504
FXUS61 KBUF 190005
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
805 PM EDT Fri Jul 18 2025

.SYNOPSIS...
High pressure will provide cool and calm weather tonight, followed
by seasonably warm conditions on Saturday with a good deal of
sunshine. A wavy cold front will bring another round of scattered to
numerous showers and thunderstorms Saturday evening, with these
potentially lingering into a portion of Sunday. Another area of high
pressure will then build across our region while bringing dry
weather for Monday and Tuesday.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
Canadian high pressure will move overhead tonight and temperatures
will fall into the 50s. Patchy fog is possible, especially in valley
locations across the western Southern Tier, western Finger Lakes,
and Black River Valley.

The surface high will move off the east coast through Saturday
morning. A dull shortwave trough will approach from the Mid-West
with moisture slowly increasing across the eastern Great Lakes
region. Forecast soundings show subsidence and dry low levels
through most of the afternoon which will result in dry weather
across the region. Warm air advection will result in warmer weather
with highs in the low to mid 80s, upper 80s across the lake plains.

An area of low pressure along with a cold front will be on our
doorstep Saturday evening. A corridor of moisture with PWAT values
near 2" (>90th percentile for July 19) will enter western NY. The
chance for showers and thunderstorms will increase from west to east
Saturday night. Upstream convection will approach the region,
however there is uncertainty how much will hold together. Hi-res
guidance including the 12z HRRR brings a line segment across Lake
Erie into the western Southern Tier. The warm lake (78F at Buffalo)
may help fuel storms through the evening hours. The Day 2 SPC
outlook includes a Slight Risk for Chautauqua, Cattaraugus, and
southern Erie counties, with a Marginal risk extending eastward to
about the Genesee River Valley. Coverage and severity is expected to
trend down the second half of the night. The cold front is expected
to move through Lake Erie and the Niagara Frontier by 8 AM Sunday,
with showers and a few thunderstorms possible across the region.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
A few showers with embedded rumbles of thunder will start the day
Sunday along a cold front before improvements will be found with
surface high pressure bringing afternoon and evening
clearing...along with lower humidity.

Fair weather can then be expected through the end of this period
with overnight fog filling the valleys of the Southern Tier.

Could see temperatures a bit lower than forecasted east of Lake
Ontario Monday night into Tuesday, where an overhead Canadian
surface high pressure (and cooler airmass at 850 hPa than tonight)
could allow for the mercury to drop into the mid 40s inland.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A warm front will lift northward across our region Wednesday,
sending summers heat and humidity back into our region...along with
chances for showers and thunderstorms through the forecast period,
highlighting Wednesday night through Thursday night with the
passage of several shortwave troughs.

NBM with a modest spread in afternoon temperatures (25th to 75th
percentile) Wednesday, becomes even greater in spread Thursday and
Friday, especially inland where higher temperatures than forecasted
are possible...which would bring heat index values possibly into the
advisory range for the traditionally warmer inland areas.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
High pressure will be overhead through tonight. Light winds and
mainly clear skies may result in patchy fog across portions of the
western Southern Tier into the Finger Lakes region and east of Lake
Ontario (light fog possible at KART), with the typical localized
more dense fog concentrated in river valley locations across the
western Southern Tier (KJHW), Finger Lakes region, and Black River
Valley second half of tonight. Local rules of thumb also show an
area of localized fog possible west through northwest of Oneida Lake
later tonight (possibly impacting KFZY) owed to a light east to
southeast flow under these atmospheric conditions.

Any fog will erode within a couple hours of daybreak Saturday
morning, with widespread VFR conditions then expected through at
least early Saturday evening as high pressure remains in control
while sliding off the southern New England coast by late in the
day. Mid and upper level decks will start to thicken and lower
from northwest to southeast ahead of an approaching area of low
pressure and attendant cold front late in the TAF period.

Outlook...

Saturday night...VFR/MVFR with showers likely along with a chance of
thunderstorms.

Sunday...VFR/MVFR with a chance of showers and thunderstorms, mainly
early.

Monday and Tuesday...VFR.

Wednesday...VFR/MVFR with a slight chance of showers and
thunderstorms.

&&

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

The next chance for disturbed weather will then arrive Saturday
night, 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 Saturday night through 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 evening
through Monday morning, especially along the southern Lake Ontario
shoreline, where conditions may approach marginal low-end Small
Craft Advisory criteria during that timeframe.

&&

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

&&

$$

SYNOPSIS...Hitchcock/JM/JJR
NEAR TERM...HSK
SHORT TERM...Thomas
LONG TERM...Thomas
AVIATION...JM
MARINE...JM/JJR