519
FXUS61 KALY 220002
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
702 PM EST Thu Nov 21 2024

.SYNOPSIS...
Low pressure will bring widespread precipitation in the
form of rain and snow tonight through Friday. Snow will be mainly
favored across the higher elevations with several inches of
accumulation expected in the Catskills. Precipitation tapers to
valley rain and high-elevation snow showers over the weekend, with
continued cool and breezy conditions.

&&

.NEAR TERM /THROUGH FRIDAY/...
Winter Storm Warning in effect for western Greene and western
Ulster counties until 1 AM Saturday for elevations mainly
above 1500 feet.

Winter Weather Advisory in effect for Schoharie County until 1
AM Saturday for elevations mainly above 1000 feet.

Update as of 615 pm EST...The H500 mid level low has moved over
PA, as a sfc low is near the Long Island and New England Coast.
The low to mid levels continue to cool with rain transitioning
to snow above 1500 feet especially west southwest of the Capital
Region. Some dynamical cooling occurred over the southern
Greens for a brief period of snow. We are getting some reports
of wet snow near Hoffmeister in Hamilton County over the past
couple hours and also parts of the eastern Catskills where the
Mesonet shows temps 32-35F. Some slight changes to rain/snow
transitioning timing and amounts, but headlines remain in place.
Some drier air has wrapped into mid and upper level low for
spotty pcpn, but will hold with categorical PoPs for now.

PREV DISCUSSION [403 pm EST]...

A dynamic low pressure system will continue to affect the region
through Friday with periods of rain and mainly higher
elevation snow. An upper-level low will slowly drift eastward
from the Ohio Valley to the mid-Atlantic overnight into Friday
with shortwave perturbations rotating around the low. One
shortwave will result in another developing surface low near
Long Island which will track west-northwestward into Friday
morning, getting wrapped into the approaching upper low.
Sufficient lift will result in continued widespread
precipitation across eastern New York and western New England.
Thus far, precipitation amounts of 0.50 to 1.00 inches have been
observed with an additional 0.50 to 1.50 inches expected tonight
through Friday. The lower additional rainfall amounts are
expected across portions of the Upper Hudson Valley where
increasing easterly winds off the southern Green Mountains in
southern Vermont will result in downsloping effects.

As temperatures slowly fall, precipitation will begin to mix
with and change to snow across the higher elevations. Mainly
rain should continue across the valleys, except a rain/snow mix
may begin around or shortly after midnight across the western
Mohawk Valley and closer to daybreak for the Hudson Valley south
of Albany. Snowfall accumulations will be dependent on surface
temperatures, elevation and precipitation intensity. In
addition, there remains a bit of uncertainty on where the
surface low tracks overnight which would impact whether or not
some southern areas become dry slotted resulting in lighter
precipitation intensities. There is a signal that if the
surface low does track closer to the Capital District, enough
cold air and frontogenetical forcing south of the low could
result in a burst of moderate snow for portions of the mid-
Hudson Valley and into Litchfield County late tonight into early
Friday morning, even in the lower elevations. If that occurs, a
slushy coating to an inch or two of snow could occur in these
areas.

The heaviest snow still appears to occur across the eastern
Catskills above 1500 feet where 6 or more inches is expected. As
a result, these areas have been upgraded to a Winter Storm
Warning. In addition, the weight of this snow could lead to some
downed trees and power lines resulting in power outages. A
Winter Weather Advisory remains in effect for Schoharie County
for amounts of 2 to 6 inches mainly for elevations above 1000
feet. Elsewhere, snowfall amounts will generally be less than 4
inches, so no winter weather products have been issued at this
time.

As the low becomes vertically stacked on Friday, precipitation
will begin to decrease in coverage and intensity, but some light
snow accumulations will remain possible, especially across the
eastern Catskills where the Winter Storm Warning is in effect.
Elsewhere, some mixed rain and snow showers are expected through
the afternoon but with little or no additional accumulation.

Temperatures will fall into the upper 20s to upper 30s tonight
rebounding to the mid-30s to mid-40s on Friday.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
The upper-level slow will slowly pull away to the east Friday
night into Saturday. Some wrap around rain and snow showers will
continue during this time but any additional snow accumulations
look to be on the order of a coating to an inch or two, mainly
for the higher elevations. There remains some model uncertainty
on if another fetch of heavier QPF advances far enough west from
another developing surface low off the New England coast into
western New England. If it does so, a period of moderate snow
would develop across the southern Green Mountains. Will monitor
trends and the progression of this system. Otherwise, the
remainder of this time period will result in mostly cloudy
conditions with a developing northwesterly breeze. Lows Friday
night will be in the upper 20s to mid-30s with highs Saturday in
the mid-30s to upper 40s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The extended forecast begins with a vertically stacked cyclone
moving into the Canadian Maritimes. A sfc trough moving through
will bring scattered rain and snow showers persisting Saturday
night into Sunday from the Capital Region north and west with
some light snow accums along the west facing slopes of the
western Dacks and southern Greens. It will be brisk and cold
with some ridging building eastward late Sunday. Lows will be in
the upper 20s to lower 30s over the higher terrain Sat night
with mid and upper 30s in the valleys. Sunday will feature brisk
conditions with seasonable temps with 30s to lower 40s over the
hills and mtns and mid 40s to around 50F in the valleys.

High pressure builds in over the region Sunday night into Monday
with a brief period of fair and dry weather. Decreasing clouds
and light to calm winds will allow for ideal radiational cooling
conditions with lows in the 20s. Mid and high clouds increase
quickly Monday during the day ahead of the next warm front to
the next system approaching from the Midwest and Great Lakes
Region. Highs will be in the 40s to lower 50s with a few cooler
readings over the mountains. The isentropic lift increases over
the region Monday night for a period of showers or stratiform
rainfall. The chances of precipitation have been raised into the
likely (55%) to categorical range (85%) Monday night into
Tuesday from the Capital Region, northern Berkshires, northern
Catskills, and west of the southern Greens north and west across
the forecast area. Probabilities look good for a quarter inch
of rain or more from the NBM. The wave quickly moves through
Tuesday. Some wet snow may mix in over the higher terrain early.
Lows will be in the upper 20s to upper 30s. Max temps for
Tuesday rise above normal, as the region gets in a dry slot
moving into eastern NY/western New England with mid 40s to lower
50s with some cooler readings over the mountains.

A weak cold front moves through Tue night with scattered rain to
snow showers especially over the Adirondack Park. Temps fall
back into the 20s to around 30F with the cold advection. The
upper low over Quebec will continue to spin and in the the
cyclonic flow, a sfc trough and short-wave will bring isolated
to scattered rain and snow showers especially west of the Hudson
River Valley. Temps will be seasonable. Attention shifts to a
disturbance ejecting out of the TN Valley and Midwest Wed night
into Thu. This storm system could bring a chance of snow/rain to
region on Thanksgiving, but there are track, evolution and
timing differences in the medium range guidance and ensembles
for Thu into Fri. Temps look colder than normal and higher pcpn
chances may be needed based on the track of the system. For now,
we will have a slight to low chance of rain/snow.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Through 00z Saturday...A complex storm system will continue to
impact eastern NY and western New England with periods of rain
and some mixing to snow over the higher terrain and near KPOU
towards daybreak. Cigs/vsbys are mainly MVFR with some lapses to
IFR noted at KPOU/KPSF. There should be a steady transition to
IFR cigs and some vsbys at all the TAF sites between
03Z-09Z/FRI. Some snow may mix with the rainfall at KPOU/KPSF
between 08Z-12Z/FRI. A brief period of wet snowfall may occur
prior to 14Z/FRI at these sites. The stalled low pressure system
will kept IFR/low MVFR cigs and occasional vsbys going through
the morning with some improvement to MVFR/low VFR cigs and vsbys
19Z/FRI at all the TAF sites. VCSH and PROB30 groups were used
for showers in the afternoon.

The winds will be north to northeast at less than 10 KT early
tonight. They will increase from the north to northeast at 10-15
KT with some gusts 20-25 KT around midnight through the early
morning hours. The winds will shift to the northeast to
southeast at 8-12 KT in the late morning with a few gusts close
to 20 KT into the early to mid afternoon.

Outlook...

Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Breezy. Chance of SHRA.
Saturday Night: Moderate Operational Impact. Breezy. Chance of SHRA.
Sunday: Moderate Operational Impact. Windy With Gusts To 30 kts. NO SIG WX.
Sunday Night: Low Operational Impact. Breezy. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
Monday Night: High Operational Impact. Likely SHRA.
Tuesday: Moderate Operational Impact. Breezy. Chance of SHRA.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Weather Advisory until 1 AM EST Saturday for NYZ047.
     Winter Storm Warning until 1 AM EST Saturday for NYZ058-063.
MA...None.
VT...None.

&&

$$

SYNOPSIS...Rathbun/Wasula
NEAR TERM...Rathbun/Wasula
SHORT TERM...Rathbun
LONG TERM...Wasula
AVIATION...Wasula