440
FXUS61 KBUF 161030
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
630 AM EDT Wed Jul 16 2025

.SYNOPSIS...
Summertime heat and humidity will prevail across our region through
Thursday...along with unsettled conditions that will feature a few
rounds of mainly scattered showers and thunderstorms...with the
greatest coverage of storms expected this afternoon and evening from
the Southern Tier into the Genesee Valley and Finger Lakes. While a
few storms may produce localized gusty winds and heavy rainfall...
other areas may receive little or no rain given their generally
scattered nature. Following the passage of a cold front...drier and
cooler air will then overspread our region for Friday and Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
During the course of today...surface-based ridging currently draped
across eastern NY/PA will slide east to the Atlantic coastline...
while a shortwave trough over the Ohio Valley makes its way
northeastward to far western New York...with this feature impinging
upon our area during peak heating of our very warm and (once again)
increasingly more humid airmass. Coupled with forcing from a
developing lake breeze boundary to the lee of Lake Erie...this will
result in scattered to numerous showers and thunderstorms developing
to the south of Lake Ontario this afternoon...with the greatest
coverage expected from the Southern Tier northeastward across
interior portions of the Genesee Valley and Finger Lakes. Given
PWATs climbing to between 1.75 and 2 inches and only weak shear in
place...the main threat from any storms will be for localized heavy
rainfall/flooding...with a secondary risk for isolated strong gusty
winds attendant to any stronger convective cores.

Prior to the initiation of convection...the combination of
temperatures climbing to the upper 80s/lower 90s across the lake
plains and increasing humidity levels should lead to a brief period
of apparent temperatures reaching the mid to upper 90s from northern
portions of the Niagara Frontier eastward across the Finger Lakes
and lower elevations of north central New York. With this in
mind...a Heat Advisory remains in place for the above areas.

Tonight the shortwave trough will eject northeastward into the Upper
Saint Lawrence Valley...and in the process will bring a period of
scattered to potentially briefly more numerous showers and scattered
thunderstorms to the eastern half of the area...while further west
pcpn should generally tend to wane over time with increasing
subsidence/drying aloft in the wake of the shortwave. Otherwise it
will be another warm and humid night...with lows ranging from the
mid/upper 60s across the interior to the lower 70s across the lake
plains.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A vigourous shortwave cuts across Lake Superior and southeast Ontario
Thursday, then east across northern Quebec Thursday evening. At the
sfc, low pressure over Michigan Thursday morning will quickly race
by to our northwest and north Thursday afternoon.  In the process it
will send its trailing cold front advancing towards and through the
Lower Lakes. CAMs show a line of showers and storms working from
west to east just ahead of the cold front associated with the
prefrontal trough. A very moist airmass will be in place and with
building instability (CAPE values pushing +1500 J/kg) we could see
some strong to severe storms form out ahead of the front. The main
focus for these stronger storms will `likely` be from the Finger
Lakes region northeast into the North Country. SPC has place the
North Country in a Marginal Risk (level 1 of 5) for the potential
for severe storms. That said...given the moist environment (PW
values north of 1.75") any stronger storms will also have the
potential to produce very heavy rainfall. WPC had outlined this
threat to include the interior of the Southern Tier northeast across
the Finger Lakes region and then into the North Country.

The cold front shifts southeast of the Lower Lakes Thursday night
and then surface high pressure builds in from the west. Any remain
convection should all but end with it turn much cooler behind the
front for Friday. Temperatures will run some 10F-15F degree cooler
with highs mainly in the 70s. High pressure slides overhead by
Friday night with clear skies and lows in the 50s, with lower 60s
closer to the lakes.

High pressure begins to exit off to our east on Saturday but will
maintain dry weather across the region. As it exits...we will see a
warming trend as southwesterly flow picks up across the region. A
weak shortwave embedded within the zonal flow aloft is advertised to
race by to south Saturday night into Sunday. Have low end PoPs (30%
or less) across much of the area, with increasing chances towards
the NY/PA line overnight. After that...Canadian source high pressure
builds southeast for the second half of the day Sunday supporting
dry weather. Highs will be found in the upper 70s to low 80s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Canadian sourced high pressure slides overhead for the start the new
work week promoting largely dry weather which possibly last through
Tuesday. Although...not all guidance supports this idea with low end
PoPs being introduced in response to a potential warm front moving
through on Tuesday.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
As we push through today...a shortwave making its way northeast from
the Ohio Valley will combine with diurnal heating of our very
warm/increasingly humid airmass to generate some scattered showers
and thunderstorms south of Lake Ontario this afternoon and early
this evening...with the greatest (and possibly briefly more
numerous) convective coverage likely found from the Southern Tier
northeastward across portions of the Genesee Valley/Finger
Lakes...along and to the lee of a developing lake breeze boundary
off Lake Erie. Of the TAF sites...KJHW currently appears to have the
greatest chance of convection and any associated brief/localized
restrictions...with KROC having the next highest probability of
such. Outside of the storms...flight conditions will be
predominantly VFR.

Tonight the shortwave will eject northeastward to the Upper Saint
Lawrence Valley...and in the process will bring a period of
scattered to potentially briefly more numerous showers and scattered
thunderstorms to the eastern half of the area...with localized/brief
reductions again possible with these. Meanwhile further west...the
pcpn should generally tend to wane over time with increasing
subsidence/drying aloft in the wake of the shortwave. Otherwise
initially largely VFR flight conditions should tend to give way to a
mix of MVFR/IFR ceilings across the Southern Tier...with patchier
MVFR ceilings becoming possible elsewhere overnight.

Outlook...

Thursday...Localized/brief restrictions with mainly scattered
showers and thunderstorms.

Friday through Saturday...Mainly VFR. Localized IFR possible in fog
each late night and early morning.

Sunday...Mainly VFR with a chance of showers and thunderstorms and
associated brief restrictions.

&&

.MARINE...
Generally light to modest winds (at or below 10 knots) will prevail
today...with localized lake breezes developing as we push through
the day. Scattered thunderstorms will also develop this afternoon
across western New York, with locally higher winds and waves
possible near any storms.

A cold front will approach the area Thursday, then will cross Lakes
Erie and Ontario Thursday night and early Friday. Southwest winds
will increase markedly ahead of the cold front Thursday, then will
become northwest following the passage of the front Thursday night
and Friday. Small Craft Advisory conditions are likely on both lakes
Thursday through Thursday night...with calmer conditions then
returning on Friday as high pressure builds across the region.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NYZ001>007-013-014.
MARINE...None.

&&

$$

SYNOPSIS...Hitchcock/JJR
NEAR TERM...JJR
SHORT TERM...AR
LONG TERM...AR
AVIATION...Hitchcock/JJR
MARINE...Hitchcock/JJR