558
FXUS61 KBUF 111741
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
141 PM EDT Sat May 11 2024

.SYNOPSIS...
A weak area of low pressure will slowly cross our region tonight...
and this will result in widespread showers and possibly a few
evening thunderstorms. The precipitation will gradually taper off
during the day Sunday...as weak high pressure will nose into the
area. While warmer weather will move in for Monday...it will also
once again become unsettled with increasingly widespread showers and
thunderstorms that will persist into Tuesday.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
Conditions will deteriorate during the remainder of the
afternoon across the western counties...as a robust shortwave and
attendant sfc low will dive southeast across the Upper Great Lakes.
A swath of deep moisture ahead of this system will push across the
western counties before moving across the Eastern Lake Ontario
region tonight. The resulting lift supplied by moderate hgt falls...
low level convergence and being in the proximity of the left front
quad of a nominal 90kt H25 jet with this scenario will prompt a
renewal in shower activity.

The weak low pressure will then slowly push across the forecast area
tonight. While the bulk of the associated showers and isolated
thunderstorms will be found along and immediately ahead of an
attendant occlusion in the area of strongest low level convergence...
the pcpn will tend to broaden out during the course of the night.
By the time we work past midnight...the showers will tend to
give way to areas of light rain and drizzle...mainly under the
stacked low itself. Rainfall amounts will generally range from a
tenth to a quarter inch...although localized amounts of a half
inch will be possible in the vcnty of any evening thunderstorm.

The stacked low will further weaken on Sunday with its mid level
support briefly `opening up` enough to allow the system to exit
across New England. Meanwhile...a low amplitude shortwave ridge will
build across Lower Michigan to southern Ontario in its wake. Drying
in the mid levels will accompany the associated subsidence so that
the pcpn will completely end from west to east with enough clearing
to allow for some afternoon sunshine and a decent ending to the
weekend.

A warm front will work its way northeastward across our forecast
area Sunday night. While this should only result in an increase in
cloud cover...there will be the chance for some showers over the IAG
Frontier and possibly the Thousand Islands region by daybreak.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Very active weather during this time frame with periods of showers
and also chances of thunderstorms.

The mid-level low spinning near James Bay will direct a cold front
towards the eastern Great Lakes Monday morning with increasing
chances for showers. There will also be some thunderstorms with this
boundary, especially as diurnal instability increases in the
afternoon. That said...another mid-level low over eastern Kansas
will begin to advance east towards the Mississippi river valley
by late Monday afternoon. As it does so...it is advertised to
interact with the front over our region. There is some indication
that it will nudge the front back north as a warm front. This would
place us again back in the warm sector with a brief period of
decreasing showers and storms by Monday night. However...it does not
appear to last very long as the eastward advancing low draws the
front back south by Tuesday with accompanying deeper moisture. We
should see our fair share of showers Tuesday but there is some level
of uncertainty as the southern stream low begins to tracks into the
mid-Atlantic region.

Tuesday night...the speed and track of the low will determine
weather we continue to see wet weather areawide or a slow but
gradual drying trend.

Overall...near to a tad bit above normal max temps with highs in the
upper 60s to low 70s. Lows will generally be found in the 50s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A weakening mid-level low centered over the northern Quebec
Wednesday morning will continue to pull northeast into the Canadian
Maritimes by Thursday morning. Meanwhile, ridging to the west across
the Upper Midwest and western Great Lakes Wednesday will build
across the remainder of the Great Lakes into Thursday night before
the next trough dives southeast across the Central Plains Thursday
night into the start of the weekend.

With weakened low and associated mid-level trough overhead overhead
of the area Wednesday, rain showers associated with the cold front
the crossed the area Tuesday, will gradually end from northwest to
southeast Wednesday.

As the aforementioned mid-level ridging pushes east across the Great
Lakes, associated surface high pressure will also move into the
eastern Great Lakes. This will result in a period of dry weather
Wednesday night thorugh much of Thursday.

The next chance for showers will return Friday and last into the
start of the weekend as warm front pushes across the area. Model
guidance this far out remains differed with the placement and track
of the upper level features and low level features. Therefore, kept
rain shower chances on the lower end due to the lack in confidence.

Expect a gradual warming trend throughout much of next week, with
subtle warming each day. By the end of the week the temperatures
will have rebounded to slightly above normal.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR conditions early this afternoon will give way to deteriorating
weather...as a stacked area of low pressure will approach from Lower
Michigan.

A swath of showers and possible thunderstorms ahead of this system
will work across the far western counties during the remainder of
the afternoon and evening before the main area of pcpn will move
across the Eastern Lake Ontario region later tonight. The pcpn will
be accompanied by cigs that will lower to MVFR levels...mainly after
nightfall when IFR cigs will become common for most areas south of
KBUF and KROC.

MVFR cigs over the region Sunday morning will then slowly improve to
VFR levels during the course of the midday.

Outlook...

Monday and Tuesday...VFR/MVFR with the likelihood for showers and
thunderstorms.
Wednesday...Improving conditions with precipitation exiting.
Thursday...VFR weather.

&&

.MARINE...
Mainly light, variable winds (less than 10 knots) will be the rule
through the most of the weekend, before a more pronounced
southwesterly flow (10-15 knots) develops ahead of a warm front
approaching from the west toward the tail end of the weekend.

&&

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

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...AR
LONG TERM...EAJ
AVIATION...RSH
MARINE...JM/TMA