176
FXUS61 KBUF 220619
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
219 AM EDT Sun Sep 22 2024

.SYNOPSIS...
A narrow ridge of high pressure will bring a dry day for most areas,
with a mix of clouds and sunshine through yet another warm day. A
cold front will near the region late tonight and Monday, bringing
showers and an isolated rumble of thunder to again primarily Western
New York. As a warm front lifts across the region Tuesday night and
Wednesday more widespread rain showers will fall upon the entire
region.

&&

.NEAR TERM /THROUGH TONIGHT/...
This early morning clearing skies and light winds are allowing for
areas of fog and low stratus to develop, including the traditionally
foggier areas of the Southern Tier, but also portions of NW NYS. Fog
may be locally dense in the river valleys through around 8-9 am.

Morning fog and low stratus will erode, and contract back towards
Lake Ontario by mid morning, leaving a mix of sun and clouds for the
rest of the day with dry weather prevailing as a narrow ridge builds
across the eastern Great Lakes. A southeast flow through the day
will meet developing lake breeze boundaries, with perhaps a spot
shower for inland areas of Western New York. However most areas
should remain dry through the day. Temperatures will remain above
normal with most highs in the mid 70s to around 80.

Dry through the evening and much of the overnight hours. It will
remain warm with a light southerly flow ahead of a cold front that
will approach from the west. As moisture increases aloft, and a
shortwave trough reaches WNY, clusters of light showers ahead
of this cold front will move into far western locations late
tonight.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Monday, a weakening mid-level warm front and the nose of a
90-100kt 250mb jet rounding the base of the southern stream
trough will enter the eastern Great Lakes by early morning.
This will provide ample large scale lift to support a round of
scattered to widespread showers from west to east through the
day Monday. As the jet weakens and lifts northward, the
attendant surface low will slow to a crawl just west of the
forecast area, leaving the washed out frontal boundary stalled
over western NY. This should lower overall coverage and
intensity of showers/storms as they move towards the central
Finger Lakes and North Country. While more frequent breaks in
the precip should also be found across far western NY by Monday
afternoon, with the low just to the west cannot rule out
additional showers through Tuesday morning. Basin averaged
rainfall amounts through Monday night are expected to be between
0.1-0.25".

The next round of widespread showers and a few embedded
thunderstorms will then move through the region from southwest to
northeast late Tuesday afternoon through Tuesday night. With greater
upper level support from the poleward exit region of the southern
jet streak, this batch looks more impressive in regards to rainfall
potential than the one on Monday. Where exactly the heaviest
rainfall will occur remains uncertain, though additional
amounts of 0.5-1" across much of the area seems likely, with
locally higher totals plausible.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A northern stream trough will cross the Great Lakes through
Wednesday night as additional robust shortwave energy peels
northeastward from the upper level closed low over the southern
Plains/lower Mississippi Valley. This will cause the northern stream
trough to also slowly close off in the vicinity of New England by
Thursday night, then quickly shift off the East Coast and into the
western Atlantic by Saturday. Meanwhile, a strong ridge of high
pressure across the western CONUS will ride over the southern stream
closed low across the Upper Midwest.

Much of how this pattern ultimately evolves will hinge upon how the
northern/southern stream branches of the jet stream phase earlier in
the week, the details of which remain murky at this range. In
general, with the northern trough moving across the lakes, expect
unsettled weather with periods of rain and possibly a few
thunderstorms through at least Wednesday. The aforementioned ridge
cresting over the southern stream low should then bring a gradual
drying trend from west to east Wednesday night through early
Thursday night, though low-end chances (15-25%) for precip linger
through Saturday as there could be diurnal, wrap-around, or even
possibly some lake enhanced showers during this period. As the
details come into better focus however, could see much of this
period ultimately being dry.

As cooler air pooled within the northern stream low pulls away from
New England, areas mainly east of the Genesee Valley will see a
gradual, day-to-day warming trend through the end of the week. Temps
may be a touch on the cool side in these areas Wednesday/Thursday,
though will otherwise average near to a few degrees above normal
across the forecast area.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
For the 06Z TAFS the concern will be the formation and location of
fog through the first 6-9 hours of the TAF cycle. Expect fog in the
traditionally Southern Tier tonight, but also NW NYS, including KIAG
where low level moisture with clearing skies should allow for fog
and low stratus. This fog or low stratus will near KBUF from the
north but struggle to pass over the airfield with slightly drier
airmass overhead...due to a lack of recent rainfall.

Otherwise for the Genesee Valley and east of Lake Ontario mainly VFR
flight conditions today.

Light winds today will become more southeasterly this evening and
overnight. This, along with increasing clouds aloft will limit fog
formation tonight. Ahead of a cold front a few showers may near the
three far western TAF sites late tonight.

Outlook...

Monday through Thursday...VFR/MVFR with chance to likely showers and
a chance of thunderstorms at times.

&&

.MARINE...
Negligible wind and waves overnight as a weak ridge builds in.
Low pressure and a cold front will approach from the west late
Sunday night and Monday, with increasing south to southeast
winds on both lakes. This wind direction will once again keep
the greater wave action well offshore and in Canadian waters.

&&

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

&&

$$

SYNOPSIS...Thomas
NEAR TERM...Thomas
SHORT TERM...PP
LONG TERM...PP
AVIATION...Thomas
MARINE...Apffel/Hitchcock