Scientific Forecaster Discussion
fxus61 kbgm 152342
Area forecast discussion
National Weather Service Binghamton New York
742 PM EDT Sat Jun 15 2019
a cold front will usher another round of showers into New York and PA
tonight and Sunday. A few thunderstorms are possible from the
twin tiers southward Sunday afternoon as unstable air works into
Near term /through Sunday night/...
545 PM update...did a quick update to account for more showers
in the twin-tier region. Showers were rapidly spreading across
western and central New York and northern PA in response to a well-
defined upper level short wave moving into the eastern lakes
region. Southwest low-level winds were increasing in response
to the arrival of this upper feature increasing moisture
transport. Model soundings show a layer of moisture between 850
mb and 600 mb which is sufficient for some light rain showers
especially given the divergence aloft. Increased pops to
account for this. Also adjusted temps, winds and sky cover also.
240 PM update...
A frontal system moving through the Great Lakes toward New York and PA
will bring thickening clouds and an increase in showers this
evening and overnight. Precipitable water values of 1.25 to 1.50 inches are
fairly typical of stormy patterns during the Summer, and without
a threat for thunderstorms, Hydro concerns are not forecast.
Showers will continue Sunday. A small amount of instability
could potentially develop over the far southern forecast area on
Sunday afternoon and cause isolated thunderstorms. High
temperatures in the lower-70s are forecast.
High pressure will briefly build southward Sunday night and
bring an end to the rain north of the southern tier. A few
showers will continue from the southern tier southward into PA.
Temperatures will fall into the 50s.
1045 am update...
A strong June sun has pushed temperatures into the middle-70s
over portions of The Finger lakes and toward Syracuse. We
increased afternoon temperatures over this region to compensate.
Model timing continues to point toward showers moving into the
northwestern forecast area between 20z and 22z.
Short term /Monday through Tuesday night/...
an active period, with multiple waves moving through a moist and
unstable westerly flow. Best chance for periods of showers and
thunderstorms will be across NE PA and perhaps up into the New York
southern tier through the short term period...meanwhile much of this
time frame may end up dry further north toward the New York thruway
corridor. Temperatures will be near average with highs in the 70s
(near 80 south) and lows in the mid-50s to low 60s.
Monday and Monday night: starting off dry as high pressure noses in
from Ontario/New England. Then a shortwave rolls through the Ohio
Valley, with a weak surface low reflection moving eastward across
southern PA. Instability increase Monday afternoon and evening,
mainly south of the New York/PA border. Precipitable waters rise to around 1.5 inches
along and south of the New York/PA border and surface dew points rise back
into the upper 50s and lower 60s. There are still minor model
differences in the exact track and timing of the above mentioned
feature, but it seems there will be a good chance for showers and a
few thunderstorms again from the New York southern tier south into NE PA
late Monday and Monday night...in fact the latest European model (ecmwf) actually
shows a period of heavier rain moving through during this time.
Therefore, went ahead and added some likely pops for our southern
and eastern zones. Also went close to wpc quantitative precipitation forecast for this period, which
was quite high; a half to three quarters of an inch near Scranton--
Honesdale and Monticello.
Tuesday and Tuesday night: zonal, moist and unstable flow continues
as the stalled frontal boundary remains over the region. Additional
weak disturbances will likely moves through the area...but tough to
time these at this range. Therefore went to high end chance to low
end likely far south in NE PA, to lower end chance for the New York
southern tier, the mainly dry or slight chance up toward the thruway
corridor of New York. Again, it looks like there could be moderate amounts
of instability mainly from the twin tiers south so added in chances
of thunder here.
Wednesday and Wednesday night: a very persistent pattern continues
with much of the same into this period. Higher chance pops still for
NE PA, fading to low chance or slight chance north. It appears there
is decent agreement between the latest guidance that the flow will
turn a bit more southwesterly out ahead of the next more significant
shortwave and low pressure system that looks to potentially impact
our area toward Thursday.
Long term /Wednesday through Saturday/...
345 PM update...
Rain chances will increase for Thursday with another surface low
moving through the Ohio Valley and towards New England. The best
chances for rain will be during the afternoon and evening ahead of
the approaching cold front, and with some elevated cape and a well-
sheared environment, thunderstorms are looking increasingly likely.
With precipitable water up to 1-1.5 in during this time, there is a
chance for heavy downpours in storms.
Chances for showers linger throughout the day Friday behind the
exiting system, and while most areas should stay dry Friday night
into Saturday morning with high pressure briefly building in,
chances for showers will increase again Saturday with another surge
of moisture across the region as another surface low developing in
the plains heads towards Lake Superior.
Otherwise, little change in temperatures with this forecast update.
Highs will generally be in the mid 70s, and lows in the mid/upper
Aviation /00z Sunday through Thursday/...
initially, conditions will be VFR all tafs as showers move
across all terminal sites. This first batch of showers will lead
to occasional MVFR restrictions between 00z and 03z/04z all
terminals except kavp where the initial showers arrivae in
northeast PA after 03z. We expect occasional restrictions to
MVFR in showers at kavp between 03z and 07z. Between 03z/04z and
10z or so, the New York terminals will drop to MVFR with occasional
IFR conditions in visibility. At krme, kith and kbgm we expect
mainly IFR conditions between 07z and 10z to 15/16z. Kbgm and
krme likely will see LIFR conditions around 07z to 12z or so. At
kavp, expect MVFR ceilings most of the day in showers with
improving conditions after 20z. An isolated thunderstorm is
possible Sunday afternoon near kavp.
Outlook... Sunday night through Wednesday...restrictions with
occasional showers. A thunderstorm or two can not be ruled out
at some point.
Winds will be southwest 8 knots or less initially at most
terminals and then variable direction under 10 knots rest of