407
FXUS61 KBUF 071013
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
613 AM EDT Mon Jul 7 2025

.SYNOPSIS...
A slow-moving cold front will cross the area this afternoon and
evening...while generating showers and thunderstorms capable of
producing localized heavy rainfall and gusty winds. In the wake of
the front...high pressure and drier/somewhat cooler air will build
across the region tonight through Wednesday...before more unsettled
conditions return later on in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
During this period broad upper troughing over eastern Canada will
gradually amplify as additional shortwave energy ripples eastward
through it...which will in turn encourage the rather wavy frontal
boundary situated just to our north and west early this morning to
our north to slowly push southeast through our area as a cold front.
Expect the cold frontal passage itself to take place between later
this afternoon and the first half of tonight...with the boundary
preceded by a composite prefrontal trough/developing lake breeze
boundary that will push east across the area between the midday and
afternoon hours.

As it has appeared for the past several days...the antecedent
airmass out ahead of these boundaries will feature rather high
moisture content...with PWATs likely to be in the vicinity of 2
inches. Diurnal heating of this subtropical airmass will quickly
lead to the development of moderate amounts of instability through
the late morning and early afternoon hours...with this increasingly
unstable airmass eventually being lifted by the aforementioned
boundaries and resulting in the development of showers and
thunderstorms. As is typical...the most widespread activity still
appears to be most likely along and ahead of the composite
prefrontal trough/lake breeze boundary...and should affect areas
from the Southern Tier northeastward across the Finger Lakes and
into portions of the North Country. This being said...there may also
be a couple secondary maxima in pcpn coverage along the northern
fringes of the developing lake breezes...with these potentially
affecting portions of the Niagara Frontier and northern Jefferson
county/the Upper Saint Lawrence Valley...first during the late
morning/early afternoon...and then again late in the day as the cold
front itself impinges upon the lingering lake breeze boundaries and
briefly enhances low level convergence.

With the convection...the biggest forecast concern remains the
potential for localized heavy rainfall and flash flooding...
especially when given the subtropical airmass...nearly
unidirectional flow profiles oriented nearly parallel to the main
surface boundaries...short MBE vectors...and rather tall/skinny CAPE
profiles. In such an environment...the risk of heavy rain/flooding
will be heightened if any training of cells can develop along the
aforementioned surface boundaries...with the greatest potential for
this still looking to lie from the Southern Tier northeastward
across the Finger Lakes/interior of the North Country in association
with the composite prefrontal trough/lake breeze boundary.

In addition...a secondary (albeit lesser) concern will be the
potential for a couple isolated stronger storms to develop and
produce localized strong gusty winds. While this potential looks
notably lower than that for localized heavy rain/flooding...cannot
completely rule this out either given the expected moderate amounts
of instability...and the potential for precip loading to lead to
some locally strong downdrafts/surface wind gusts. With all this in
mind...have continued to mention the heavy rainfall potential in the
grids...and have also added a mention of gusty winds in conjunction
with surrounding WFOs.

Otherwise...it will be very warm to hot again today out ahead of the
cold front/prefrontal trough with highs reaching the mid to upper
80s in most places...with a some spots in the Finger Lakes/Oswego
county again potentially reaching the lower 90s. Coupled with
surface dewpoints in the upper 60s/lower 70s...this will probably
result in much of the Finger Lakes region and Oswego county reaching
low-end Heat Advisory criteria for at least a few hours prior to the
arrival of any convection...and with this in mind have hoisted
another Heat Advisory for these areas. These conditions will then
improve once the showers and storms arrive.

By the time we get to sunset most of the convection will be on the
wane with the loss of daytime heating...with just a few more
showers/storms possible through midnight or so in tandem with the
trailing cold frontal passage. After that...generally dry conditions
are expected for the second half of the night as drier and cooler
air begins to filter in behind the departing front...though plenty
of lower clouds will remain in place in its wake. Where these
intersect the higher terrain...some fog will become possible as we
push through the night. Otherwise it will be cooler...with lows
settling into the lower to mid 60s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Cold front through the region by Tuesday, but stalling just to the
southeast of the region due to the presence of the remnants of
Chantal working up along the east coast. While the impacts of
Chantal will not be felt in our region, there could be a chance for
a stray shower across far southeastern portions of the area.
Otherwise, building high pressure behind the front will bring a dry
day for much of western and north central New York.

High pressure remaining across the region Wednesday, with dry
weather continuing through at least the first half of the day.
The frontal boundary to our south will then shift northward as a
weak wave travels through the Ohio Valley. Southerly flow sends
warmer air into the region bringing the low risk for some diurnally
driven summertime convection.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The later half of the week, will feature a longwave trough axis
overhead of the central Great Lakes to traverse east into New
England by this weekend. This pattern will support several windows
of unsettled weather, but no days look to be complete washouts.
Otherwise with the troughing pattern overhead, temperatures will be
near to slightly above normal.

&&

.AVIATION /10Z MONDAY THROUGH FRIDAY/...
Mainly dry/VFR conditions will prevail through early this morning.
As we push through the rest of the day and early this evening...a
slow-moving surface cold front and leading prefrontal trough will
push through our region...with these features and diurnal heating of
our very warm and humid airmass helping to generate showers and
thunderstorms...some of which could produce locally heavy rainfall
and isolated gusty winds. The best convective coverage is expected
to focus from the Southern Tier northeastward across the Finger
Lakes and interior portions of the North Country this afternoon in
association with the prefrontal trough...though secondary maxima in
coverage may also occur at times across portions of the Niagara
Frontier and Jefferson county...along the northern fringes of
developing lake breeze boundaries. Expect the potential for
reductions to MVFR or even highly localized IFR (mainly due to
reduced visibilities) within any convection...with the risk for this
again highest across interior portions of the area.

After sunset coverage of showers and storms will be on the wane...
though a few more widely scattered showers and storms may still
accompany the cold frontal passage through the balance of the
evening. In the wake of the front dry weather is expected...though
lower stratus will also develop and lower flight conditions to MVFR
across the lower elevations and IFR/LIFR across the higher terrain.
Where the developing stratus layer intersects the higher terrain of
the Southern Tier and North Country...some patchy fog will become
possible as we push through the night.

Outlook...

Tuesday...Improvement to VFR.

Tuesday night and Wednesday...Mainly VFR.

Thursday and Friday...A chance of showers and thunderstorms with
MVFR restrictions possible.

&&

.MARINE...
While winds will likely remain below SCA levels today and into this
evening...there will be the threat of showers and thunderstorms in
association with the approach and passage of a slow-moving cold
front. In its wake...winds will become northerly to northwesterly
while remaining at light to modest levels into early Tuesday, with
generally light winds and sub-advisory conditions then expected to
continue through the rest of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory from 11 AM this morning to 6 PM EDT this evening
     for NYZ003>006-013-014.
MARINE...None.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...TMA
LONG TERM...EAJ/TMA
AVIATION...JJR
MARINE...JJR