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000
FXUS61 KALY 280255
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
955 PM EST Sat Feb 27 2021

.SYNOPSIS...
Dry weather will return to the area tonight as high pressure
builds into the area. Another system will move across the region
later Sunday with periods of rain and perhaps a wintry mix
across the higher terrain. A strong cold front will cross the
area later Monday, possibly accompanied by some snow squalls and
followed by much colder temperatures.

&&

.NEAR TERM /THROUGH SUNDAY/...
Clearing has occurred in some areas with clouds anchored to
terrain in the southern Adirondacks, southern Green Mountains,
the Berkshires and NW CT. The clouds will gradually decrease in
coverage as high clouds spread over our region through tonight
ahead of the next system. The mid Hudson Valley has cooled into
the lower 30s due to light winds but high clouds are rapidly
spreading over the region and should slow or stop temperatures
from falling much there. The rest of the region is warmer but as
lower clouds decrease in coverage and winds trend to light,
temperatures will fall elsewhere.

Steady surface winds from the west and northwest this evening
should trend to light or calm toward daybreak. Some patchy fog
could form in areas that see the most clearing. Fog should not
be widespread or dense enough to mention in forecast. Some minor
adjustments to temperatures and sky cover through the night and
the previous AFD has a few more details and is below...

High pressure builds southeast toward the area. The airmass
associated with this high pressure is not particularly cold, and
no lake response over and east of Lake Ontario is expected,
which should help with some clearing overnight. Low temperatures
tonight will be mainly in the 20s to near 30.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
The next wave of low pressure will approach our area on Sunday.
This next system looks to be a combination of two unphased
waves; one approaching from the Great Lakes and one from the
Tennessee Valley. Model consensus is good that the heaviest
precipitation associated with the Tennessee Valley wave will
track just south of our area, while precipitation associated
with the northern branch wave will be heaviest to our north and
west. Despite this split in the pattern, it looks like at least
some light precipitation will be overspreading the area Sunday
afternoon and continuing Sunday night. With the timing of the
precipitation not until later Sunday, all areas should be above
freezing before the onset of the precipitation and the p-type
with this next system should be mostly rain. A little wet snow
could mix in over higher higher elevations north and west of the
Capital District, but no accumulations are expected.

Periods of light rain will be widespread across the area Sunday
night as this unphased system crosses the area. After the
passage of these waves, there should be some clearing early
Monday as weak cold advection develops. Temperatures will likely
recover into the upper 30s and 40s in this pattern by early
Monday afternoon, then a strong cold front will approach from
the northwest later Monday. West-southwest winds will increase
ahead of this system, and will likely become quite gusty before
shifting to the northwest Monday evening. In addition, some snow
showers will likely develop west of the Hudson Valley Monday
afternoon, and could intensify into heavier squalls late in the
day or Monday evening. Models are indicating some instability
ahead of this system and with surface temperatures likely to
reach the 40s just ahead of the front some small amounts of CAPE
appear to be possible. The best chance for up to 2 or 3 inches
of snow with this system will likely be over the western Mohawk
Valley and southwest Adirondacks, but one or two squalls could
reach as far east as the Capital District Monday evening and
this will have to be watched. The cold front will be followed by
blustery and much colder weather later Monday night. The flow
appears to have enough of a northerly component behind this
front so that most of the lake effect will shift into central
NY rather quickly overnight, so that no major accumulations are
expected for our areas east of Lake Ontario.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A fairly benign weather pattern is upon us as we head into the long
term period. We begin on Tuesday with an anomalously cold airmass in
place. The latest GEFS 850mb temps of -20 to -25C  are 2 to 3
standard deviations below normal. This should translate to high
temps below freezing area-wide (teens in the southern Dacks). In
addition to the chilly temps, winds will also be gusty out of the
northwest. So despite plentiful sunshine, temps will feel quite
chilly throughout the day.

The upper trough responsible for the cold airmass departs by Tuesday
night with a general zonal flow setting up across the northeast. A
northern stream trough looks like it will stay set up across Quebec
and at times dip down into New York and New England throughout the
remainder of the long term period. This may lead to a period of
light lake effect snow showers downwind of Lake Ontario on Thursday.
But all of the southern stream energy is progged to stay south of
our region and therefore, looks like a mostly dry forecast.

Temperatures will be above normal Wed-Thur, with highs in the mid
30s to mid 40s. A brief return to seasonable temps is expected Fri-
Sat as the upper trough dips south, but temps return to above normal
by the end of the weekend. Overnight lows will be the coldest of the
period Tuesday night with temps in the single digits to upper teens.
Lows for the remainder of the long term period look fairly
seasonable.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
System that brought the rain has departed and much of the cloud
cover has lifted above 3000 feet and in some areas has cleared.
Only KGFL is seeing some MVFR visibilities as the wind shift
and steady winds have not cleared out the fog yet.

Based on satellite and radar trends, intervals of clouds above
3000 feet and partial clearing through daybreak at all sites.
Fog should lift at KGFL later this evening but during periods of
clearing, as winds diminish to light to calm later this evening
and through the night, some intervals of MVFR visibilities in fog
are possible, especially between 08Z-12Z but as early as 04Z at
KGFL.

After about 12Z, just intervals of high clouds well above 10000
feet until afternoon when the next storm system approaches. Some
showers could begin to affect areas around KPOU and KPSF after
18Z Sunday.

Winds will be west to northwest at 10 Kt or less at KGFL and
KPOU but around or just above 10 Kt at KALB and KPSF this
evening, with some gusts around 20 Kt. Wind shear is being
indicated at all TAF sites through about 02Z-04Z until the
strong west to northwest winds at around 40 Kt aloft exit by
that time. Winds diminish to less than 6 Kt by daybreak and
light winds continue through Sunday morning. Winds become
southeast at 6 Kt or less Sunday afternoon.

Outlook...

Sunday Night: Moderate Operational Impact. Chance of SHRA.
Monday: Low Operational Impact. Breezy. Slight Chance of SHRA.
Monday Night: Moderate Operational Impact. Windy With Gusts To 31 kts. Chance of SHSN.
Tuesday: Low Operational Impact. Breezy. 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.

&&

.HYDROLOGY...
No major hydrologic issues are foreseen through the middle of
next week.

Some melting and sublimation of the snowpack in the valleys is
expected during the day time over the next several days.
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.

Low pressure tracking across the area later Sunday and Sunday
night will bring mainly rain. Total QPF for this system will
range from 0.10 to 0.30 of an inch.

A strong cold front with snow showers is expected to move
through later Monday through Monday night. Much colder air
returns Monday night and Tuesday.

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...MSE
NEAR TERM...MSE/NAS
SHORT TERM...MSE
LONG TERM...Wasula
AVIATION...NAS
HYDROLOGY...NAS/Rathbun