Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 291118
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
718 AM EDT Wed Mar 29 2017

.SYNOPSIS...
Deep low pressure over central Quebec this morning will continue
to provide abundant cloud cover to the North Country today,
along with areas of fog and drizzle this morning, and some
scattered rain and snow showers across north-central Vermont
this afternoon. A brief period of sunnier and drier conditions
is expected on Thursday as a ridge of high pressure builds over
the region, but unsettled weather returns for the end of the
week and into the weekend, as another storm system will bring
valley rain and mountain snow Friday into Saturday.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 718 AM EDT Wednesday...Deep low pressure over central
Quebec this morning continues to provide abundant low level
moisture to the North Country in the form of areas of cold
drizzle and fog with current temps ranging through the 30s. Cold
air advection continues through the day on northerly flow, and
while precipitation chances generally wane across the majority
of the region, additional shortwave energy rounding the base of
the upper trough will skim along the international border
maintaining the threat for scattered valley rain and mountain
showers across central and northern portions of Vermont through
the afternoon. Abundant cloud cover will persist through the day
as well, keeping temps in the mid 30s to low 40s in the valleys
while the higher summits gradually fall through the 20s.

For tonight, the upper trough finally begins to swing east of
the area with surface high pressure and and upper ridging over
the Great Lakes and Ohio Valley edging ever so slowly eastward
towards the region. Low levels finally begin to dry out with
subsidence aloft winning out, so a gradually clearing of skies
is expected though mainly after midnight with valley locales
clearing the most, mountain areas less so. Lows will range
mainly in the 20s with some teens in the Adirondacks.

Thursday will be the best day of the week as the aforementioned
high centers over the Northeast with skies continuing to clear
through the day. Unfortunately temps won`t really change to much
as weak cold air advection will continue on light northerly
flow, but we should realize widespread highs in the low/mid 40s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 341 AM EDT Wednesday...Most active period of weather then
affects the region by late Thursday night and especially Friday
into Friday night as upper closed energy tracks east from the
Ohio Valley into the Mid Atlantic region. The forecast remains
quite complex in regard to precipitation timing, amounts and
type with lower boundary layer thermal profiles playing a
critical role through the period. This is not uncommon with
early spring systems with subtle changes of 1 to 2 degrees
either way potentially leading to large differences in sensible
weather. For now will maintain our prior idea of snows arriving
into our southwestern counties later Thursday night into mid
morning on Friday before a transition to all rain in lower
elevations, or rain/snow mix from 1000-2500 feet on Friday as
precipitation shield advances into the remainder of the forecast
area. At higher elevations above 2500 feet p-type may remain as
all snow. Negligible amounts of sleet or freezing rain is
expected. Lows Thursday night mainly in the 20s with afternoon
highs on Friday from 35 to 40 below 1500 feet and 30 to 35 above
that level.

Bulk of precipitation then affects the area Friday night as warm
thermal advection aloft will be peaking and as thermal profiles cool
slightly a transition to all snow is expected after midnight.
Amounts may be a bit tricky as flow trends southeasterly and some
slight shadowing effects may occur. Time will tell. I was also
cautious in leaning too high on our QPF given known model high bias
during warm thermal advective events. Nonetheless the potential will
exist for a light to moderate wet snow accumulation in many areas
with higher amounts possible in elevated southern terrain. Did lean
on the milder side of guidance given clouds and lack of appreciable
low level advection - mainly lower to mid 30s (upper 20s at
elevation). Please see our winter weather page at
www.weather.gov/btv/winter for specific accumulation forecasts and
probabilities.

By Saturday widespread light snows taper to scattered rain/snow
shower activity as system exits the Mid Atlantic coast and
gradually loses influence. Any additional snow accumulations
will be minor as late day temperatures top out in the upper 30s
to lower 40s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
As of 341 AM EDT Wednesday...Relatively quiet weather then
returns by later Saturday into early next week with mean high
pressure building back across the region. Any lingering
rain/snow shower activity will wane in coverage, becoming more
confined to northern higher terrain into Sunday as highs top out
in the 40s. Temperatures will be similar on Monday with dry
weather expected. The next threat of steadier precipitation
potentially arrives toward the middle of next week with chances
of rain and/or snow showers. Temperatures will remain at, or
slightly above seasonal early April norms.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Variable flight conditions from VFR at
KMSS/KBTV/KPBG to LIFR at KMPV/KRUT will continue through 14z
before IFR sites lift to MVFR and SLK remains MVFR. Heading into
the mid-day hours a gradual improvement at all sites to VFR is
expected by the afternoon with some lingering rain/snow showers
across central/northern portions of Vermont through about 18z.
Further clearing is expected overnight. Winds calm/light this
morning trend to the north/northwest at 5-15kts after 12z with
some gusts up to 20kts possible from the Champlain Valley
eastward through Vermont.

Outlook 12Z Thursday through Sunday...

12Z Thursday through 12Z Friday...VFR under high pressure.

12Z Friday through 00Z Monday...MVFR/IFR in periods of rain and
snow.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Lahiff
SHORT TERM...JMG
LONG TERM...JMG
AVIATION...Lahiff


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