Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 300554
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
154 AM EDT Thu Mar 30 2017

.SYNOPSIS...
Surface high pressure will build in briefly and provide a
period of sunny and dry conditions on Thursday, but unsettled
weather returns for the end of the week and into the weekend, as
another storm system will bring a mix of rain and snow to valley
locations, and higher elevation snowfall Friday into Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1045 PM EDT Wednesday...Ridge of surface high pressure
extending from nrn Ontario swd across wrn NY/PA will gradually
shift ewd through the remainder of the overnight, and slowly
move across nrn NY and VT during the daylight hours Thursday.
This will set up a tranquil period of wx, albeit brief. Still
dealing with widespread stratus clouds at 0230Z per latest IR
imagery, with a moist nly flow trapping cloud layer beneath
strengthening subsidence inversion. Will eventually get some
drying/clearing from west to east during the pre-dawn hrs, but
trends suggest a slow process. As a result, increased overnight
lows by a few degrees with clouds mitigating radiative cooling
effects. Generally looking at lows in the mid-upr 20s, and
locally around 30F near Lake Champlain.

With high pressure across the area Thursday, should see mostly
sunny conditions with a trend toward increasing high clouds,
especially during the aftn hrs. Anticipate light north winds and
weak low-level CAA. We`ll be a few degrees below normal but
temps should still warm into the lower 40s in most locations.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
As of 355 PM EDT Wednesday... A Winter Storm Watch has been
issued for Southern Vermont for the potential for 6-10 inches of
heavy wet snow on Friday. Friday will be the most active period
as snow moves in late Thursday night and then continues to
throughout on Friday before finally tapering off Saturday.

The biggest issues with the forecast remain the precip type.
Timing will dictate p-type as we will see warm air advection
bring snow initially but then a shallow boundary layer in the
lowest 1000 feet or so will warm leading to rain. Between
1000-2000 feet, expect a rain or snow mix with more snow than
rain, and above 2000 feet expect all snow. The bulk of the
precip arrives from noon on Friday through the overnight hours
on Saturday. During this time we should see a burst of heavy wet
snow with some western slope enhancement. In the watch area
expect 6-10 over the 24 hour time period, and a gradient as we
move further north. Storm Total snows vary from south to north
but the general idea is that along the international border we
can expect 2-4 inches. Across central Vermont and the
Adirondacks we can expect 4-7 for the duration of the event and
again expect 6-10 across Southern VT. I leaned towards some of
the colder guidance for hourly temps mainly due to the idea that
by Friday afternoon we will be wet-bulbing down and seeing temps
likely a few degrees cooler than our normal diurnal process.
Please see our winter weather page at www.weather.gov/btv/winter
for specific accumulation forecasts and probabilities.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 335 PM EDT Wednesday...A low pressure area will off the
southern New england coast early Saturday. Expecting steady
precipitation Saturday morning to taper off by Saturday
afternoon, as the low pressure area slides east out to sea
toward Georges Bank by early Saturday evening. Will have slight
chance pops for some snow showers Saturday night into Sunday. A
ridge of high pressure will build into the region Sunday night
and Monday, with fair and dry weather expected.

Models showing some significant differences late Monday night
and Tuesday through Wednesday. GFS brings in a chance of rain or
snow on Tuesday and Wednesday, while The ECMWF model has
precipitation further south and mainly south of New England for
Tuesday and Wednesday. Thus, forecaster confidence is low for
the Tuesday and Wednesday forecast, given the model differences.
Thus, have stuck with superblend pops for Tuesday and Wednesday,
and will have a chance of rain and snow in the forecast at this
time.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Through 06Z Friday...VFR conditions persist as surface high
pressure builds into the North Country. Deck of VFR low and mid
level clouds will persist through the overnight, gradually
diminishing in coverage and lifting to mid and high level clouds
around day break. Winds are 5-10 kts out of the North.

Outlook 06Z Friday through Monday...

06Z Friday through 09Z Friday...VFR under high pressure.

09Z Friday through 00Z Sunday...MVFR/IFR in periods of rain and
snow.

00Z Sunday through 00Z Monday...Areas of MVFR in scattered
light snow showers.

00Z Monday through 00Z Tuesday...Mainly VFR conditions expected
as a ridge of high pressure builds into the region.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Storm Watch from late tonight through Saturday
     afternoon for VTZ011-012-018-019.
NY...None.

&&

$$
SYNOPSIS...Deal
NEAR TERM...Banacos/Deal
SHORT TERM...Deal
LONG TERM...WGH
AVIATION...Neiles


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