Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 271801
Area Forecast Discussion
National Weather Service Burlington VT
201 PM EDT Sat Aug 27 2016
High pressure over the North Country today will bring a good deal of
sunshine...dry weather...and temperatures a few degrees above
seasonal normals. The dry weather continues tonight...but the high
pressure system will be moving east and this will allow moisture to
begin increasing ahead of an upper level trough of low pressure. As
this feature moves into the region on Sunday expect increasing
chances for showers and thunderstorms...especially Sunday afternoon
and night. High temperatures will be at or slightly above seasonal
normals on Sunday.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --As of 201 PM EDT Saturday...Current forecast in good shape, so no
changes have been made.
Previous discussion from 701 AM EDT Saturday...Cannot seem to
shake the mid level clouds across the area this morning...but
areal coverage is slowly decreasing and this trend will continue.
The clouds have had an impact on fog with areal coverage being a
bit limited. The fog should burn off completely by mid-morning.
Otherwise high temperatures will be a few degrees above normal
today with highs in the upper 70s to mid 80s. Winds will be light
For tonight...the high moves off to the east and we begin to see
more south to southwest flow in the lower levels. Clouds will be on
the increase...especially mid and high level clouds. However...forcing
is weak across the area and thus going with a dry forecast as it
appears Sunday will have the better chances for precipitation. Lows
will generally be in the mid 50s to mid 60s.
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.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
As of 327 AM EDT Saturday...A strong mid/upper level ridge of high
pres centered over VA will slowly break down as northern stream
energy moves from the Great Lakes into the NE Conus. The flow
around this area of high pres will advect pw values between 1.50
and 1.75 inches across our region ahead of a surface cold front.
This available moisture...combined with modest upper level forcing
from 5h vort will produce scattered showers on Sunday Afternoon
into the overnight hours. Highest pops will be across northern NY
between 18z-00z Sunday...but shift southeast into most of VT after
00z...as boundary crosses our region. Instability parameters show
a modest axis of surface based CAPE values between 500-1000 J/kg
between 21-00z Sunday...with greatest values located over northern
NY. Have included the mention of scattered thunderstorms...but not
heavy rain...as dynamics are limited and surface convergence is
weak. Temps on Sunday will be tricky as progged 850mb temps are
between 14-16c...supporting highs well into the 80s...but with
clouds and precip...expecting readings in the mid 70s mountains to
lower 80s valleys...with a few mid 80s near VSF. Humidity levels
will be increasing throughout the day...as dewpoints climb into
By Monday surface boundary is located just east of our cwa...with
any lingering showers quickly ending as much drier air advects
into the region. Progged pw values fall below 1.0 with moderate
cold air advection on breezy northwest winds. 850mb temps cool 4
to 6 degrees by 12z monday with highs mainly in the 70s
anticipated. will mention low chc pops in the morning for eastern
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 327 AM EDT Saturday...a cool night is expected on monday
night with surface high pressure located over northern NY and
building heights aloft. This will produce calm winds and clear
skies with temps ranging from the upper 30s/lower 40s to upper
40s/mid 50s warmer valleys.
On Tuesday...surface high quickly shifts into the Gulf of
Maine...as return flow develops ahead of approaching boundary.
Some uncertainty on amount of low level moisture return before
front arrives and overall instability on Tuesday afternoon. Pw`s
climb to 1.50...with weak ribbon of CAPE around 500 J/kg. Will
mention chance pops after 00z Wednesday with schc for
thunder...as instability is limited. If front is earlier and
greater instability develops from afternoon heating...then
a greater coverage and intensity of storms will be
possible...given upper level dynamics and associated jet.
Strong low level cold air advection follows boundary on Thursday
into Friday with 850mb temps falling between 2 and 4c. This low
level thermal profiles supports temps dropping back to below
normal by Thursday with highs mainly in the 60s to lower 70s and
lows in the 40s to mid 50s. Expect mainly terrain driven showers
on Thursday into Friday associated with upslope flow and some mid
level moisture. Will mention schc/low chc pops for the mountains
of NY into northern VT...based on position of closed 5h trof and
.AVIATION /18Z Saturday through Thursday/...
-- Changed Discussion --Through 18Z Sunday...mainly VFR through the period. Expecting
cumulus clouds over the Adirondacks and Green Mountains to
dissipate by 00Z Sunday, due to the loss of daytime surface
heating. Expecting a gradual increse in high and mid level clouds
overnight as a weak disturbance approaches from the Great Lakes.
There could be some light scattered rain showers over northern New
york between 15Z-18Z Sunday. Surface winds expected to be mainly less
than 10 knots through the period.
Outlook 18Z Sunday through Thursday...
18Z Sunday through Thursday...mainly VFR through the period with
high pressure. Two main threat periods for scattered showers and
brief MVFR conditions - Sunday afternoon and Sunday evening, then
again Tuesday afternoon/Wednesday with weak trough passages.
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