Area Forecast Discussion
Issued by NWS Albany, NY

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000
FXUS61 KALY 170342
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1042 PM EST Mon Jan 16 2017

.SYNOPSIS...
High pressure will remain off the east coast overnight. A storm
system approaching from the Great Lakes will bring a wintry mix of
snow, sleet and freezing rain to the region for Tuesday into
Wednesday. Afterward, temperatures will be above normal for the
remainder of the week with mainly dry conditions.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
High clouds continue to stream across across the region with mid
level clouds approaching. Temperatures expected to bottom out in
the teens mainly north of I-90 with warmer readings in the 20s to
the south I-90. Again only some minor adjustments were made as
forecast is in track.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Winter Weather Advisories/Freezing Rain Advisories for Tuesday
into Tuesday night...

Low pressure will move across the southern Great Lakes Tuesday,
pushing a warm front towards the area. The low and mid level flow
out of the S-SE will allow for warm air advection/isentropic lift
and some light precip looks to spread from southwest to northeast
across the area Tuesday morning, becoming more steadier and
widespread during the mid to late afternoon hours. So, it is
possible that a band of very light precipitation, perhaps some
sprinkles of freezing rain/sleet or very light snow overspreads
southern portions of the region between roughly 7 AM - 10 AM
Tuesday morning, mainly for areas south of the I-90 corridor, and
the reason that the freezing rain advisory area start time is so
early / 7 AM/. Then, there could be a distinct break with little
or no precip, until mid to late afternoon when steadier
precipitation quickly overspreads the region from W to E.

Model soundings suggest a warm layer will be in place around 800
hpa. This warm nose will allow for a variety of p-types across the
area, as boundary layer temps and the exact temp within the warm-
nose will determine what occurs across the area, which will vary
greatly from southwest to northeast and with elevation as well.
Northern/northeastern areas (such as the southern Adirondacks
into Southern vermont) will likely stay mainly snow/sleet during
this event, while areas further south will see generally sleet
changing to rain/freezing rain. There`s the potential for several
inches of snow/sleet across the Adirondacks, into higher
elevations of Bennington CO VT and throughout Windham CO VT, with
the best potential across portions of Windham County, VT, where
locally 3-6 inches of snow will be possible.

Further southeast across the Berkshires/NW CT, temps aloft will
be warmer, but some colder air trapped at the surface may allow
for a more prolonged period of freezing rain for late Tuesday into
Tuesday night, as the departing high pressure area allows for some
colder air to remain locked in sheltered valley areas. A Winter
Weather Advisory remains in effect for Tuesday afternoon into
Tuesday night to account for the potential for this freezing rain
across the Berkshires/NW CT. Icing may locally exceed 0.25", which
will make for slippery travel and possibly a few power outages.
This potential will be greatest for elevations above 1000 feet,
across eastern Berkshire CO.

Elsewhere, additional Winter Weather Advisories are now in effect
for the aforementioned areas of the southern Adirondacks, the Lake
George/Saratoga region and southern VT, where alternating P-types
of snow, sleet and some freezing rain/rain will be possible, again
favoring more snow and sleet at least for higher terrain.

Across the Capital Region and points south, once the steadier
precipitation develops Tuesday afternoon and into Tuesday night,
there could be areas of freezing rain across mainly higher
elevations of the eastern Catskills/Helderbergs and also within
portions of the central/western Mohawk Valley, as low level cold
and initially dry air wet bulbs and cools back closer to freezing.
Even in valley areas, including the immediate Capital Region, can
not rule out some freezing rain in pockets Tuesday night, although
any ice accretion in these areas should remain below one tenth of
an inch. Across the higher elevations of the Catskills/Helderbergs
and Schoharie CO, as well as portions of the western Mohawk
Valley, ice accretion of up to or slightly greater than one
quarter of an inch is possible.

For the mid Hudson Valley and Taconics, it appears that the best
potential for any freezing rain should be with any spotty light
precipitation in the morning hours, and it is possible, based on
afternoon temperature trends, that this portion of the freezing
rain advisory may be dropped early.

There`s also the chance that precipitation could start to go back
to sleet or even some snow by late Tuesday night, as the
approaching upper level shortwave trough starts to cool temps
aloft, just before precip starts to taper off. Temps on Tuesday
into Tuesday night will remain in the 30s, with northern/sheltered
valley areas staying right at or just below the freezing mark.

Behind the storm`s occluded front on Wednesday morning, precipitation
will taper off to light rain or drizzle. Spots that remain below
freezing could still see some freezing rain, but as precip
lightens up, temps should be able to rise everywhere on Wednesday
morning above freezing by midday. There could even be a little
lingering drizzle, light rain or snow showers into Wednesday
afternoon thanks to the trough overhead and cyclonic flow. As
temps continue to cool aloft, this could change to some light snow
for the high terrain, but any additional accumulation looks minor
at this time. Temps should rise through the 30s on Wednesday, with
some lower 40s possible across portions of the mid Hudson Valley.

For Wednesday night, lots of clouds, and some spotty
drizzle/freezing drizzle could linger into the evening. There is
some possibility of clearing late at night. If this occurs, it
could lead to areas of fog, and also additional black ice
formation as ground surface temps cool back close to freezing in
some areas by daybreak Thu. Will need to watch trends closely.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Very complex and chaotic upper pattern through the period.  Upper
ridging building into our region Thursday and Friday as upper energy
tracks southeast across southeastern Canada. The upper confluence
around the U.S./Canadian border is expected to act as a barrier to
moisture and forcing tracking north associated with an upper low
developing in the Midwestern U.S.

So, dry weather Thursday and Friday with highs in the lower to mid
40s but mid to upper 30s higher terrain.  Some of the moisture and
forcing could build north with some intervals of clouds and just
slight chances for some rain Saturday. Upper ridging ahead of the
developing upper low in the TN Valley will again prevent much rain
but again, there could be some residual moisture that could bring
some intervals of clouds and a slight chance of rain Saturday and
Saturday night. Highs Saturday in the 40s but some upper 30s higher
terrain.

The upper low in the TN Valley slowly moves east and there will be
increasing clouds and moisture Sunday and Monday, especially Sunday
afternoon through Monday. Highs Sunday and Monday in the 40s but
upper 30s higher terrain. There could be considerable coverage of
rain later Sunday night into Monday with mixed precipitation in
northern areas.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
VFR conditions through the nighttime with widespread MVFR
developing Tuesday as precipitation overspread the area.

Higher levels clouds will be on the increase tonight with mid
level clouds moving in late. Clouds will thicken and lower during
the day Tuesday as precipitation overspreads the area from southwest
to northeast with conditions lowering to MVFR due to both ceilings
and visibilities. Expecting IFR conditions to develop at KPOU by
late Tuesday afternoon.

As for precipitation types at the TAF sites, initially a mix of
snow, sleet and rain is expected with a changeover to rain.
However, at KPOU freezing rain is possible as the precipitation
arrives here earlier in the morning when surface temperatures will
be colder with plain rain by mid late morning. Precipitation
arrival at KALB and KPSF is expected late morning/early afternoon
and mid/late afternoon at KGFL. Once the changeover to plain rain
occurs it will through the end of the TAF period; 00Z/Wednesday.

Calm to light/variable winds tonight with a light northeast to
southeast flow developing Tuesday.

Outlook...

Tuesday Night: High Operational Impact. Definite RA...FZRA...SLEET.
Wednesday: Moderate Operational Impact. Scattered SHRA...RA...SN...SLEET.
Wednesday Night: Low Operational Impact. Isolated SHRA...SHSN.
Thursday: No Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: Low Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHSN...RA.

&&

.HYDROLOGY...
Dry weather is expected through tonight with high pressure in
control. A storm system will bring a wintry mix to the region on
Tuesday into Wednesday. Total liquid equivalent amounts will be
one half inch to one inch. Although some of this precipitation
will be frozen, some minor rises on rivers and streams can be
expected. However, no flooding is expected.

Behind this storm system, temperatures will average above normal
for the remainder of the week. Some snow melt over the Adirondacks
and southern Vermont may contribute to some additional runoff,
but any rises on rivers and streams will only be minor. Little, if
any, precipitation is expected for Thursday into the weekend.

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...Winter Weather Advisory from 10 AM Tuesday to 7 AM EST
     Wednesday for CTZ001-013.
NY...Freezing Rain Advisory from 7 AM Tuesday to 7 AM EST Wednesday
     for NYZ038-040-047>054-058>061-063>066.
     Winter Weather Advisory from 10 AM Tuesday to 7 AM EST
     Wednesday for NYZ032-033-039-041>043-082>084.
MA...Winter Weather Advisory from 10 AM Tuesday to 7 AM EST
     Wednesday for MAZ001-025.
VT...Winter Weather Advisory from 10 AM Tuesday to 7 AM EST
     Wednesday for VTZ013>015.

&&

$$
SYNOPSIS...Frugis/KL
NEAR TERM...IAA/Frugis/KL
SHORT TERM...Frugis/KL
LONG TERM...IAA/NAS
AVIATION...NAS
HYDROLOGY...Frugis/KL



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