Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 271932
Area Forecast Discussion
National Weather Service Burlington VT
332 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 /THROUGH SUNDAY/...
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.
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
-- Changed Discussion --As of 330 PM EDT Saturday...Short term period picks up with the
surface front on the St. Lawrence Valley doorstep and southerly
flow ahead of it. Plenty of low level moisture streaming northward
ahead of the front, with precipitable water over 1.5 inch until
the front passes. Residual daytime heating, low level forcing
along the front, and weak 500 mb dynamic support in the form of a
sheared vort center. Kept chance to low likely pops going 00 to
late evening, then tapers off. As the vort center passes the 500mb
flow flattens, with a secondary and better defined shortwave
trough moving across the area Monday in northwest flow.
Despite the second trough on Monday precip chances decrease as
northwest low level flow brings in much drier air. Slight chance
to chance pops continue over higher terrain from 00-18z Monday,
then dry thereafter. Clearing late Monday into Monday night with
1000-500 mb RH dropping below 30%. Fog formation possible Monday
night under surface and upper ridging and clear skies for good
radiational cooling, but didn`t inlude in forecast this far out.
For temps, Sunday night still relatively warm with residual
moisture limiting lows into the 60s. Highs Monday a little cooler
under lower heights and 850 mb temps cooling to around 11C in
support of max temps in the 70s.
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
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.LONG TERM /TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --As of 312 PM EDT Saturday...On Tuesday...surface high quickly
shifts into the Gulf of Maine...as return flow develops ahead of
approaching boundary. Northwest upper flow over the region, with
500mb shortwave trough moving through central Canada towards
forecast area trough passes well north of region Tuesday
night/Wednesday, dragging a surface front behind. Return of
moisture, weak instability and frontal lift good for chc showers
in the north Tuesday night and areawide Wednesday.
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
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.AVIATION /19Z Saturday THROUGH Thursday/...
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.