Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
656 am EST Sat Nov 28 2015
a cold front has brought cooler temperatures to the region. Behind
that front...clouds...light rain or drizzle...and patchy high
elevation fog can be expected to linger for a time today before
drier air moves in from the north. High pressure and a sunny sky
will build in for Sunday...lasting into Monday...before our some
rain arrives Tuesday with our next system.
Near term /through tonight/...
645 am update...
Post-frontal light rain and drizzle...already figured to linger
awhile...is progressing even slower than had been anticipated.
Forecast adjusted to linger it for a longer segment of the day. As
far as clouds...sky grids also tweaked for an even slower erosion
from the north tonight into early Sunday...since it appears there
will be plenty of low level moisture trapped under the inversion.
cooler Post-frontal regime will be the theme today...with slow
north-to-south transition from clouds light rain and drizzle this
morning...to gradual clearing late today through tonight.
Cold front as of 1 am has reached a Towanda to Sidney to
Cooperstown line and continues its slog press southeast. With no
support aloft...in fact if anything the opposite considering we
are getting into right exit region of jet...frontal precipitation
is very light. Front is also slowing down since the wave that is
forcing its movement...is flattening with time and becoming nearly
parallel with the front. We are figuring on light rain chances
focusing mainly on twin tiers southward during the coming day yet
also decreasing. Saturated layer will continue to get shallow with
time...so indeed drizzle will end up getting favored over light
rain. Some late day sun is possible for the New York thruway
corridor...but generally speaking the Post-frontal clouds will be
persistent for majority of our region.
Last of lingering Post-frontal light rain or drizzle will shift
out of northeast PA-Sullivan County New York this evening...but exodus
of clouds will be more gradual. High pressure will also start to
build in from the west...trapping low level moisture beneath
subsidence inversion. Eventually...advection of drier air from the
north will win...but it may take until after dawn Sunday morning with
mixing of the sun for clouds to actually eradicate from the
southern zones. Lows tonight will range from middle 20s north to
lower 30s south.
Short term /Sunday through Monday night/...
320 am update...
dry weather and seasonal temperatures through Monday...followed
by an increasing chance for light rain late Monday night ahead of
our next system. There is a small potential for brief light
freezing rain in eastern parts of the area predawn hours of
Broad high pressure will translate from upper Midwest-central
Ontario Sunday...to Quebec Sunday night...and on to New England
Monday. It will control our weather...not only with the mainly
clear sky Sunday through Monday...but also with temperatures and
precipitation type Monday night.
The placement of the high over coastal New England and shifting
offshore Monday night...will set up a cold air damming scenario
against Catskills-Poconos-Tug Hill. Meanwhile...southwesterly flow
ahead of approaching front will cause warm air advection and thus
non-diurnal temperature trend Monday night...that is...creeping up
overnight instead of down. There is a question as to how quickly
light rain can spread in late Monday night-predawn Tuesday. GFS is
slowest of the models...European model (ecmwf) and especially NAM and Canadian Gem
models allow light quantitative precipitation forecast into the area. This is important because
the cold air damming in Catskills-Poconos-Tug Hill could result in
surface temperatures still being below freezing for a brief time
as the light rain arrives. Warm air aloft ensures that there will
be no flakes. Confidence in light rain arriving before
temperatures get above freezing...remains on the low side. So
while the chance of light freezing rain is mentioned in the
forecast of the more vulnerable areas...we have not put it in the
local hazardous weather outlook just yet. Stay tuned.
Long term /Tuesday through Friday/...
430 am update...extended forecast in good shape just made minor
adjustments based on latest wpc guidance. Tuesday morning as surface
low pressure tracks into the upper Great Lakes and pushes a warm front
toward the region, temperatures may still be cold enough in parts of the
western Catskills and western Mohawk Valley for a brief period of
mixed rain/freezing rain. By middle morning light rain is likely
across the entire with activity expected to continue into Tuesday
night as the surface occlusion moves through.
2 PM Friday update... in the big picture, a progressive upper-
level pattern is shown by our medium-range model guidance. An
upper-level trough and associated frontal complex is slated to
come through New York/PA on Tuesday/Tuesday night. Heights will slowly
build/flatten out, behind this feature, for the middle and latter
portions of next week.
As for the daily sensible weather, light rain/drizzle should
overspread the region Tuesday, becoming steadier for a time
Tuesday night. Temperatures may be cold enough for a brief period
of freezing drizzle early Tuesday, over our eastern zones, if
precipitation comes in soon enough.
For Wednesday, light rain/snow showers are expected, as wrap-
around moisture, and cyclonic flow prevail, behind a cold frontal
Thursday into Friday, should feature drier conditions, and
Aviation /12z Saturday through Wednesday/...
a cold front with Ana-front characteristics crossed the terminals
early this morning. In general light rain/drizzle is expected
behind this boundary through early afternoon with IFR/low MVFR
ceilings. Late this afternoon and into this evening ceilings may improve
to MVFR/low VFR but model soundings continue to suggest low level
moisture will be trapped under a subsidence. For now decided to
scatter out krme/ksyr while continuing with MVFR/low VFR ceilings
across the southern terminals.
North/northwest winds at 5-8 knots.
Tuesday ngt-Wed...restrictions possible in showers.