912
FXUS61 KBUF 060219
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1019 PM EDT Sat Oct 5 2024

.SYNOPSIS...
Clear starlit skies will be in place tonight...as high pressure will
exit to our east. While an approaching cold front will promote late
summer warmth on Sunday...it will also generate some late day
showers and strong thunderstorms. Notably cooler weather will follow
for the bulk of the upcoming week...as daytime highs will only be in
the 50s and 60s. The very cool weather will support periodic early
season lake effect rain showers.

&&

.NEAR TERM /THROUGH SUNDAY/...
...Strong to Severe Thunderstorms Possible Late Sunday..

High pressure drifting overhead this evening with maintain clear
skies. The high will shift east of the region late tonight with
the pressure gradient tightening ahead of a cold front. Increasing
southerly component winds late tonight should limit fog potential,
although in some sheltered valley fog may still occur. Low
temperatures in the 40s will likely occur by the second half of
the night, before leveling out or even rising a few degrees by
daybreak.

Deepening trough arrives into the eastern Great Lakes Sunday with
western New York emerging into the warm sector. Robust warm air
advection develops within the warm sector as a 40 to 45 knot low level
jet focuses on the region, sending 850 mb temperatures to 14-15C. This
will send temperatures into the lower to mid 70s for most areas, with
some upper 70s possible across western New York.

A strong cold front will arrive by late afternoon with a narrow
corridor of dewpoints reaching into the 60s pooling ahead of the front.
Cooling aloft along with steepening mid-level lapse rates will overlap
modest boundary layer moisture to support an area of moderate
instability along and just ahead of the cold front. The expectation is
that a band of convection will develop along and just ahead of the cold
front entering western New york around 4 PM. Strong wind fields aloft
with nearly 50 knots of deep layer shear will likely yield a narrow
band of organized convection. Damaging wind gusts will likely be the
PRIMARY threat associated with the strong wind fields aloft. Bufkit
profiles showing sufficient low-level hodograph curvature and SRH
signals to suggest the potenial for supercell development with an
isolated tornado possible, especially across southwest New York. SPC
has much of the area in a Marginal Risk for severe thunderstorms with a
Slight Risk area highlighted for southwest New York.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A sharp cold front will begin to cross Western NY early Sunday
evening, with a line of showers working from west to east through
the region. While there `likely` will be some measure of
thunderstorm activity, the potential for stronger storms will
decrease with the loss of daytime heating. The greatest threat for
stronger storms will initially be found across Western NY, then
decrease the further east you go Sunday evening. Its worth
noting that CAMS show 0-6km shear values up to 35 knots and
instability of 850-1000 j/kg early on. With the passage of the
cold front we should see shower activity quickly diminish in
coverage as drier air works in across the Lower Lakes Sunday
night. It will also turn much cooler as 850H fall to +1C to +2C
by Monday morning. Some brief clearing may take place behind the
front, but given the cool airmass spilling into the region
clouds will `likely` redevelop southeast of the lakes.
Otherwise...lows Sunday night will be found in the mid 40s to
mid 50s.

Cool WNW cyclonic flow will continue to produce plenty of cloud cover
Monday along with some measure of shower activity. Highs on Monday
will be as much as 15F-20F degrees cooler than Sunday with 50s to
low 60s across the region. Monday night lows will be found in
the upper 30s to mid 40s. Given that there will be some wind
flow...frost more than `likely` will not be much of an issue. Even
so...it would be wise to take precautions or atleast get prepared
for frost by Tuesday night.

It definitely will feel like fall has arrived Tuesday across the
forecast area. Highs on Tuesday will be found generally in the 50s,
maybe a few readings around 60F. With the trough still hanging
around we still can`t completely eliminate the potential for a
passing shower. Mainly low end chances 15%-40% with most locales
seeing mainly dry weather.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
An amplified pattern this week across North America, with a stout
upper level ridge slowly pushing a cool, downstream trough from
southern Canada/Great Lakes region out to sea.

Under this trough a mix of daytime instability showers and lake
effect showers will be common Wednesday. Temperatures around 0C at
850 hPa will support the lake effect precipitation, and also keep
much of the region in the 50s for daytime highs through Thursday.

As this trough and its associated moisture exits, clearing skies
will allow for chilly temperatures for both Thursday and Friday
mornings with increasing frost potential depending upon cloud
clearing.

Surface high pressure will slide towards our region next Saturday,
though the ECMWF and its ensembles maintain more of a zonal flow
aloft with some cloud cover.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR conditions with light winds will remain in place through
early Sunday morning.

While VFR weather will persist through early Sunday afternoon...
winds will significantly freshen ahead of an approaching strong
cold front. Southerly winds could gust to 30 knots. By mid to
late afternoon...a line of showers and strong to severe
thunderstorms will start to push across the western counties of
the state. This convection could be accompanied by short periods
of MVFR conditions.

Outlook...

Sunday night...VFR to MVFR with early evening showers and
thunderstorms giving way to just scattered nuisance showers
late.
Monday through Wednesday...VFR/MVFR with a chance of showers...
especially east/southeast of the lakes.
Thursday...Mainly VFR.

&&

.MARINE...
High pressure moving through the lower Great Lakes will maintain
quiet weather on Lake Erie and Lake Ontario through tonight.

A warm front followed by a much stronger cold front will move
through the region Sunday and Sunday evening respectively. South
winds will increase 15-20 knots  behind the initial warm front,
directing much of the higher wave action offshore. The cold front
will then shift winds to the west-northwest by Sunday night, likely
resulting in a period of SCA conditions into Monday for Lake Erie,
and Monday night for Lake Ontario.

&&

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

&&

$$

SYNOPSIS...RSH
NEAR TERM...TMA
SHORT TERM...AR
LONG TERM...Thomas
AVIATION...RSH
MARINE...PP/TMA