382
FXUS61 KBUF 040533
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
133 AM EDT Thu Jul 4 2024

.SYNOPSIS...
A weak cold front will drop to near the New York and Pennsylvania
State line today, with showers fading east of Lake Ontario this
morning, and an afternoon spot shower forming near the state
line. Otherwise today and tonight will feature dry, but still
very warm and humid conditions. Another system will bring more
showers and thunderstorms Friday night and Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Regional radars this morning display clusters of showers, primarily
east and southeast of Lake Ontario as a weak cold front drops
southward across our region.

Forecast profiles and SPC objective mesoanalysis shows moderate CAPE
and shear available, but very poor mid level lapse rates are proving
difficult to overcome as developing updrafts quickly weaken as they
encounter the unfavorable thermodynamics of the mid levels. PWAT
values are around 2" so any storms that develop will produce
brief/local downpours, but the progressive nature of the system and
disorganized nature of convection should prevent anything
problematic.

Otherwise...It will be a rather muggy night with lows in the upper
60s to low 70s and plenty of residual humidity.

Shower coverage will taper off late tonight into early Thursday
morning as the frontal boundary moves south and stalls across
Pennsylvania. Mainly dry weather will then persist through
Independence Day as the better moisture and forcing for precipitation
remains well to our south, but an isolated shower or thunderstorm
can`t be ruled out across the Southern Tier and southern Finer Lakes
region. With very little of an airmass change on the `cooler` side
of the boundary, expect another warm and humid day, though not
quite as oppressive. Highs will range in the low to mid 80s with
dewpoints still well into the 60s.

Mainly dry weather for Thursday night as weak surface high pressure
remains over the region. Light winds at the surface and aloft will
make any firework smoke slow to clear. Lows will again be warm,
ranging in the mid to upper 60s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
Potent southeasterly flow will encompass the area on Friday. This
flow will strengthen through the afternoon and evening hours,
eventually turning more southerly. Off the deck, consensus 850 hPa
temperatures surge toward +18 to +19C and momentum mixes through the
boundary layer below that level. This combined with southeasterly
flow, which relegates the lake influence to almost nil across the
majority of the area, should all for temperatures to skyrocket on
Friday. Highs should jump toward 90F, especially along the Lake Erie
shoreline, Buffalo area, and the Genesee Valley.

Friday`s warmth will be short-lived as the brisk southerly flow
comes in advance of a southwesterly low-level jet nose that nudges
into the area by Friday evening. This combined with a right entrance
of an upper jet streak and solid DPVA should work on the remaining
instability from the hot day on Friday to trigger widespread showers
and thunderstorms Friday evening in WNY that spread eastward
overnight.

Organized ascent slowly translates across the area into Saturday,
when the North Country should be the shower focus for the early half
of the day at least. The remainder of the area looks to largely move
into the mid-level dry slot of the system that will be occluding by
that juncture over the northern Lake Huron region. Thus, deep layer
dry advection and modest cold advection should at least temporarily
cut off rain chances from west to east as the afternoon ensues on
Saturday. Likewise, temperatures will be falling back in cold air
advection to a bit below normal across at least the western half of
the area.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Surface ridging and drier air moving in behind the cold frontal
passage gives fairly high confidence that the area will see dry
weather through Monday. Showers and thunderstorms return to the
forecast for the Tuesday through Wednesday period as a mid level
trough enters the region and a wave of low pressure tracks to our
north bringing a cold front through the region.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
For the 06Z TAFS mainly VFR flight conditions are found. There are a
few showers near KART, remaining here for the next few hours.
Ceilings may lower to MVFR for KART. Across Lake Erie satellite
imagery displays a deck of low stratus, that mesoscale modeling
expands northeastward within a light southwest wind and moisture
rich lower boundary layer. This would bring a scattered to broken
deck of low ceilings to KBUF, in a 10Z to 13Z window. Otherwise,
within this humid airmass some patches of fog or low ceilings may
develop...especially across the Southern Tier (KJHW).

A weak cold front will drop across the region this morning from
north to south, stalling near the State line this afternoon and
overnight...before fading. Any showers this afternoon and overnight
along the front will likely stay just south of KJHW - KELZ, with VFR
flight conditions across the TAF sites through tonight.

Winds will be weak tonight with high pressure extending across the
region.

Outlook...

Friday...Mainly VFR with increasing chances for showers and
thunderstorms.
Friday night...MVFR with showers and thunderstorms likely.
Saturday...Mainly VFR with decreasing chances for showers.
Sunday and Monday...VFR.

&&

.MARINE...
A weak cold front will cross the lower Great Lakes tonight with a
few rounds of showers and widely scattered thunderstorms. A
southwest breeze will persist ahead of this front, with a moderate
chop on the eastern nearshore waters through early tonight.

In the wake of the cold front...fair weather will return to the region
late tonight with subsiding southwest breezes.

Looking ahead to the Fourth of July...gentle to moderate winds will be
in place throughout the region. These winds will be from the
southwest on Lake Erie and primarily from the west on Lake Ontario,
becoming locally onshore in the afternoon. Winds will then shift out
of the east Friday, becoming southwesterly again by Saturday when
the another round of SCAs appears likely.

&&

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

&&

$$

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