Irondequoit, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

250
FXUS61 KBUF 191704
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
104 PM EDT Sat Jul 19 2025

.SYNOPSIS...
Fair weather this evening will end briefly as a cold front with
showers and thunderstorms upon it crosses our region tonight and
through Sunday morning...with a few of these storms containing
strong gusty winds tonight. Storm activity will exit the Genesee
Valley and Finger Lakes region early Sunday afternoon and while a
few breaks in the clouds are possible a cool northwest flow will
maintain mostly cloudy skies through the night that may even yield a
few light, brief rain showers across upper terrain south of Lake
Ontario.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
Fair weather this afternoon with surface high pressure slipping to
the east.

A return southerly flow will bring back mugginess tonight and early
tomorrow morning with dewpoints rising back into the 60s...and even
into the upper 60s just ahead of the cold front. This increase in
moisture in the lower levels will bring modest amounts of MUCAPE, of
1000 to 1500 J/KG that will support thunderstorms through the night.

The 0-6km bulk shear values rise to 40-45 knots ahead of the front,
for which portions of our western region (in conjunction with deeper
instability) will remain in a marginal threat for severe
thunderstorms yielding stronger wind gusts...if stronger upstream
earlier in the evening convection can maintain its intensity as it
enters our region during a less favorable time for severe storm
development.

Showers and even a few embedded rumbles of thunder will start the
day Sunday, with activity exiting the Genesee Valley and Finger
Lakes region through the early hours of the afternoon. There will be
some clearing behind the front tomorrow afternoon, but strong cold
air advection, with 850 hpa temperatures falling down into the upper
single digits C tomorrow night along with a brisk northwest flow,
will bring back a deck of strato-cumulus clouds through the night.

A few of these lake clouds may yield a brief light rain shower and
have introduced low end PoPs across higher terrain south of Lake
Ontario to account for this potential lake effect activity.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...

High pressure will transition from the upper to lower Great Lakes
for early this week with dry weather and cooler temperatures
initially. Afternoon highs will be 5-10 degrees below normal for mid-
July in the low 70s Monday before climbing into the upper 70s
Tuesday with mostly sunny skies.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...

Headed into the middle of next week, the upper level trough over ME
and the Canadian Maritimes will continue to slide east with 500mb
height rises across much of the Northeast and Mid-Atlantic. High
pressure center that was positioned more overhead earlier in the
week will begin to slide eastward with moist southerly flow
beginning to work back into the region Wednesday. Warm and muggy
conditions are mostly expected with potential heat concerns as "Feels
Like" temperatures climb into the mid-90s, especially on Thursday. A
late week cold front associated with a surface low well to the north
in Canada passes through Thursday night into Friday bringing the
chance of showers and thunderstorms across much of western and north-
central NY, but uncertainty remains with the timing of the frontal
passage.

Heat: Starting with late Tuesday, 850mb temps will begin climbing
from around 10 degC up near 15 degC Wednesday and approaching 19
degC headed into Thursday per the latest GEFS. These 850mb temps
will exceed the climatological 90th percentile value across much of
western NY. High uncertainty remains in place at this time. Looking
at cluster analysis, ~60% of EC members favor a deeper ridge axis
into southern Ontario, but still has internal variation in timing.
GEFS members favor a slightly deeper and more progressive mid-level
trough cutting through the ridge that would subdue warmer
temperature aloft. However, latest model trends begin to lean toward
the slower progression of the next frontal system through the lower
Great Lakes.

&&

.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
For the 18Z TAFS VFR flight conditions are found and these
conditions will prevail for the next 9-12 hours.

This evening upstream convection will be blossoming over southern
Ontario, with this activity then entering WNY and the SLV this late
evening, with clusters of storms then expanding across all TAF sites
within a modestly unstable environment. While the thunder threat
will diminish through the night, still lingering instability ahead
of the cold front will linger a rumble of thunder across all TAF
sites through 12Z, with then slow improvements from west to east
across all TAF sites the final 6 hours of this TAF cycle.

Flight conditions will likely lower to MVFR within these storms
tonight, with IFR ceiling heights possible across higher terrain. A
deck of MVFR ceiling heights will be common tomorrow morning, with a
scattering out of clouds or bases beginning to rise to VFR through
the final hours of the TAF cycle.

Outlook...

Sunday afternoon...improvement to VFR. Low end VFR strato-cu deck
south of Lake Ontario Sunday night.

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

Thursday...MVFR/VFR with showers and thunderstorms possible.

&&

.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...Thomas
NEAR TERM...Thomas
SHORT TERM...Brothers
LONG TERM...Brothers
AVIATION...Thomas
MARINE...JM/JJR