Area Forecast Discussion
Issued by NWS Albany, NY

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FXUS61 KALY 261023

Area Forecast Discussion
National Weather Service Albany NY
622 AM EDT Wed Oct 26 2016

High pressure will build into the region today, and move off the
New England coast tonight, accompanied by fair but chilly
conditions. Low pressure will then approach from the Great Lakes
region Thursday, bringing rain or a wintry mix to the region.
Precipitation will continue into Thursday evening, before tapering
off late. Blustery conditions will return for Friday, with a few
rain or snow showers across higher elevations.


As of 615 AM EDT, still quite a bit of low clouds lingering
across the eastern Catskills and southwest Herkimer CO, the
western Adirondacks, as well as for the Lake George/Saratoga
region into southern VT. Temperatures remain in the mid/upper 30s
where cloud cover remains, while falling into the 20s where breaks
developed, including portions of the mid Hudson Valley and NW CT.

Biggest challenge for today will be how much cloud cover lingers.
Latest RAP13 suggests, based on H850 RH, that clouds may hang
tough for some areas north of I-90, such as the southern
Adirondacks, southern VT, and perhaps the Lake George/Saratoga
region through much of the day, after a few possible breaks this
morning. To the south of I-90, expect more in the way of sunshine
after occasional clouds this morning, with clouds more prevalent
across the eastern Catskills.

Temps will be chilly, with highs mainly in the mid/upper 40s
across valley areas, and mid 30s to lower 40s across higher


...Winter Weather Advisory for Thursday-Thursday evening across
the southwest Adirondacks and elevations above 1500 feet in the
eastern Catskills and northern Warren County...

Tonight, high clouds should be increasing this evening, with mid
level clouds expected to thicken after midnight. Temps will likely
fall rapidly this evening, although perhaps not quite as quickly
as both the MAV and MET MOS suggest. Have sided closer to a blend
of 2-meter temps from the GFS/NAM, which would suggest mainly
mid/upper 20s in valleys, and lower 20s across some higher
elevations. Some light snow could develop across the southeast
Catskills toward daybreak.

Models continue to remain slower than previous cycles with regard
to precip start times. However, will remain cautious, as warm
advective precip regimes often arrive faster than models suggest.
Updated near-term models such as the HRRR/RAP13 will be watched
very closely for this possibility, as a slightly quicker onset
would bring snow or a wintry mix into portions of the region right
during the morning commute.

For now, have indicated chance for snow arriving between 8-10 AM
for most areas west of the Hudson River and near/south of I-90,
then likely for these areas by mid to late morning, and areas to
the north and east by early afternoon. Strong wet bulb cooling of
an initially dry low level air mass should allow for precipitation
to start as snow or a rain/snow mix in valley areas, before
changing to all rain or perhaps a rain/sleet mix by late morning,
except early afternoon across the Saratoga/Lake George region. In
these areas, a coating to less than one inch will be possible,
mainly on colder surfaces, with some slush buildup possible on
mainly secondary less traveled roadways, especially north of
I-90. For the mid Hudson Valley and most of Litchfield CO CT, only
a coating of snow on colder surfaces is currently expected,
perhaps a bit more on colder surfaces for higher elevations
within Litchfield CO.

For the eastern Catskills and southwest Adirondacks, periods of
moderate snow will be possible into the afternoon, before mixing
with and/or changing to rain/sleet. Snowfall accumulations of 3-6
inches are expected in these areas, mainly for elevations above
1500 feet. A Winter Weather Advisory has been issued for these
areas, using elevation dependency above 1500 feet for the
Catskills and northern Warren County.

For the Berkshires and southern VT, most accumulations should be
in the 1-3 inch range, again mainly for elevations above 1500 feet
with less in valleys. There could be additional accumulations for
southern VT Thursday night as the low redevelops along the
southeast New England coast, and additional low level moisture
wraps back to the southwest. It is possible that the highest
elevations, mainly 2000 feet and above, could receive moderate
snowfall accumulations between Thursday and Thursday night, so
additional elevation-dependent winter weather advisories for
southern VT could be issued later today.

In most valley areas, mainly rain is expected for late Thursday
afternoon into Thursday night, some of which could be moderate to
briefly heavy. In fact, can not rule out a few rumbles of thunder
close to the I-84 corridor where some elevated instability is
suggested. Precip across higher terrain should be mainly rain for
Thursday evening, although some pockets of sleet could persist.
Eventually, colder air aloft will move in with the upper trough,
changing the precipitation back to snow later at night for most
higher terrain before tapering off.

It will become breezy Thursday night across higher elevations of
the southern Adirondacks, and especially the southern
Greens/northern Berkshires, where some gusts could reach as high
as 40 mph.

High temperatures on Thursday should occur after sunset, with
lower/mid 40s in most valley, except near 40 north of I-90. Higher
elevations should reach the mid 30s. Thursday night lows should
fall into the 30s to lower 40s.

Friday will be quite blustery, with gusty west/northwest winds
developing, with some gusts possibly reaching up to 35 mph. Clouds
should persist for most areas north of I-90, along with some
rain/snow showers. Breaks in the clouds are possible south of
I-90. Highs will generally reach the mid 40s to around 50 in
valleys, with upper 30s/lower 40s for most higher terrain.


A near zonal flow is expected through the weekend.  Global models
usually have a difficult time with these synoptic flow patterns as
this is evident with the 00Z guidance.

Friday night, we find our region between two systems, one departing
off the New England coast and the next system quickly approaching
along the US/Canadian border into the western Great Lakes.  So a
narrow subsidence area should result in a period of tranquil weather
Friday night for most of the region with partial clearing early on
then increasing cloud coverage overnight.  Some light precipitation
may impact portions of the Adirondacks where we will continue with
the slight chance to chance PoPs.

Global models are in a good agreement with the Great Lakes systems
tracking across the St Lawrence Valley with its associated cold
front moving across the entire region Saturday afternoon.  As
thermal profiles look quite mild, most of the precipitation should
fall as liquid.  Temperatures are expected to range between 45 and
55 degrees.

Frontal passage should occur by 00Z Sunday, as this is where models
begin to diverge.  The Canadian is the most aggressive with a large
surface high building southeastward to keep our region dry with at
least partly sunny skies.  On the other end of the spectrum is the
ECMWF.  The 00Z ECMWF takes the PV-Anomaly over the Big Sky Country
of Montana and quickly tracks this feature eastward with not only an
increase in cloud coverage, but a chance for light precipitation
mainly south of I90.  The GFS is near the middle of the guidance
envelope yet is a little further south with the track and its
associated precipitation.  WPC favors more in line with the ECMWF as
we will have a graduated PoP forecast with higher chance values
south of I90 and slight chance to the north.

Then higher confidence returns for Monday with a large surface high
and building heights aloft across the northeast with seasonable
temperatures and at least partly cloudy to mostly clear skies. As
this high slides further offshore Monday night, next system upstream
begins its approach, however, vast differences return in the
GFS/ECMWF as we will carry nothing higher than slight chance PoPs.
Temperatures begin to rebound as H850 temperatures are expected to
climb back above +10c which should allow for highs well into the 50s
and overnight lows in the 40s.


Satellite imagery and METARs reveal a scattered to broken VFR
stratus deck between 4000-5000 feet.  Exception to this would be
across the Mid Hudson Valley where skies were clear at this time.
Trends in the satellite imagery are for some breaks in the overcast
to occur, however, with daytime heating some additional cloud
coverage is expected yet remaining VFR.

Winds should increase from the west or northwest at speeds up to 10
kts with gusts up to 20kts.  Winds subside tonight to light and
variable or calm.

Skies should clear briefly this evening before our next system
approaches with an increase in high and mid level moisture in the
form of CI/CS.


Thursday Night: High Operational Impact. Definite SHRA...RA.
Friday: Moderate Operational Impact. Breezy Scattered SHRA.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: Low Operational Impact. Slight Chance of SHRA.
Sunday: Moderate Operational Impact. Chance of SHRA.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.


High pressure will build into the region today, and move off the
New England coast tonight, accompanied by fair but chilly
conditions. Low pressure will then approach from the Great Lakes
region Thursday, bringing rain or a wintry mix to the region.
Precipitation will continue into Thursday evening, before tapering
off late. Blustery conditions will return for Friday, with a few
rain or snow showers across higher elevations.


Widespread precipitation is expected Thursday into Thursday
night. With a cold start to the morning on Thursday...areas west
of the Hudson Valley and the higher elevations could see a period
of snow before going over to or mixing with rain. By Thursday
afternoon/night...rain will be over much of the area...with snow
mixing in across the Adirondack region.

Forecast precipitation totals will generally be from three
quarters of an inch to around an inch through daybreak Friday.

For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our


NY...Winter Weather Advisory from 8 AM Thursday to midnight EDT
     Thursday night for NYZ032-033-042-058-063-082.


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