340
FXUS61 KBUF 152041
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
441 PM EDT Wed May 15 2024

.SYNOPSIS...
Weak high pressure will build into the Lower Great Lakes which will
bring mainly dry weather later tonight and Thursday morning before a
frontal boundary brings rain back to the region Friday through
Saturday.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
A broad 500mb trough overhead will slide east into southern New
England tonight. This combined with diurnal heating and
instability will result in some showers and a few thunderstorms
this afternoon into this evening. These will mainly be focused
along and inland of a surface convergence boundary which will be
to the south of the lakes. The stabilizing influence of the northeast
flow across the Niagara Frontier and near the south shores of
the lakes will limit showers at these locations.

Showers will taper off later this evening and overnight, but
there still will be lots of low moisture, cloud cover, and fog.
The exact location of the fog is difficult to pin down, but it
should be more widespread than it was last night, and it could
be locally dense. The cloud cover will limit radiational
cooling tonight with lows in the mid 50s.

A diffuse area of surface pressure and a mid level ridge will build
into Western NY during Thursday. This will bring mainly dry weather
to the region, although there may be a few showers east of Lake
Ontario where there will be some instability and weaker ridging.
Temperatures will remain above normal, with highs in the upper 60s
to lower 70s. The ridge will strengthen Thursday night, providing
fair and rain free weather overnight.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A shortwave trough will ripple over a diminishing mid level ridge
this period, promoting more coverage area to showers and a few
thunderstorms, especially in the Friday night to Saturday timeframe.

Instability grows to around 500 to 750 J/KG of MUCAPE and this could
bring a few thunderstorms, mainly later on Friday into Friday
evening.

Just a lingering shower or isolated thunderstorm for the remainder
of Saturday behind the shortwave trough. If some clearing over Lake
Ontario develops, and a lake breeze boundary forms, could see a few
showers forming south of the Lake, in convergence with a general
light southeast synoptic flow.

Similar airmass this period, with 850 hPa temperatures between 10
and 12C through the afternoon will allow for low to mid 70s across
lower terrain, and around 70F for inland higher terrain.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
To begin this period a mid/upper level low will be off the Carolina
coastline, with weak ridging aloft over our region. Much of the
shower activity will remain to our south, leaving most of Sunday
through Tuesday dry with a fair amount of sunshine. A deeper
shortwave trough will cross the Plains and near our region
Wednesday. Increasing moisture in the southern flow, and warmth
aloft will increase instability, that along with lift ahead of the
incoming trough will greatly increase the chances for showers and
thunderstorms. Later Tuesday night and into Wednesday will be the
most favorable timeframe for showers and thunderstorms this period.

Temperatures several degrees above normal Sunday and Monday, will
become even more above normal ahead of the trough Tuesday
and Wednesday.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Stratus originating across Lake Ontario will expand as it pushes
south tonight. This is likely to lower cigs into the IFR flight
category, with areas of fog likely as well. Vsby in the fog is more
difficult to forecast, with a potential for locally dense fog even
though IFR is likely to be more common. The low moisture and fog
will dissipate during the morning hours with conditions improving to
mainly VFR by Thursday afternoon.

Outlook...

Thursday night...VFR.
Friday...VFR/MVFR. Showers like late.
Saturday...Areas of MVFR with showers likely.
Sunday...Mainly VFR with a chance of showers.
Monday...VFR.

&&

.MARINE...
Generally light winds will continue through the remainder of the
week. Northeast winds in the 10-12 knot range will produce mainly
light chop on Lakes Erie and Ontario through tonight. Otherwise,
light winds will return Thursday as weak high pressure builds over
the eastern Great Lakes. An offshore flow will then develop Thursday
night and Friday with gentle to moderate southeasterly breezes in
advance of the next system approaching from the west.

&&

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

&&

$$

SYNOPSIS...Apffel
NEAR TERM...Apffel
SHORT TERM...Thomas
LONG TERM...Thomas
AVIATION...Apffel
MARINE...Apffel