Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Buffalo New York
455 am EDT sun Aug 25 2019
high pressure will ridge across the region today and then
slowly move off New England through Monday. This will provide a
dry pattern which will last through Monday night. It will be
warmer and chances for rain will increase ahead of a cold front
which will move across the region early on Wednesday.
Near term /through tonight/...
high pressure will continue to ridge across today. Nighttime
microphysics satellite imagery shows mainly clear skies early
this morning, with some fog developing across the southern tier
and Black River valleys. This patchy fog will last until around
daybreak then dissipate by mid-morning.
Otherwise, today will start off mostly sunny, but clouds will
develop mid to late morning with fairly cool air aloft and ample
boundary layer moisture. Unlike yesterday, the flow aloft will
be more east-southeast which will limit lake moisture contribution and lead
to more patchy cloud cover which will mix out more quickly late this
afternoon. At least it should be sunny over the lakes. By the
end of the day, some cirrus should start to move in from the SW,
but it should be rather thin.
Meanwhile, temperatures aloft have bottomed out, and will be on the
rise today (and into next week). Expect highs today to average
in the lower to mid 70s today.
The surface high will drift into New England tonight, and this
will maintain fair weather tonight. A weak southeasterly flow
will develop tonight, and this will limit but probably not
entirely prevent fog from developing tonight. Slightly warmer
air aloft and the light flow will lead to slightly warmer
temperatures with lows mainly in the 50s.
Short term /Monday through Wednesday/...
high pressure will remain nearly stationary across northern New
England and the Canadian Maritimes Monday. This will provide one
more pleasant day with comfortable temperatures and humidity levels.
Highs will be in the mid to upper 70s, with some low 70s across the
A warm front will approach from the west Monday night then cross the
area on Tuesday, as high pressure retreats eastward off the New
England coast. Expect the majority of the area to remain dry on
Monday night, however strengthening warm advection on the nose of 30-
35kt low level jet across western New York Tuesday morning will bring the
chance for some showers to The Finger lakes and points west. The
best warm advection and upper dynamics will remain across western New York
as the warm front finishes pushing northeast of the area Tuesday
afternoon. This should keep most of the shower activity confined to
the western half of Lake Ontario and points south (remaining dry
across Eastern Lake Ontario region), before tapering off later in
the afternoon as the front moves north into southern Ontario. This
should leave behind a brief period of dry weather for the entire
area in its' wake late Tuesday, before a cold front draped across
the central Great Lakes approaches for Tuesday night. Another night
with comfortable temperatures and humidity levels in store, with
lows Monday night ranging from the upper 40s to lower 50s across the
higher terrain, to the mid and upper 50s elsewhere. High
temperatures on Tuesday will be similar to Monday, however there
will be a noticeable uptick in the humidity, especially across
western NY, as dew points rise into the mid 60s.
The cold front will move into western New York by late Tuesday night, then
slowly move east across the remainder of the forecast area during
the day Wednesday. Main threat with this front appears to be a
period of heavy rain just ahead of the boundary with precipitable water values
rising to 1.75-2.00" within a ribbon of deep moisture pooling just
ahead of the cold front on the leading edge of 30-40kt low level
jet. Will keep just the chance for thunder in the forecast as
instability along the front is marginal. Deep southerly flow
combined with increased cloud cover will keep low temperatures
across most areas in the 60s Tuesday night, with some upper 50s
across the higher terrain east of Lake Ontario. Highs on Wednesday
will be in the mid to upper 70s for most areas, with some low 70s
across the higher terrain.
Long term /Wednesday night through Saturday/...
behind this front a cooler airmass will flow over the region. Under
an upper level trough, steep mid level lapse rates and lingering
moisture will allow skies to become mostly cloudy through the
afternoon. As the cold air deepens, with 850 hpa temperatures
falling into the upper single digits celsius there may be some lake
enhanced rain showers later Wednesday night and through Thursday
night. Will have low chance pops near the lakes for this activity,
as it may not be cold enough/unstable enough to encourage a more
widespread lake effect rain event.
Another weak cold front will cross our region Friday night. Better
lift will be found along Lake Ontario and points eastward. This will
return a chance for rain showers to close out the week.
Temperatures will not stray much from normal...with highs in the 70s
and lows in the mid to upper 50s through this period.
Aviation /09z Sunday through Thursday/...
high pressure will dominate with mainly VFR flight conditions
and light winds through the 06z taf cycle. The only real concern
is the potenial for radiation fog, which will develop across the
southern tier and Black River valley. This will be patchy with
variable conditions and lower visibility possible at kjhw and
kart. Expect kbuf/kiag/kroc to remain fog-free with a light
Otherwise, diurnal cumulus will develop mid to late morning,
but cloud bases should be around 4k ft and in the VFR flight
category. These clouds will dissipate late afternoon with
widespread VFR conditions through this evening.
Monday...mainly VFR with nothing more than southern tier valley
fog producing local IFR conditions.
Monday night and Tuesday...mainly VFR.
Tuesday night through Thursday...VFR with some short periods of MVFR
from showers and thunderstorms.
relatively light and variable winds with corresponding light wave
action are expected into Monday as surface high pressure moves
slowly east across the region.