-- Discussion containing changed information from previous version are highlighted. --
404
FXUS61 KBUF 080538
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
138 AM EDT Wed May 8 2024

.SYNOPSIS...
-- Changed Discussion --
A warm front will move across the area overnight, 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.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Regional radar shows showers and a few thunderstorms across southern
Ontario to eastern Lake Erie late tonight. A few light showers are
currently across the Niagara Frontier. While coverage of upstream
activity has become less widespread, there still remains the chance
for thunderstorms overnight. In particular, a thunderstorm just east
of Long Point Ontario will likely reach the Niagara Frontier
including Buffalo by 3AM. A brief period of heavy rain and lightning
are the main concerns with this storm.

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 warm sector will
impinge upon the warm front and enhance moisture transport and
isentropic upglide. Available forcing and moisture will continue to
support the idea of some showers and some embedded thunderstorms
moving from southwest to northeast across the area overnight,
however recent radar trends suggest that activity will be less
widespread especially across the western Southern Tier to the Finger
Lakes region overnight. Mesoanalysis depicts greater instability
further south, however there still remains some elevated instability
across the southern half of western NY. Showers and a few
thunderstorms remain possible across western NY overnight. Any
storms we do see could produce brief periods of heavy rain, but
they`ll be moving along quickly enough to prevent any real flooding
concerns.

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.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
The main challenge for this period will be periodic embeded
shortwaves and the positioning of the H850 thermal boundary.
This feature is advertised to set up near the eastern Great
Lakes, or even become draped across the region. This will impact
temperatures, shower activity, and even thunderstorm potential
through Friday. What is certain, it is looking `likely` that it
will be very unsettled through at least Friday. Given the
unsettled weather anticipated...it would be highly recommended
to have an umbrella handy through Friday. As was mentioned
temperatures will be impacted...we could find ourselves on the
cooler side of the thermal boundary with below normal
temperatures. This will result in highs on Thursday only in the
60s, and then a tad bit cooler Friday with a range of 50s. May
find a few spots in the low 60s.

Friday night...it looks like we will see a general decrease in
shower coverage but can`t completely rule out some showers
overnight.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A broad upper level trough will become nestled across much of the
Northeast through the weekend, and possibly will begin to retreat
early next week. This pattern will `likely` continue the theme of
unsettled weather (showers), and also cool conditions (slightly
below normal) across much of the region for this time of year.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
An area of showers and a few embedded thunderstorms resides across
southern Ontario and will enter western NY late tonight. While
coverage of upstream activity has become less widespread, there
still remains the chance for thunderstorms overnight. In particular,
a thunderstorm just east of Long Point Ontario will likely reach the
Niagara Frontier including Buffalo by 3AM. A brief period of IFR
conditions with heavy rain and lightning are the main concerns
with this storm. Prevailing VFR conditions will deteriorate to
MVFR/IFR into Wednesday morning as a warm front moves into the
region. The main concern will be lowering ceilings, however fog
may develop on Lake Erie and move onshore by 15z Wednesday.
Confidence is low to medium that the fog will reach KBUF before
winds ramp up Wednesday morning. Speaking of winds, low level
winds will ramp up prior to surface winds early Wednesday
morning. There is a low concern of low level wind shear, mainly
from KIAG, KBUF to KROC this morning. It will be short lived and
will be monitoring wind profiles.

Flight conditions will improve to VFR from west to east across the
region Wednesday. As mentioned above, winds will ramp up and
southwest winds 15-25kts with gusts up to 30kts are possible late
Wednesday morning through early Wednesday afternoon from KIAG to
KROC. Another round of showers and a few thunderstorms are possible
east-southeast of Lake Ontario Wednesday afternoon into the evening.
VFR conditions will become low-end VFR/high-end MVFR at KART during
this time.

Outlook...

Wednesday night...VFR/MVFR.

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

Saturday and Sunday...VFR/MVFR. A chance of showers.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
WSW winds will then increase late tonight and Wednesday. This will
particularly be the case across Lake Erie...where winds and wave
action will be sufficient to support Small Craft Advisories as
outlined below. Elsewhere choppy...but sub-advisory conditions can
be expected.

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.
-- End Changed Discussion --

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NY...None.
MARINE...Small Craft Advisory from 8 AM this morning to 8 PM EDT this
         evening for LEZ020.
         Small Craft Advisory from 5 AM early this morning to 11 PM
         EDT this evening for LEZ040-041.
-- End Changed Discussion --

&&

$$

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