064
FXUS61 KBUF 091823
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
223 PM EDT Sun Jun 9 2024

.SYNOPSIS...
An upper level trough will move through the area, producing
widespread showers and scattered thunderstorms through early
evening. Scattered showers and cool temperatures will continue
tonight through Monday. High pressure will then build in, resulting
in a drying and warming trend through Thursday.

&&

.NEAR TERM /THROUGH MONDAY/...
Early this afternoon, showers and a few thunderstorms are
developing across the region. This is due to diurnal
instability, combined with a compact shortwave which is
rotating through longwave trough and dropping southward across
the region. Initially showers/storms are developing along a
convergence zone from the Niagara Frontier east across the
Genesee Valley and Northern Finger Lakes, and along a boundary
across the Saint Lawrence Valley. Mesoscale guidance in good
agreement showing the area of showers expanding and dropping
southward, following the progression of the shortwave.

Model agreement and upstream radar trends provide high
confidence in the development of showers which should have quite
a bit of areal coverage. These will hold off until closer to
sunset across the Southern Tier due to the north to south
movement. While severe thunderstorms are unlikely, low freezing
levels around 7k feet on the Buffalo 12Z sounding suggest a risk for
small hail with any thunderstorms. Gusty winds can`t completely be
ruled out either, but for the most part these won`t be much stronger
than the 25 to 35 mph winds outside of the storms.

Showers will decrease in coverage from northwest to southeast this
evening as the vorticity maxima moves southeast of the area.
Overnight, additional weaker shortwaves, deepening moisture, and
even some lake induced instability will support a few more scattered
showers, increasing in coverage towards Monday morning.

A cool northwest flow with 850mb temperatures falling to +3C on
Monday will result in the coolest day of the recent stretch of
unsettled weather. Highs will mainly be in the upper 50s to lower
60s. Cyclonic flow aloft will result in lots of cloud cover and
possibly a few showers although coverage will be limited.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As we move into Monday night any diurnally-driven shower activity
will fade out during the early evening with the loss of heating.
This same loss of diurnal influences and a continued sufficiently
cool (925 T`s lowering to around +6C) and moist cyclonic NW flow may
then support the development of some rare June lake effect/enhanced
showers southeast of Lake Ontario during the late evening and
overnight hours...though with some shear and a cap of only 3-5 kft
in place...any such activity will remain rather spotty and weak.
Otherwise a fair amount of lower clouds will linger...with the cool
airmass also supporting below average lows ranging from the lower-
mid 40s in our normal interior cool spots to around 50 near the
lakeshores.

On Tuesday surface-based ridging and drier air will build across our
region. Coupled with renewed diurnal influences...this will help to
bring about a quick demise to any spotty weak lake response
southeast of Lake Ontario during the morning. The incoming drier
airmass and daytime heating will also result in the lingering lower
clouds evolving into a SCT-BKN diurnal cumulus field...with the
coverage of the latter greatest inland from the lakeshores.
Otherwise it will be dry...with some gradual airmass modification
allowing highs to climb back into the mid to upper 60s...still below
normal for this time of year...but also not as cool as those of the
previous day.

The surface high will then crest directly across our region Tuesday
night...with its axis then only slowly drifting to a position just
to our southeast during Wednesday. This will result in fair dry
weather for this 24-hour period...along with partly cloudy to mainly
clear skies Tuesday night...and mostly sunny skies Wednesday. With
respect to temperatures...the overhead position of the surface ridge
will support good radiational cooling Tuesday night...allowing lows
to range from the mid 40s across the interior Southern Tier/North
Country to the lower 50s across the lake plains of western New York.
Warm advection/continued airmass modification will then allow highs
to finally climb back to normal or slightly above normal levels on
Wednesday...when most areas should see readings peak in the mid to
upper 70s.

Wednesday night the surface ridge will slide further east and off
the mid-Atlantic coastline...while a weak to modest shortwave trough
approaches our region from the northwest. Cannot rule out this
latter feature producing an isolated shower or two as it approaches
later Wednesday night...however conditions should remain largely
dry. With a deepening southwesterly flow of warmer air in place
between these two systems...lows Wednesday night will be much warmer
than those of the preceding three nights...with mins ranging from
the mid 50s across the interior to the lower 60s across the lake
plains of western New York.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A trough will deepen across the Great Lakes region as an upper level
ridge builds across the Rockies late in the work week. A strong,
southerly flow will promote warm weather Thursday through Friday. An
area of low pressure is expected to track across northern Ontario
and Quebec Thursday through Friday with a cold front impacting the
region during this time. There is low confidence in the timing of
the front, however this should bring a period of scattered showers
and thunderstorms. An area of high pressure is expected to move into
the region this weekend with medium confidence of dry, fair
weather.

Temperatures will be near to around five degrees above normal for
Thursday through the weekend.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
A mid level trough will move southeast across the area, and
combine with modest daytime instability and lake/terrain
generated low level convergence boundaries to generate another
area of showers and scattered thunderstorms crossing the area
from north to south. Expect areas of MVFR CIGS/VSBY to develop,
with local/brief IFR in thunderstorms. Thunderstorms may
produce some small hail.

The more organized showers and scattered thunderstorms will taper
off this evening, although a few scattered showers may linger
overnight. CIGS/VSBY should improve back to VFR initially in the
evening, but areas of MVFR CIGS will likely develop overnight in
stratus. This stratus will linger most of the day Monday, with
MVFR cigs lasting into the afternoon hours at most locations.

Outlook...

Monday night through Thursday...Mainly VFR.
Friday...VFR/MVFR. A chance of showers and thunderstorms.

&&

.MARINE...
Moderate westerly winds today, with another round of Small
Craft Advisory conditions on both lakes. Winds will decrease on
Lake Erie this evening, but Small Craft Advisory conditions will
continue much of tonight on Lake Ontario. Winds will be
somewhat lower Monday, but still expect choppy conditions on
both lakes.

More favorable winds and waves for boating will return by the middle
of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Beach Hazards Statement through Monday morning for NYZ004.
     Beach Hazards Statement through Monday morning for NYZ005>007.
     Beach Hazards Statement until 11 PM EDT this evening for
     NYZ010-019-085.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LEZ020.
         Small Craft Advisory until 11 PM EDT this evening for
         LEZ040-041.
         Small Craft Advisory until 5 AM EDT Monday for LOZ042.
         Small Craft Advisory until 11 AM EDT Monday for LOZ043>045.

&&

$$

SYNOPSIS...Apffel/Hitchcock
NEAR TERM...Apffel/Hitchcock
SHORT TERM...JJR
LONG TERM...HSK
AVIATION...Apffel/Hitchcock
MARINE...Apffel/Hitchcock