Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
503 am EDT Tuesday Jul 28 2015
high pressure will remain across the region with warm and humid
conditions through midweek. The next front will bring a chance of
precipitation by Wednesday night and Thursday. Seasonable conditions
return for the end of the work week into the weekend.
Near term /through tonight/...
high pressure centered over over the eastern Great Lakes region will
bring another day of dry...very warm and humid weather today.
Temperatures remain mild early this morning providing a good
launching pad for very warm temperatures this afternoon. Light winds
and clear skies will again support River Valley fog across the
southern tier and into the southern Finger Lakes later this morning.
The big story today is with very warm temperatures rising a couple
degrees warmer what we saw yesterday in most locations as 850 mb
temperatures edge toward +20c. This pool of warm air aloft will mix
down this afternoon and support widespread surface temperatures in
the upper 80s with many sites across the Lake Ontario lake plain
recording 90 or better including Buffalo and Rochester. While 90
degrees has already been reached in Rochester this year...today
could be the first time since July 2013 for Buffalo to reach 90. The
humidity will remain in place with dewpoints holding in the lower to
middle 60s. Expect sunny skies with high pressure and subsidence
remaining in control... the only exception will be some scattered cumulus
forming over the higher terrain of the inland southern tier in the
Tonight...the center of the surface high and middle-level ridging will
shift overhead. This will allow another clear night with light winds
and mild temperatures only sliding back into the 60s again. This set
up will again support River Valley fog across the southern tier.
Short term /Wednesday through Thursday night/...
surface/mid-level ridging will crest across the lower Great Lakes on
Wednesday...continuing the sunny and hot weather for one more day as
highs climb into the upper 80s to lower 90s. Light synoptic flow
should allow for the development of lake breezes that will provide
some nominal relief near the lakeshores where highs will run in the
low to middle 80s. Warm and moist air will surge northwards across the
region ahead of an approaching cold frontal boundary...making for a
sultry night across western and north-central New York with
temperatures along the lake plains only falling into the lower 70s
with middle to upper 60s across the higher elevations.
The aforementioned frontal boundary will cross the forecast area
during the morning and early afternoon hours on Thursday. The timing
of the frontal passage and lack of strong upper level support should
keep convection along the front sporadic as it moves through western
New York...though convection may become a little more widespread
across the far eastern portions of the forecast area as the front
should have a little more in the way of diurnal heating/instability
to tap into by the time it reaches the area early Thursday afternoon.
Cooler and drier air will advect across the region in the wake of
the front...providing for a sunny end to the day for most areas. The
fair weather will last through the end of the period as surface
based ridging builds across the lower Great Lakes. Temperatures will
represent the more moderate airmass with highs in the upper 70s to
lower 80s and lows in the low to middle 60s near the lakes with cooler
readings dipping into the upper 50s across the higher terrain of the
southern tier and the Tug Hill plateau.
Long term /Friday through Monday/...
a large upper level low will remain in the vicinity of Hudson Bay
through the period...maintaining low amplitude troughing across the
Great Lakes. While a series of weak shortwaves moving through this
flow may provide the impetus for the development of a few afternoon
showers and perhaps an isolated thunderstorm...the timing of these
features is ambiguous at best and at any rate with prevailing
westerly flow keeping available moisture limited...am not confident
we will see much if any widespread convection through the weekend.
At any rate...with weak surface ridging in place...there should be a
decent amount of sunshine to be had.
The GFS is indicating a potential for more robust convective
activity Sunday night through Monday night as it attempts to dig the
Hudson Bay low south across Ontario...however would like to see this
trend continue for a few more runs before buying into it. Thus for
now will stick close to continuity...maintaining low end chance probability of precipitation
through the period. With the broad troughing in place across the
region...temperatures will run close to average through the weekend
with highs in the upper 70s and lower 80s. With flow backing more
southwesterly on Monday...we may see readings begin to climb back
towards the mid-80s. Likewise...lows will run close to average with
low to middle 60s near the lakes cooling to upper 50s/lower 60s across
higher elevations of the southern tier and north country.
Aviation /09z Tuesday through Saturday/...
high pressure and light winds will keep VFR conditions through today
and tonight with the only exception in the southern tier where
MVFR/IFR River Valley fog is again expected to form later this
morning and again late tonight.
Wednesday night and Thursday...mainly VFR with a chance of
showers and thunderstorms.
winds and waves will remain light as high pressure remains in place
through midweek. An approaching cold front will bring the threat of
showers/thunderstorms Wednesday night/Thursday but winds and waves
should continue to remain light away from storms.