Area Forecast Discussion
Issued by NWS Albany, NY

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541
FXUS61 KALY 232019
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
419 PM EDT Thu Mar 23 2017

.SYNOPSIS...
Tranquil weather will continue through most of the night as
high pressure gradually slides off to the east. Unsettled
conditions arrive tomorrow morning and persist into the upcoming
work week, with a wintry mix of precipitation expected.
Initially, the warm front tomorrow will bring a mix of snow,
sleet and freezing rain before transitioning over to rain by
the mid to late afternoon.

&&

.NEAR TERM /THROUGH 6 PM EDT FRIDAY/...
...A Winter Weather Advisory has been issued from 6 AM to 2 PM
Friday for the eastern Catskills, Schoharie Valley, Mohawk
Valley, Greater Capital Region, northern and central Taconics,
as well as the Berkshires...

...A Winter Weather Advisory has been issued from 6 am to 4 pm
Friday for the southern Adirondack Region, Lake George Northern
Saratoga Region and southern Vermont...

As of 330 PM EDT...A 1038 hPa sfc anticyclone continues to be over
the Northeast and Mid Atlantic Region this afternoon.  This is a
chilly air mass for early Spring with max temps running 10 to 15
degrees below normal.  It is an exceptionally dry air mass with sfc
dewpts in the single digits to below zero.  The latest IR/Visible
satellite loop shows a few high clouds getting closer to western NY
and PA, but overall the skies should be clear/mainly clear at sunset
with light to calm winds.  Temps should plummet early on in the
teens to lower 20s with a few single digits over the southern
Adirondacks.

Mid and high clouds should begin to increase quickly from the south
and west ahead of a warm front approaching from the OH Valley and
the Mid Atlantic Region.  Min temps will likely occur around or
shortly before midnight, and then temps will likely be steady or
slowly climb towards daybreak in the warm advection regime.

The thickening and lowering clouds with the strengthening isentropic
lift on the 285/290K surfaces will quickly allow the lower levels of
the atmosphere to saturate from the west/southwest to the
north/northeast across the region between 6-9 am with snow
overspreading the region.  Our forecast favors the colder NAM/SREFS
with the threat of some light snow transitioning to sleet and likely
freezing rain. It will take some to erode the cold, subfreezing air
in place with the arctic high retreating offshore. The GFS thermal
profiles were slightly warmer in the late morning into the afternoon
than the NAM. Multiple times this past winter, it took more time to
dislodge the shallow subfreezing air in place at the sfc. This event
it may take some time for the northern most zones into the mid
afternoon.

Critical partial thicknesses from both the NAM and the GFS kept some
elevated freezing rain in over the mountains into the mid afternoon
/the southern Adirondack Region...southern Greens and even the
eastern Catskills/.  Some sleet is possible in most locations.  Our
confidence was greatest for a few hours /2-5 hours/ of freezing rain
from the eastern Catskills, Greater Capital Region, central
Taconics, and Berkshires northward. If the southerly winds kick in
quicker over the Capital Region, temps may surge above freezing
quickly.  Before the sleet and freezing rain, we are expecting a few
tenths of an inch to an inch of snow/sleet in these areas.  Further
north, BUFKIT NAM/GFS model soundings indicate a period of snow with
some sleet is possible over the southern Adirondack/Lake George
Region into southern VT.  Utilizing 10:1 snow to liquid ratios, we
came up with 1 to 3 inches of snow and sleet.  The higher totals
over the Dacks/Greens.  A coating/trace to tenth of an inch of ice
is also possible which was the reasoning for the WSW.

The warm front should lift through most of the region by the mid to
late afternoon with the pcpn leftover changing to a cold plain rain.
If the cold /below freezing/ air remains in place especially in the
sheltered valleys, then the advisories up north may need to be
extended.  We blended the guidance and went closer to the colder
METMOS temps with mid 30s to lower 40s across the region late in the
afternoon.  The southerly winds should increase from the south at 10
to 15 mph with some gusts in the 25 to 30 mph range.


&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A very complex forecast in the short term involving periods of
a wintry mix and rain. The complexity of the forecast includes
positioning of frontal boundaries relative to the large ridge of
high pressure to the north. This will ultimately determine
precipitation type.

Starting on Friday night, a warm front will be lifting north
through the area as a cold front sinks south out of Canada
towards the US/Canadian border. High pressure southwest of James
Bay will start to move southeast allowing for colder air to
start to drop southward from Canada. Precipitation Friday night
should primarily be in the form of rain but this depends on how
quickly the cold air can start infiltrating the forecast area.
Lows Friday night will generally be in the 30s.

Saturday through Monday...Much of the precipitation will be
diurnally driven with mainly rain during the daytime hours and
mainly freezing rain during the overnight hours into early
morning hours as indicated by BUFKIT model soundings. The
frontal boundary will slowly sink south across the forecast area
throughout the day Saturday as high pressure pushes further
south into northern NY. The frontal boundary is expected to drop
more southward into the mid-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 appears to be between around midnight and 10 AM
both Sunday and Monday. While there is still uncertainties on
the location of the frontal boundary and precip type through
this period, there is the possibility of a tenth to a third of
an inch of ice accretion totals across a good portion 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 lower 40s. Lows Saturday night
will be in the low 20s to mid 30s with lows Sunday night
generally in the 30s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Unsettled weather will be prevalent for much of the period before
high pressure and drier air eventually moves into the region late in
the week.

The period starts out on Monday with a surface boundary still draped
across the region. It appears we will be on the cool side of the
boundary with a cold air damming (CAD) signature evident on surface
pressure field on both GFS/ECMWF. Aloft, models in good agreement
with a progressive short wave trough moving eastward across the
area, so will mention likely pops. Most of the precip should be
rain, with temps aloft well above zero, although surface
temperatures may be cold enough for freezing rain across parts of
the southern Adirondacks and southern Green mountains in the morning.

As the short wave moves well east into New England Monday night,
rain should taper off to scattered showers. With a continued CAD
signature noted, some light frozen precip may occur again late
Monday night into early Tuesday morning across parts of the Dacks
and southern Greens.

The next system then moves in for late Tuesday and especially
Tuesday night as a progressive open wave upper trough and associated
surface cyclone traverse the area. The GFS is depicting a deeper
upper trough and associated stronger surface cyclone with slower
evolution, while the ECMWF is weaker and more progressive. The GFS
solution also allows for possible secondary development near the New
England coast late Wednesday into Wednesday night. If the stronger
storm scenario evolves, there could be enough cold air produced for
rain/snow issues. Best chances for any snow would be Tuesday night
into Wednesday and across the higher terrain. A lot of uncertainty
exists for this period.

Drier and colder air looks to move during the Wednesday night into
Thursday time frame, as high pressure builds eastward across the
Great Lakes.


&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
High pressure will be over NY and New England this afternoon,
and then will drift offshore tonight. A warm front will approach
from the south and west tonight and will bring mixed
precipitation to the region late tomorrow morning into the
afternoon.

Clear skies will give way to increasing mid and high clouds by
the 06Z/FRI. The clouds will continue to lower between 06Z-12Z
FRI with snow overspreading the region from the southwest to
northeast especially after 12Z/FRI. Expect cigs and vsbys to
quickly lower to low MVFR/IFR levels between 12Z-15Z. Our
confidence was greater in terms of vsbys in the IFR range late
in the TAF period. The snow will quickly transition to sleet and
freezing rain especially at KALB/KPSF north to KGFL between
15Z-18Z. KPOU may only have a light mix of rain and snow. Temps
should continue to climb above freezing in the afternoon.

The north to northwest winds of 5-12 kts this pm will quickly
become light to calm early this evening. The winds will increase
from the south at 5-10 kts towards daybreak FRI, except at KALB
where the winds could increase sooner at 5-10 kts around 10Z.
The winds will increase to 8-13 kts by the late morning with
some gusts in the 20-25 kt range at KALB/KPSF.

Outlook...

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

&&

.FIRE WEATHER...
A deep snow pack remains in place across much of eastern New
York and western New England. Temperatures will drop into the
teens and low 20s tonight before moderating into the low 40s
tomorrow. Unsettled weather arrives tomorrow morning,
continuing through the weekend, with the potential for a
a mix of rain, snow, sleet and freezing rain.

&&

.HYDROLOGY...
No precipitation is expected through most of tonight, with
below normal temperatures expected. There is a potential for
several rounds of precipitation Friday 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 Friday 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 from 6 AM to 2 PM EDT Friday for
     NYZ038>040-047>054-058>061-063.
     Winter Weather Advisory from 6 AM to 4 PM EDT Friday for
     NYZ032-033-041>043-082>084.
MA...Winter Weather Advisory from 6 AM to 2 PM EDT Friday for
     MAZ001-025.
VT...Winter Weather Advisory from 6 AM to 4 PM EDT Friday for
     VTZ013>015.

&&

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



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