000
FXUS61 KBTV 251133
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
633 AM EST Sat Jan 25 2020

.SYNOPSIS...
A complex weather system will bring wintry mixed precipitation
to the North Country this afternoon through Sunday. A Winter
Weather Advisory is in effect from 1 PM today to 4 AM Sunday
for portions of northern New York and Vermont. Ice accumulations
of a trace to two tenths are expected, with locally higher
along the spine of the Green Mountains. Locally gusty winds
upwards of 40 mph will also be possible this afternoon along
the western slopes of Green Mountains. Any mixed precipitation
will transition to rain or snow showers by Sunday afternoon.
Snow showers will linger through Tuesday morning with additional
accumulations of several inches likely. Quiet weather returns
by mid-week with seasonable conditions expected.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 625 AM EST Saturday...Minor tweaks made to hourly
temperatures based on current observations. Main forecast
challenge for the remainder of the day will be temperatures,
especially given low cloud cover across much of eastern Vermont
where temperatures remain in the teens/mid 20s, as well as some
sheltered locations across northern New York. Road surface
temperatures across Vermont, provided by AOT, show most surfaces
in the low to mid 20s, however a few locations along the
northern I-91 corridor and along the international border are
reporting road temps in the mid to upper teens. Even with
temperatures warming into the low to mid 30s, some of these
colder surface may remain below freezing for a period time at
onset of precipitation. Additionally, elevated surfaces in these
areas including overpasses and bridges may also remain below
freezing for a period of time. Otherwise, going forecast remains
in good shape with no other changes needed.

Previous Discussion...Overall, no significant changes made to
the forecast with no substantial changes in 00z guidance suite.
Winter Weather Advisories remain in effect beginning 1PM today
through 4AM Sunday.

Current surface observations show highly variable temperature
readings across the area. Valleys across the Northeast Kingdom and
northern Adirondacks, as well as the northern Champlain Valley, have
fallen into the mid to upper teens overnight. More widespread
temperatures in the mid to upper 20s exist across much of Vermont
and the St Lawrence Valley of New York, while the western slopes and
higher terrain of the Adirondacks and Green Mountains currently
range from the upper 20s to upper 30s. These early reading
temperatures, along with cloud cover, have a real bearing on
expected warming today and thus precipitation type and impacts. Have
settled on a blend of the NAM/ECMWF using the top-down method, along
with high-res models for surface temperatures, all of which seem to
be capturing the current trends well. This largely lead to mainly
rain across the broader valleys, with a mix of freezing rain and
sleet for the Northeast Kingdom and northern St Lawrence Valley as
temperatures warm today into the low to upper 30s.

Radar imagery as of 345 AM shows precipitation slowly beginning to
spread eastward into central New York. Precipitation should begin to
overspread our far western areas of northern New York towards 18z,
before spreading to the east and north with everywhere seeing
precipitation by 01z. This shot of essentially warm air advection
precipitation will be rather quick as dry slot moves in by 09z.
Expect precipitation to taper off outside the confines of the higher
terrain & Northeast Kingdom with mainly dry weather during the first
part of Sunday. Colder air will begin to work its way back in
towards Sunday morning as upper level low moves overhead. Any
lingering mixed precipitation should transition to snow or rain
showers by Sunday afternoon.

QPF amounts are between 0.50-0.75", with locally lower amounts
between 0.25-0.30" due to downsloping along the western slopes of
the Adirondack and Green Mountains, as well as across the northern
CT River Valley (due to shadowing off the White Mountains). Although
a few ice jams exist along the St Regis and Winooski Rivers we are
not expecting any hydro concerns with this system. Snowfall totals
(including sleet) through Sunday evening are less than 0.50". Ice
accumulations between a trace and 0.20" are expected across the
Advisory area with locally higher amounts up to 0.40" along the
spine of the southern Green Mountains.

Lastly, the threat for gusty winds remain for portions of the
Adirondack and Green Mountains as 30-40 kt 925mb southeasterly
jet sets up across this area. Model soundings show best timing
for mixing will be between 15-20z before precipitation saturates
and stabilizes the low levels. Expect gusts between 30-40 mph
for locations in western Addison and Rutland counties, such as
Bristol, Goshen, Brandon and Rutland. Localized gusty winds will
be likely across the Adirondacks including Saranac Lake and
Lake Placid. These values remain sub- criteria, however very
isolated power outages may be possible.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 419 AM EST Saturday...Low pressure will pull away from the
region through the first part of next week, but a series of upper
shortwaves will rotate over the region. This with the continued
northwest flow will allow mountain snow showers to linger through
Tuesday. Mixed rain/snow showers will possible in the wider valleys,
particularly Sunday night and Monday. Additional snow accumulation
of a few inches will be possible during this time frame.
Temperatures will warm into the mid and upper 30s Monday afternoon,
but then turn slightly cooler on Tuesday with everyone near or below
freezing.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 419 AM EST Saturday...Quiet weather prevails through the last
half of the week as high pressure settles across the region. This
also means it`ll trend a little colder, especially overnight when
mostly clear skies and light winds will allow for good radiational
cooling. Our next chance for precipitation arrives next weekend when
low pressure will move from the southern Appalachians northeastward.
Not a lot of agreement between the GFS and ECMWF on where this low
tracks, and a fair amount of spread in the GFS ensemble members as
well, so have stayed with just low chance PoPs for now.

&&

.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
Through 12Z Sunday...Deteriorating avaiation conditions today as
storm system is expected to bring wintry precipitation to the
area this afternoon. Generally high clouds across the airspace,
however maritime airmass remains locked in across eastern
Vermont where 1500-2500 ft ceilings are being reported. Towards
18z, all areas will see MVFR ceilings/visibilities as deeper
moisture moves into the region. At the same time precipitation
will also be moving in, which will start as rain, periods of
sleet and/or freezing rain mixing in, especially after 21z. The
best chances for any mixed precipitation will be at KMPV &
KMSS. Increasing 925mb low level jet of approximately 30-40 kt
will bring the threat for LLWS at all TAF sites towards 20z.
Winds be generally out of the southeast around 10-15 kt. The
exceptions will be at KRUT where winds may gust as high as 30 kt
at times Saturday afternoon and KMSS where NE winds around 10
kt should hold on through the period.

Outlook...

Sunday: Mainly VFR, with local IFR possible. Chance RA, Chance
SN.
Sunday Night: Mainly MVFR, with local IFR possible. Chance SHSN.
Monday: Mainly MVFR, with local IFR possible. Chance SHSN, Chance
SHRA.
Monday Night: Mainly MVFR, with local VFR possible. Slight chance
SHSN.
Tuesday: Mainly MVFR, with local VFR possible. NO SIG WX.
Tuesday Night: Mainly VFR, with areas MVFR possible. NO SIG WX.
Wednesday: VFR. NO SIG WX.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 1 PM this afternoon to 4 AM EST
     Sunday for VTZ003-004-006>008-010-012-018-019.
NY...Winter Weather Advisory from 1 PM this afternoon to 4 AM EST
     Sunday for NYZ026-027-030-031-034.

&&

$$
SYNOPSIS...LaRocca
NEAR TERM...LaRocca
SHORT TERM...Hastings
LONG TERM...Hastings
AVIATION...LaRocca