533
FXUS61 KBUF 200106
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
906 PM EDT Fri Jul 19 2024

.SYNOPSIS...
Sprawling high pressure will remain across the Great Lakes through
Saturday. This will provide fair weather and comfortable conditions
through at least the first half of the weekend, then a weak moisture-
starved cold front will fall apart over our region on Sunday. Our
next chance for widespread shower activity will come Tuesday and
Wednesday of next week when mid summer humidity will return.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
High pressure will remain across the area through Saturday
evening, then a moisture starved cold front will approach from
the north late Saturday night.

Mainly clear skies tonight with just some patchy thin cirrus during
the second half of the night. Combined with light winds, this will
bring another night with good radiational cooling conditions. Some
patchy Southern Tier valley fog will develop again later tonight.
Lows will range through the 50s.

Expect an outstanding first half of the weekend with near
normal highs in the upper 70s to lower 80s and comfortable
humidity levels. Continued drying and some warmer air moving in
aloft on Saturday will greatly reduce the amount of diurnal cu
that forms along and inland of any lake breeze boundaries.
Otherwise, the northwestern fringe of deeper moisture associated
with low pressure moving through the Mid Atlantic will just
graze southcentral NY bringing increased cloud cover and
possibly a widely isolated shower as far northwest as
southeastern Allegany County during the afternoon.

A moisture-starved weakening cold frontal boundary may spark an
isolated shower across the Saint Lawrence Valley and far North
Country late Saturday night as it sags south across the Canadian
border into far northern NY. Dry weather will prevail elsewhere.
Lows will range from the mid 50s to low 60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A weak shortwave trough will traverse through the midlevel
longwave over northern Quebec Sunday, supporting a backdoor cold
front to slide southeast across the forecast region Sunday
afternoon. Along this front, clouds will gather within a ribbon
of deeper 850-700 hPa moisture, however despite this a few
spotty showers can`t be ruled out, especially across the Niagara
Frontier.

This front will then stall across New York State Monday. While the
area will remain mostly dry, a few afternoon showers will be
possible with the frontal boundary overhead. The better activity
Monday lies across the southeastern portions of the area from
Allegany County to the Finger Lakes.

Temperatures will be near to slightly above normal with the base of
a longwave trough over our region.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A weak broad, positively tilted trough will drop south from central
Canada into the Great Lakes region this week. This trough will allow
a gradual northward advection of GOMEX based moisture into the
Northeast.

Translating this pattern for the weather across the lower Great
Lakes, the increasingly unstable environment will allow for a return
to a much more unsettled pattern with chances for showers and
thunderstorms Tuesday through Thursday. In general, chances will be
highest across the interior in the afternoon hours each day when
diurnal heating is at its strongest, while diminishing overnight and
into the morning hours. PWATs near or exceeding 1.7" within this
increasingly humid airmass will allow for periods of heavy rain,
though there remains typical long range model discrepancies on how
exactly the trough across the East will evolve which limits
certainty in timing, placement and amounts.

Temperatures Tuesday will top out in the low to mid 80s in most
spots, while reaching the upper 70s and low 80s Wednesday and
Thursday though with increased humidity. Overnight lows with range
in the 60s each night.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Surface high pressure will remain across the region through Saturday
evening, resulting in predominantly VFR flight conditions.

Other than some patchy thin cirrus later tonight, expect mainly
clear skies and light winds through the overnight. This will likely
lead to the development of valley fog across the Southern Tier again
later tonight and may cause localized IFR conditions. This fog did
not make it into KJHW last night, and with continued drying and a
slightly warmer airmass in place overnight, will continue to keep it
out of the terminal later tonight. Otherwise, any valley fog mixes
out quickly Saturday morning with widespread VFR flight conditions
on Saturday with weak lake breeze circulations developing in the
afternoon.

Outlook...

Saturday night through Monday...VFR.

Tuesday and Wednesday...Mainly VFR/MVFR. Showers and thunderstorms
possible.

&&

.MARINE...
High pressure will remain across the Great Lakes through Saturday. A
weak cold front will wash out as it drops southward across the
eastern Great Lakes early Sunday. This will result in a weak
pressure gradient only supporting gentle to occasionally moderate
breezes and negligible waves through the weekend.

&&

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

&&

$$

SYNOPSIS...Apffel/RSH/TMA
NEAR TERM...JM
SHORT TERM...EAJ/Thomas
LONG TERM...EAJ/PP
AVIATION...JM
MARINE...Apffel