Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 202327
AFDBTV

AREA FORECAST DISCUSSION
National Weather Service Burlington VT
727 PM EDT Wed Mar 20 2019

.SYNOPSIS...
Dry weather continues as we sit under mostly clear skies today.
Clouds will begin to move in and thicken heading into the
overnight hours as an upper level system starts progressing from
the Great Lakes into the North Country. Expect scattered
mountain snow showers and valley rain as the system tracks
through. Precipitation becomes more widespread heading into the
weekend as a strengthen winter system couple potentially bring
widespread accumulating snowfall.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 724 PM EDT Wednesday...Dry conditions will persist across
the North Country tonight as southerly winds continue. Expect
warm air advection to hold temps in the mid 30s through the
overnight hours, as our min temps don`t fall much this evening.
Clouds increase and thicken during the overnight hours and we`ll
see precip start to move into the region by mid afternoon
Thursday. The upper level trough that brings precip continues to
track slower than previous guidance indicates so I think its
going to be mid day before we really start to see much in the
way of precip. Precip type looks to be highly dependent on
elevation with PBL temperatures in the 30s. Snow levels start
out between 1000-1500 feet but quickly increase to around
2500-3000 feet mid day on Thursday. Then heading into the
evening Thursday night we`ll see them come down to around 1000
feet. So the net result is that in the valley floors we are
looking at mostly rain through the onset while in the mountains
we`ll see mostly snow with some rain mixing in. As we head into
Thursday night I think we`ll start to see some accumulation of
snow. Model soundings are favorable for snow-to-liquid ratios
lower than climo, likely in the 8-10:1 range with 0.1-0.4" of
liquid Thursday night. That turns into no accumulation in the
valleys and between 2-4 inches highly dependent on elevation.
During the overnight hours the upper level trough will transfer
energy to a deepening coastal low and that`s when we`ll start
to see a ramp up in forcing for ascent and snowfall rates toward
daybreak on Friday.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 325 PM EDT Wednesday...Overall very little change in
today`s NWP guidance compared to yesterday and overnight as
models are locking into the upcoming pattern nicely. By 12Z
Friday morning, surface low pressure will be well established
near Long Island and will move northeast along the New England
coast through the day before stalling over northern Maine Friday
night. Morning snow across the region will transition to a
rain/snow mix in the valleys as snow levels briefly rise above
1-2kft, but as the surface to mid- level flow shifts to the
north/northwest in the afternoon, strong cold air advection will
quickly transition the entire region back to snow for the
evening commute.

Favorable conditions then continue to appear likely Friday night for
a 12-18 hour period of moderate to heavy upslope snow across the
Adirondacks and western slopes of the central/northern Green
Mountains as a secondary trough shifts southwest into the region
consolidating with the initial trough to form a single broad upper
trough over the Northeast. At the same time, the surface-700mb low
parks itself over northern Maine providing an excellent feed of
moisture and lift on north/northwest flow resulting in the potential
for 6-10" mid-slopes and up to a foot or more above 2000 feet.
Beginning the event snow density will be quite high with ratios
generally 8-12:1 through midnight Friday, but expect after
that through Saturday ratios will rise to a general 15-20:1
making for superb skiing/riding on Saturday. With all this in
mind, have gone ahead and issued a Winter Storm Watch for
portions of the area. Please see our winter page online for
graphics.

Snow should be ongoing Saturday morning but will rapidly decrease in
coverage beyond the noon hour as coastal low pressure finally shifts
east and surface high pressure over the central CONUS begins to
filter in from the west.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 325 PM EDT Wednesday...Aforementioned surface high
pressure over the central US begins to shift east over the mid-
Atlantic and Northeast Saturday night resulting in a crisp, cool
night Saturday night with temps dropping well below normal into
the teens and lower 20s. Sunny skies will allow for a nice
rebound in temps through Sunday with highs bumping well into the
40s before a cold front looks to drop southward into the
region, cooling things off again for the remainder of the period
and bringing some scattered snow showers to the region Sunday
night through Monday. Temps next week will run a good 5-10
degrees below normal with highs ranging through the 30s and lows
in the teens and single digits.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...VFR conditions and light winds will persist
through the overnight hours and much of Thursday. An approaching
storm system will bring MVFR ceilings to southern terminals
around 20Z Thursday and work northward to the remaining
terminals close to 00Z Friday. Precipitation, which looks to be
a rain/snow mix will move into KSLK and KRUT right around 00Z
but have left them at VCSH for the time being as there are a few
discrepancies in timing at this time.


Outlook...

Thursday Night: MVFR/IFR conditions possible. Definite RA,
Definite SN.
Friday: Mainly IFR, with areas MVFR possible. Definite RA,
Definite SN.
Friday Night: Mainly MVFR, with local IFR possible. Windy with
gusts to 30 kt. Definite SN.
Saturday: Mainly VFR, with areas MVFR and IFR possible. Likely
SN, Chance SHSN.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHSN,
Chance SHRA.
Monday: VFR. Chance SHSN.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Storm Watch from Friday afternoon through Saturday
     morning for VTZ003-004-006-016>019.
NY...Winter Storm Watch from late Thursday night through Saturday
     morning for NYZ029>031-034.

&&

$$
SYNOPSIS...Deal
NEAR TERM...Banacos/Deal
SHORT TERM...Lahiff
LONG TERM...Lahiff
AVIATION...Clay



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