WX in text

453
FXUS61 KBUF 200721
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
321 AM EDT Mon Oct 20 2025

.SYNOPSIS...
Showers this morning will continue across the area as a cold front
tracks east. Showers will taper off for WNY late in the
morning/afternoon, but linger through tonight for areas
east/southeast of Lake Ontario as a surface low forms along the
passing front. After a brief break, showers will then return
starting Tuesday afternoon and continue through the remainder of the
week for most areas as lake enhanced/effect rain. Cooler
temperatures and periods of breezy winds can also be expected
through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Morning showers east of Rochester associated with an earlier
pre-frontal trough and a newly developing sfc low over CNY will
continue to slowly push east this morning. At the same time, a
cold front will push into WNY, with another batch of more
organized showers. Locations between these two area of showers
have a more intermittent and scattered nature to the showers as
some drier air along with some downsloping has helped to
diminish the rain some.

Today, showers will continue this morning across the entire forecast
area, especially for areas east/southeast of Lake Ontario, where
rain will continue for the entire day as a sfc low develops over
CNY and the cold front tracks into the area. For WNY, showers will
start to diminish during the late morning and early afternoon as the
sharp trough over the region pushes east and as drier air pushes in
and ridging increases. Rainfall today of a quarter to three quarters
of an inch is possible, with some locally higher amounts possible.
Winds today will increase once again across the area as the cold
front tracks east and CAA helps to bring winds to the sfc from a 30-
40 kt LLJ, resulting in wind gusts of 30 to 35 mph at times.
Temperatures today will cool to near to slightly above normal with
afternoon highs reaching the low 50s to near 60, which will be
around 15 to 20 degrees cooler than Sunday afternoon values for most
areas.

Tonight, showers east/southeast of Lake Ontario will end during the
early evening and the rest of the night will remain mostly dry as
ridging briefly builds into the region ahead of the next approaching
system. Winds will also weaken this evening into the overnight;
before increasing again early Tuesday morning for the far western
areas as the pressure gradient starts to tighten once again ahead of
the next approaching system. Temperatures tonight will drop to the
mid 30s to low 40s, with the coolest spots over the higher terrain,
away from the lakes.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
...HEAVY LAKE EFFECT RAIN POSSIBLE DOWNWIND OF THE LAKES DURING THE
MID WEEK PERIOD...

Progressive nature of the long wave pattern will allow for the mid
level ridge to slide quickly off to the east Tuesday. Phasing of mid
level short wave energy into an upper tough moving into the northern
plains will evolve into a deep closed upper low over the upper
Midwest Tuesday, before tracking into the upper Great Lakes by
Wednesday and into Ontario/Quebec by the end of the period.

Tuesday should start out dry as the ridge shifts east, before a
surface cold front arrives into the region Tuesday afternoon. While
the forcing with the front will be brief, a narrow moisture plume
and steep mid level lapse rates suggest a round of showers will
sweep across the region.

Sharp dry slot shifts into the region behind the showers/frontal
passage, but this will only be a brief period of drying. A cold
cyclonic flow will become established that will bring chances for
additional showers. More notably will be 850 mb temperatures
averaging from zero to -2C or -3C and lake surface temperatures of
+15C/+16C, with plentiful mid/upper level moisture sitting atop this
cold low level airmass within the cyclonic flow. This will elicit a
strong lake response in the Tuesday night through Thursday night
timeframe with the potential for localized heavy rainfall downwind
of Lakes Erie and Ontario.

Off Lake Erie: Lake effect rain will focus northeast of the lake
(Buffalo metro area) Tuesday night into Wednesday night under a
southwest flow, before a trough swings through the area veering
winds to the west, sending the lake plume east of the lake (south of
Buffalo Metro) for Thursday and Thursday night.

Off Lake Ontario: Similar setup, although response will be a bit
delayed before southerly flow eventually veers southwesterly by
later Wednesday into the first half of Thursday with main band
northeast of the Lake (Watertown area and north). Winds then veer
west for Thursday afternoon and Thursday night as the trough passes
through sending the plume east of the Lake (Watertown/Tug Hill).

Localized substantial rainfall will be possible in areas downwind of
the both lakes if the bands persist over any one area for an
extended period of time. A few rumbles of thunder, and/or small
hail/graupel will also be possible in some of the heavier convective
elements closer to the Lakes.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
Large upper low will start to shift east with the main trough axis
crossing the lower Great Lakes region Friday. This will veer winds
more to the west-northwest sending lake bands east-southeast of the
Lakes before weakening Friday night into Saturday as mid level
moisture is stripped away behind the main trough axis and surface
high pressure tries to build in from the south. That said, Medium
range guidance continues to struggle with how fast the large upper
level low exits the region next weekend. This will determine if we
start to dry out or if periodic synoptic and/or weaker lake effect
showers continue.

Below average temperatures will trend back toward average by the end
of next weekend.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Showers will continue through the morning with a varying range of
flight categories. A cold front will track east across the area this
morning, while a sfc low also forms over central NY. The plethora of
moisture associated with these two features will bring a mixture of
IFR/MVFR CIGs this morning with some occasional LIFR possible at
times. Early periods of VFR CIGs is expected to lower this morning.
VSBYs in the MVFR to VFR range is expected for most areas this
morning, but periods of IFR within heavier showers and mist over the
higher terrain will be possible. Flight categories will start to
improve during the later portion of the morning and into the
afternoon to a mixture of MVFR/VFR from west to east as showers
taper off. Improvements will also be slower over the higher terrain.
Winds will also increase from west to east this morning as the cold
front tracks east and cold air advection helps brings winds to the
surface from a 30-40 kt LLJ. South/southwest winds will shift to the
west and the northwest behind the passing front and wind gusts in
the 25 to near 35 knot range will be possible, especially southeast
of Lake Ontario.

Tonight, any showers from earlier should be out of the area as a
ridge builds into the region briefly. Flight conditions will
continue to slowly improve to mainly VFR, though some spotty MVFR
CIGs can`t be ruled out at times over the higher terrain. With the
pressure gradient weakening briefly, winds will weaken through the
night from west to east, but then increase again early Tuesday
morning across far western NY as the next system approaches from the
northwest.

Outlook...

Tuesday...VFR deteriorating to MVFR and IFR from west to east with
showers developing later in the day.

Wednesday through Thursday...MVFR/IFR with showers likely. Heavier
lake effect rain east of Lake Erie and Lake Ontario.

Friday...VFR/MVFR with a few showers likely, especially southeast of
Lake Ontario and Lake Erie.

&&

.MARINE...
Increasing winds behind a passing cold front this morning will veer
to the west/northwest across the entire area. Winds will increase to
the 25-30 knot range for most of the lake zones at least for a
portion of the day today, with some near gale force values on Lake
Ontario possible. Winds will start to weaken late this afternoon and
into the overnight from west to east. Small Craft Advisories are in
place through at least least this evening on all lake zones for both
Lakes Erie & Ontario for higher end advisory conditions. A SCA is in
place for the entire Niagara River until 00Z this evening.

Winds will weaken briefly tonight, but then increase early Tuesday
morning as another storm system tracks toward the region. Winds will
continue to increase through the day on Tuesday, reaching SCA levels
on Lake Erie Tuesday morning and then on portions of Lake Ontario by
Tuesday afternoon. Winds are expected to remain at SCA levels for
much of the remainder of the week on both Lakes Erie & Ontario with
an active pattern continuing.

Lake enhanced/effect rain is also expected over and east/northeast
of the lakes for the middle portion of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ020.
         Small Craft Advisory until 11 PM EDT this evening for
         LEZ040-041.
         Small Craft Advisory until 8 PM EDT this evening for
         LOZ030.
         Small Craft Advisory until 5 AM EDT Tuesday for LOZ042-043.
         Small Craft Advisory until 8 AM EDT Tuesday for LOZ044-045.

&&

$$

SYNOPSIS...SW
NEAR TERM...SW
SHORT TERM...JM/TMA
LONG TERM...JM
AVIATION...SW
MARINE...SW

NWS BUF Office Area Forecast Discussion