605
FXUS61 KBUF 181801
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
201 PM EDT Thu Jul 18 2024

.SYNOPSIS...
A much drier airmass will settle upon our region today and through
much of the weekend. A stray shower this afternoon east of the Lakes
as a secondary surface trough passes through the region, but no
widespread rain showers until the middle of next week when summer`s
humidity returns.

&&

.NEAR TERM /THROUGH SATURDAY/...
A mid level trough is across the Great Lakes region this afternoon.
Surface high pressure over the Corn Belt region extends into the
forecast area. Daytime heating and low level moisture below the
trough has allowed for cumulus clouds to develop. There is a low
chance (15-25%) that showers may form across the Niagara Frontier
and the North Country through the late afternoon hours.

The main mid-level trough axis will move east of the forecast area
tonight. Light winds and clearing skies will result in radiational
cooling tonight. Lows will reach the low to mid 50s with patchy fog.

High pressure will continue to build across the region Friday.
Daytime heating and low level moisture will result in cumulus cloud
development, however there should be less coverage than today,
Thursday. Highs will reach the mid to upper 70s across the region.
It will be another night of light winds and mostly clear skies, with
high clouds entering the forecast area into Saturday.

Troughing occurs across the Great Lakes Saturday. A southwest flow
in the mid-levels will bring increasing moisture and warm air across
the region. Dry conditions are expected with temperatures rising
back into the 80s across most of the region.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
Mid-level low pressure centered over the northern portions of the
providence of Quebec Saturday night will continue to deepen and
rotate eastward toward the Canadian Maritimes Sunday and Monday. At
the surface, high pressure overhead of the region will continue to
exit east toward the Atlantic coastline Saturday night, maintaining
dry weather.

A weak shortwave trough will traverse through the aforementioned
longwave pattern Sunday, supporting a backdoor cold front to slide
southeast across the forecast region Sunday afternoon. This front
continues to look moisture starved, 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.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
The longwave pattern across the CONUS will gradually shift moving
further into the new workweek. This will come as a deep closed low
slinks out of the Gulf of Alaska and towards the Pacific Northwest,
causing a deeper amplification of the ridging over the Desert
Southwest while downstream troughing remains over the Mississippi
Valley. Reinforcing shortwave energy will concurrently propagate
southeast out of central Canada and into the Great Lakes region,
resulting in a broad, positively tilted trough replacing the zonal
flow over much of the eastern half of the the Lower 48. This trough
will allow a gradual northward advection of GOMEX based moisture
into the Northeast.

In terms of how this will impact the sensible weather across the
eastern 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 THURSDAY THROUGH TUESDAY/...
VFR flight conditions are found across the region this afternoon.
Some congested cu has resulted in a bkn deck of 030-040 across the
Niagara Frontier and North Country. A stray shower is possible but
the chance is low (15-24%.)

Surface high pressure will build into the region tonight through
Saturday. Light winds and mostly clear skies will result in VFR
conditions through Saturday morning. Patchy fog is possible, mainly
across valley locations and may approach KJHW and KOLE overnight.
Confidence is low that it will reach the airports at this time.

Outlook...

Friday through Monday...VFR.
Tuesday...Showers and thunderstorms possible. Mainly VFR/MVFR.

&&

.MARINE...
High pressure over the Upper Mississippi valley this afternoon will
slowly settle across all of the Great Lakes region today and through
the weekend. There is a light northwest to north flow over the Lakes
this morning, with waves a foot or so on the southern and
southeastern shores of the lower Great Lakes.

This flow will become light and variable tonight, with waves under a
foot on the Lakes. The weak surface pressure gradient with the
surface high will bring gentle to moderate breezes and negligible
wave action through the weekend.

&&

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

&&

$$

SYNOPSIS...HSK/Thomas
NEAR TERM...HSK
SHORT TERM...EAJ
LONG TERM...PP
AVIATION...HSK
MARINE...HSK/Thomas