129
FXUS61 KALY 052323
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
623 PM EST Wed Feb 5 2025

.SYNOPSIS...
Dry conditions continue through tonight with increasing clouds. A
weather system arrives tomorrow morning bringing an onset of snow,
changing over to a wintry mix late tomorrow morning and early
afternoon before departing to the north and east by tomorrow
evening. Chances of lake effect snow across the western Adirondacks
Friday, then potential for another weather system for this
weekend.

&&

.NEAR TERM /UNTIL 4 AM THURSDAY MORNING/...
Updates:

As of 6:10 PM EST...A quiet evening is in store for eastern New
York and western New England with high pressure still overhead.
Temperatures currently range from the upper teens to low 20s,
with lighter winds around 5-10 MPH our of the west. Slight
changes have been made to sky cover to account for increasing
clouds aloft ahead of an approaching system across the Ohio
River Valley; otherwise the forecast remains on track. See
previous discussion below...

Previous Discussion...Dry conditions continue through tonight
under surface high pressure. Winds have been periodically
gusting between 15 and 25 mph across the Mohawk Valley, Greater
Capital District, the Berkshires, and southern Vermont this
afternoon that should decrease to less than 10 mph through
tonight. Temperatures tonight stay cold with lows in the
negatives across the western Adirondacks and ranging in the
sinle digits to low teens elsewhere. Clouds begin to increase
after midnight as the next weather system starts to approach for
tomorrow morning.

&&

.SHORT TERM /4 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Key Messages:

  - High confidence (>75%) in a quick moving weather system
    bringing snow for tomorrow morning then transitioning over
    to a wintry mix during the early afternoon hours.

 - Slippery conditions are expected for the morning and
   afternoon commute tomorrow.

Discussion:

A surface low pressure system arrives tomorrow morning as surface
high pressure departs to our east and our next weather system
arrives from the south and west. As temperatures start off being
below freezing, precipitation is going to begin as all snow between
5 AM and 8 AM. Snow continues through the early morning hours
and could be moderate and heavy at times through the morning
hours. Snow then transitions to a wintry mix of sleet/freezing
rain/rain as temperatures warm to above freezing during the
early afternoon hours as warmer air aloft develops. As this
system is fast moving, precipitation quickly comes to an end
between 2 PM and 5 PM from south to north across eastern New
York and western New England. High resolution model guidance is
in good agreement for lingering light freezing drizzle or light
freezing rain for southern Vermont and the western Adirondacks
through the early evening hours before diminishing for the
overnight hours.

The snowfall forecast is still on track for widespread amounts
between 1 to 4 inches. For ice accumulations, we are still
expecting a light glaze to a few local spots receiving up to a
ten of an inch. The Winter Weather Advisories continue for
tomorrow morning into tomorrow evening for all of eastern New
York and western New England. Slippery pavement conditions are
expected for tomorrow morning and afternoon commutes, use extra
caution while traveling tomorrow.

A cold front moves through Thursday night and Friday bringing a
return to cooler air with Lake Effect snow showers favored to
develop for Friday across the western Adirondacks and upslope
snow for the southern Greens and northern Berkshires. Additional
snowfall amounts range between 1 and 3 inches. High temperatures
Friday stick around to near freezing with the exception of the
Mid-Hudson Valley where temps could reach into the upper 30s.
Otherwise breezy conditions are in store for Friday with wind
gusts between 25 and 35 mph and a mix of sun and clouds.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Key Message:

 - Winter storm system is expected to bring mainly snow north of
   I-84 and/or mixed wintry precipitation towards I-84 Saturday
   night into Sunday, with a 60-95 percent chance of greater
   than 4 inches of snow across the entire forecast area and a
   50-70 percent chance of 6" or greater from the I-90 corridor
   north and east.

Discussion:

The weekend begins with high pressure building in over the region
with cold and dry conditions, as a cold front sags south of the
region. Temps will be slightly below normal with mainly 20s to lower
30s.  Attention shifts to low pressure organizing over the Midwest
and moving towards the Ohio Valley early Saturday night.  The mid
and upper level flow will be flat ahead of a developing progressive
open wave cyclone.  Clouds quickly thicken and lower with the low to
mid level isentropic lift increasing for snow to blossom across the
forecast area.  The strengthening low-level jet will focus some gulf
moisture with the snow increasing in intensity, as the low-level
baroclinic zone enhances.  The latest medium range
guidance/ensembles including the GFS/CMC/EC/GEFS/GEPS are converging
with the sfc cyclone redeveloping further south and east near
eastern NJ and Long Island by 12Z/SUN. The location for the
secondary cyclogenesis will be critical for the coverage of the snow
ptype. This track would favor more of a snow solution with perhaps
some mix near the mid Hudson Valley/I-84 corridor into NW CT.  We
have maintained mostly snow with this forecast with some minor
deviations from the NBM...but a moderate to locally heavy snowfall
looks possible and Winter headlines including Winter Storm Watches
may be needed for portions of the ALY forecast area later in time.
The latest NBM4.2 24-hr probabilities for >4" of snow 00Z Sun/7 pm
Sat to 00Z Mon/7 pm Sun are 60-95% from approx. I-84 northward, and
>6" from roughly I-90 northward.  Closer to I-84 low chance
probabilities for ice are the greatest in the 25-40% range for 0.01-
0.10".  All said, an impactful storm Sat night through most of
Sunday morning is likely.  The storm  should wind down quickly Sun
morning. The upper deformation snowfall may linger close to the
early pm across parts of western New England and northeast of the
Capital Region with additional light snow accums. A little light
rain may mix in south of Albany too. Lows will be in the teens and
lower 20s and will steadily rise towards daybreak with highs in the
20s to lower/mid 30s.

High pressure builds back in the wake of the quick moving storm
system Sunday night into Monday. A few lake effect snow showers and
flurries are possible early on over the western Dacks and western
Mohawk Valley.  Lows fall back into the single digits and teens with
a few below zero readings over the Adirondack Park.  Cold and dry
conditions continue Monday with the mid and upper level flow
remaining zonal and split.  The  dry weather mainly only last into
Tuesday with another southern stream system ejecting out of the
Southeast and Mid Atlantic States. Lows will be chilly in the single
digits and teens.

Confidence remains low with the next system with a lot of spread in
the medium range guidance and ensembles with the track and timing.
We followed the NBM and bring chances of light snow across the
region Tuesday from south to north and continued those chances into
Tue night and Wed.  Its possible Tuesday remains dry, as the mid and
upper level trough amplifies over the central CONUS with the storm
slipping out to the south with a sharp cutoff in the snowfall.
However, accumulating snowfall does look possible over some portion
of the forecast area into the mid-week.  Temps Tue-Wed look slightly
below normal, as we head into mid-Feb.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...VFR conditions expected to prevail through
the first several hours of the TAF forecast. Then snow will
quickly develop from southwest to northeast between 11z and 13z
with conditions quickly deteriorating to IFR after onset of
snow. Within an hour after onset, a 2-4 hour period of moderate
snow is expected with further deterioration to LIFR expected at
all TAF sites. Between 14z-17z, snow will mix with sleet and/or
freezing rain before tapering off to freezing drizzle
thereafter. Mainly IFR conditions should prevail once the steady
precipitation tapers off.

Will mention low level wind shear mainly between 12z-18z
Thursday at KALB/KGFL/KPOU as southerly winds increase to 30-40
kt during this time with surface winds less than 10 kt. The LLWS
will dissipate after 18z. Surface winds will be variable around
5 kt or less through 12z Thursday, then become east-southeast
around 4-8 kt.

Outlook...

Thursday Night: Low Operational Impact. Breezy. NO SIG WX.
Friday: Moderate Operational Impact. Windy. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: High Operational Impact. Definite SN.
Sunday: High Operational Impact. Breezy. Likely SN.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 4 AM to 6 PM EST Thursday for
     CTZ001-013.
NY...Winter Weather Advisory from 4 AM to 6 PM EST Thursday for
     NYZ038-040-047>049-051>054-058>061-063>066.
     Winter Weather Advisory from 7 AM to 6 PM EST Thursday for
     NYZ032-033-039-041>043-050-082>084.
MA...Winter Weather Advisory from 4 AM to 6 PM EST Thursday for
     MAZ001-025.
VT...Winter Weather Advisory from 7 AM to 6 PM EST Thursday for
     VTZ013>015.

&&

$$

SYNOPSIS...Webb
NEAR TERM...Webb
SHORT TERM...Webb
LONG TERM...Wasula
AVIATION...JPV