300
FXUS61 KALY 012011
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
311 PM EST Mon Dec 1 2025

.SYNOPSIS...
Widespread moderate to heavy snow begins early tomorrow morning
through very early Wednesday morning, resulting from a coastal
low pressure system. Drier, but colder, conditions return
Wednesday before additional, light snow showers spread into the
region Wednesday night in association with a cold front. After a
dry end to the work week, another coastal system takes shape
for the weekend, but the probability of impacts to eastern New
York and western New England is low.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Key Message:

 - Winter Storm Watches have been upgraded to Winter Storm
   Warnings and Advisories for most of eastern New York and
   western New England from 7 AM Tuesday through 1 AM Wednesday.

 - Expected snowfall totals range from about 2 to 11 inches of
   snow are anticipated across eastern New York and western New
   England with the heaviest totals anticipated to fall across
   the Eastern Catskills, Greater Capital District, Lake
   George-Saratoga Region, Berkshires, and southern Vermont.

 - Within those areas of greatest snowfall, moderate to heavy
   snowfall rates of 0.5" to 1" per hour are expected from
   mid/late morning through late afternoon/early evening
   tomorrow.

Discussion:
Surface high pressure centered across the eastern Great Lakes
has maintained pleasant, though brisk, conditions across the
region today ahead of a highly anticipated winter storm.
Throughout the afternoon and into this evening, as the high
drifts eastward overhead, breezy winds will begin to decline
whilst clouds increase from west to east. Low temperatures
tonight, despite increasing cloud cover, will be rather chilly
with values in the tens to 20s.

While the aforementioned surface high traverses the Northeast
this evening, a positively-tilted, southern-stream shortwave
will deepen across the Southern Plains/Southeast regions, owing
to a surface response in the development of a weak area of
surface low pressure in the Deep South near the northern Gulf.
Simultaneously, a northern-stream shortwave will become
neutrally tilted across the upper Midwest/western Great Lakes
regions. Alignment of the axis of the neutrally-tilted,
northern-stream disturbance and the forward flank of the one
associated with the southern- stream will create a southwest to
northeast-oriented moisture axis that will surge northward along
the East Coast and into the region from its Gulf origin. With
the aforementioned surface high having exited into New England,
stratiform precipitation will spread into the region from west
to east near the western Mohawk Valley and Southwest Adirondacks
between 4 and 6 AM, initially as a result of increased
cyclonic vorticity advection in advance of the northern-stream
shortwave. However, with isentropic lift increasing from south
to north ahead of the warm front of the ares of low pressure,
precipitation will start filling in to the south by 6-8 AM. With
temperatures remaining at or below freezing within these onset
periods, precipitation is expected to be snow for everyone to
start. Additionally, snow will also be light to start as forcing
for ascent remains weaker.

By mid-morning tomorrow, the aforementioned area of low pressure
looks to begin its inland exit, deepening fairly rapidly as it
enters the western Atlantic. As the northern-stream shortwave
nears and the now coastal low deepens along its northeasterly
track, forcing for ascent will increase with bands of low-level
FGEN taking shape across the eastern Catskills, north and east
through the Capital District and into western New England.
Latest forecast soundings and atmospheric cross sections
indicate decent omega intersecting the DGZ as well as some areas
where FGEN intersects the DGZ, supporting efficient snow
production processes. Upslope flow within the higher terrain of
the Eastern Catskills, Southern Greens, and Berkshires will also
help to enhance vertical ascent in these areas. One concern that
we had for this forecast was the potential for downsloping into
the Capital District courtesy of southwest flow off the
surrounding higher terrain. However, seeming to overcome the
effects of this is not only the presence of low-level FGEN
bands, but the strong divergence located within the favored
right entrance region of an anticyclonically curved jet
aloft. Additionally, based on the consensus of a more
northwesterly (closer inland) track of the low, the probability
of the Capital District, Lake George-Saratoga Region, Eastern
Catskills, Southern Vermont, and Berkshires being in a favored
position for strong deformation bands is moderate to high. In
fact, the latest HREF highlights these areas as seeing prolonged
0.5 to 1 and possibly as high as 1.5 inch per hour snowfall
rates tomorrow morning through tomorrow afternoon. Therefore,
we had the greatest confidence in seeing the highest snowfall
totals of 7 to 11 inches within these areas through late Tuesday
night. Elsewhere, light to moderate accumulations of 2 to 6
inches looks more likely, especially since, for areas within the
lower Mid-Hudson Valley, southern Litchfield County, and far-
southern Berkshire County will see some rain mix in as
temperatures diurnally warm.

As this is a fairly progressive system, snow should taper off,
as previously mentioned, through late Tuesday night as the
causing system swiftly departs to the northeast. Highs Tuesday
will span the upper 20s to low/mid 30s. Wednesday will then be
a much drier day as high pressure builds in at the surface with
flat ridging aloft. Temperatures will remain on the cool side
with similar values, though a couple degrees "warmer", than
Tuesday. Lows Wednesday night will fall back to the tens and 20s
with chances of precipitation increasing once again, this time
from northwest to southeast, in advance of a cold front draping
down from a low traversing northern Quebec. All snow is
anticipated once again as the precipitation type, and will be
concentrated mainly within, north and west of the Capital
District.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Snow showers from the aforementioned cold front linger into
Thursday, with some light, upslope and lake effect showers
contributing additional accumulations of 1-2" or so in the
Southwest Adirondacks and upslope regions of the Southern Green
Mountains. Accumulations elsewhere look to be slim to none. High
temperatures Thursday will be in the 20s and 30s.

Upon the passage of the cold front Thursday, high pressure
builds in across the region Thursday night, bringing fair
weather once again for the end of the work week. Arctic cold air
moves in behind the cold front however, with low temperatures
Thursday night looking to fall into the negative and single
digits for the first time this season. Highs Friday will then
only rise into the tens and 20s. Dry conditions linger into at
least part of the night Friday with lows dropping into the
single digits to tens.

The forecast for the weekend retains a fair amount of
uncertainty at this time. Medium to long range guidance shows
another coastal system developing Saturday, but most keep it
well south of our area such that no impacts from it occur at
all. One or two models show the storm clipping some of our
southern areas, but the overall probability of just 0.1" of
snow is around 20%. Therefore, we did not deviate from the
latest run of the NBM, which favors additional snow showers from
another northern-stream shortwave and cold front Saturday into
Sunday. Highs Saturday and Sunday will be in the 20s and 30s
with lows in the 10s and 20s Saturday night and single digits to
10s Sunday night.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR conditions continue for all TAF sites through 11z. A coastal
storm arrives between 11z and 13z across all TAF sites bringing
widespread snowfall. Conditions rapidly deteriorate due to low
vsibilities from falling snow between 12z and 15z becoming IFR to
LIFR. LIFR conditions continue through 02/18z.

Through 00z, winds continue to be breezy between 10 and 20
knots. Winds are forecasted to be light and variable thereafter and
through the end of the TAF period.

Outlook...

Tuesday Night: Moderate Operational Impact. Chance of SN.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Breezy. Chance of SHSN.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: Moderate Operational Impact. Chance of SN.
Saturday: Moderate Operational Impact. Chance of SN.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 7 AM Tuesday to 1 AM EST
     Wednesday for CTZ001.
NY...Winter Weather Advisory from 7 AM Tuesday to 1 AM EST
     Wednesday for NYZ032-033-038>040-042-043-047-060-061-
     064>066-082.
     Winter Storm Warning from 7 AM Tuesday to 1 AM EST Wednesday
     for NYZ041-048>054-058-059-063-083-084.
MA...Winter Storm Warning from 7 AM Tuesday to 1 AM EST Wednesday
     for MAZ001-025.
VT...Winter Storm Warning from 7 AM Tuesday to 1 AM EST Wednesday
     for VTZ013>015.

&&

$$

SYNOPSIS...37
SHORT TERM...37
LONG TERM...37
AVIATION...05