Forecast Discussion

Forecast Discussion for BUF NWS Office
FXUS61 KBUF 260220

Area Forecast Discussion
National Weather Service Buffalo NY
1020 PM EDT Sun Jul 25 2021

High pressure across the Mid-West will gradually move eastward
across Ohio, keeping our area mostly rain-free through Monday night.
A cold front will drop across the region on Tuesday with some
showers and thunderstorms possible. High pressure will then build
back across the area providing dry weather for Wednesday.


The axis of a ridge of high pressure centered to our west will
ridge across the region tonight. This will maintain dry weather
and mostly clear skies. This will support fairly good
radiational cooling, especially across interior valleys where
temperatures should drop into the 50s tonight. Fog may develop
across the Southern Tier valleys.

Mainly dry again on Monday as the surface high moves closer and
provides mostly sunny skies south of Lake Ontario. The St. Lawrence
Valley will be closer to a mid-level trough, perhaps enough to
support a stray showers or thunderstorm along the lake breeze
boundary northeast of Lake Ontario. Otherwise, it will be a bit
warmer than today with highs in the upper 70s to mid 80s.
Visible satellite and observations show near surface smoke from
the western wildfires across Northeastern Ontario this evening.
HRRR guidance depicts this area moving near northern NY Monday
which may produce hazy conditions across north central NY.

A cold front will approach late Monday night, but model consensus
keeps any precipitation associated with the front to our north
and west. Fair radiational cooling with partly to mostly clear
skies. Lows in the upper 50s to mid 60s.


There will be two systems that impact our region this period, both
occuring with a west to northwest flow aloft.

The first system will arrive Tuesday. Two shortwaves aloft will help
to push a cold front across the region...with the first shortwave
near the Saint Lawrence Valley and a second shortwave later across
Western New York. Showers and thunderstorms blossoming along the
cold front and ahead of the shortwaves will likely first be
concentrated east of Lake Ontario by early afternoon Tuesday...and
then later in the afternoon and early evening across WNY. There
continues to be sufficient instability ahead of this front, along
with 0-6km bulk shear values 35 to 40 knots to support the potential
for a few stronger storms.

As the cold front pushes across our region from northwest to
southeast, showers and thunderstorms will taper down Tuesday Night.
Much drier air aloft will push into the North Country by early
evening, and then across WNY through the night. Lingering low level
moisture could bring some patches of fog late Tuesday Night.

Weak high pressure near the region Wednesday should bring a dry day
with a mix of clouds and sunshine.

Wednesday Night the next system will impact our region, mainly
during the second half of the night. A mid level shortwave will
cross our region, bringing renewed chances for showers and
thunderstorms. PWAT values a little higher with this second
system...nearing 1.75 inches could allow for heavier
downpours...though at this time, an earlier timing in the day
Thursday of convection could lower the threat for severe potential.

With a decent amount of clouds around, especially Tuesday and
Thursday high temperatures will be near or just below normal...while
overnight lows dip to near normal levels.


In the wake of the cold front, high pressure builds east across
the lower lakes bringing cooler and drier air to the region. The
high will maintain dry conditions through Saturday. An area of
low pressure moving across Ontario will bring the risk of some
showers Saturday night and Sunday.

Highs Friday will be in the upper 60s to low 70s, about 5 to 10
degrees below normal, followed by a slow warming trend with
temperatures within a few degrees of the norm by Sunday.
Overnight lows too will start cool with some interior sections
of the southern tier and north country seeing lows in the 40s
Friday night gradually moderating to near normal upper 50s to
low 60s Saturday night.


Mainly clear tonight will support mainly VFR flight conditions.
Fog is likely to develop across the Southern Tier Valleys, with
a period of IFR likely at KJHW. Any fog will dissipate quickly
on Monday. Prevailing VFR flight conditions expected during the
day however haze from upstream smoke may track into the region.
This may cause MVFR conditions at KROC and KART through the


Monday night...VFR.
Tuesday and Tuesday night...VFR/MVFR with showers and thunderstorms
Thursday...VFR/MVFR. A chance of showers and thunderstorms.


High pressure will build across the lower Great Lakes tonight and
Monday. Pressure gradient will relax some across Lake Erie with
lowering winds and waves, while winds remain somewhat elevated on
Lake Ontario keeping choppy conditions in place, however waves
should be less than 2 feet.






NWS BUF Office Area Forecast Discussion