Brockport, New York Weather Forecast Discussion

644
FXUS61 KBUF 061035
AFDBUF
Area Forecast Discussion
National Weather Service Buffalo NY
635 AM EDT Mon Oct 6 2025
.SYNOPSIS...
High pressure draped along the eastern seaboard will slowly drift
offshore today...while providing our region with one last day of dry
and unseasonably warm weather. A sharp cold front will then generate
some beneficial rainfall as it slowly crosses the region Tuesday and
Tuesday evening...with Canadian high pressure then building across
our region and ushering in dry and much cooler weather for Wednesday
and Thursday...when high temperatures appear likely to remain mostly
confined to the 50s. Continued dry weather and a gradual warming
trend will then follow for Friday and Saturday as the high slides
off the New England coast.
&&
.NEAR TERM /THROUGH TONIGHT/...
Deep-layer ridging stacked along the eastern seaboard will only very
slowly drift offshore today...while upper-level troughing over
central Canada and the northern Plains states digs across the Upper
Great Lakes. The sharp cold front attendant to the eastern flank of
this trough will remain well to our north and west through the
day...with only some very limited high cloud cover consequently
spilling across our region. Coupled with 850 mb temps of +13C to
+15C and a somewhat stronger southwesterly flow...the resultant
sunshine will lead to one more day of midsummerlike warmth...with
highs again mostly in the lower to mid 80s...and a few of our
typical warm spots in the Genesee Valley and western Finger Lakes
reaching the upper 80s. While these should remain safely below
record levels at Buffalo and Rochester (85/1900 and 87/1900
respectively)...the record at Watertown (82/1990) will probably at
least be approached.
Tonight the upper level trough will slowly dig further southeastward
across the Great Lakes...with its attendant cold frontal boundary
correspondingly making its way into Southern Ontario. After a dry
and uneventful first half of the night...the approach of the front
and a lead shortwave should drive a west-east increase in cloud
cover overnight...followed by increasing chances for some showers
and perhaps an isolated thunderstorm late...primarily across far
western New York and Jefferson county. Did make some adjustments to
NBM PoPs (which appeared too broadbrush/fast) to bring these more in
line with some of the higher-resolution guidance...which suggests a
more realistic-looking and sharper west-east gradient given the slow
approach of the cold front. Otherwise we can expect a very mild
night by early October standards given the expected decent southerly
low-level flow out ahead of the front...which should result in low
temps ranging from the low-mid 50s across the far interior of the
Southern Tier/North Country to the lower half of the 60s across the
lake plains of western New York.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Potential for a widespread beneficial rainfall continues to look on
track for Tuesday through the first half of Tuesday night. In fact,
forecasted rainfall amounts continue to tick upward, with western
and north-central NY looking to be the bullseye for the highest QPF
amounts. However, confidence remains low with respect to
location of the highest QPF amounts.
Starting off the day Tuesday, potent mid/upper level trough will be
digging southeast across the western Great Lakes aiding with the
eastward progression of the strong surface cold front that will lie
from just east of Georgian Bay southwestward across the southern tip
of Lake Huron and southeastern Lower Michigan. Good news for our
region is the eastward progression of the boundary is expected to
slow a bit as this feature starts its` trek across western and north-
central NY. There are two reasons for this: 1. The mid/upper level
trough will progressively sharpen while encroaching on the lower
Great Lakes region, which will slow the eastward progression of this
feature, thus translating to the overall forward progress of the
surface cold front. 2. A weak surface wave or two are forecast to
ripple northeast along the boundary as it trudges into our area,
which will help to enhance rainfall amounts along and ahead of the
front over those areas. Confidence remains low at this time with
respect to the exact timing and placement of these aforementioned
features. As mentioned above, the total event will last about 18
hours or so for any one location. The actual cold front will not
cross the area until late Tuesday through Tuesday evening, with the
last of the showers expected to exit our eastern areas by late
Tuesday night as a large area of strong Canadian-sourced high
pressure over the upper Great Lakes starts to build southeast across
the lower Great Lakes region in the wake of the cold fropa.
Rainfall amounts now look to range from around 0.75" on the lower
end, to as much as 1.25-1.50" on the higher end. Embedded convection
is expected with the favorable diurnal timing of the front, however
no more than some rumbles of thunder are expected, although this
will act to boost localized rainfall amounts.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Dry and seasonably cool weather through the first part of the
period with frost/freeze potential Wednesday night and Thursday
night. Dry weather and a slow warming trend is then expected for the
tail end of the work week into the first half of the weekend, which
may hold through Sunday, dependent on the track and speed of a
strong coastal storm moving north along the Eastern Seaboard.
The aforementioned large area of Canadian high pressure will expand
across the lower Great Lakes region Wednesday, ushering in another
very dry airmass, but more notably the coolest air we have seen so
far this season with temperatures falling a bit below normal for the
Wednesday through Thursday night timeframe. 850mb temps are progged
to bottom out between 0C and -3C Wednesday night into Thursday. This
is some 2 to 3 degrees C colder than 24 hours ago. The main impact
of this trend will be increasing confidence for frost (freeze
interior higher terrain) Wednesday night, with all areas now
potentially at risk under favorable radiational cooling conditions.
One would expect a lake response as well, however despite this
chilly airmass flowing across the much warmer lake waters, the
plethora of dry air in the mid levels and within the northerly
boundary layer flow will limit any lake response to no more than
possibly some extra clouds south of Lake Ontario Wednesday night.
Center of the high will continue sliding east-southeast Thursday,
crossing right overhead Thursday afternoon and to the New England
coast by Friday afternoon. This will translate to another chilly
night Thursday night, with the speed of eastward progression and
exact position of the surface high center determining the extent of
the frost/freeze potential for a second consecutive night.
Weak WAA will begin late Thursday night/early Friday morning and
continue into the weekend with gradually warming temperatures as a
light southerly return flow ensues on the west side of the high.
High pressure will remain ridged back westward across the area
keeping dry weather intact through at least Saturday, with Sunday
again dependent on position of strong coastal system moving up the
Eastern Seaboard. Near average temperatures Friday will trend a bit
above normal for the weekend.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Deep-layer ridging stacked along the eastern seaboard will only very
slowly drift offshore today...and in the process will keep VFR
conditions intact across our region through the day...with only some
limited cirrus-level cloudiness passing across our region.
Tonight the ridge will slide further offshore...while upper level
troughing digs across the Great Lakes and pushes its attendant sharp
cold front into Southern Ontario. The approaching front will spread
increasing/lowering clouds across our region as we push through the
second half of the night...followed by increasing chances for some
showers and perhaps an isolated thunderstorm late...primarily across
far western New York and in the vicinity of KART. Expect flight
conditions to remain primarily VFR through much of the night...
before potentially falling to MVFR/IFR across extreme far WNY late.
As a modest (30-40 knot) low level jet works into the region late...
some lower-end LLWS may develop in the vicinity of KBUF/KIAG.
Outlook...
Tuesday and Tuesday night...MVFR/IFR with widespread showers and a
couple isolated thunderstorms possible...diminishing later Tuesday
night.
Wednesday...Areas of MVFR ceilings early, otherwise VFR.
Thursday and Friday...VFR.
&&
.MARINE...
High pressure will slowly drift offshore of the eastern seaboard
today and tonight as a cold front approaches from the northwest. As
a result southerlies and south-southwesterlies will gradually pick
up through thought. While this will lead to the development of some
chop...the orientation of the flow will direct the greatest wave
action across Canadian waters.
The cold front will then cross the Lower Great Lakes Tuesday and
early Tuesday evening...bringing fairly widespread showers and
perhaps a couple isolated thunderstorms. In its wake...winds will
freshen and veer to northwesterly and then northerly Tuesday night
and early Wednesday. This will likely bring advisory-worthy
conditions to areas along the south shore of Lake Ontario...and
possibly also to areas southwest of Dunkirk on Lake Erie.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...JM
LONG TERM...JM
AVIATION...JJR
MARINE...JJR

NWS BUF Office Area Forecast Discussion