Albany Office Forecast Discussion

000
FXUS61 KALY 180853
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
353 AM EST Sun Nov 18 2018

.SYNOPSIS...
High pressure will be over eastern New York and western
New England briefly today, then clouds will increase during the
late morning into the afternoon with mainly light snow
overspreading the region with low pressure tracking across
Pennsylvania. The light snow will continue through tonight
before tapering to scattered rain and snow showers on Monday.
Unsettled weather continues on Tuesday with another low pressure
system bringing some rain and snow to locations south of the
Capital Region, while a cold front brings snow showers to
locations north and west of Albany.

&&

.NEAR TERM /Until 6 PM EST TODAY/...
As of 353 AM EST...The lower clouds are continuing to erode
some on the 10.3-3.9 micron GOES-16 low cloud product across
eastern NY and western New England. High pressure /1030 hPa/ is
building in from the eastern Great Lakes Region, and southeast
Ontario over upstate NY and New England late this morning into
the afternoon. Mid and high clouds will begin streaming in from
the south and west as the broad upper level trough centered over
north-central Canada will continue to influence the weather
over the region. The mid and upper tropospheric flow becomes
west to southwest. A short-wave moving through the Midwest/OH
Valley will move east/northeast towards the region.

High pressure will retreat downstream during the afternoon.
North of the old cold front, and ahead of the weak wave moving
across the OH Valley, an over-running scenario will set-up.
Low-level warm advection with a modest low-level jet will tap
appreciable moisture for light snow to overspread the region
from the west/southwest to the north/northeast during the
afternoon. The isentropic lift increases on the 290K sfc, and
the right entrance region of an H250 jet streak will help focus
the light snow. The baroclinic zone looks like it will set-up
over the central portion of the forecast area with a sharp
gradient in the light snow across the southern Adirondacks, and
a light rain/snow mix across the mid-Hudson River Valley/NW CT
with the boundary layer being a tad too warm initially.

Snowfall amounts prior to nightfall will be an inch or less for
the northern/eastern Catskills, Schoharie Valley,
western/central Mohawk Valley and Helderbergs. A coating to a
few tenths for the Capital Region north and east. Temps will
continue to be below normal with mid 20s to lower 30s over the
mountains, and lower to mid 30s in most locations, except upper
30s in the mid Hudson Valley and portions of Litchfield County,
CT.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
Tonight...A stratiform region of light snow will continue to
impact a large portion of the forecast area, as the low-level
baroclinic zone continues to be situated over the region with a
modest low-level southerly wind anomaly at H850 /1-2 STD DEVS/
above normal on the latest 00Z GEFS passes south and east of the
region. The sfc low moves along the PA-MD border with the
best FGEN in the low to mid levels passing from roughly the I-90
corridor south and east. We kept the phrasing light snow for
most of the night with generally total light snow accumulations
of 1-2". The best chance of 2-3" will be over the eastern
Catskills, northern Taconics, Berkshires, and southern Greens.
The Lake George Region, and southern Dacks may only get an inch
or less. Also, the mid-Hudson Valley and NW CT may also get an
inch or less. A few spot 3-4" amounts are possible in the
northern Berkshires based on the HREFs, bit confidence is not
great enough for a 12-hr window for an advisory with the
criteria being a widespread 3". The Capital Region, Mohawk
Valley, Saratoga Region, and Schoharie Valley will be in the
1-2" range. If the wave moves slightly further north and east
over southern NY like some of the guidance, temps may warm
enough for the transition back to light rain for locations south
and east of the Capital Region. Precipitation efficiency does
not look that great in the BUFKIT soundings, and snow to liquid
ratios for the majority of the event look lower than climo
values in the 8-12:1 range.

In the warm advection pattern, temps will likely cool due to
wet bulb processes, and then steady or slightly rise. Lows will
be in the upper 20s to lower 30s from the Mohawk Valley, Capital
Region, and southern VT south and east. Expect lower to mid 20s
to the north and west.

Monday...Some lingering light snow will continue through the
morning commute which may contribute to some slick spots. The
light snow and mix of rain/snow should shut off fairly quickly
from northwest to southeast in the mid to late morning. The rain
and snow showers may linger the longest south and east of the
Capital Region. Additional accumulations look very light after
sunrise with a coating to a few tenths over the higher
terrain/mountains. The low-level moisture will be stubborn to
depart and mostly cloudy/cloudy day is expected. There is a
small chance some partial clearing may reach the Capital
District/Mohawk Valley and southern VT in the mid to late
afternoon with the subsidence in the wake of the low pressure
system moving into the Gulf of Maine. Highs will still run below
normal with upper 30s to lower 40s in the lower elevations with
perhaps some mid 40s over the mid-Hudson Valley and NW CT.
Expect upper 20s to mid 30s over the higher terrain.

Monday Night...The forecast becomes a little uncertain during
this time frame, as a northern stream short-wave associated
with the upper level trough approaches in the southwest flow for
northern NY and the western Adirondacks. Some lake moisture
will be tapped and lake effect snow showers are possible just
before or after midnight ahead of the short-wave and a cold
front. Another short-wave associated with the southern stream
will approach from eastern WV and northern VA. Clouds will
thicken and lower once again with another round of over running
light snow ahead of the wave impacting locations especially
south and east of the Capital Region. The northern extent of the
QPF is variable on the GFS/NAM/ECMWF/CMC. A few inches of snow
is possible for NW CT and perhaps the southern Taconics, and Mid
Hudson Valley if the column cools quickly, as we are expecting
lows in the 20s to around 30F in the southern most zones. The
commute may be challenging with a few inches of snow in the
southeast zones Monday night/Tue morning.

Tuesday...A low confidence forecast here depending how close the
sfc wave tracks near Long Island. If enough Atlantic moisture is
tapped with decent low-level convergence in the northwest
quadrant of the sfc low snow amounts could flirt with advisory
levels for the Berkshires and Litchfield. The mid-point for an
advisory there is 3", and our present forecast has 1-3". If we
have to increase to 2-4" or greater than an advisory maybe
needed. Further north and west a coating to an inch of snow is
expected with perhaps 1-3" in the southern and central Taconics
and the mid Hudson Valley. Lake effect snow showers/flurries are
possible over the southern and western Adirondacks with light
snow accums ahead of the cold front and the mid level trough
axis. Will mention the snow accums possibly in the HWO getting
close to advisory criteria for Berkshire and Litchfield Co.

The snow should transition to scattered rain and snow showers
in the afternoon. The rain showers will be mainly in the valley
areas with the boundary layer warming and the H925 temps above
freezing. Highs will be in the mid and upper 30s in the valleys,
and upper 20s to mid 30s over the hills and mtns.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Prior to the arrival of a bone-chilling airmass, there will be a
chance for snow on Wednesday with a cold frontal passage. In fact,
snow squalls look likely, especially along and north of Albany,
which could impact any holiday travelers during the afternoon and
evening hours. Temperatures on Wednesday will generally be in the
upper 20s to upper 30s ahead of the cold frontal passage but then
drop into the single digits Wednesday night.

Thanksgiving Day will be dangerously cold, albeit dry and sunny, as
an arctic airmass arrives in the region Wednesday night behind the
cold front. This will be the coldest airmass of the season with high
temperatures rivaling the record low max temperature of 25 degrees
set at Albany in the year 1880. Wind chill values could dip as low
as -15 degrees in the Dacks to near 0 degrees in the valleys with
breezy northwest winds. Caution should be exercised if spending
ample time outdoors during the day. Overnight lows Thanksgiving night
will be near 0 in the high terrain to low teens in the mid-Hudson
valley.

Upper level shortwave and surface ridging begins building into the
region on Friday, allowing temperatures to moderate slightly along
with some sunshine. Highs look to be in the mid 20s to low 30s,
which is still 15-20 degrees below normal. Saturday will be even
warmer as low level flow turns out of the south to southwest as the
next potential low pressure system approaches the region. Highs on
Saturday will reach the mid 30s to low 40s.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected through most of the day today, with
high level clouds increasing as the next wave of low pressure
approaches from the Ohio Valley. This low pressure will bring
the chance for snow across all TAF sites. Conditions are
expected to lower to MVFR/IFR late in the period, especially at
KALB/KPSF, as the snow begins and remain that way through the
end of the forecast period.

Winds will trend to light and variable early this morning.
Winds will then become south to southeast at 4-8 KT this
afternoon.

Outlook...

Monday Night: Low Operational Impact. Slight Chance of SHSN.
Tuesday: Moderate Operational Impact. Chance of SHRA...SHSN.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SHSN.
Wednesday Night: No Operational Impact. NO SIG WX.
Thanksgiving Day: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
High pressure will be over eastern New York and western
New England briefly today, then clouds will increase during the
late morning into the afternoon with mainly light snow
overspreading the region with low pressure tracking across
Pennsylvania. The light snow will continue through tonight
before tapering to scattered rain and snow showers on Monday.
Unsettled weather continues on Tuesday with more light rain and
snow showers expected. Temperatures will continue below normal
with most of the area snow covered.

&&

.HYDROLOGY...
Flows will continue to lower into next week with colder than
normal temperatures continuing, and mainly light precipitation
events. No widespread hydro problems are anticipated.

A disturbance moving along a front south of the region will
bring some light snowfall amounting to light accumulations of a
few inches or less late this afternoon through Monday. Total
liquid equivalents will range from a few hundredths to a quarter
of an inch in a few spots.

Another disturbance and a cold front will bring chances of snow
showers or a period of light snow on Tuesday and Wednesday with
light QPF once again of a tenth to a quarter inch.

Colder than normal temperature persist into the Thanksgiving
holiday with flows continuing to recede.

For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...Wasula
NEAR TERM...Wasula
SHORT TERM...Wasula
LONG TERM...JLV
AVIATION...JLV
FIRE WEATHER...Wasula
HYDROLOGY...NAS/Wasula

NWS ALY Office Area Forecast Discussion