Area Forecast Discussion
Issued by NWS Albany, NY

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FXUS61 KALY 070626
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
126 AM EST Wed Dec 7 2016

.SYNOPSIS...
A quick moving low pressure system will bring another
period of light snow to the region this morning. Lake effect snow
developing in its wake as much colder air is ushered in across the
relatively warmer waters of the Great Lakes for Thursday into
Friday.

&&

.NEAR TERM /THROUGH TODAY/...
As of 1241 AM EST...Over running light snowfall continues across
eastern NY and western New England from southwest to northeast
north and west of a coastal wave east of the Delmarva region...and
a cold front over the eastern Great Lakes Region and the OH
Valley. The column saturated and cooled right around midnight at
KALB with light snowfall underway. The light rain transitioned to
snow at KPOU. Have increased totals slightly in the mid Hudson
Valley/southern Taconics/eastern Catskills. This is based on the
steadier radar echoes with the warm advection/isentropic lift
stronger in these locations. Also a report of slightly greater
than 3" came in from Orange Co. south of our forecast area. We
have 2-4"forecasted now for the eastern Catskills, 1-2" in the
Mid- Hudson Valley...and 1-3" over the southern Taconics and the
northern Litchfield Hills. Further north expect an inch or two in
the valley areas...and 1-3" over the southern Adirondacks and
portions of the western Mohawk Valley. Lows will be in the mid 20s
to around 30F.

Overall lift weakens quite a bit toward sunrise Wednesday as we
expect a diminishing trend in overall coverage and intensity.
Furthermore, mid level dry slot quickly approaches to further
diminish the precipitation. However, expectations are for cloud
coverage to remain as per the IR imagery, mid level clouds were
quite extensive across the mid Mississippi Valley which advects
northeast through Wednesday. High temperatures Wednesday afternoon
may be close to our afternoon highs today as valley locations
should climb close to 40F with 30s elsewhere.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
Lake Effect Snow to develop and possible impacts to the western
Adirondacks Thursday through Friday morning.

A tranquil period of weather expected Wednesday night with ample
cloud coverage in place as broad southwest flow regime remains in
place. Some light snow with lake enhancement may approach
northern Herkimer County as seeder-feeder processes could enhance
some light precipitation. Then arctic boundary is expected to
approach Thursday with the chance for more snow showers and
possible squalls as lake effect develops later in the day and into
the night. Lake instability index`s quickly increase Thursday
night as boundary layer flow becomes more westerly. Now per CSTAR
research, inland extent through the event impacts northern
Herkimer County which is where we will place Lake Effect Snow
Watch. Could be a significant event unfolding as H850 temperatures
continue to drop back into the negative teens. Otherwise, a brisk
flow with falling temperatures with the chance for snow
showers/squalls.

Secondary cold front/trough axis is expected to slide southeast
Thursday night as boundary layer flow becomes more northwest. This
should take the bands rather quickly out of Northern Herkimer
County as bands break up and move across the Mohawk Valley then
Catskills Region. Partly to mostly cloudy conditions as
temperatures drop back into the 20s with wind chills down into the
teens.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Active and fast moving upper pattern through the period. One system
exits Friday but with deep cold advection and northwest boundary
layer flow, Lake Effect snows are expected into the western Mohawk
Valley to the Schoharie Valley and eastern Catskills. Mainly multi
band with the northwest flow so higher snow amounts could be very
localized. Isolated snow shower activity could extend through
eastern NY and southern VT to the northern Berkshires. Lake Effect
multi bands could linger and gradually decrease in coverage through
Saturday, when boundary layer winds weaken. Highs Friday in the 30s
but 20s higher elevations. Highs Saturday in the upper 20s to mid
30s but around 20 higher elevations.

The next organized upper system approaches Sunday with an increasing
consensus for clouds and precipitation spreading across our region
through the day Sunday. Warm advection increases as does south to
southwest boundary wind flow and associated forcing and isentropic
lift.  Highs Sunday in the 30s but upper 20s in higher elevations.

Chances for snow Sunday night at least into Monday morning, with
possible mixing with rain in the mid Hudson Valley and NW CT.
Uncertainties Monday and Tuesday as to the timing of warm advection
ahead of a strong piece of upper energy dropping out of Canada
heralding the advance of the leading edge of the first big cold air
outbreak of the season.  So, just some lingering snow shower
activity Monday, then the leading edge of some snow shower activity
with the warm advection Tuesday.  The beginning of the big cold
outbreak looks to be just beyond Tuesday.

Highs Monday in the upper 30s to lower 40s but mid 30s higher
terrain. Highs Tuesday in the mid 30s to near 40 but upper 20s
higher terrain as clouds and advancing precipitation limit the high
temperatures a bit.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Light snow event is unfolding across the region. Expect steady
light snow to generally continue through around 09-10Z before
becoming more intermittent, and possibly mixing with rain/drizzle.
At POU, precip has already lightened up, with a light rain/snow
mixture being reported. Regardless of precipitation intensity, IFR
conditions should dominate well past daybreak due to a mixture of
low clouds, mist, and light precipitation. LIFR is being observed
at POU due to low ceilings, and LIFR could briefly occur at the
other terminals early in the TAF period due to precipitation.

Conditions expected to improve to MVFR during the late morning
with clouds scattering by the afternoon as winds turn westerly
bringing in drier air. Will watch for the potential of patchy MVFR
cigs tomorrow night.

Light variable/easterly flow overnight becoming and south to
southeast Wednesday morning, veering to westerly during the
afternoon at less than 10kts.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Chance of SHRA...SHSN.
Thursday Night: Moderate Operational Impact. Breezy Chance of SHSN.
Friday: Low Operational Impact. Slight Chance of SHSN.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SHSN.

&&

.HYDROLOGY...
Active week with unsettled weather as a couple more systems impact
the region followed by the development of a lake effect snow event
Thursday night into Friday night. Precipitation will fall mainly
as snow through the weekend.

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
website.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Lake Effect Snow Watch from Thursday morning through Friday
     morning for NYZ032.
MA...None.
VT...None.

&&

$$
SYNOPSIS...BGM/Wasula
NEAR TERM...BGM/Wasula
SHORT TERM...IAA/BGM
LONG TERM...NAS
AVIATION...Thompson
HYDROLOGY...IAA/BGM



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