Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 191405
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1005 AM EDT Thu Apr 19 2018

.SYNOPSIS...
Low pressure will move over the North Country today leading to
widespread light rain and mountain snow. Higher elevation
locations will see the potential for 3 to 6 inches of snow with
a dusting to an inch possible in the valleys. Temps will remain
below normal through the rest of the week before a warming
trend begins over the weekend. Coming out of the weekend we
should see near normal to slightly above normal temperatures
along with dry conditions and plentiful sunshine.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 945 AM EDT Thursday...going forecast in fairly good shape.
Blended in the current observations to tweak the next few hours.
That system that brought the snow to areas south of here is
gone, but it was never really "our" weather maker. It`s the
upper trough that is moving into the area. As that trough, which
is very well defined on water vapor imagery, moves closer,
temperatures aloft will fall. 500mb temperatures currently
around -18C will drop to near -23C by late day. Even with the
clouds, the strong late April sun will result in some daytime
heating, and the combo will produce some instability -- enough
for convective showers to develop. Given freezing levels around
1200ft MSL, expect that snowflakes will make it to the surface,
even if surface temperatures are in the lower 40s (though at
that point they may be mixing with rain). Have blended in some
of the latest HRRR and 4km BTV WRF output to show the scattered
snow shower development. Just like summer, the higher terrain
will be the focus for more of the snow showers. Given the
relatively "warm" (above freezing) surface temperatures, not
expecting any accumulation below 1000-1200ft elevation this
afternoon.

Gets a bit interesting overnight. Looks like blocked flow
develops within the overall northwest flow. So snowshowers will
be most focused on the upslope areas, but the blocked nature
could push those snow showers further west of the Green
Mountains into the Champlain Valley. Forecast already has this
covered, but just mentioning it from what I saw in reviewing
data. Not sure about you, but this forecaster is not a huge snow
fan to begin with and decidely not a fan of snow (at least at
lower elevations) this late into April. At least it melts
quickly.

Previous discussion follows...

An upper level trough will swing through the North Country
today with a surface low pressure tracking generally south of
the area. By mid morning the upper level trough will move over
the region and low level moisture will increase as the flow
turns more northwest. This will lead to precip lifting north and
becoming scattered across the North Country. The best chance
for prolonged precip will be in the mountain areas but all sites
should see measurable rain or snow. Snow levels during the day
will be in the 1000-1500ft range during the day and then will
fall to the valley floors during the evening hours Thursday. So
a dusting to an inch of snow will be possible in elevations less
than 1000 ft and in the high elevation sites above 2500 feet
will have the potential for 3-6 inches of snow with the
potential for the Mt Mansfield stake to get close to 100 inches
by Friday afternoon.

Because we`ll be dominated by the upper level trough through the
rest of the week, we`ll continue to be well below normal with
highs in the low to mid 40s. Temps overnight will be just below
normal with lows in the upper 20s to low 30s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 352 AM EDT Thursday...A deep-layer trough will be
departing to our north and east across the Canadian
Maritimes/Newfoundland, with a prevailing NW low-mid level flow
in place across the North Country. Should see lingering
rain/higher elevation snow showers generally ending during the
first half of Friday night (30-40% PoPs early) with decreasing
moisture/cyclonic flow. Some partial clearing expected by
daybreak Saturday with overnight lows generally in the upper 20s
to lower 30s.

The weekend generally looks seasonably cool and dry with high
pressure across the Great Lakes gradually building eastward.
Should see partly sunny conditions with highs in the mid-upr 40s
on Saturday, followed by temperatures moderating into the upr
40s to lower 50s with mostly clear conditions and lighter NW
winds on Sunday. Precipitation is not expected Saturday or
Sunday.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 352 AM EDT Thursday...A deep-layer ridge will build
across the northeastern CONUS early next week, finally setting
up a warming trend for the region. Should see high temps in the
mid-upr 50s for Monday, and into the low-mid 60s for valley
locations on Tuesday (normal high for BTV is 57F). Next northern
stream shortwave trough expected to arrive on Wednesday per 00Z
GFS. Some indication of phasing with a srn stream system from
the Carolinas, which would have implications for overall
rainfall amts. The 00Z ECMWF has a similar synoptic pattern with
possible phasing, though the evolution is about 18-24hrs
slower. Too early to say, but a stronger, phased system with
better influx of moisture would potentially have implications
for moderate to heavy precipitation at the end of the period.
We`ll be monitoring this potential. Anticipate high temperatures
remaining near 60 degrees for highs on Wednesday.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Through 12Z Friday...Generally VFR lowering to MVFR with
periods of IFR possible in snow this afternoon and evening. Low
ceilings currently are producing IFR at SLK but cloud cover
should lift to low MVFR by mid morning before dropping again
once snow moves this evening. Widespread light rain and snow
will move across the North Country generally between 19-21z.
Higher elevation TAF sites will see mostly snow with the lower
elevation sites seeing a mix of rain and snow during the
daylight hours transitioning to all snow and lowered
visibilities during the overnight hours. Winds will generally be
less than 10 kts through the period becoming west to northwest
after 18z and perhaps becoming some what gusty at MSS with gusts
up 15kts after 08z.

Outlook...

Friday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance
SHSN.
Friday Night: Mainly VFR, with local MVFR possible. Slight chance
SHSN.
Saturday: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.

&&

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

&&

$$
SYNOPSIS...Deal
NEAR TERM...Deal/Nash
SHORT TERM...Banacos
LONG TERM...Banacos
AVIATION...Deal


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