940
FXUS61 KALY 092106
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
406 PM EST Tue Dec 9 2025

.SYNOPSIS...
After a chilly Tuesday, expecting a quick moving clipper to
usher in widespread snow starting late tonight through the day
tomorrow. A period of moderate to heavy snow is likely in the
higher terrain areas through early afternoon leading to
slippery travel while marginal temperatures likely keeps snow
accumulations light elsewhere. Then, much colder temperatures
and gusty winds arrive for Thursday with potential for
additional snow accumulations from lake effect and upslope snow.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Key Messages:

- Winter Storm Watches have been upgraded to Winter Storm
  Warnings for the western and southern Adirondacks from 4AM
  Wednesday through 7AM Thursday.

- Winter Weather Advisories have been issued for the southern
  Greens, the Upper Hudson Valley, and portions of the eastern
  Catskills from 4AM Wednesday to 1AM Thursday where 3 to 6
  inches of snowfall is expected. Slippery travel for the
  Wednesday morning and evening commute is likely.

- There is 30 to 60% chance for wind gusts to exceed 35mph on
  Thursday as well as 20 to 40% chance for at least 2 inches of
  snow in the western Mohawk Valley, southern Greens, and
  southern Adirondacks from lake effect and upslope snow. The
  combination of gusty winds and freshly fallen snow can also
  result in blowing/drifting snow on Thursday.

Discussion:

High pressure and the continental polar air mass that resulted
in frigid temperatures today will continue shifting to our east
this evening. Then, a series of clipper disturbances will
impact portions of the Northeast tonight through tomorrow. The
first is set to arrive this evening and while the sfc low is
displaced well to our north and west tracking through the Upper
Midwest, a quick push of warm air and moisture advection will
lead to a period of steady snow in the southern Adirondacks and
southern Greens mainly from 00 to 06 UTC. Upsloping along the
south facing slopes of the Adirondacks looks to enhance QPF
amounts tonight leading to a quick 1 to 2 inches of snow.
Otherwise, temperatures tonight will likely be coldest at the
beginning of the night tonight in the 20s and then stay steady
or even rise a few degrees overnight as clouds thicken/lower.

Our next stronger and quick moving clipper will arrive right on
its tail late tonight as it tracks through the Great Lakes and
up the Saint Lawrence River Valley through the day tomorrow.
Given its westerly track, a period of strong isentropic lift
starting 09 - 15 UTC tomorrow morning will lead to snow quickly
breaking out over the southern Adirondacks, Mohawk Valley,
Upper Hudson Valley and northern/eastern Catskills. Upsloping
enhancements along the south facing slopes of the southern
Adirondacks will quickly promote moderate to heavy snowfall
rates developing shortly after snow begins with the HREF showing
50 to 80% chances for hourly snowfall rates to exceed 1" with
even 20 to 30% chance for 2"+ snowfall rates through early
afternoon. Moderate to heavy snowfall rates 0.5-1" per hour even
spill into the foothills of the Adirondacks and into parts of
the Upper Hudson Valley and southern Greens which can lead to
slippery travel for the morning commute. Further south and east,
temperatures will be cold enough to support all snow but
forecast soundings show the thermal profiles quickly moderating
in response to the strong southerly winds/warm air advection so
snow to liquid ratios look to be under climo ranging 7-10:1.
This we likely result in a wetter type of snow with a reduced
snow accumulation efficiency. Therefore, our current forecast
only shows coatings up to 2 inches for the rest of eastern NY
and western New England and there is less than a 20% chance for
snowfall amounts to exceed 2 inches. The highest chance for snow
to accumulate in these areas will be through early afternoon as
temperatures continue to slowly warm into the mid-30s
thereafter, making it more difficult for snow to accumulate.
Even still, travels should drive carefully and allow extra time
to their destination as the recent stretch of cold weather
means the ground will be plenty cold and any untreated wet
surfaces can quickly turn slippery/icy. Latest forecast shows 7
to 12 inches for the southern Adirondacks most of which falls
through the day Wednesday so that was certainly enough
confidence to warrant winter storm warnings with winter weather
advisories in the western Mohawk Valley, Upper Hudson Valley,
southern Greens and portions of the eastern Catskills where 2 to
5 inches is expected. Locally higher amounts 5 to 8 inches in
the southern Green Mountains of southern VT.

By late Wednesday afternoon into the evening, the warm sector
and strongest isentropic lift escapes to our east with a dry
slot wrapping into the region. This will reduce the coverage of
snow (or rain/mix in valley areas) for the evening hours as
enter in a bit of a lull. However, shortly after Midnight, the
main cold front and trough axis swings through from west to east with
winds quickly shifting to the west-northwest and turning
breezy as another chilly Canadian air mass surges eastward.
Additional snow showers are possible with this front with
upslope snow developing in the southern Adirondacks. Otherwise,
it will turn chilly again by early Thursday morning as many drop
into the low to mid 20s with even teens in higher terrain areas.

Thursday remains chilly and blustery as strong cold air
advection continues through the day as our clipper deepens in
southern Quebec. Forecast soundings show deep boundary mixing
ensuing as the colder Canadian air pours into the region with
the top of the mixed layer even reaching 40-50kts. Latest
probabilistic guidance shows 30 to 60% chance for wind gusts to
exceed 35mph with the highest values down the Mohawk Valley,
Capital District into western MA/southern VT. While there is
low confidence that we will need wind advisories, there is a
strong signal that lake effect and upslope snow showers will
develop on Thursday as the parent closed cyclone tracks through
Quebec and pushes into northern New England. Once the closed
low pushes to our east by midday, guidance shows lake bands
becoming better organized off Lake Ontario as strong west-
northwest winds flow over the long fetch of the lake. The set-up
at 500hPa even hints at the potential for a multi-lake
connection but there seems to be higher confidence for a multi-
lake band to form off Lake Erie and be directed into northern
PA. We will continue to monitor trends as the RGEM shows the
potential for a single lake band to track into portions of the
Mohawk Valley and northern Catskills midday into the afternoon
on Thursday. Despite uncertainly in the exact placement of any
lake bands, we will also need to monitor upslope snow in the
western Adirondacks, southern Greens, western MA and Taconics
late Thursday P.M into Thursday night as flow becomes more
westerly. Given blustery winds and freshly falling snow, blowing
snow can also reduce visibility and recover any cleared
surfaces. Latest guidance shows a 30 to 50% chance for at least
2 inches of snow from 7AM Thurs to 7AM Fri in the western Mohawk
Valley and western Adirondacks with a 10% chance in the
southern Greens, Taconics and western MA. Depending on how
trends shift with the lake effect and upslope snow, additional
winter weather advisories may needed.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Key Message:

- High confidence in below normal temperatures continuing,
  along with chances for light snow or snow showers.

Discussion:

It will remain chilly into Friday as weak surface ridging builds
overhead on Fri promoting dry conditions, although a westerly
flow aloft can support lingering light lake effect snow showers
in the W. Adirondacks and W. Mohawk Valley. Then, an upper
level low and large scale trough dig across the Great Lakes and
SE Canada Saturday night into Sunday which could result in a
brief window for cyclogenesis along/near the mid Atlantic coast
early Sunday. At this time guidance is showing potential for
development, but it may occur just to our east depending on when
the trough takes on a negative tilt. This could spread some
light snow into at least parts of the area. Will continue to
monitor trends.

The upper trough settles into the Northeast Sun into Mon, with
another Arctic air mass building in. So temperatures should be
well below normal again during this time. 850 mb temperature
anomalies from the NAEFS are forecast to be -1 to -2 STDEV.
There will be some wind at least through Sun night with high
pressure to the west, so wind chills could be below zero across
much of the area. High pressure builds in on Mon with winds
diminishing, but temperatures remaining cold.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
VFR conditions will prevail at area TAF sites through this
afternoon. There will likely be periods of low level wind shear
from 00Z-06Z as a 40+ knot low level jet moves across the
region. A clipper system will result in snow overspreading the
area between 12Z-15Z Wednesday morning with IFR conditions
likely at most TAF sites after 15Z with the exception of KPOU.
Snow is generally expected to end from west to east after 21Z on
Wednesday, but MVFR/IFR conditions will likely continue into
Wednesday evening.

Outlook...

Wednesday Night: Moderate Operational Impact. Chance of RA.
Thursday: Low Operational Impact. Breezy. Slight Chance of SN.
Thursday Night: Low Operational Impact. Slight Chance of SN.
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...None.
NY...Winter Storm Warning from 4 AM Wednesday to 7 AM EST Thursday
     for NYZ032-033-082.
     Winter Weather Advisory from 4 AM Wednesday to 1 AM EST
     Thursday for NYZ038-041>043-063-083.
MA...None.
VT...Winter Weather Advisory from 4 AM Wednesday to 1 AM EST
     Thursday for VTZ013-014.

&&

$$

SYNOPSIS...31
SHORT TERM...31
LONG TERM...07/31
AVIATION...91