829
FXUS61 KALY 121130
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
630 AM EST Wed Feb 12 2025

.SYNOPSIS...
Seasonable temperatures are expected today with a partly
to mostly cloudy sky.  A storm system will bring a wintry mix to the
region tonight, which will change to some spotty light rain for many
areas before ending on Thursday.  As colder air returns, lake effect
snow will impact the western Mohawk Valley on Thursday night into
Friday before another large storm impacts the entire region over the
weekend with more rain and snow.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 630 AM EST...Storm system continue to depart off the mid
Atlantic coast this morning. There had been some light snow that
impacting far southern parts of Dutchess and Litchfield
Counties earlier in the overnight, but this has settled south
and east of the region and no additional snowfall is expected
for these areas this morning.

Meanwhile, a surface cold front continues to slowly settle
southward and this front is now located across the Catskills,
mid Hudson Valley and eastward towards the southern Berkshires
and NW CT. Areas south of the front continue to see some mid
and high level clouds (along with some lower clouds closer to
the departing storm near the coast). Meanwhile, areas to the
north are fairly clear, with just some spotty lower clouds over
the western Adirondacks and some thin cirrus, especially for
areas closer to the frontal boundary.

Through the morning hours, this front will be slowly pushing
southward, but also starting to dissipate and fall apart. Sky
cover will continue to be fairly clear for a good portion of the
area for this morning, but far southern areas will still see a
fair amount of mid and high level cloud cover. Temps vary across
the region to start the day, with fairly cold conditions for
northern areas with temps near zero or the single digits where
skies have cleared, while southern areas continue to be in the
20s.

Although the morning will start with fairly clear skies for
northern areas, clouds will be on the increase for the entire
area by the late morning and afternoon hours, as the next system
starts to approach from the southwest. Otherwise, temps will
reach the mid 20s to mid 30s across the region by this afternoon
with light winds and no precip through the daylight hours.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Key Messages:

 -Winter Weather Advisory in effect as light wintry mix to
  bring slippery conditions to the Thursday morning commute

 -Winter Storm Watch issued for western Mohawk Valley for
  Thursday night into Friday, as localized lake effect snow
  totals may approach 7 inches for areas close to the Oneida
  County border.

Discussion:

Surface low pressure will be lifting from the Ohio Valley
towards the eastern Great Lakes for tonight. A warm front
associated with this low pressure area will be approaching from
the southwest. Isentropic lift, aided by a 40-50 kts southerly
low level jet, will allow for a period of light precip to
spread across our area for the overnight hours. The precip will
not be quite as steady as what models had suggested a few days
ago, and precip may be somewhat spotty and sporadic. While areas
close to the coast may see a more steady areas of precip thanks
to a developing secondary area of low pressure, the main areas
of lift associated with the primary low pressure area will be
well west of the area across Ontario and Quebec.

As a result, precip will be light and intermittent overnight,
but may be aided in areas of terrain, where upslope flow may
help squeeze out some more precip. While all areas are expected
to see light snow initially, the strong low level jet will be
allowing a warm nose aloft to move towards the area for the late
night hours. This will allow for precip to mix with and change
over to sleet and freezing rain by the late night hours from
south to north. A change over to plain is even expected for
parts of the Capital Region and mid Hudson Valley around
daybreak or on Thursday morning, as surface temps rise just
above freezing. The storm`s dry slow will also be rapidly
approaching on Thursday morning as well, so most areas will see
precip become even more intermittent and spotty for during the
day on Thursday, with some patchy light rain or drizzle (perhaps
freezing drizzle in colder, sheltered areas) through the day on
Thursday, as the low pressure passes by to northwest.

Most areas will only see a coating to an inch or two of snow.
Some colder areas of southern VT and the Adirondacks could
locally see up to 4 inches, although most locations will not see
much snow with this system due to the limited QPF, poor ratios
and mixing with sleet/zr. A light glaze of ice can be expected
as well (locally up to two tenths across sheltered high terrain
areas) and a tenth or two of sleet is possible as well. Slippery
travel is anticipated for the Thursday morning commute,
especially on untreated surfaces and across northern areas and
higher elevations. After overnight lows rising through the 20s,
temps on Thursday will reach into the 30s, with some lower to
middle 40s possible across far southern areas. In addition,
gusty winds are possible on late Wed night into Thursday
morning, especially for western and high terrain areas, with
some gusts up to 30-35 mph at times.

By Thursday evening, the storm will be well past the area and
colder air will start to filter in behind the departing storm.
With temps cooling off at the surface and aloft, a band of lake
effect snow looks to develop off Lake Ontario. With the
northwest flow in place, this will primarily impact central NY
and into parts of the western Mohawk Valley. The band may drift
from the western Mohawk Valley towards parts of Schoharie County
at times, but a moderate accumulation is possible for parts of
far southwestern Herkimer County. Locally heavy accumulation
can`t be ruled out between late Thursday night into Friday, so a
Winter Storm Watch has been issued for that area. Elsewhere, it
will be colder and windy for Thursday night into Friday with
some passing flurries. Temps will be in the teens and 20s on
Thursday night and won`t be rising too much more on Friday
thanks to the strong cold advection in place.

Lake effect snow may start to wind down on Friday night, but it
will remain cold with a diminishing wind. Although skies will be
fairly clear to start Friday night, some clouds will be increase
late ahead of the next storm system, with lows in the single
digits and teens.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Messages:

- Another potentially high-impact storm system is expected to bring
widespread precipitation, including snow, a wintry mix, and/or rain,
to the entire region Saturday and Sunday.

- Confidence in precipitation types and the timing of the transition
from snow to a mix or rain remains low.

- A period of very cold and windy weather with lake effect snow is
possible behind the departing storm system early next week.

Discussion: Very active long term period begins at 12z Saturday. A
TPV lobe centered over south-central Canada will eventually phase
with a potent southern stream shortwave disturbance Saturday night
into Sunday. The resulting surface low that forms near the lower
Mississippi River Valley will rapidly strengthen as it tracks towards
the northeast Saturday night and Sunday. The storm system will
likely track over NY State, as opposed to off the coast.

Out ahead of this system, an area of light to possibly moderate snow
is expected to overspread the region from west to east during the
day Saturday. This will be forced by isentropic lift along the
system`s warm front and will occur beneath the right entrance region
of an anti-cyclonically curved upper jet streak that will be lifting
to our northeast. As the surface low intensifies and tracks closer
to our region, the warm front will eventually lift northwards,
allowing for the snow to transition to a wintry mix from south to
north, with a changeover to a cold rain possible on Sunday,
especially south of I-90. Precipitation could be heavy at times
Saturday night and Sunday, but will taper off to snow showers Sunday
evening or night.

Now, there remains considerable uncertainty in the exact storm
track, which will have large implications for how much wintry precip
(snow, sleet, freezing rain) our area sees. Confidence is fairly
high that even the Mid Hudson Valley will start as snow Saturday,
but confidence decreases substantially beyond that. Recent trends
have been for the TPV lobe in southern Canada to be located further
to the west, as well as for stronger downstream ridging over the
North Atlantic. Both of these trends are associated with a further
west shift in the storm track, and we have indeed seen that in the
ensemble mean MSLP fields over the past 24 hours or so. This is why
there has been a trend towards a warmer solution with higher
probabilities for a changeover to rain Sunday, especially south of
the Capital District. Nevertheless, there are still several ensemble
members, as well as the deterministic CMC, that have a colder
solution with more snow for our region. Even with this recent trend
warmer, NBM probabilities still show around a 25% chance of
exceeding advisory criteria (>4" of snow) near the I-84 corridor,
with higher values further north/in the higher elevations where
probabilities for >4" of snow are over 90%. Will mention that
despite the uncertainty, qpf amounts look to be over 1" for most of
the region, so this storm does have some potential for higher
impacts especially if the forecast trends back colder.

The surface low continues to intensify as it tracks into
southeastern Canada and becomes occluded beneath the upper low. The
cold front will track through the region Sunday night into Monday,
ushering in a very cold airmass in the storm`s wake as the TPV lobe
swings by to our north through the first half of the week. Guidance
suggests 850 mb temperatures could approach -25C, which would
translate to highs in the 10s to 20s Monday and Tuesday with
overnight lows in the single digits to below zero. With a very tight
pressure gradient between the deep low to our northeast and a strong
high building over the center of the country, winds could become
quite gusty, making for wind chills that are substantially colder
than the actual air temperature. The combination of very cold
temperatures and strong low-level W/NW winds could also lead to the
development of a band of lake effect snow off of Lake Ontario that
could extend well into our forecast area early next week. While the
potential is there, will note that it is rather early to get any
more specific regarding the lake effect potential as even the larger-
scale details surrounding the track of the weekend storm remain
uncertain. Temperatures should begin to moderate more towards the
middle of the week, but then we will be monitoring the potential for
yet another storm system that could track somewhere near the east
coast.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Through 12z Thursday...VFR conditions at all TAF sites this morning
persist through late this afternoon or early evening with just
increasing mid and high clouds through the day today. An area of low
pressure will bring light snow to the region tonight. Start time
remains somewhat in question due to the fact that snow showers will
be rather scattered for the first few hours of the event, so have
used tempo groups to highlight this and will continue to refine with
future updates. Within snow showers, IFR vsbys and MVFR to IFR cigs
expected, with prevailing MVFR cigs outside of any snow.
Precipitation becomes steadier overnight, with a transition to
sleet, freezing rain, and possibly plain rain at POU by 12z
Thursday. Have tried to time out the precip type transitions using
prob30 groups, but these too may need to be refined with subsequent
TAF issuances.

Winds will be from the north/northeast at 5-8 kt this morning, then
veer more to the east by this afternoon and eventually the southeast
this evening, except at GFL where light northerly winds remain
through the night. Southeast winds could become gusty, especially at
PSF tonight. Will also mention LLWS at all terminals for most of the
overnight period as a strong low-level jet moves overhead.

Outlook...

Thursday Night: Low Operational Impact. Breezy. Slight Chance of SHSN.
Friday: Moderate Operational Impact. Breezy. Chance of SHSN.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: High Operational Impact. Definite SHSN...SN.
Saturday Night: High Operational Impact. Definite SN...FZRA.
Sunday: High Operational Impact. Definite RA...SN...FZRA.
Sunday Night: Moderate Operational Impact. Windy With Gusts To 30 kts. Likely SHSN.
Washingtons Birthday: Moderate Operational Impact. Windy With
Gusts To 37 kts. Slight Chance of SHSN.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Thursday for CTZ001-013.
NY...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Thursday for NYZ032-033-038>043-047>054-058>061-063>066-
     082>084.
     Winter Storm Watch from Thursday evening through Friday
     evening for NYZ038.
MA...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Thursday for MAZ001-025.
VT...Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Thursday for VTZ013>015.

&&

$$

SYNOPSIS...Frugis
NEAR TERM...Frugis
SHORT TERM...Frugis
LONG TERM...Main
AVIATION...Main