Scientific Forecaster Discussion
fxus61 kaly 182355
Area forecast discussion
National Weather Service Albany New York
655 PM EST Mon Nov 18 2019
a strong disturbance in the upper levels of the atmosphere will
bring a variety of precipitation to the area tonight into
Tuesday morning with rain, freezing rain, sleet and snow all
expected. A fast moving disturbances will bring some spotty
mountain rain and snow showers to the region Tuesday night and
Near term /until 6 am Tuesday morning/...
winter weather advisories are in in effect for all but the
Hudson Valley from the Poughkeepsie area up into the capital
district and for Ulster and southern Litchfield counties.
As of 655 PM EST...strong upper level short wave trough will
become negatively tilted as it swings through the region
overnight into early Tuesday.Surface temps, according to New York state
mesonet observations and ASOS sites generally are in the lower
to middle 30s already, with the coldest readings across the high
terrain. However, 00z kaly sounding shows a pretty strong warm
nose about 850 hpa, with temps in the warm nose as high as 5 c.
Currently, precip is very light and spotty, with the most
activity occurring across the Taconics. As surface temperatures
continue to cool this evening and the trough approaches, precip
will start to become more widespread and steady in nature.
Precip will initially be either rain or freezing rain based on
surface temps, with the freezing rain generally occurring across
the advisory area. This will allow for a light accretion of ice
in this area, with up to a tenth of an inch of flat ice
As colder air is drawn in aloft the precipitation will
tranistion to sleet and eventually snow after midnight or 1 am
EST. The cooling will be occurring southwest to northeast
across the area. The transition to mainly snow will be occurring
closer to sunrise and this may be when precip is
steadiest/heaviest. Some of the latest model guidance (18z NAM/
21z hrrr) suggest there is the potential for a quick burst of
heavier precip towards end of the night/start of the morning
commute that may be primarily snow (especially for the higher
terrain). However, other guidance is still showing enough of a
warm nose to keep precip as rain, outside the highest terrain.
We have increased snow amounts slightly, with a few inches
across the higher terrain and a coating to an inch for valley
areas. However, it will need to be watched closely.
Low temperatures will generally be in the 30s (some upper 30s
across the highest terrain).
Short term /6 am Tuesday morning through Wednesday night/...
winter weather advisories are in effect until 10 am.
Precipitation tapers off during the morning as colder continue
to be ushered as the short wave trough moves off to our east.
However, the best chances for a burst of accumulating snow looks
to be during the morning commute, early, mainly across the Lake
George Saratoga region and the Taconics and western New England
with a quick inch of snow possible with less than an inch
Fair weather is expected by the afternoon between short waves
with mainly cloudy skies. Temperatures are expected to warm up
into the 30s with lower to mid 40s in the Mid Hudson valley up
into the capital district and across northwestern Connecticut.
The next short wave will pass to our south across the mid
Atlantic region Tuesday night into Wednesday and with moisture
off Lake Ontario contributing to some lake enhanced mainly snow
showers across the higher terrain to the north and west of the
capital district with some showers across the higher terrain of
southern Vermont. Seasonable lows in the mid 20s to lower 30s
Tuesday and with similar highs Wednesday as Tuesday.
Fair weather Wednesday night with cloud cover decreasing as the
short wave trough exit and ridging builds in with lows once
again in the mid 20s to lower 30s.
Long term /Thursday through Monday/...
low pressure will be lifting across the upper Midwest on Thursday
and moving across the upper Great Lakes for Thursday night. This
storm system will lift across Ontario and Quebec for Friday.
Ahead of this system, most of Thursday looks dry across our area as
the upper level ridge axis will still be situated across the
northeast, but clouds will be increasing, especially for later in
the day. Highs look a little below seasonal normals, with afternoon
temps in the mid 30s to mid 40s.
On Thursday night, southwest flow will be increasing at all levels
across the area. This will allow for some warm advection, which
should make for some light precipitation. With the best forcing
northwest of the area, the best chance will probably be across the
Adirondacks and Upper Mohawk valley. Temps may initially fall into
the upper 20s to mid 30s in the evening, but then look to hold
steady or rise through the rest of the overnight hours. As a
result, there could potentially be a wintry mix or some snow across
the highest terrain and/or northern areas to start, but precip looks
to generally transition over to rain over the area.
The storm's cold front will be moving across the area on Friday,
which will bring the most widespread precip to the area. Most of
this will be in the form of rain, but it could transition back over
to snow before ending across the higher terrain, as colder air
quickly returns back in behind the storm. Temps look to reach into
the 40s across most of the area during the morning, but should be
falling in the afternoon hours. Colder and breezy conditions are
then expected for Friday night behind the departing storm with lows
in the 20s. Skies should clear out for most spots, although some
lake clouds and flurries/snow showers may occur for northwestern
Uncertainty remains high regarding the forecast for the upcoming
weekend. Following the passage of an upper trough and surface low
pressure system on Friday, a secondary positively-tilted upper
trough will Glide across the central states on Saturday. At the
surface, an area of low pressure will attempt to form along a cold
front stretching from the lower Mississippi Valley to New England.
Where and how quickly this low forms will determine whether or not
rain and/or snow will return for the weekend. The 12 UTC GFS is
slower in forming the surface low and pushes this system offshore,
bypassing our area to the south and east. Meanwhile, the 12 UTC
European model (ecmwf) forms this low quicker and sends this system directly
overhead. With the large spread in guidance, will go with
chance to slight chance pops across the viewing area for this update.
Later Sunday into Monday, a fast-moving upper-level shortwave will
slide across the region, which may bring a few rain and/or snow
showers to the Adirondacks. Upper-level ridging and surface high
pressure will then build across the region on Monday with a dry
start to the week.
Aviation /00z Tuesday through Saturday/...
flying conditions will be lowering this evening and will be
mainly IFR overnight for both visibility and ceilings.
Initially, precip will be light and spotty, but steadier precip
is expected after midnight. Precip will start out as rain for
taf sites, but will transition towards snow by daybreak on
Tuesday. There could also be a wintry mix of sleet/freezing rain
at kgfl/kpsf for the late night hours as well.
Snow will taper off by mid-morning, allowing for flying
conditons to improve back to MVFR and then VFR by early
afternoon. The exception may be kpsf, where lingering low
stratus may keep it MVFR through the rest of the day.
Light north winds this evening will become northwest overnight
at 5-10 kts. Winds will then become westerly at similar speeds
on Tuesday morning and continue into the afternoon at around 5
kts or so.
Tuesday night: no operational impact. No sig weather.
Wednesday: no operational impact. No sig weather.
Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
Thursday night: moderate operational impact. Chance of rain showers.
Friday: moderate operational impact. Likely rain showers.
Friday night: moderate operational impact. Chance of rain showers...shsn.
Saturday: low operational impact. Slight chance of rain...sn.
a strong disturbance in the upper levels of the atmosphere will
bring a wintry mix of precipitation to the area tonight into Tuesday
morning including freezing rain, sleet and snow. A fast moving
disturbances will bring some spotty mountain rain and snow showers
to the region Tuesday night and Wednesday.
looking at a wintry mix of precipitation across the area
tonight into Tuesday morning with rain, freezing rain, sleet
and snow all expected. Overall quantitative precipitation forecast amounts of up to around a
half of an inch are possible for some area south and east of the
capital district with general a quarter to a third of an inch
expected. The potential for hydrologically significant
precipitation is low for the remainder of the forecast period.
For details on specific area rivers and lakes, including latest
observed and forecast river stages and lake elevations, please
visit the advanced hydrologic prediction service /ahps/ graphs
on our website.
CT...Winter Weather Advisory until 10 am EST Tuesday for ctz001.
New York...Winter Weather Advisory until 10 am EST Tuesday for nyz032-033-
Massachusetts...Winter Weather Advisory until 10 am EST Tuesday for maz001-025.
Vermont...Winter Weather Advisory until 10 am EST Tuesday for vtz013>015.