750
FXUS61 KBUF 071753
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
153 PM EDT Tue May 7 2024

.SYNOPSIS...
A warm front will move across the area tonight, with an area of
showers and a few thunderstorms crossing the area from
southwest to northeast. The showers will exit the eastern Lake
Ontario region Wednesday morning. Dry weather will then prevail
most of the time for the rest of Wednesday, although a few more
showers and thunderstorms are possible later in the afternoon
and evening, especially east of Lake Ontario. Unsettled weather
will then last Thursday through the weekend with a series of low
pressure systems crossing the region.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
High pressure across New England will maintain sunny skies most
of this afternoon. Visible satellite imagery shows high clouds
located just to our southwest and about to enter far western NY
late afternoon.

Tonight through early Wednesday morning a mid level trough will move
northeast across the Great Lakes, with an associated warm front
moving northeast across our area overnight. A 40+ knot southwesterly
low level jet in the upstream warm sector will impinge on the warm
front and enhance moisture transport and isentropic upglide. The
quality of forcing and moisture continue to support the idea of an
organized area of showers moving from southwest to northeast across
the area overnight. This area can be seen on radar as a semi-
broken line across Western Ohio early this afternoon. Model
guidance in good agreement bringing this into Western NY late
this evening, shortly after midnight for the Genesee Valley and
western Finger Lakes, and the pre-dawn hours east of Lake
Ontario. Forecast soundings show enough elevated instability to
support a few thunderstorms as well, especially during the first
half of the night. Storms may produce brief periods of heavy
rain, but they`ll be moving so flooding is not a concern.

Wednesday, the warm front will still be over the eastern Lake
Ontario region early in the morning with showers and a few isolated
thunderstorms. Rain will have already ended across Western NY as the
better forcing and moisture move east. It`ll be quite breezy
with wind gusts around 35 mph downwind of Lake Erie. This will
result in a lake shadow which should keep most of Western NY
rain free. The exception will be just south of Lake Ontario on
the northern fringe of the shadow where limited instability may
spark a few afternoon thunderstorms.

There may be a brief break in the showers east of Lake Ontario
late Wednesday morning, but chances there will increase again
when a strong mid level shortwave moves across southern Ontario.
The best chance for showers and thunderstorms will be along the
boundary which will be across northern Jefferson and Lewis
Counties. In addition, instability to the south of this will
feed into it, and potentially produce some stronger storms with
heavy rain. SPC just clips this area with its Marginal Risk in
the Day 2 Outlook.

Finally, an increasingly moist airmass crossing the cold lake waters
will likely produce marine layer fog late tonight through Wednesday
morning. Some of the Lake Erie fog will likely move onshore into
downtown Buffalo for a few hours Wednesday morning. Some of the Lake
Ontario fog may move onshore into Jefferson County as well.

A weak area of low pressure will be east of the forecast area
Wednesday night. The vast majority of the night will be rain-
free with only small chances for showers east of Lake Ontario
early and across the Western Southern Tier late.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
A shortwave trough across the Mid-Western states will approach
the region Thursday. A westerly flow aloft will become southerly
by late Thursday and moisture and warm air advection will
increase the chance for showers across the region. An associated
area of low pressure will move south of the forecast area
through Thursday night while the shortwave trough deepens across
the Northeast. While there is uncertainty in the track and
strength of this system, periods of showers are likely ahead of
this system Thursday into Thursday night. There is a slight
chance of thunderstorms during peak heating Thursday afternoon,
however confidence is low. Rainfall amounts will average
0.25-0.50 inches across the region Thursday through Thursday
night.

Temperatures will average slightly above normal Wednesday night and
Thursday night, however a northeast wind across the region Thursday
will keep high temperatures slightly below normal.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
An upper level trough will become nestled across the Great Lakes
region and Northeast through the weekend. This will bring unsettled
and cooler weather across the eastern Great Lakes region.

Initially, an area of low pressure should be departing to the east of
the region Friday. The 00z GFS/GEFS is an outlier at this point and
keeps the area of low pressure over to the region. Daytime heating
and cooler temperatures aloft will likely lead to showers developing
across the region Friday. Drier weather is expected Friday night
into Saturday as a ridge briefly moves into the region, however any
clearing and daytime heating may result in scattered showers
Saturday. The upper level trough will move overhead while the
surface low pressure approaches the region Sunday into Sunday night.
There are low to medium chances for showers to end the weekend. The
trough will move east of the region the start of the work week with
chances for showers lingering into Monday.

While confidence is low on the coverage and timing of showers Friday
through Monday, confidence is higher that it will be a period of
cooler weather across the eastern Great Lakes region. Temperatures
will average below normal with temperatures reaching near normal by
Monday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
High pressure across New England will maintain VFR flight
conditions through this evening. Tonight, a warm front will
move quickly northeast across the eastern Great Lakes. This will
bring about a three hour period of showers to most locations,
with a risk of some thunderstorms within this line. The rain
will be moving into a dry airmass, so expect mainly VFR
CIGS/VSBY initially. The low levels will saturate near the back
edge of the rain, with areas of MVFR/IFR CIGS expanding late
tonight. Patchy fog is possible behind the front, especially
northeast of the lakes at KBUF and KART. The stratus and fog
will dissipate mid to late morning, giving way to mainly VFR
flight conditions for the afternoon. The only exception is KART
where showers and thunderstorms will be possible along the
stalled boundary.

Outlook...

Wednesday night...Mainly VFR.

Thursday and Friday...Mainly MVFR. Showers likely and MVFR stratus.

Saturday and Sunday...VFR/MVFR. A chance of showers.

&&

.MARINE...
High pressure across New England will maintain generally light
winds this afternoon. The one exception will be the west end of
Lake Ontario, where ENE winds will increase this afternoon and
evening, producing choppy conditions on Lake Ontario west of
Rochester, but winds and waves are generally expected to remain
below Small Craft Advisory criteria.

WSW winds will increase Wednesday, especially on Lake Erie. This
will produce very choppy conditions Wednesday through Wednesday
evening, possibly near Small Craft Advisory criteria.

An increasingly moist airmass crossing the cold lake waters will
likely produce marine layer fog late tonight through Wednesday
morning on Lake Erie and Lake Ontario with visibility restrictions.

&&

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

&&

$$

SYNOPSIS...Apffel/Hitchcock
NEAR TERM...Apffel/Hitchcock
SHORT TERM...HSK
LONG TERM...HSK
AVIATION...Apffel
MARINE...Apffel/Hitchcock