764
FXUS61 KBUF 071118
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
618 AM EST Thu Nov 7 2024

.SYNOPSIS...
One last frontal segment will cross the region this morning, which
has resulted in a few showers southeast of the Saint Lawrence and
Lake Ontario. A stretch of dry cool weather will span from today
through Saturday as high pressure builds into the Great Lakes and
Ohio Valley. Low pressure will then cross the Great Lakes late
Sunday through Monday, supporting the next chance of rain.

&&

.NEAR TERM /THROUGH FRIDAY/...
Current nighttime microphysics satellite imagery this morning
depicts a strip of clouds across the county warning area along with
a few upslope showers across the northern portions of the eastern
Lake Ontario region. These clouds and showers area related to the
last frontal segment sliding southeast with the cold frontal zone
moving southeast into Pennsylvania. As this frontal segment slides
south colder air will usher in across the area, supporting a few
lake showers. However, much of the area will remain dry.

Surface high pressure to the west will slide east across the Lower
Great Lakes and Ohio Valley today, supporting dry air and
subsidence. Overall this will allow a northwest to southeast
clearing trend this afternoon.

Northwest flow of cooler air and associated lake effect and upslope
processes will continue to produce plenty of cloud cover overnight
through Thursday morning. Surface high pressure to the west of our
region will then begin to ridge into the central Great Lakes and
southern Ontario, with associated drier air and subsidence bringing
a northwest to southeast clearing trend in the afternoon.

High pressure centered over the Upper Great Lakes will support dry
weather to persist tonight into Friday. Meanwhile surface low
pressure sliding southeast across the Northeast Friday afternoon and
evening will allow for some wrap around moisture and support a few
showers across northeastern New York.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Shallow cold, moist air advection Friday night may continue a stray
rain shower east and southeast of Lake Ontario early in the night
before drying with an approaching area of high pressure begins to
deplete cloud cover. This clearing, along with diminishing winds
across western zones will allow for a chilly night. Farther to the
east there may be enough of a pressure gradient to maintain a light
northerly flow through the night, limiting good radiational cooling.

Surface high will crest across our region Saturday with mostly sunny
skies. Good radiational cooling conditions early to the east will
allow temperatures to quickly fall at night, but on the back side of
the surface high a light southerly flow will allow for overnight
lows to be a few degrees higher than the previous night.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The long term will become wet, at least through the first day or two
of the new work week. A trough and sfc low will track toward and
across the region Sunday through Monday. This will re-introduce
showers/rain from Sunday morning into Monday morning. This trough
will track east from the intermountain west where it currently is in
place. The trough and mid-level low will become cut off from the
northern stream jet over the central Rockies and then slowly track
northeast through the week and into the weekend as the southern
stream jet strengthens some and begins to push it northeast. Lee
cyclogenesis east of the Rockies will help to develop a sfc low
that will also track northeast through the week. An influx of
GOMEX moisture out ahead of the trough and sfc low will push
northeast out ahead of the system. As both the moisture and
system track northeast, showers will expand in coverage across
the mid- Mississippi and Ohio Valleys before continuing to track
northeast into the western & north central NY area. There is
some uncertainty among the guidance packages with how far north
the warm front and better forcing moves and its proximity to the
forecast area with the sfc low occluded at that point. This may
keep the heavier and steadier rain/showers just south of the
area and into PA. Widespread showers/rain should taper off
Monday morning behind the systems associated cold/occluded front
as it tracks across the area.

Behind the departing front and sfc low, some lake enhanced/effect
and upslope showers will be possible down wind of both lakes. This
will occur as temperatures aloft cool to the low single digits. As
of now, the airmass behind the front doesn`t look to cold, and with
the lake water sfc temperatures around 14c, the instability between
the 850 hPa to lake sfc layer may only promote a weak lake response.
A ridge building into the region fairly quickly may also help to
limit the response off of the lakes as well. Any lingering lake
showers should end by Tuesday afternoon.

This ridge will remain over our region Wednesday, with a tightening
pressure gradient between the ridge and a deepening surface low over
the Northern Plains providing for gusty south-southwest winds
through the day. Any rain with this upstream system should hold off
until after sunset Wednesday with a stout 500 hPa ridge axis over
our region.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
Overcast skies with low end VFR to high end MVFR CIGS currently
grace the forecast area. These clouds are due to a pair of weak cold
frontal segments early this morning. Additionally across the areas
east of Lake Ontario and south of Lake Ontario a few showers are
being reported, with lower CIGS.

Surface high pressure will build east into the region today causing
clouds to dissipate from northwest to southeast, supporting all TAF
sites to return to VFR, which will last through tonight.

Outlook...

Friday through Saturday...VFR.
Sunday...MVFR/IFR with showers.
Monday...MVFR with showers likely.

&&

.MARINE...
A weak cold frontal segment will finish crossing the Lower Great
Lakes this morning with winds veering to the northwest. Winds will
remain elevated near or a little over 15 knots at times, producing
choppy conditions on both lakes.

Another period of stronger westerly winds will develop tonight
through Friday,as the pressure gradient tightens across the Great
Lakes, producing solid Small Craft Advisory conditions on Lake Erie
and Lake Ontario.

&&

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

&&

$$

SYNOPSIS...EAJ
NEAR TERM...EAJ
SHORT TERM...Thomas
LONG TERM...SW/Thomas
AVIATION...EAJ
MARINE...EAJ/Hitchcock