Area Forecast Discussion
Issued by NWS Albany, NY

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FXUS61 KALY 241018
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
618 AM EDT Fri Mar 24 2017

.SYNOPSIS...
Unsettled conditions will arrive this morning and will persist
into the upcoming weekend, with a wintry mix of precipitation
expected. Initially, the warm front will bring a mix of snow,
sleet and freezing rain before transitioning over to rain by the
mid to late afternoon today.

&&

.NEAR TERM /THROUGH TONIGHT/...
...A Winter Weather Advisory remains in effect from 6 AM to 2
PM Today for the eastern Catskills, Schoharie Valley, Mohawk
Valley, Greater Capital Region, northern and central Taconics,
as well as the Berkshires...

...A Winter Weather Advisory remains in effect from 6 AM to 4
PM Today for the southern Adirondack Region, Lake George
Northern Saratoga Region and southern Vermont...

As of 615 AM EDT, isolated snow showers containing snow pellets
just passed through portions of the Capital Region, and now
should be moving into portions of the southern Greens/Berkshires
and Litchfield Hills. This occurred despite sfc dewpoint
depressions of over 20 F. Only a light coating occurred from
these brief snow showers thus far, with individual snow pellets
visible on the ground. Additional snow showers are likely
occurring across portions of northern Hamilton CO, and should
move into northern Warren CO over the next hour. This band is
well ahead of the deeper isentropic lift approaching from the
southwest. A quick few tenths of an inch of snow is likely with
this band as it passes through.

The strengthening isentropic lift and steadier precip shield
across the eastern Great Lakes and western NYS will overspread
the region from the west between roughly 8-11 AM this morning.
Regional VWP`s indicate a low level jet currently translating
NE across central/western NY and PA. As this low level jet
impinges on the region, we expect sufficient moistening of the
sub cloud layer to initiate precipitation, particularly from
around the I-88 and I-90 corridors northward between roughly
8-11 AM this morning.

P-type should initially be snow at its leading edge, before a warm
nose aloft between H750-850 causes sleet to mix in, and eventually
rain/freezing rain. We expect some wet bulb processes to cool the
boundary layer in areas where precipitation occurs, so even though
temps may briefly rise to or slightly above freezing in some areas
prior to precipitation developing, it likely will fall back to
freezing or slightly lower for a period, resulting in the potential
for freezing rain.

The steadiest precipitation and greatest wet bulb processes are
expected to remain mainly north of I-90, with a snow/sleet mix
changing to freezing rain/sleet later this morning into early
afternoon. Warm advection should allow for temps to gradually rise
above freezing this afternoon, but it could take until late
afternoon across portions of the southern Adirondacks and sheltered
valleys of southern VT, and perhaps portions of eastern Berkshire
CO. Will have to watch temperatures closely in these areas in case
current winter weather advisories need to be extended later in time.

Snow/sleet accumulations should generally remain light from I-90
south, generally a coating to less than an inch. To the north, a
coating to up to an inch is possible for lower elevations, while 1-2
inches occurs across higher terrain, esp across southern VT and the
northern Berkshires.

Ice accretion should generally be a trace to less than one tenth of
an inch, with the greatest amts across portions of the western
Mohawk Valley.

Late day highs should reach the mid/upper 30s for northern and
eastern areas, with lower 40s farther south across the mid Hudson
Valley.

For tonight, the best forcing should lift north of the region, but
pockets of light rain and drizzle may continue. As winds shift into
the north toward daybreak across northern areas, there could be some
pockets of freezing rain/drizzle developing, and trends will need to
be watched. Low temperatures will mainly be in the 30s.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
A very complex forecast including a wide variety of
precipitation types are in the forecast during the short term
period. The complexity of the forecast requires speaking in
general terms as positioning of frontal boundaries relative to
the large ridge of high pressure to the north hold the key to
the forecast. Much of the short term forecast period will have
precipitation.

Saturday through Monday...Much of the precipitation types will
be diurnally driven with mainly rain during the daytime hours
and mainly freezing rain and sleet across northern areas during
the overnight hours into early morning hours as indicated by
partial thickness values and BUFKIT model soundings. A frontal
boundary is expected to drop southward into the middle Atlantic
region on Sunday as a wave of low pressure over the midwest
tracks northeast reaching the eastern Great Lakes by Monday
morning. The best chances for freezing rain appear to be between
around midnight and 10 AM both Sunday and Monday. While it is
still too early to pinpoint ice accretion there is certainly the
possibility of a tenth to a third of an inch of ice accretion
totals across the northern half of the forecast area. Fortunately
it does not look like temperatures will be below freezing
during the afternoons which will allow what freezing rain which
accretes to melt in most areas. Highs on Saturday are expected
to be in the upper 30s to mid 50s with highs on Sunday in the
mid 30s to mid 40s and highs on Monday in the upper 30s to
around 50. Lows Saturday night will be in the upper teens to
mid 30s with lows Sunday night in the upper 20s to mid 30s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Generally cool and unsettled conditions are expected through at
least Tuesday, as another upper level impulse tracks toward the
region from the southern Plains, producing rain and drizzle. Once
this system lifts north and east of the region, there remains
significant uncertainty regarding the timing of yet another southern
stream impulse approaching. Latest 00Z/24 deterministic models and
ensembles suggest there could be a break from the clouds and precip
Wed into Thu, and will therefore lower pops during this period, but
with low confidence. It is possible that a stronger northern stream
impulse produces some snow showers across portions of the region
Wed. Temps will remain below average, with highs Tue mainly in the
lower/mid 40s, if not cooler, with highs Wed-Thu in the mid/upper
40s in valleys and 30s to lower 40s across higher elevations.
Overnight lows will mainly be in the 30s Monday night, with 20s and
lower 30s for Tue-Wed nights.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
A warm front will approach from the south and west later
tonight and will bring a wintry mix of precipitation to the
region late Friday morning into the afternoon, than changing to
plain rain.

A mix of snow, sleet and freezing rain with MVFR to IFR
conditions expected to develop during the morning hours at
KALB/KPSF/KGFL, with a rain/snow mix initially at KPOU quickly
changing to rain by Noon. The transition to plain rain will take
until early afternoon at KALB/KPSF, with KGFL likely taking the
longest into mid afternoon as is typically the case in these
types of situations with warm air aloft over-running cold air in
the low levels. Precip will then taper to scattered rain
showers or patchy drizzle by late afternoon with mainly VFR/MVFR
conditions expected.

For tonight, most of the best forcing will be north of the TAF
sites. However, some spotty drizzle may develop. In addition,
low CIGS and some fog could develop as well given the moistening
boundary layer. Expect areas of MVFR to IFR, with worst
conditions expected at KGFL and KPSF.

Light and variable to calm winds will become southerly around
10-15 kt by mid morning. Gusts of 20-30 kt will be possible
from late morning through the afternoon hours, especially at
KALB/KPSF.

South to southwest winds will decrease late this afternoon and
tonight to mainly 5-10 KT, although may remain a bit stronger at
KPSF.

Outlook...

Friday Night: Moderate Operational Impact. Chance of RA.
Saturday: Moderate Operational Impact. Chance of RA.
Saturday Night: Moderate Operational Impact. Likely RA...FZRA...DZ...FZDZ.
Sunday: Moderate Operational Impact. Chance of RA...DZ.
Sunday Night: High Operational Impact. Likely RA.
Monday: High Operational Impact. Likely RA.
Monday Night: Moderate Operational Impact. Chance of RA.
Tuesday: Moderate Operational Impact. Chance of RA.

&&

.FIRE WEATHER...
A deep snow pack remains in place across much of eastern New
York and western New England. Unsettled conditions will arrive this
morning and will persist into the upcoming weekend, with a
wintry mix of precipitation expected. Initially, the warm front
will bring a mix of snow, sleet and freezing rain before
transitioning over to rain by the mid to late afternoon today.

&&

.HYDROLOGY...
There is a potential for several rounds of precipitation today
into the upcoming week, with a mix of rain, freezing rain, snow
and sleet possible. Temperatures look to be warm enough during
the afternoon hours each day that most of the precipitation
should fall in the form of rain before changing over to a wintry
mix at night. While there is still some uncertainty with
precipitation types and amounts, there is the potential for
between three quarters of an inch of rain up to an inch and a
half today through Sunday night. Latest MMEFS forecast
indicates a few locations going into action stage by next 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...None.
NY...Winter Weather Advisory until 2 PM EDT this afternoon for
     NYZ038>040-047>054-058>061-063.
     Winter Weather Advisory until 4 PM EDT this afternoon for
     NYZ032-033-041>043-082>084.
MA...Winter Weather Advisory until 2 PM EDT this afternoon for
     MAZ001-025.
VT...Winter Weather Advisory until 4 PM EDT this afternoon for
     VTZ013>015.

&&

$$
SYNOPSIS...11/JVM
NEAR TERM...KL
SHORT TERM...11
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...11/JVM
HYDROLOGY...11/JVM



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