Scientific Forecaster Discussion
fxus61 kbgm 231620
Area forecast discussion
National Weather Service Binghamton New York
1220 PM EDT Wed Oct 23 2019
a generally dry and breezy day is expected, though spotty lake
effect rain showers may occur at times north of the New York
thruway. Dry weather continues into Thursday as high pressure
passes to our south. A cold front will move through Friday with
a chance of showers. The weekend starts dry, but a low pressure
system will likely bring rain Saturday night through Sunday.
Near term /through Thursday/...
1215 PM update...
Mostly sunny skies is sending temperatures few degrees higher
than previously forecast this afternoon, so increased high
temperatures this at all locations. Diurnal cu will likely keep
some locations a bit cooler, but for the most part, widespread
high temperatures in the 60 degree range are expected.
915 am update...
Forecast remains mostly on-track this morning as valley fog is
dissipating quickly now that the sun is up. Did make some minor
adjustments to cloud cover, based on latest metsat imagery.
630 am update...
despite increasing flow just above the inversion, along with
cool/dry air advection, the quicker-than-expected eradication of
clouds allowed for valley fog to develop in a more typical
fashion for late October from the twin tiers southward as well
as even The Finger lakes. Which in this case, was more than
expected. In the immediate wake of a half inch to inch of rain,
perhaps this should not have been a surprise; the clearing sky
clinched it even with a decent pressure gradient. Fog is thus
still in the forecast for a few more hours until the sun can doe
its work to mix down the increased winds and dry air.
mainly dry weather is anticipated in the near term.
Delicate balance between lingering low level moisture from
recent rainfall, and incoming drier air plus winds, is yielding
temperamental patchy fog in the valleys of the southern tier of
New York through much of northeast Pennsylvania. Trend towards
dawn will be for fog coverage to decrease via mixing from dry
cool air advection and increasing winds.
The center of high pressure will be making its way through the
southern Appalachians to the midatlantic coast today through
tonight. There will remain a decent pressure gradient between
the high, and the front departing well to our east. This along
with cool air advection aloft will allow steeper lapse rates to
mix down westerly pressure gradient winds during diurnal heating
hours today. Sustained 10-15 mph, with gusts of 20-25 mph, can
be expected and perhaps a few gusts to around 30 mph at higher
elevations. This of course is nothing unusual for late October.
Highs will be mainly in the 50s; some lower elevations of
northeast Pennsylvania could reach 60 especially considering the
larger proportion of sunshine from the twin tiers southward
today. Meanwhile, temperatures at 850mb will be around
freezing; cold enough to perhaps touch off spotty lake effect
rain showers north of the New York thruway late afternoon-early
evening and at least some stratocumulus for other northern parts
of the area.
A mostly clear sky is expected tonight with lows in the mid 30s
to lower 40s. Winds will slacken while turning more southerly
One high pressure will brush by to our south Thursday, as
another approaches from the western Great Lakes. In between the
two, a very weak trough could bring some clouds mainly north of
the twin tiers and perhaps even an afternoon sprinkle north of
the New York thruway. Otherwise a good amount of sunshine is
anticipated. Southwesterly flow ahead of the trough will advect
in slightly warmer air to produce highs of upper 50s-mid 60s.
Short term /Thursday night through Saturday/...
400 am update...
Surface high pressure will be over the area Thursday night,
bringing mostly clear skies to start. With light winds patchy
valley fog could form. Mid and high level clouds do increase
from SW to NE later at night out ahead of the next frontal
system. Cool with lows in the mid-30s to low 40s.
Friday features ridging off the southeast coast and a cold front
trying to push east out of the Great Lakes. Ridge slows the
progress of the front as ripples of low pressure race to the
northeast in the southwest flow aloft. The chance for showers
increases through the day as the front drops into the area,
with the highest chance over the western and northern zones.
There are model forecast differences in the position and timing
of the front, which of course is typical when the surface front
lies parallel to the upper flow. Overall though any rain that
falls will be relatively light as the system moving through are
weak. A few showers linger into Friday evening, but then it
looks to gradually dry out overnight as the trough swings east
and riding quickly builds.
Removed most pops for Saturday as models have trended milder
and drier under partly sunny skies and high pressure overhead.
Clouds may increase late in the day from the southwest as the
next weather system gathers moisture in the Ohio Valley. Highs
should reach well into the 50s with light winds.
Long term /Saturday night through Tuesday/...
415 am update....
Rather significant changes in the beginning of the long term
period. Latest model guidance has come into much better
agreement that a moisture laden low pressure system will track
through the area Saturday night into Sunday. A closed upper
level low is progged to track from Arkansas northeast toward
Lake Erie...this system will tap into Gulf of Mexico moisture
bringing a strong push of warm advection stratiform rain to our
region. GFS is slightly faster than the ECMWF, but generally
went close to the latest superblend/wpc guidance for pops and quantitative precipitation forecast
this time period. Temperatures are also looking much warmer now
Saturday night (40s), with the strong warm air advection,
clouds and rain around. Lingering rain Sunday morning, looks to
exit west to east (if current timing holds). Seasonable
temperatures in the 50s.
Looking mainly dry for Monday, and seasonable with weak high
pressure building. Rather significant model differences then
reappear Tuesday/Wednesday next week. The 00z GFS brings a
strong, early season blast of cold air to the region with rain
showers and eventually lake effect snow showers. Meanwhile the
00z Canadian and European model (ecmwf) build the Southeast Ridge back, keeping the cold
air locked across the upper Midwest and Great Lakes. These
solutions would also keep out weather mainly dry. For the
official forecast went close to the nbm, considering these
differences and lower confidence.
Aviation /16z Wednesday through Sunday/...
in the wake of a rainy cold front, clearing sky overnight
allowed for restrictions/valley fog at most terminals. However,
winds are in the process of picking up and veering westerly
while bringing in drier air. Fog should thus mix out fairly
quickly after sunrise, except kelm as usual will take longer.
VFR conditions are otherwise expected today through tonight,
with west or west-southwest winds. Gusts will reach to around 20
knots late morning through afternoon hours. Winds will slacken
at the terminals tonight, but a low level jet of 35-45 knots
will develop out of the southwest to pose low level wind shear
for at least kelm-kith-ksyr-krme.
Thursday through early Friday...VFR except for valley fog
restrictions possible at kelm late Thursday night-early Friday.
Friday afternoon through Friday night...chance of showers and
minor restrictions for the New York terminals; mainly VFR kavp.
Saturday night through Sunday...rain and restrictions becoming
likely from passing low pressure system, especially Sunday.