688
FXUS61 KBUF 071406
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1006 AM EDT Tue May 7 2024

.SYNOPSIS...
High pressure will bring abundant sunshine today, with temperatures
quickly warming after a cool start. A warm front will then 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/...
High pressure will move from Ontario and Quebec east across New
England today. Full sunshine will prevail most of the day, with a
modest increase in high clouds later this afternoon. Temperatures
will quickly warm today after the cool start, with highs in the
low to mid 70s in most areas. A light northeast flow will keep
the south shore of Lake Ontario much cooler.

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. Expect an arrival time of late evening in far
Western NY, around or 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.

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. The warm frontal showers will
largely end by mid to late morning east of Lake Ontario. A strong
mid level shortwave will then move across southern Ontario in the
afternoon, crossing northern NY during the late afternoon and early
evening. Diurnal instability will increase by this time, aided by
steep mid level lapse rates within a remnant EML plume crossing the
Ohio Valley into PA and portions of NY. The increase in large scale
forcing and instability will support another round of scattered
showers and thunderstorms east of Lake Ontario later Wednesday
afternoon and evening. A few of these storms may contain gusty winds
and small hail, with a Marginal Risk of an isolated severe storm or
two per the SPC Day 2 outlook.

Farther west, Wednesday will stay mostly dry from Western NY into
the Genesee Valley. A relatively dry and capped warm sector will be
difficult to overcome for any deep moist convection that attempts to
develop. In addition, a gusty WSW breeze will develop off Lake Erie,
with a stable lake shadow expanding inland during the afternoon. The
best chance of a few isolated showers will be along the northern
edge of the stable flow off Lake Erie, from the Niagara Peninsula
east across the Niagara Frontier to areas along the south shore of
Lake Ontario.

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.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A weak area of low pressure will be east of the forecast area
Wednesday night. Isolated showers will persist east of Lake Ontario
Wednesday evening before tapering off after midnight. Dry conditions
are expected across the remained of the forecast area. Mostly
cloudy conditions with low temperatures in the upper 40s to low 50s.

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 MONDAY/...
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 /14Z TUESDAY THROUGH SATURDAY/...
High pressure will drift east across Ontario and Quebec today,
reaching New England by late afternoon. VFR will prevail areawide
with clear skies and light winds.

Tonight, a warm front will move quickly northeast across the eastern
Great Lakes. Expect an area of showers and possibly some embedded
thunder to cross the area from southwest to northeast overnight.
Expect the rain to reach Western NY around midnight, then move to
the eastern Lake Ontario region by daybreak. 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.

Outlook...

Wednesday...Areas of MVFR/IFR CIGS in the morning, improving to
mainly VFR in the afternoon. A chance of showers and thunderstorms,
mainly east of Lake Ontario.

Thursday...VFR/MVFR. Showers likely with a chance of thunderstorms.

Friday...MVFR. Showers likely.

Saturday...Mainly VFR. A slight chance of showers.

&&

.MARINE...
High pressure will drift east across New England and weaken today.
Winds will be light for most of the area. 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...Hitchcock
NEAR TERM...Apffel/Hitchcock
SHORT TERM...HSK
LONG TERM...HSK
AVIATION...Hitchcock
MARINE...Hitchcock