272
FXUS61 KALY 191607
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
1107 AM EST Sun Jan 19 2025

.SYNOPSIS...
Areas of snow overspread eastern NY and western New
England this afternoon from southwest to northeast with snow turning
moderate to even briefly heavy this evening, mainly for areas south
of Interstate 90. Then, dangerous cold Monday through Thursday with
the coldest temperatures likely Tuesday and Wednesday. Lake Effect
snow showers develop across the western Adirondacks Monday through
Wednesday.

&&

.NEAR TERM /THROUGH MONDAY/...

Key Messages:

- Hazardous travel late this afternoon into this evening as snow
  turns moderate to heavy at times. There is a 30-60% chance for
  snowfall rates to range 0.5 - 1 inch per hour (4pm to 11pm),
  mainly for areas near and south of Interstate 90.

- Cold and turning breezy tonight as snow diminishes after
  Midnight. Feel-like temperatures drop towards zero in the
  valley and between -5F and -15F above 1000 feet in elevation.

Latest water vapor imagery shows a pronounced moisture plume
streaming northeastward out of the Gulf of Mexico off the
Carolina coast with the latest RAP analysis indicating our sfc
low is developing over eastern NC. Increasing warm air and
moisture advection to its north and west over PA has resulted in
snow showers breaking out and advancing northeastward. Latest
high res guidance is struggling to play catch up with the latest
radar trends and observations so we have adjusted our POPs to
show the onset of light snow to be 1-2 hours earlier. We now
show chance POPs by 16 - 18 UTC in our mid-Hudson Valley,
eastern Catskills, and NW CT with chance POPs advancing
northward into the Capital District and southern VT by 18 - 20
UTC. This lines up with nose of the highest 700 hPa RH and onset
of mid-level WAA. Initial snow should be light but as the mid-
level FGEN intensifies in response to the deepening coastal
low, snow will likely become moderate to even briefly heavy at
times. Probabilistic guidance still shows 30 - 60% chances for
snowfall rates to reach 0.5 - 1 inch per hour from 21 - 03 UTC
with the highest probabilities mainly south of I-90. During this
time, travel will the be the most hazardous and we advise
everyone to stay off the roads for non-essential travel. A light
northerly breeze will also be in place which will reduce
visibility further. As mid-level forcing intersects the DGZ
during this time, SLRs will increase to 15 - 18:1 leading to
very light/fluffy snow. Still expecting snowfall rates to be
lower mainly north/west of the Capital District which will be
farther removed from the strong snow bands within the deformation
zone.

This will be a fast moving storm with the strongest mid-level
forcing/FGEN exiting by Midnight. However, high res guidance
suggests that some Mohawk Hudson Convergence (MHC) develops in
the wake of the coastal low around or shortly after Midnight as
winds remain northerly down the Hudson but shift westerly down
the Mohawk. This looks to support a period of steady light snow
in the immediate Capital District and eastern Mohawk Valley
through 09 UTC producing an addition inch of light/fluffy snow.
Sometimes the "bonus snow" we receive on the back end of storms from
MHC can overperform but latest high guidance is not overly
enthused so up to 1 inch additional snow seems reasonable at
this time. Will continue to monitor trends. Upslope snow
showers also lingering across the Taconics and southern Greens
after Midnight as northwesterly winds develop producing up to an
additional inch of snow as well. ALl in all, expecting 3 to 6
inches in the Winter Weather Advisory areas, again lower amounts
north/west of Albany. For areas in the Winter Storm Warning,
expecting 5 to 8 inches with the highest amounts in the
Taconics, western MA, NW CT and southern VT where the
probabilities for up to 1 inch per hour snowfall rates this
evening are highest. Probabilities for snowfall amounts to
exceed 6 inches range 60 to 80% for the winter storm warning
areas and 30 to 60% for the winter weather advisory areas.
Probabilities decrease heading north/west of Albany with only 25
to 40% for the southern/western Adirondacks, western/central
Mohawk Valley and Lake George area.

Temperatures will be at their highest before snow arrives
reaching into the low 30s. Then, temperatures fall through the
afternoon as snow begins quickly dropping into the low 20s by
sunset. Temperatures continue decreasing overnight as cold air
advection in the wake of the departing coastal low intensifies
reaching into the single digits by sunrise (even sub-zero in the
western Adirondacks). Given northerly winds will turn a bit
breezy becoming sustained 5-10kts with gusts up to 20-25kts,
wind chills or "feel-like" temperatures will be even colder and
more like around -10F to 0F.

Monday...Dry conditions are in store as the coastal low is
further north and high pressure to our south builds in expect
for the western Adirondacks where Lake Effect snow showers begin
during the afternoon hours on Monday. Arctic air settles in
Monday with highs in the teens and low 20s and sticks around for
the short and long term (discussions below).

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
Key Messages:

 - Bitter cold temperatures begins Monday night

 - Lake effect snow starts Monday into Tuesday across the
   western Adirondacks.


Discussion:
Dry conditions return through Tuesday with the exception of the
western Adirondacks. Lake Ontario is favored by latest forecast
models to bring chances of lake effect snow showers to the
western Adirondacks through Tuesday. Exact band placement and
snowfall amounts are uncertain due to shifting in latest model
guidance of where the heavy snowfall occurs, but confidence
continues to increase with upper level flow to favor lake effect
snow development off of Lake Ontario to bring these chances of
snow showers to the western Adirondacks.

For temperatures, the arctic cold air continues. Tuesday
morning lows are forecasted to be in the negatives and single
digits. Feel like temperatures are going to be even colder as
winds continue to be breezy through Tuesday afternoon with
temperatures feeling 5 to 25 degrees below zero (colder in
mountainous terrain). Highs on Tuesday are cold with mountainous
terrain locations in the single digits and in the teens for the
valley locations (ranging between 10 to 17 degrees). Winds
decrease Tuesday evening. Forecast confidence is very high due
support of high probabilities being greater than 95 percent by
latest National Blend of Models 4.2 data for across all of
eastern New York and western New England for high temperatures
being below 20 degrees and low temperatures being below 5
degrees. Cold Weather Advisories for high terrain locations
continues to be monitored for this time period.

&&

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

- High confidence for bitterly cold temperatures Tuesday
night through Thursday morning.

- Strong upper level impulses may bring a period of light snow or
snow showers to the region Tuesday night into Wednesday and again on
Friday.

Discussion:

Main story for the long term period will be the persistence of a
bitterly cold air mass across the entire area through Thu morning.
Tue night and Wed night, Cold Weather Advisories may be needed
especially for higher terrain areas. 850 mb temperature
anomalies are forecast to be -1 to -3 STDEV, which is significant
for mid January. Actual low temperatures Tue and Wed night expected
to be around zero to -10F, with even a light breeze of 5-10 mph at
times would result in minimum feels-like temperatures of -5F to -15F
in valleys and -15F to -25F in the higher terrain. Not much relief
will occur during the daylight hours, with highs only in the single
digits to mid 10s Tue and Wed. Some slight moderation out of the
frigid cold is expected Thu afternoon with highs in the mid 10s to
lower 20s. Lows should drop into the single digits Thu night, but
not below zero like the previous several nights. Temperatures should
eventually get back to near normal levels Fri into Sat.

In terms of precipitation, lake effect should linger into Tue
night over northern Herkimer County and northwest Hamilton County.
Strong upper level impulses may bring a period of more widespread
light snow or snow showers to the region Tuesday night
into Wednesday and again on Friday. We will need to monitor second
impulse for potential coastal storm development and how far
north/west it may get. Deterministic and ensemble guidance
indicating it will remain too far south/east to bring significant
snow to our area at this time.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Through 12z Monday...VFR conditions at KALB and KGFL. IFR
conditions at KPOU and KPSF. Conditions should gradually improve
to VFR all TAF sites Sunday morning. VFR conditions should then
prevail until snow develops associated with an approaching
coastal storm. Snow looks to begin between 19-21Z and LIFR
vsbys/cigs in snow expected at KALB KPOU and KPSF with IFR
conditions forecast at KGFL. Winds will be northwest this
morning at 5-15 kt before becoming north to northeast Sunday
afternoon at 10 to 15kt. Some gusts to 20 kt are possible Sunday
night at KPOU and KPSF.


Outlook...

Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Storm Warning until 7 AM EST Monday for CTZ001-013.
NY...Winter Storm Warning until 7 AM EST Monday for NYZ054-058>061-
     063>066.
     Winter Weather Advisory until 7 AM EST Monday for NYZ040-041-
     043-047>053-084.
MA...Winter Storm Warning until 7 AM EST Monday for MAZ001-025.
VT...Winter Storm Warning until 7 AM EST Monday for VTZ013>015.

&&

$$

SYNOPSIS...Speciale/Webb
NEAR TERM...Speciale/Webb
SHORT TERM...Webb
LONG TERM...SND
AVIATION...SND