the low 80s for
lower elevations and upper 70s for higher terrain. The
aforementioned increase in low level moisture will translate to a
moderate increase in humidity levels as surface dewpoints start to
creep upward some, reaching the lower 60s by Thursday.


This period will feature a pattern change across North America
as lingering ridging in the west and weak troughing in the east
transitions to at least a general quasi-zonal flow. With ridging
surface and aloft remaining firmly anchored over the western
Atlantic, this evolution in the pattern will allow for a slow, but
persistent influx of increasing amounts of heat and humidity into
our region. This will translate into conditions slowly becoming more
uncomfortable as we work through this period. Daytime highs Friday
through Sunday will generally hover in the upper 70s to mid 80s,
however humidity levels will continue a slow day-to-day rise, so an
increasingly more `sticky` feeling will take hold as we progress
through the end of the work week into the upcoming weekend. The
western Atlantic ridge will build southwest then west across the
southern third of the CONUS heading into the start of the new work
week, with a upper ridging possibly also building north across the
Mid Atlantic and interior Northeast. This will bring a fairly
substantial increase in heights aloft, which will help induce an
increase in temperatures for the start of next week as daytime highs
rise into the mid and upper 80s, with lower 90s possible across the
traditionally warmer spots. Increasing moisture will also start to
nudge our humidity levels toward the `oppressive` level as dew
points near 70F.

With respect to precipitation chances, weak impulses will generally
traverse from west to east along or near the Canadian border through
the larger-scale quasi-zonal flow aloft. These disturbances will
combine with building heat and humidity to yield the potential for
some widely scattered to scattered showers/storms each day, with
these generally coming each afternoon/early evening in tandem with
peak heating. In general the best opportunities for these will be
found in the vicinity of any lake and terrain-driven boundaries that
develop, though the passage of any more well-defined shortwaves
could help result in better areal coverage. While the exact timing
of these remains difficult to pin down this far out, guidance
continues to show the potential for one such feature to cross our
region sometime during Saturday or Saturday night.


VFR expected today with light winds as surface high pressure remains
near the region. The one exception is valley fog (IFR) in the
Southern Tier impacting the KJHW terminal through about 12Z.

VFR tonight with IFR in river valley fog late, possibly impacting


Wednesday through Saturday...Mainly VFR. A few isolated showers and
thunderstorms possible inland from the lakes each afternoon.


A general light flow regime will be in place this week. Southwest
winds less than 15 knots today will become locally onshore Wednesday
and Thursday.





SHORT TERM...Hitchcock/JM

NWS BUF Office Area Forecast Discussion