Tonawanda Town, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

675
FXUS61 KBUF 191023
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
623 AM EDT Sat Jul 19 2025

.SYNOPSIS...
High pressure will exit across New England and out to sea today...
while still providing our area with dry and seasonably warm weather.
A wavy cold front will then bring another round of showers and
scattered thunderstorms tonight and Sunday morning...before another
area of high pressure builds across our region and provides us with
dry weather for Monday and Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface high pressure will slide across New England and out to sea
today...while broad...low-amplitude troughing and a corresponding
weak/wavy surface cold front make their way across the Upper Great
Lakes. This next system will remain too far to our west to bring
much more than a very modest increase in mid and high clouds to our
area during the afternoon... with fair dry weather continuing to
prevail. With some warming of our airmass developing around the
backside of the departing ridge... daytime highs will climb back
into the lower to mid 80s in most places...with a few spots in the
Genesee Valley reaching the upper 80s. Dewpoints will also climb
back to the lower half of the 60s...thereby lending a somewhat more
humid feel to our warming airmass.

Tonight the low-amplitude trough will continue to gradually dig and
extend eastward across our region as an embedded shortwave slides
through its southern periphery...while at the surface the associated
wavy cold front looks to make it to about Lakes Erie and Ontario by
the start of Sunday morning. This system will bring a continued
increase in synoptic moisture as it approaches...with precipitable
water values climbing to between 1.5 and 2 inches. Coupled with lift
provided first by the passage of the aforementioned shortwave and
then the approach of the surface cold front...this will generally
bring an increasing potential for showers and some scattered
thunderstorms as we push through the late evening and overnight
hours...which is reflected in the forecast by PoPs increasing into
the likely range. This being said...the short term guidance suite
continues to exhibit differences in just how well the initial
convection attendant to the lead shortwave will hold together during
the late evening and early overnight hours...with some packages
looking rather anemic in this respect given the potential for the
warm waters of Lakes Erie and Ontario to provide sustenance. For now
have stuck pretty close to blended guidance for PoPs...with the
better pcpn chances accompanying the approach of the wavy cold front
later on in the night.

At this juncture...the potential for strong to severe storms appears
to be lessening given the unfavorable later-night timing to the
convection...which will help to keep instability levels modest at
best across our area. This being said...there is certainly enough
shear in place to result in a non-zero risk of a stronger storm or
two with isolated damaging wind gusts...with this especially the
case across portions of far WNY closest to Lakes Erie and Ontario
where the warm lake waters could help to give the convection a
boost. Isolated locally heavy rainfall also cannot be completely
ruled out given the increased atmospheric moisture content...though
this would likely require training of heavier convective cells given
the relatively quick flow aloft.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
A cold front directly over the region to start the period Sunday
will trek southeast and move out of the forecast area by the late
morning hours. Lingering scattered showers and/or thunderstorms
along this front will move further inland from the lakes and clear
out in tandem as a large expanse of Canadian-sourced high pressure
builds back in from the northwest. Relatively cooler, quieter, and
less humid weather should then prevail through the rest of the
period with valley fog possible Sunday night and Monday night.

Temperatures Monday and Monday night in particular will average some
5-10 degrees below normal for mid to late July. Could see sfc
temperatures Monday night being several degrees cooler than
currently forecast with 850H temps on either side of +8C and good
radiational cooling in place, potentially leading to low/mid 40s
across parts of the interior. In addition...This cool airmass
flowing over the very warm lake waters and limited low level
moisture could potentially lead to more lake effect clouds than
forecast or even some isolated showers/sprinkles over the Finger
Lakes.

Temps (and to a lesser extent dewpoints) recover a several degrees
Tuesday and Tuesday night as the high begins to move east of the
area, though remaining dry.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
The area of high pressure that will bring cooler and drier weather
earlier in the week will move into the western Atlantic Wednesday
through Thursday as mid/upper level ridging dominates the southern
CONUS. Deepening offshore anticyclonic flow will force a warm front
through the region on Wednesday, opening the door to increasing heat
and humidity through the end of the week. Heat indices Thursday and
Friday could reach advisory levels, though confidence is low as
spread among the NBM percentiles becomes quite large by this point,
while its dewpoints look vastly overdone in some areas.

In addition to the return of summer`s warmth, shower and
thunderstorm chances begin to ramp up again later Wednesday night
through Thursday and remain elevated through Friday as the airmass
becomes increasingly unstable and several shortwaves take aim at the
region.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Any limited patchy valley fog will quickly dissipate this morning
with renewed daytime heating/mixing...with widespread VFR conditions
then prevailing through the balance of the day as high pressure
remains in control of our weather while sliding off the New England
coast.

Tonight a wavy cold front will approach our region from the central
Great Lakes...with this feature reaching Lakes Erie and Ontario by
12z Sunday. This will bring an increasing likelihood of showers and
scattered thunderstorms with associated restrictions as we push
through the night...while ceilings gradually lower to MVFR/localized
IFR across the higher terrain and MVFR/low VFR across the lower
elevations.

Outlook...

Sunday...IFR/MVFR with a chance of showers and thunderstorms in the
morning, then improvement to VFR.

Monday through Wednesday...VFR...with localized river valley fog/IFR
possible each late night and early morning.

&&

.MARINE...
High pressure will keep quiet conditions in place across the Lower
Great Lakes region today, with continued weak large-scale flow
allowing local lake breezes to develop again this afternoon.

The next chance for disturbed weather will then arrive tonight, when
a wavy cold frontal boundary will make its way across the Lower
Great Lakes, bringing a renewed threat for showers and scattered
thunderstorms. The front is then forecast to slip south of Lakes
Erie and Ontario later Sunday morning with Canadian high pressure
then providing dry weather later Sunday through Tuesday.

A brief period of elevated northerlies in the wake of the cold front
will bring choppy conditions Sunday night...especially along the
southern Lake Ontario shoreline where conditions may approach
marginal low-end Small Craft Advisory criteria. Generally light to
modest winds and minimal waves will then follow for Monday and
Tuesday.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...PP
LONG TERM...PP
AVIATION...JJR
MARINE...JM/JJR