315
FXUS61 KBUF 070741
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
341 AM EDT Tue Oct 7 2025

.SYNOPSIS...
A sharp cold front will slowly ease its way south across our area
this afternoon and evening...and in the process will generate some
desperately-needed beneficial rainfall. In its wake...strong
Canadian high pressure will build across our region Wednesday and
Thursday and provide us with dry weather...along with the coolest
temperatures of the fall so far. Expect highs mainly in the 50s both
Wednesday and Thursday...with Wednesday and Thursday nights both
likely to feature a frost or freeze across many areas away from the
immediate lakeshores. Continued dry weather and a gradual warming
trend will then follow for Friday and the weekend as the high slides
off the New England coast.

&&

.NEAR TERM /THROUGH TONIGHT/...
Upper-level troughing draped from Ontario Province to the Upper
Mississippi Valley will continue to sharpen and dig southeastward
across the Great Lakes through this period...with its axis reaching
southern Ontario by 12z Wednesday. At the surface...this will
encourage a rather sharp cold frontal boundary currently over
southern Ontario/Quebec to slowly push southeast and across our
region this afternoon and evening.

Out ahead of the front...a narrow but deep plume of rich Gulf-based
moisture will advect northeastward across our area today...with
precipitable water values climbing to between 1.5 and 1.75 inches.
At the same time...this moisture will encounter increasing amounts
of large-scale lift provided by a combination of low-level
convergence from the front and one or more weak surface waves
rippling along it...increasing height falls/DCVA aloft...and the
broadly diffluent flow regime in the right rear quadrant of a 120+
kt upper level jet streak. Coupled with some very weak
instability...all this will lead to periodic showers and perhaps a
few embedded thunderstorms developing from west to east this
morning...with the showers then becoming most widespread and/or
(more likely) outright transitioning to a swath of anafrontal rain
following the frontal passage later this afternoon/early this
evening. This post-frontal pcpn should then linger for roughly a 3-5
hour period at any given location...before sharply tapering off from
northwest to southeast through the rest of tonight as strong
Canadian high pressure and much cooler/drier air begins building in
behind the cold front.

In terms of rainfall amounts...the favorable moisture and forcing
should translate into a round of much-needed beneficial rainfall
across our region. Latest multi-model consensus generally suggests
that basin-average amounts may range from two thirds of an inch to
an inch across interior portions of the Southern Tier and Finger
Lakes to as much as 1 to 1.5" further north and west across the
remainder of the region...with localized amounts of up to 2"
possible. This being said...the ultimate location of the axis/axes
of heaviest rainfall will be very much dependent upon the forward
speed of the front...the track/timing of any embedded subtle waves
rippling northeastward along it...and any localized areas of
embedded convective enhancement...all details that the guidance
suite still exhibits some differences on. All of which is to say
that the expected distribution of rainfall amounts outlined above is
far from set in stone...and could well change as this event evolves.

As for temperatures...the expected cloud cover and precipitation
should help to keep highs largely confined to the upper 60s to mid
70s today...with lows tonight then falling into the 40s as cool air
advection increases behind the departing cold front.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Strong cold front that brought the much needed rainfall to western
and north-central NY will have shifted east into New England, while
an expansive area of Canadian-sourced high pressure centered over
the upper Great Lakes will be building southeast across the lower
Great Lakes region. This feature will bring a return to dry, but
more notably MUCH cooler conditions for this period, with potential
for frost and freeze headlines being the main item of interest for
both Wednesday night and Thursday night.

Strong CAA will already be underway Wednesday morning with an
airmass much more representative of the season pouring across the
region, with most areas only recovering into the 50s Wednesday
afternoon. The axis of the trailing mid/upper level trough will
cross the area Wednesday afternoon with a secondary shot of even
cooler air flowing into the eastern Great Lakes behind it with 850mb
temperatures plummeting to between -2C and -5C (coldest North
Country) for Wednesday night and Thursday. There are two main
factors that will keep temperatures from tanking further Wednesday
night: 1. Surface winds will likely not completely decouple from
flow aloft with the center of the surface high still located well to
our west over Michigan. 2. This will be more localized, however
despite the plethora of dry air, the cool northerly flow may produce
some extra lake clouds south of Lake Ontario Wednesday night.
Overall frost coverage may be limited to some degree owed to these
two aforementioned factors, however there is potential that our
normal colder areas see a freeze.

Dry and cool weather continue Thursday with daytime highs averaging
5-10 degrees below normal, which will equate to the Tug Hill and
western Adirondacks not getting out of the mid/upper 40s under full
sunshine. Center of the cool Canadian high will then slowly drift
from western to eastern NY Thursday night. After an already chilly
day to start and IDEAL radiational cooling conditions setting up,
temperatures will quickly fall back through the evening hours, with
much of the forecast area dropping into the mid 30s and lower
(mid/upper 20s normally colder areas), possibly requiring
frost/freeze headlines areawide. WAA will begin aloft second half of
Thursday night, however with a stout radiational inversion in place,
this will have little impact on surface temperatures.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
After a chilly start Friday morning, diurnal heating under near full
sunshine will eventually erode the radiational inversion allowing
the return flow of warmer air aloft to mix down to the surface, with
daytime highs returning to near average readings. Continued gradual
WAA advection will trend daytime highs back to a little above
average for the weekend into the start of next week.

Both the NBM/ensemble and deterministic medium range guidance have
struggled with locking in on the overall pattern evolution for late
in the weekend into the start of next week, battling with the
northward extent of a coastal low making its` way up the Eastern
Seaboard, the southward reach of a low pressure system moving across
eastern Canada, and the strength and position of high pressure
relative to these to systems. Simply put, there are a lot of factors
at play here. Latest 07/01Z NBM/ensemble and 07/00Z deterministic
medium range guidance are currently fairly well aligned that a
strong area of surface high pressure will set up over southern
Quebec Sunday and remain ridged southwestward across lower Great
Lakes region and Ohio Valley through Monday, which would provide a
dry forecast right through the holiday weekend. That said, some
differences remain in the upper level pattern evolution. This is
again somewhat of a change from the previous guidance package, so
further fluctuations will definitely be possible going forward being
six to seven days down the road, keeping overall forecast confidence
low to medium for the tail end of the period.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Current VFR conditions at all sites will rapidly deteriorate today
as a sharp...mositure-laden cold front slowly pushes south from
southern Ontario/Quebec and across our region...with the frontal
passage itself taking place between the late afternoon and early
evening hours.

The approaching front coupled with the arrival of an attendant
disturbance aloft will lead to increasingly widespread showers
developing from west to east this morning...and perhaps also a few
embedded weak thunderstorms (though have kept the latter out of the
TAFs for now given continued very low confidence in location/
timing). The showers will then likely transition to a swath of
anafrontal rain that will persist for 3-5 hours or so very late
today and this evening...with the latter then sharply tapering off
from northwest to southeast through the rest of tonight as strong
Canadian high pressure and much cooler/drier air begins building
into the area.

In terms of flight conditions...expect these to fall from VFR to
widespread MVFR with pockets of embedded IFR this morning...with
further deterioration to a period of widespread IFR (with embedded
LIFR across the higher terrain) expected following the frontal
passage later this afternoon/evening. After about mid-evening...the
advent of the aforementioned ridging will then result in conditions
gradually improving back to VFR from northwest to southeast through
the balance of tonight.

Outlook...

Wednesday...Mainly VFR.

Thursday through Saturday...VFR.

&&

.MARINE...
A sharp cold front currently over southern Ontario and Quebec will
gradually ease its way south across the Lower Great Lakes this
afternoon and early this evening...bringing fairly widespread
showers and perhaps a couple isolated thunderstorms. In its wake...
winds will freshen and veer to northwesterly and then northerly
tonight and early Wednesday. This will bring advisory-worthy
conditions to areas along the south shore of Lake Ontario much of
the time between tonight and Wednesday night...and possibly also to
areas southwest of Dunkirk on Lake Erie.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory from 7 PM this evening to 5 AM EDT
         Thursday for LOZ042.
         Small Craft Advisory from 7 PM this evening to 8 AM EDT
         Thursday for LOZ043-044.

&&

$$

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