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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KALY 282335
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
635 PM EST Sun Feb 28 2021

.SYNOPSIS...
Clouds will continue to thicken and lower with
increasing chance for rain showers and perhaps a wintry mix across
some higher terrain areas. A strong cold front will cross the area
Monday afternoon and evening. A much colder air mass, strong wind
gusts along with scattered snow showers and a few squalls. A cold
night expected Monday night with dangerous wind chills, especially
for the higher terrain.  The blustery and cold conditions persist
into Tuesday as an area of high pressure builds into the region.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --
Break in the precipitation with just scattered showers over the
region. Temperatures have fallen into the lower 30s in the
eastern Catskills but after a long time above freezing and
temperatures just touching freezing, any precipitation that
spreads over our region tonight associated with warm advection
should allow for temperatures and dew points to rise a degree
or two through the night. Radar is showing the beginning of
development of more rain in central and western NY spreading
northeast and there is a consensus in sources of
guidance/ensembles for coverage of rain to increase, especially
between midnight and daybreak. So, some minor adjustments to
temperatures, sky cover and timing of rain through the night.
Previous AFD has a few more details and is below...

Rather challenging forecast tonight with respect to
precipitation coverage, intensity and some slight concerns with
near freezing temperatures for the highest terrain. Regional and
local radar depicts an expanding area of mainly rain-rain
showers across eastern NY and southern New England. The degree
of low level warm advection and isentropic lift is rather strong
and per local research, we would anticipate portions of the
southern Dacks, Catskills and east of the Hudson to be the most
susceptible for additional precipitation overnight. However, a
quick look at the latest HRRR, there could be a lull in the
precipitation overnight (perhaps some drizzle along with patchy
fog). While temperatures overnight should generally be above
freezing, wet bulb processes and per NY Mesonet dewpoint
depressions, some sleet or freezing rain is possible at or above
the 1500-2000 foot elevations. Coverage should remain rather low
as SPS could be issued to address these concerns if they unfold
tonight. Otherwise a damp period of weather tonight with lows
mainly into the 30s. Cold front will be approaching our
northwest portions of the CWA toward 6 AM Monday. A band of
showers are expected to accompany the front.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Two frontal passages are expected Monday. The initial cold front
will bring about a period of scattered showers during the
morning hours. Our initial shot of cold advection will commence
which will be more noticeable with our dewpoints dropping as
dry slot advects into the region. This is where we should see
some breaks in the clouds for a partly sunny day for most areas
to unfold. Still some showers are possible as we will keep in
the 20-40% PoPs in the grids/forecast at this time with the
higher values into the terrain. As per BUFKIT, expectations are
for good mixing to occur as forecast highs ranging from the mid
30s across the Dacks to mid 40s for the mid-Hudson Valley and
southern Litchfield County. This will be changing quickly toward
sunset Monday with the passage of an arctic boundary.
Conditions appear favorable for both high winds and snow squalls
across the region. Mixing layer heights within the cold
advection are forecast to climb toward 5k feet where near 50kts
reside along with funneling down the Mohawk. After close
coordination with neighboring forecast offices, a wind advisory
was issued where the highest confidence was with respect to
those higher magnitudes. Additional adjustments may be needed
with future updates. As for the snow squalls, with deep cold
advection along with some contributions off Lake Ontario and
steep low level lapse rates over 8C in the 1000-700MB layer, the
BTV snow squall parameters are rather high as well.

Rapidly dropping temperatures too may also result in moisture
freezing with potential icy patches developing into Monday
evening. The winds and lake effect snow will likely continue as
low level wind trajectories become more northwest overnight
which would take lake band(s) into the Catskills. As for
accumulations, difficult to say due to the scattered and
transient nature of the shallow convection. Winds will remain a
challenge with the falling temperatures which brings about
another hazard, low wind chills. Wind chill headlines may be
needed for the higher terrain of the CWA (best potential would
be the Adirondack Park). Overnight lows drop back to near zero
across the Dacks to near 20F for the mid-Hudson Valley.

As sub -20C @ 850MB advects across the region Tuesday morning,
high pressure just upstream should allow for those wind gusts
to diminish as we will end the wind advisory headline at this
time (again, adjustments are possible). The heart of the cold
air is expected to moderate and advect east of the region as
next clipper type system approaches the heart of the Great Lakes
region toward days end. Some clouds will be on the increase as
well as afternoon highs rebound to around freezing for the mid-
Hudson Valley and southern Litchfield County to mainly 20s
elsewhere.

Tuesday night, this clipper and warm front may bring some light
precipitation, mainly in the form of snow, across the Dacks.
Otherwise, should be a rather tranquil night and a bit milder
with lows into the teens and lower 20s, some single digits
possible for the Dacks.

Seems the start of March will be coming in like a lion.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
We start the long term period with above normal temperatures on
Wednesday as a weak low pressure system tracks across New England.
Highs during the afternoon will range from the mid 30s to upper 40s.
At the surface, a moisture-starved cold front is progged to track
through the forecast area Wednesday night, shifting the winds out of
the north-northwest. This will set up chilly weather through the
weekend with Friday and Saturday looking like the coldest days. The
latest GEFS 850mb temps, which are -1 to -2 standard deviations
below normal, persist across the northeast through Saturday. Highs
on Fri-Sat will likely range from the upper teens to low 30s, with
overnight lows in the single digits to upper teens.

At upper levels, a large upper trough is expected to set up across
Quebec mid-week and remained positioned there through the end of the
period. This upper trough will be responsible for the weather
through the weekend. At times throughout this period, pieces of
upper energy will track southward out of Canada and help reinforce
the upper trough and result in it undulating into New York. Despite
the upper trough nearby, the majority of the forecast area should
remain dry through the long term period, albeit partly cloudy. The
main exception is the southern Dacks which may see some snow showers
Wed into Thur and again Fri into Sat as upper energy dips south.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Scattered showers around the region this evening with VFR
conditions. Rain is developing and spreading northeast into our
region, timed to begin at TAF sites around or a little after
midnight. Ceilings and visibilities will become predominantly
MVFR in the steady rain with intervals of IFR visibilities and
ceilings, especially between 08Z-13Z. Steadier rain exits after
12Z-13Z with visibilities returning to VFR but ceilings will
take until the afternoon and the approach of a cold front to
lift above 3000 feet. VFR conditions Monday afternoon but winds
will increase to very strong and gusty from the northwest.

So, southeast winds this evening and tonight at less than 10 Kt.
Strong winds aloft will cause some wind shear as winds at 2000
feet will be around 15035 Kt. Wind shear will end before 12Z.
Surface winds will shift to southwest at 6 Kt or less by mid
morning Monday then to west and northwest by Monday afternoon at
around 20 to 25 Kt with gusts over 30 Kt and perhaps approaching
40 Kt at KALB and KPSF.

Outlook...

Monday Night: Moderate Operational Impact. Windy With Gusts To
38 kts. Scattered SHSN.
Tuesday: Moderate Operational Impact. Windy With Gusts To 34
kts. 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.
-- End Changed Discussion --

&&

.HYDROLOGY...
No major hydrologic issues are foreseen through the upcoming
week.

Some melting and sublimation of the snowpack in the valleys is
expected during the day time over the next several days with the
exception of Tuesday. NERFC forecasts show minor up and down
changes in river flows due to the diurnal freeze/thaw cycle.
River ice is not expected to break up over the next several
days.

The next system will track across the area later tonight into
early Monday with mainly rain (some frozen precipitation across
the higher terrain). Total QPF for this system will range from
0.10 to 0.30 of an inch.

A strong cold front with snow showers, and a few squalls, is
expected to move through the area Monday afternoon through
Monday night. Much colder air returns Monday night and Tuesday.

Mainly dry weather is then expected for the remainder of the
week.

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...Wind Advisory from 1 PM Monday to 7 AM EST Tuesday for CTZ001-
     013.
NY...Wind Advisory from 1 PM Monday to 7 AM EST Tuesday for
     NYZ038>040-047>054-058-063-082.
MA...Wind Advisory from 1 PM Monday to 7 AM EST Tuesday for MAZ001-
     025.
VT...Wind Advisory from 1 PM Monday to 7 AM EST Tuesday for VTZ013-
     014.

&&

$$
SYNOPSIS...BGM/Rathbun
NEAR TERM...BGM/NAS
SHORT TERM...BGM
LONG TERM...JLV
AVIATION...NAS
HYDROLOGY...BGM/Rathbun