138
FXUS61 KBUF 191743
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
143 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 most of Saturday,
then a moisture starved cold front will approach from the north late
Saturday night. Visible satellite imagery shows a fair amount of
cumulus has developed inland of lake influences this afternoon.
These diurnal cumulus will dissipate tonight, leaving clear skies
and light winds. Good radiational cooling conditions, with some
patchy Southern Tier valley fog developing again tonight.

Slightly warmer aloft on Saturday, which should reduce the amount of
diurnal cloud cover for most areas.  The exception is across the
Upper Genesee River Valley where there will be a bit more
moisture and cloud cover. Near normal highs in the upper 70s to
lower 80s.

A weak frontal boundary may spark an isolated shower across the St.
Lawrence Valley late Saturday night, otherwise it`ll be rain-free.

&&

.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 /18Z FRIDAY THROUGH WEDNESDAY/...
Surface high pressure will remain across the region through
Saturday, resulting in predominantly VFR flight conditions. Diurnal
cumulus this afternoon will mainly have VFR bases around 4k
feet. These will dissipate tonight. Patchy valley fog will
develop again in the Southern Tier tonight, but it has not made
it into KJHW last night so will keep it out of the terminal
tonight. 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...Apffel
SHORT TERM...EAJ/Thomas
LONG TERM...EAJ/PP
AVIATION...Apffel
MARINE...Apffel