558
FXUS61 KBUF 071628
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1228 PM 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 TUESDAY/...
Latest satellite imagery shows ongoing convective initiation
primarily focused along lake breeze boundaries east of Lake Erie and
south of Lake Ontario early this afternoon. Latest RAP analysis
highlights a mid-level shortwave passing through southern Canada
with the cold front stretching from the surface low in southern
Quebec back southwest across western Lake Ontario and portions of
Lake Erie. Continued convergence ahead of the front with 1000-1500
J/kg of MLCAPE within a warm, moist environment will support
additional thunderstorm development through this afternoon across
western NY and eventually north-central NY with heavy rainfall and
gusty winds being the main hazards (more details below).

Behind the frontal passage, drier weather is expected headed into
Tuesday with temperatures 5-10 degF cooler than Monday, especially
across the southern Lake Ontario shoreline where Heat Advisories
were in effect. Morning fog will be present across the Southern Tier
along with a few light showers extending into the Finger Lakes
region as the frontal boundary stalls just to the southeast of the
CWA. High pressure will build across western NY through the
afternoon.

Heat: Heat Advisories remain in effect for much of the Southern Lake
Ontario shoreline and Finger Lakes region through early Monday
evening. "Feels Like" temperatures are currently climbing into the
mid-90s and will remain in place at least through the early
afternoon. With storms expected later this afternoon and the frontal
passage by early this evening, overnight relief from the heat will
be provided along with cooler temperatures and lower humidity
Tuesday.

Thunderstorms and Heavy Rainfall: The 12z KBUF sounding highlighted
moistening low-levels up through 600mb with a PW of 1.76" which is
above the climatological 90th percentile value. Deeper moisture is
expected to continue to advect eastward as PW values approach the
2.0" mark along with long skinny CAPE profiles off forecast
soundings and deep warm cloud layers (>10 kft) that would be
supportive of heavy rainfall with afternoon thunderstorms. Mean 850-
300mb cloud layer winds oriented to the northeast will be parallel
to the prefrontal trough and lake breeze boundary off Lake Erie. This
would lead to training storm motions that will need to be monitored
through this afternoon for excessive rainfall and the potential for
localized flash flooding, especially in areas of hilly or complex
terrain from the Southern Tier across to the Finger Lakes region.
Latest CAMs continue to track these storms across western NY through
5 PM and remaining across portions of north-central NY through 7 PM,
however this hi-res guidance is a little more conservative with QPF
totals remaining well below FFG.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
Zonal flow in the base of the general longwave troughing pattern
overhead Tuesday night will give way to the next shortwave trough
diving southeast across the Great Lakes. This shortwave will cause
the troughing pattern to gradually shift east, passing across the
lower Great Lakes Wednesday and Thursday before trudging further
eastward into the Northeast Friday and into the weekend.

Translating this pattern down to the surface, surface high pressure
will remain overhead of the lower Great Lakes Tuesday night and the
first half of Wednesday, supporting a period of mainly dry weather
to persist. Meanwhile, to the south a wavy stationary front will lie
across Pennsylvania and into the Ohio Valley. As the aforementioned
shortwave crosses the Great Lakes, a weak wave will traverse the
frontal boundary and lift it northward towards the western Southern
Tier, and ultimately ensuing southerly flow across the region. With
this being said, warm air will be advected into the area under the
southerly flow and spark a risk for some afternoon and early evening
diurnally driven convection.

The axis of the upper level trough will lie across the area Thursday
and Friday will support periods of rain showers with chances for
thunderstorms, especially in the afternoon hours each day due to
diurnal effects.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
Brief mid-level ridging will pass across the central Great Lakes
Friday night and into Saturday morning. Meanwhile, the next trough
will be in the middle of passing across the Northern Plains and into
the upper Great Lakes Saturday before lifting northeast into the
northern portions of the Ontario province Sunday night and Monday.
Overall after a dry night Friday, the next chances for a few showers
and thunderstorm will arrive into the start of the weekend and last
into Monday. While there is a chance for rain each day, should
mention that no days look to be complete washouts. Additionally,
with the brief ridge and the exit branch of the trough to the west
of the region, temperatures will gradually warm into the mid to
upper 80s for late in the week and into the weekend.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
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 until 6 PM EDT this evening for NYZ003>006-013-
     014.
MARINE...None.

&&

$$

SYNOPSIS...JJR
NEAR TERM...Brothers
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...JJR
MARINE...JJR