040
FXUS61 KBUF 160635
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
235 AM EDT Fri Aug 16 2024

.SYNOPSIS...
High pressure draped across New York State will slowly drift east to
New England through Friday. This will keep fair weather in place
through most of Friday...with just a chance of showers and
thunderstorms reaching far western New York later in the day. A
large...slow moving storm system will then track across the region
and bring periodic rounds of showers and scattered thunderstorms
Friday night through Monday...with locally heavy rainfall and a few
stronger storms possible over the weekend. Otherwise temperatures
will remain near to above normal through the weekend...before
falling below normal early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure draped across western New York will gradually drift
across central and eastern New York overnight...while a vertically
stacked storm system drops across the Upper Mississippi Valley. Some
high clouds well out ahead of this next system will continue to
spill across far western New York overnight...with fair dry weather
otherwise continuing. Radiational cooling may allow for some patchy
fog to develop within the Southern Tier river valleys and (to a
lesser extent) east of Lake Ontario overnight...with overnight lows
ranging from the mid 50s across the far interior of the Southern
Tier and Lewis County to the lower to mid 60s across the lake plains
of western New York.

On Friday the surface high will drift out across New England...while
the aforementioned...increasingly expansive storm system slowly
makes its way across the Upper Great Lakes. Out ahead of this system
broad upper level ridging will crest across our region during the
morning...before sliding east into eastern New York/western New
England during the afternoon. The combination of lingering plentiful
dry air and subsidence attendant to the upper level ridge should
help to keep our region dry through the midday to early afternoon
hours...with just a general west to east increase in mid and high
cloud cover that will be most pronounced west of the Genesee Valley.
As the upper ridge axis slides further east during the afternoon...
a continued increase in moisture out ahead of the approaching low
will result in mid and high cloud cover continuing to increase and
lower from west to east. Coupled with daytime heating and the
arrival of some weak lift on the eastern periphery of the low...this
may allow for some scattered showers and thunderstorms to develop
across far western New York during the late afternoon and early
evening hours...though coverage should remain on the limited side
through 22/23z. With respect to high temperatures...the warm airmass
out ahead of the low and a modest south to southeasterly low level
flow will allow for another warm day...with highs ranging from the
upper 70s to mid 80s across far western New York to the mid to upper
80s across much of the Finger Lakes and eastern Lake Ontario region.

Friday night the center of the large storm system will make its way
into northern Lower Michigan...and in the process will push its
attendant warm front into our region...with this latter feature
roughly making it to about the south shore of Lake Ontario by 12z
Saturday. This boundary will be accompanied by a surge of GOMEX-
based moisture attendant to a 30+ knot low southerly level jet that
will push precipitable water values up into the 1.5-2 inch range.
At the same time...isentropic upglide along/ahead of the warm
front...convergence at the nose of the low level jet...and a broadly
diffluent flow aloft will all help to lift this deepening moisture
and thereby lead to a round of showers and scattered thunderstorms
that will work across the area from west to east through the course
of the night. Given the quality of the forcing and moisture that
looks to be in place have raised PoPs into the categorical range...
with most of western New York likely to pick up a quarter to a half
inch of rain before the warm frontal pcpn begins to wind down across
far WNY late in the night. Otherwise it will be a notably warmer and
more humid night...with lows ranging from the low-mid 60s east of
Lake Ontario to the mid 60s to lower 70s elsewhere...and surface
dewpoints rising into the lower to mid 60s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The closed mid level low over the upper Great Lakes will
gradually move east across the Great Lakes this weekend and
become an open wave by late Sunday as it moves over the eastern
Great Lakes. A weak vertically stacked low beneath the
aforementioned mid-level feature will gradually move east across
the Great Lakes throughout this time as well. An abundance of
moisture will spill across the region as shown by PWAT values
ranging between 1.5 and 1.75 inches throughout the entirety of
the weekend. The combination of the moisture and the forcing
aloft will support showers Sunday and Sunday, with a chance for
some thunder as well. A few storms may become severe with the
primary threat being damaging winds and heavy rain. This being
said, there is a marginal risk for severe storms across much of
the forecast area Saturday and a marginal risk for excessive
rain both Saturday and Sunday.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Slow moving mid-level trough spread across the Atlantic Coast
Monday, will support weak secondary cyclogenesis along the New
England Coast. This will support chances for showers and
thunderstorms to pull east out of the area throughout the day
Monday. However, thunder chances will gradually wane from northwest
to southeast as a cooler and more stable airmass arrives behind a
slow approaching cold front.

The mid-level trough axis will pull east out of the forecast area
Monday night through Tuesday, supporting the plume of deeper
moisture to gradually move east off the coastline. This will support
a return of dry and seasonably cooler weather for the middle portion
of the next week.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
Expect fair dry weather to continue overnight...with just some
increase in high clouds across far western New York. Flight
conditions will be VFR...save for localized reductions in patchy fog
within the Southern Tier river valleys and east of Lake Ontario.

On Friday high pressure will slide off to our east...while the next
storm system drops across the Upper Great Lakes and spreads
increasing mid and high clouds across our area from west to east.
Later Friday afternoon and early Friday evening the above system
will get close enough to potentially trigger a few scattered showers
and thunderstorms across far western New York...with dry VFR weather
otherwise prevailing.

Our weather will then trend steadily downhill Friday night as the
center of the aforementioned low makes its way across northern Lower
Michigan and pushes its attendant warm front into our region. This
will result in a round of fairly widespread showers and scattered
thunderstorms making its way across our region from west to
east...with flight conditions lowering to lower-end VFR/MVFR across
the lower elevations and MVFR/IFR across the higher terrain as the
atmosphere moistens.

Outlook...

Saturday and Sunday...Occasional rounds of showers and scattered
thunderstorms with associated reductions to IFR/MVFR...and MVFR/VFR
otherwise.
Monday...MVFR/IFR ceilings with showers likely and a chance of
thunderstorms.
Tuesday...Improvement to VFR.

&&

.MARINE...
A modest southeasterly to southerly flow will develop overnight and
Friday as a warm front approaches the region, however wind speeds
should remain less than 15 knots. Right out ahead of the warm
front...southeasterlies may briefly freshen to 15 to 20 knots across
central and eastern portions of Lake Ontario later Friday night and
Saturday morning...however the offshore nature of the flow will
direct the bulk of any greater wave action across Canadian waters.
Following the warm frontal passage...a general south to southwest
flow will ensue over the weekend, though winds should again
generally remain below 15 knots.

Of greater concern to marine interests will be the potential for
scattered thunderstorms with locally higher winds and waves...with
this beginning Friday afternoon across Lake Erie and western Lake
Ontario, then spreading east across the rest of the region over the
weekend.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...JJR
MARINE...JJR