902
FXUS61 KBUF 221950
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
350 PM EDT Sat Jun 22 2024

.SYNOPSIS...
Warm and humid weather will continue this weekend. An oscillating
frontal boundary will support showers and thunderstorms this
weekend with the risk of torrential downpours and severe weather.

&&

.NEAR TERM /THROUGH SUNDAY/...
A surface boundary was positioned just south of Lake Ontario this
afternoon. North of the boundary plenty of clouds along with
lingering scattered showers. South of the boundary within the warm
sector, dewpoints in the 70s and temperatures well into the 80s
with a few near 90 degree readings. SPC meso analysis showing
surface based CAPES have increased to over 2000 J/KG with
convection starting to fire along the Lake Erie lake breeze from
northwest Pennsylvania into the western southern Tier. Lastest
HRRR/HREF suggesting convection will continue to develop across
the Southern Tier before growing northeast into the Finger Lakes
through the rest of the afternoon. Shear profiles are less than
favorable, so think this activity stays below severe limits, but
will likely see tropical downpours along with some gusty winds
and perhaps some small hail.

Convection should die off this evening as diurnal instability wanes.
The surface boundary will gradually lift north tonight as a surface
low strengthens over the central Great lakes. This will place more
of the region within the warm sector. Some scattered showers may
continue close to the boundary over northern portions of the area.
Isolated convection is possible within the warm sector. Some
patchy fog may occur in areas which received rain during the
day. Overnight temperatures will be muggy and generally in the
lower to mid 70s, with some upper 60s across the Southern Tier
and east of Lake Ontario.

An active weather day is expected on Sunday, especially during the
afternoon. A potent upper shortwave and associated deepening surface
cyclone tracking from the central Great Lakes along the
international border. A pre-frontal trough will work into the
region early in the day ahead of the main of the cold front
which tracks into the region late in the day.

There may be two rounds of convection, first with the pre-frontal
trough and then ahead of the cold front later in the afternoon.
Surface instability will certainly be present with SBCAPES forecast
to be near 2000 J/KG. Shear profiles become increasingly favorable
with around 35 knots of flow at 850 mb and near 50 knots at 500
mb, with some turning with height allowing hodographs to
lengthen with time. SPC has maintained a Slight Risk for severe
storms for much of the area inland from the lakes. Main threat
looks to be damaging winds, with a lesser threat of large hail,
but with the lengthening hodographs could see an isolated
supercell. Heavy rain potential is there with high atmospheric
moisture content, but the convection should be progressive
making the flash flood threat more limited.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
A fairly fast quasi-zonal flow will be in place for the upcoming
work week, as the strong upper level ridge that brought the
oppressive heat and humidity to the region this past week is
suppressed over the southern half of the CONUS. Overall, there looks
to be bouts of comfortable temperatures along with periods of more
typical mid summer warmth ahead of a couple cold frontal
passages...one mid week and the second toward next weekend.
This will also translate to periods of dry time, with storm
chances ramping up along and ahead of the aforementioned frontal
boundaries. The details...

A few strong storms (gusty winds/heavy rain) will remain possible
into Sunday evening, mainly east of the Genesee Valley, as the lead
shortwave and accompanying surface cold front push into eastern NY.
However, a trailing shortwave will strengthen as it digs across the
central Great Lakes first half of Sunday night, then crosses the
lower Great Lakes later Sunday night and Monday. This will keep the
threat for at least scattered showers/isolated non-severe
thunderstorms in the forecast through the start of the new work
week. Likelihood for showers will be greatest east of Lake Ontario
closer to the better dynamics/lift and moisture associated with this
feature. Some gusty NW winds will also be possible on Monday as
boundary layer flow increases with the passage of the trough. There
is still some good news for those looking for a break from the
oppressive heat and humidity as a cooler and less humid airmass
moves into the region. Lows Sunday night will drop back into the
upper 50s to lower 60s for much of the area. Highs Monday will range
mainly from the upper 60s to mid 70s, with dew points dropping into
a more comfortable range, mainly in the mid to upper 50s.

High pressure is then slated to cross the area Monday night and
Tuesday bringing a brief period of well deserved quiet weather. A
comfortable Monday night with lows generally in the 50s, with some
low 60s closer to the lakeshores. Flow will then shift back to the
southwest on Tuesday as a return flow sets up on the back side of
the surface high as it slides southeast of the area. This will boost
high temperatures back into the low to mid 80s for the majority of
the region, although humidity levels will remain tolerable.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As mentioned above, the quasi-zonal flow will continue with a
similar weather pattern to the Short Term expected through this
period. The details...

A weak mid level ripple will move across the area Tuesday night,
while a low level warm frontal segment moves northeast across the
region. PWATs increase to near 1.5 inches, however lack of forcing,
not expecting much more then some scattered showers/isolated rumble
of thunder overnight.

Next round of more significant weather looks to be centered around
the Wednesday timeframe as showers and storms accompany the next
cold frontal passage. Way to early to get into severe weather probs,
but will need to be monitored. Timing/etc still a bit in question as
well. Of more certainty is the return of mid summer warmth and
humidity. Highs will be upper 70s to mid 80s, with dew points
climbing into the mid and upper 60s.

High pressure then looks to build in bringing another much more
refreshing airmass back into western and northcentral NY for the
latter part of the work week. This should result in mainly dry
weather Thursday and Friday with highs low to mid 70s Thursday, then
tacking on several degrees for Friday as airmass starts to modify
with surface high moving east of our area. Dew points in the 50s
will mean very tolerable humidity levels for late June.

Mid summer warmth and humidity along with shower/storm chances then
look to return as we head toward the first half of next weekend as
the next frontal system approaches from the west.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
A frontal boundary across northern portions of the area will waver
northward through tonight. While CIGS today north of the boundary
(KART) will be mainly MVFR, all other terminals will be VFR south of
the boundary. The main impact through this evening will be the
threat for convection, particularly across the western Southern
Tier into the Finger Lakes. Low confidence in overall coverage,
so left out of airfield forecasts, except for KJHW where the
proximity to the Lake Erie lake breeze places a bit more
confidence at that location for at least a VCTS mention.

Chances for showers and thunderstorms will continue tonight
inland from the lakes. Patchy fog is also possible where rain
occurred during the day, but low confidence where restrictions
will occur.

Outlook...

Sunday...VFR/MVFR. Showers and thunderstorms likely.
Monday...Mainly VFR. A chance for afternoon and evening
thunderstorms inland from the lakes.
Tuesday...Mainly VFR conditions.
Tuesday night and Wednesday...MVFR/VFR with a chance for showers and
thunderstorms.
Thursday...Mainly VFR.

&&

.MARINE...
Light winds and minimal wave action is expected to continue across
the lower lakes through tonight.

A cold front will approach the region Sunday with increasing
southwest winds which will likely bring a period of small craft
conditions, especially on the east end of Lake Erie. A round or two
of thunderstorms Sunday will bring the potential for locally strong
winds and waves.

Northerly flow behind the cold front will then bring continued
choppy conditions to the lakes through Monday. High pressure builds
in late Monday with diminishing winds and waves for Tuesday.

&&

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

&&

$$

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