667
FXUS61 KBUF 130213
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1013 PM EDT Mon Aug 12 2024

.SYNOPSIS...
While a few showers will still be possible this
evening...expansive high pressure centered over the Mississippi
valley will build east to support generally fair dry weather
tonight through at least Wednesday night.
Meanwhile...temperatures this week will gradually increase back
to above normal late summer levels.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
Cloud and shower coverage are slowly diminishing this evening as a
trough tracks away from the area, and as temperatures aloft slowly
warm. Temperatures across the forecast area are in the upper 50s to
upper 60s.

An expansive area of high pressure will build across the Upper Great
Lakes tonight. While this will keep fair weather in place for much
of the region...a northwest flow of 10C H85 air will be JUST chilly
enough to encourage some lake effect strato-cu and possibly an
isolated shower or two between KROC and KSYR. It will be cool with
mins away from the lakes in the 50s.

The large sfc high will build across all of the Great Lakes region
Tuesday and Tuesday night...while ongoing subtle warm advection will
eliminate the morning instability over the lakes and minimize
diurnal instability inland during the midday and afternoon. The
result should be partly to mostly sunny skies Tuesday with a non
zero potential for showers...then mainly clear skies for Tuesday
night.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A strong ridge of high pressure will slowly build east across the
Great Lakes as upper level troughing remains anchored across New
England to the Canadian Maritimes this period. While mainly dry
weather is expected to prevail across the forecast area, a few
showers or thunderstorms can`t be ruled out. This will mainly be the
case across the North Country during peak heating in the afternoon
hours, in closer proximity to the eastern trough. Mid-range guidance
shows some light QPF further south across the Finger Lakes and even
the Southern Tier during this time, and while an isolated shower or
two is not completely out of the question, model soundings look very
dry and thus will lean towards a rain-free forecast at this point.

Temperatures this period will be a bit warmer than the previous few
days and average near to a couple of degrees above normal for mid
August. This will translate to daytime highs in the upper 70s to low
80s. Overnight lows will range from the mid 50s across the hilltops
to the low 60s across the Lake Plains Wednesday night, with Thursday
night being just a couple of degrees warmer.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
During this period the axis of large-scale, nearly vertically
stacked troughing will slowly make its way from the Upper
Mississippi Valley/Upper Great Lakes to Southern Ontario and the
Lower Great Lakes. While the medium range guidance continues to
exhibit some differences in the finer details of the evolution of
this trough...in general the various packages remain in good
agreement on the overall large-scale pattern. For our area...this
will result in increasingly unsettled and also more humid weather as
we push through this period...particularly from Saturday onward as
GOMEX-based moisture (PWATs of 1.5 to 2 inches) gets drawn northward
and wrapped into this system`s circulation.

Looking a little more closely at the forecast details...Friday will
be the best day of this period...with highs in the upper 70s to mid
80s and chances for scattered afternoon showers/isolated storms
across western New York as the front flank of the above system
begins to impinge upon our region. More numerous showers and
scattered storms then appear to be likely from Saturday through
Monday...with the periods of greatest coverage tied to the diurnal
heating cycle as well as the passage of shortwave impulses rotating
through the base of the larger-scale trough...with the latter still
extremely difficult to time at this distant vantage point. Owing to
the progressively more humid airmass...there`s also at least a low
chance that some of the showers and storms could pose a risk for
heavy rain and flooding at times...though the where and when of this
remain difficult to pin down given the usual uncertainty in the
finer-scale details this far out in time.

Otherwise...high temperatures should generally trend downward a bit
Saturday through Monday with the continued encroachment of the large-
scale trough and the increased cloud and convective coverage...
though this will be offset by warmer overnight lows such that
temperatures will average out near to slightly above normal.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Tonight into Tuesday morning, cool air within the overhead trough
will be enough to generate a weak lake response southeast of the
lakes. This should mostly result in stratocumulus with cigs in VFR
range, though MVFR to localized IFR will be possible across the
higher terrain areas. A few showers may move into the vicinity of
KROC late. Otherwise, some patchy fog will be possible in the
Southern Tier, possibly reaching KJHW by sunrise.

Tuesday night...Mainly VFR.

Wednesday through Thursday...Mainly VFR. Low chances for showers and
thunderstorms east of Lake Ontario.
Friday...Mainly VFR. Chance for showers late.
Saturday...Flight restrictions possible with showers and
thunderstorms likely.

&&

.MARINE...
High pressure will begin to build into the eastern Great Lakes
tonight. This will bring about lighter winds and wave action through
most of the remainder of the work week.

&&

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

&&

$$

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