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000
FXUS61 KALY 120910
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
410 AM EST Wed Dec 12 2018

.SYNOPSIS...
Chilly and mainly dry weather is expected through Thursday,
with some light snow showers possible Thursday. Milder
temperatures arrive Friday into the weekend, along with periods
of rain.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 410 AM EST, still quite a bit of clouds across the region,
although some breaks were developing across portions of the
upper Hudson Valley. Some lingering snow showers/flurries
continue across portions of the Taconics/southern Greens and
Berkshires. With widespread clouds and some wind, temps remain
in the lower/mid 20s in many areas, with even some temps near 30
close to the Capital Region.

Tough call once again for today regarding cloud cover. While
abundant at this time, we expect breaks to develop within the
Hudson Valley region through the morning, as a combination of
increased subsidence in the wake of the passing shortwave, and
some downsloping occur. Across higher terrain areas, clearing
may be more gradual, occurring later this morning across the
Taconics/southern Greens/Berkshires, and last across western
areas such as the Mohawk Valley, eastern Catskills and SW
Adirondacks.

Some flurries/snow showers may also linger a bit past daybreak
across portions of the Taconics/southern Greens and Berkshires,
where scattered additional coatings are possible.

Temps should reach the lower/mid 30s in most valley areas, with
mainly mid/upper 20s across higher terrain areas. Some portions
of the mid Hudson Valley and lower elevations in Litchfield
County could approach 40.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Tonight, clear skies early, before high/mid level clouds
increase from SW to NE later this evening and overnight ahead of
a compact shortwave approaching from the southern Great Lakes
region. There is a slight chance that some light snow/snow
showers develop between 3 and 6 AM for areas mainly south of
I-90/I-88, per some hi-res models suggest, although with low
levels remaining very dry, some of this may be tough to reach
the ground. Low temperatures should reach the single digits
above to slightly below zero across the southern Adirondacks and
southern VT, where skies remain clear longer, with mainly teens
farther south and west as clouds increase and limit radiational
cooling potential.

Thursday, aforementioned compact shortwave looks to track east
across northern PA or southern NYS, while weakening within
overall confluent flow aloft. Deformation along the northern
periphery of this feature should allow for at least some forcing
to produce light snow or snow showers, which will be mainly from
the I-90/I-88 corridor south and west. Dry low levels could
limit how much reaches the ground, however enough forcing could
allow for some spotty light accumulations of a coating to less
than an inch in some of these areas, with best chances across
higher terrain areas of the SE Catskills. Otherwise, mostly
cloudy with high temps mainly in the mid 20s to lower/mid 30s.

Thursday night-Friday night, initial weakening shortwave departs
off the New England coast, before increasing isentropic lift
ahead of next system overspreads region from southwest to
northeast Friday afternoon and night. Expect a general lull in
precipitation Thursday night, however with developing low level
warm advection and increasing Atlantic moisture, some patchy
freezing drizzle or snow grains could occur across portions of
the SE Catskills and perhaps mid Hudson Valley, especially late
Thursday night into Friday morning. Will include some mention of
patchy freezing drizzle/drizzle in these areas, but overall low
confidence remains at this time for this to occur, especially
for lower elevations in the mid Hudson Valley. Better chances
for precipitation arrive Friday afternoon and Friday night. Wet
bulb cooling processes could lead to areas of snow or a
rain/snow mix across higher terrain areas of the SW Adirondacks,
southern VT, and the Berkshires, especially at precipitation
onset. Also, if low level cold air remains anchored, some
freezing rain can not be ruled out as well in some northern areas,
and trends will need to be watched as we get closer in time.
Lows Thursday night mainly in the 20s, highs Friday warming into
the mid 30s to lower 40s, and lows Friday night mainly in the
mid/upper 30s except for lower 30s across portions of the SW
Adirondacks, southern VT and Berkshires, and possibly portions
of the Mohawk and upper Hudson Valley.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Upper level split flow still affecting the consistency of long range
guidance/ensembles.  There is still considerable spread in the track
and timing of northern stream dominated upper energy and moisture.
Northern stream upper energy looks strong and low level forcing
along the leading edge of cold advection looks strong but moisture
lacking. Also, boundary layer temperatures are predicted to be
warmer than temperatures below the boundary layer, implying that the
scattered coverage of precipitation could involve patchy light sleet
or freezing rain when we do have chances for precipitation.

However, this is really the first indication in long range guidance
for chances for mixed precipitation.  Also, there are considerable
differences in the predicted amounts of moisture during the time
window of the potentially best upper dynamics and low level forcing
ahead of 2 cold fronts, one in the Saturday and Saturday night time
frame and the other in the Monday time frame.

Regardless of how the track, timing and moisture get sorted out,
quite a bit of cloudiness and at least chances for rain and snow
showers through Monday. More details will be known as we get closer
and changes to the forecast can be expected between now and next
weekend as details get clearer.

Highs Saturday in the 40s with some upper 30s northern areas. Highs
Sunday and Monday in the 30s to near 40 with a few lower 40s
southern areas. Highs Tuesday in the 30s but mid to upper 20s higher
terrain.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Upper system exiting and low level flow across Great lakes has
supported extensive cloud cover over our region with some snow
flurries at times. Clouds and flurries will continue through about
09Z-11Z at KGFL, KALB and KPSF.  The flurries are expected to stay
north of KPOU but the cloud cover will persist there. Some flurries
around KPSF could bring the ceiling down to around 1500 feet at
times through about 10Z.

Clouds will break up through the morning as the upper energy exits
and low level flow turns more north.  Ceilings above 3000 feet
should break up at KPOU by mid morning and the rest of the TAF sites
around midday or early afternoon. The sky will become clear and
remain clear through this evening.

Light and variable winds through mid morning will become northwest
to north at less than 10 Kt, continue through the afternoon and then
diminish to light this evening.

Outlook...

Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of RA.
Friday Night: High Operational Impact. Likely RA.
Saturday: Moderate Operational Impact. Likely SHRA...RA.
Saturday Night: Moderate Operational Impact. Scattered SHRA...SHSN.
Sunday: Low Operational Impact. Isolated SHRA...SHSN.

&&

.HYDROLOGY...
No hydrologically significant precipitation is expected through
at least Thursday. Temperatures averaging below normal, and
mainly below freezing, will support expansion and thickening of
ice on area waterways.

A warm-up appears possible Friday into the weekend ahead of a
strong low pressure system approaching from the southern US.
There is still considerable uncertainty on the track of this
system and resulting QPF. Current indications are for areas
from the Albany-Saratoga region through southern VT and points
south and east receiving 0.25-0.50 liquid equivalent, while
areas to the north and west receive mainly under 0.25". However,
should the low pressure system track slower and farther north,
greater rainfall amounts would occur.

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...KL/Thompson
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/Thompson