611
FXUS61 KBUF 301816
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
216 PM EDT Sun Jun 30 2024

.SYNOPSIS...
Notably less humid airmass will pour into the Lower Lakes today,
with a few showers possible this afternoon...especially east of Lake
Ontario. High pressure over the Upper Mississippi valley will then
build east tonight and overhead on Monday. This will guarantee near
perfect weather to start the week. The next chance of showers and
storms arrives Wednesday with the next cold front.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
Strong cold air advection behind the front is bringing in a
drier and much cooler airmass to the Lower Lakes. Dwpts have
already fallen into the 50s behind the front in many spots. As
advertised mercury levels are also dropping this afternoon.
This is something that is quite unusual during the warm
season...let alone for the end of June when the sun
angle/intensity is at its peak. Furthermore...we are seeing some
lake induced clouds this afternoon off Lake Erie. This
shouldn`t be much of a surprise given how cool the core aloft is
of +6C to +7C @ 850mb.

Otherwise...a few showers will be possible this afternoon but
nothing like we saw yesterday or last night.

Tonight...a secondary cold front will push south through our region
with some nuisance showers early on and mainly east of Lake Ontario.
Given northerly flow and a relatively warm Lake Ontario we will also
see a fair amount of cloudiness across our region. Cool night
expected with lows in the 40s to 50s.

High pressure over the Upper Great Lakes will make its way across
our region Monday during the afternoon and evening. Max temperatures
Monday will be within a few degrees of 70 with low humidity and wall
to wall sunshine. Little chance Monday night with quiet dry weather
as high pressure moves through the region. Lows will be found in the
upper 40s in the cooler locales to low to mid 50s elsewhere.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Sprawling Canadian high pressure will build directly across our
region Monday night before slowly making its way to the mid-Atlantic
coastline on Tuesday...while low-amplitude upper level ridging
builds in aloft. This will provide us with continued fair dry
weather for this 24-hour period...with mainly clear skies Monday
night giving way to some increase in some high clouds Tuesday.
With respect to temperatures...ideal conditions for radiational
cooling will allow Monday night`s lows to range from the mid-
upper 40s across the interior of the Southern Tier/North Country
to the lower to mid 50s elsewhere...then a developing southerly
return flow around the backside of the surface high will allow
highs to climb back into the upper 70s to lower 80s on Tuesday.
Meanwhile humidity levels will remain comfortable...with surface
dewpoints only inching up into the mid to upper 50s by later
Tuesday.

Tuesday night the surface ridge will slip a little further
offshore...while the next mid/upper level trough and surface low
pivots across Manitoba and Ontario Provinces. With our region firmly
embedded within the deepening/strengthening southerly flow in
between these two systems...it will be a much warmer night than the
preceding two...with readings generally ranging through the 60s.
Meanwhile humidity levels will remain tolerable...as surface Td`s
will linger in the mid to upper 50s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Wednesday and Thursday the aforementioned trough and surface low
will continue to make their way to northeastern Quebec and
Labrador...and in the process will ease a weak trailing cool front
across our area Wednesday night and early Thursday.

Out ahead of this boundary heat will build on Wednesday...with 850
mb temps surging into the mid to upper teens...thereby supporting
highs climbing back to the 85-90 range in many areas. Humidity
levels will also be on the increase...with surface dewpoints
climbing into the mid-upper 60s and lending an increasingly muggy
feel to the afternoon. As the cool front impinges upon this sultry
airmass later Wednesday afternoon and evening...it will bring about
an increasing likelihood for convection...with this especially the
case during the late afternoon and evening hours. With continued
good model agreement on this scenario have bumped PoPs up a little
more from continuity...with this round of showers and storms still
appearing likely to pose a problem for any fireworks displays
scheduled for Wednesday evening.

Convection should then tend to diminish in coverage from northwest
to southeast later Wednesday night and Thursday as the passing cool
front slips off to our south and ushers in a slightly cooler and
less humid airmass...though still cannot completely rule out some
spottier showers and storms lingering into Thursday afternoon near
the NY/PA border. Otherwise slightly cooler highs in the lower to
mid 80s are expected for Independence Day...though humidity levels
will likely remain elevated.

Thursday night into Friday the weak cool front will stall out just
to our south as a convectively-enhanced shortwave ripples eastward
along this boundary...with the medium range guidance packages
continuing to exhibit some differences on its strength...track...and
timing...factors that will heavily influence the extent to which any
associated pcpn will spread back across our region during this 24-
hour period. Given the resultant uncertainty...will continue to
cover the passage of this feature with a mix of slight chance to
chance PoPs...with the highest values located along the NY/PA
border.

After that the medium range guidance is in loose agreement on
another mid-level shortwave trough and surface low/weak cold front
crossing our region in the Friday night-Saturday period...albeit
with the usual differences in its timing...strength...and track
common at this distant vantage point. With this in mind have
continued to broadbrush lower-end chances for showers and storms for
the end of this period.

As for temperatures for the end of the week...these look to be on
the warm side with daily highs in the lower-mid 80s and nightly lows
in the 60s...while humidity levels should remain elevated with
surface dewpoints remaining in the 60s.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Low VFR to MVFR cigs will be found across area terminals for much of
the day behind the cold front. A few showers will also be possible.

A secondary cold front will push through tonight. This will lead to
most areas experiencing MVFR cigs. That said...a few terminals
across the higher terrain might also see IFR cigs overnight.

Outlook...

Monday through Tuesday...VFR.
Wednesday...VFR/MVFR with showers and thunderstorms likely.
Thursday...Mainly VFR with a chance of a shower or thunderstorm
across the western Southern Tier.
Friday... Mainly VFR with a chance of a shower or thunderstorm.

&&

.MARINE...
Moderate to strong west to northwest winds behind the front is
producing small craft conditions on both lakes. Small craft
advisories have been put in place through all of this evening.

The fresh to strong westerlies will persist into tonight before
approaching high pressure encourages winds and waves to subside late
tonight and Monday.

Nearly ideal conditons for recreational boating can then be expected
for Monday and Tuesday...as high pressure will cross the region.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Beach Hazards Statement until 11 PM EDT this evening for
     NYZ002.
     Beach Hazards Statement until 2 AM EDT Monday for NYZ003>006.
     Beach Hazards Statement until 8 PM EDT this evening for NYZ007.
MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ040-
         041.
         Small Craft Advisory until 11 PM EDT this evening for
         LOZ042.
         Small Craft Advisory until 2 AM EDT Monday for LOZ043-044.
         Small Craft Advisory until 8 PM EDT this evening for
         LOZ045.

&&

$$

SYNOPSIS...
NEAR TERM...AR
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...AR
MARINE...AR