965
FXUS61 KBUF 161831
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
231 PM EDT Thu May 16 2024

.SYNOPSIS...
A few slow moving showers east of Lake Ontario into the early
evening hours, otherwise our region will remain dry with above
normal temperatures through today and tonight. A poorly organized
cold front will bring more coverage area to showers for the eastern
Great Lakes region tomorrow and tomorrow night, with a few rumbles
of thunder also possible. Showers may linger Saturday before
drier air builds in from the north and returns partly sunny
skies.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
An area of low pressure continues to swirl south of Long Island this
afternoon, with visible satellite imagery displaying clouds in
general light east to west flow on the periphery of this low over
our region. Our region will remain partly to mostly cloudy through
the afternoon hours.

Instability is quite weak this afternoon and early evening, with
just a few hundred J/KG of MUCAPE, and low level lapse rates around
6.5 to 7.0 C/KM. With a capping inversion around 600 hPa east of
Lake Ontario any showers that form in this light flow will be slow
moving, but likely not to grow too tall. Will have just a chance for
showers in the forecast.

Any diurnal convective showers will quickly diminish this evening.
Light flow with weak ridging in the lower levels. Dewpoints a just a
touch lower tonight, and with minimal to no rainfall today fog
coverage should be less than in recent nights. Will have some fog in
the river valleys of the Southern Tier and Black River Valley.

The next system will be approaching our region later tonight. Winds
will veer to southeasterly through the night. Just a 20 knot LLJ so
downslope wind gusts will be minor. While the cold front with this
next system is ill defined at times, looking in the mid levels a
distinct 700/500 hPa shortwave trough will carry northeastward from
the Ohio Valley. Increase in moisture and lift ahead of this
shortwave will bring rain showers to our doorsteps tomorrow morning.

As this shortwave passes across our region tomorrow a band of
showers and embedded thunder will move from west to east across our
region. Better instability remains across WNY, but better lapse
rates quickly move towards the east. Will carry a chance for
thunderstorms, with likely convection across WNY tomorrow moving
into the eastern Lake Ontario region tomorrow evening. As daytime
instability wanes, the threat for thunder will also diminish, though
lingering troughiness aloft will maintain chances for showers
through the entire night.

Basin average rainfall Friday and Friday night will average a
tenth to a third of an inch. Any thunderstorm or heavier shower
does have the potential for localized higher amounts.

Lows tomorrow night will be a few degrees higher than tonight...due
to the southerly flow firmly entrenched for our region, and
lingering cloudiness. Highs on Friday will remain above normal in
the low to mid 70s.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
A mid level ridge will begin to increase in strength on Saturday,
but before it does, a few showers are likely to linger behind the
recent passage of a mid level shortwave, especially towards the
State line. A few hundred J/KG of MUCAPE across SW NYS will aid in
shower formation.

If clearing of the sky over Lake Ontario develops, and a lake breeze
boundary forms, could also see a few showers forming south of the
Lake, in convergence with a general light southeast synoptic flow.

Drier airmass from the north will bring partial clearing through the
afternoon. This drying trend from the north will bring a dry night
Saturday night.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
A low pressure system will start this period near the Carolina
coastline, with an upper level ridge building northeastward across
our region. Subsidence from this ridge should keep the Sunday
through Tuesday timeframe dry, with perhaps just an isolated shower
on a lake breeze boundary.

The southwesterly flow will steadily increase temperatures aloft at
850 hPa, such that at the surface most areas will see day to day
warming of a degree or two. Could see a fair amount of temperatures
in the low to mid 80s in the traditional warmer spots of our region
before clouds begin to thicken ahead of the next system Tuesday.

A more vigorous shortwave trough will drop across the Plains
Tuesday. The 12Z deterministic models display a fair amount of
agreement with this shortwave, with a line of showers and
thunderstorms passing across our region Wednesday. Both the ECMWF
and GFS bring a decent LLJ near our region, which depending upon
timing of the cold front, could allow for taller updrafts and
potential gustier winds at the surface.

Will keep Tuesday night on the warm side of guidance with the
southerly flow and increasing clouds. Could see a few temperatures
in the upper 70s again east of Lake Ontario before the cold front
passage Wednesday.

Cooler behind the front Thursday. A trailing secondary trough may
bring a shower or two to areas east of Lake Ontario Thursday,
otherwise WNY should be dry with dewpoints returning back into the
50s.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
For the 18Z TAFS a deck of MVFR and low end VFR ceiling heights are
found. There are some breaks, but these clouds will remain into the
evening hours. A few showers east of Lake Ontario, otherwise we
should remain dry through 12Z.

Dewpoints are a tad lower tonight, and even though light flow, fog
should not be as widespread as the previous night or two. Will have
a little valley fog, that may near KJHW...otherwise mainly VFR
tonight.

Tomorrow a weak cold front, and mid level shortwave will near the
region. MVFR ceiling heights in the Southern Tier tomorrow morning
will spread north and eastward through the day across WNY. Showers
will near KJHW/KBUF and KIAG between 15Z and 18Z...slowly working
their way eastward through the day. Weak flow aloft will keep wind
gusts to a minimum.

Outlook...

Friday night...A chance for showers, with patches of fog around.

Saturday...Areas of MVFR with a chance for showers.

Sunday through Tuesday...Mainly VFR. An isolated shower Tuesday on
Lake Erie lake breeze.

&&

.MARINE...
A weak pressure gradient will continue general light winds
through the remainder of the work week. A mainly offshore,
southeast, flow will develop tonight and increase a little on
Friday as a weak cold front crosses the Lake. Following the
passage of the weak cold front winds are not expected to
increase much, and in fact remain light through Tuesday morning.
The next system of note will be a cold front Wednesday, one that
has a bit more structure, and a deeper surface low...with the
increasing pressure gradient likely to bring a bit more wind
and waves to the Lakes.

&&

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

&&

$$

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