Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 280449
Area Forecast Discussion
National Weather Service Burlington VT
1249 AM EDT Sun Aug 28 2016
A ridge of high pressure will move east of the region overnight.
An upper disturbance over the Great Lakes will approach the
region Sunday with a chance for showers and thunderstorms Sunday
afternoon and Sunday night. a cold front will move south from
Canada Sunday night and early Monday. A ridge of high pressure
will then build into the north country Monday night and Tuesday.
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
-- Changed Discussion --As of 1249 AM EDT Sunday...Some minor adjustments to the forecast
with respect to clouds and temperatures. High level clouds moving
in early this morning will be just enough to keep temperatures up
just a bit and have raised overnight lows up by two degrees. Also
removed any mention of showers in the Saint Lawrence River Valley
early this morning as any activity is not expected until after
On Sunday, expecting showers and thunderstorms to develop across
the region by Sunday afternoon as an upper disturbance shifts east
from the Great Lakes. Instability is marginal Sunday afternoon, so
have stuck with mainly chance pops for now. SPC has area in a
general thunderstorm outlook for Sunday. Precipitable water values
per bufkit forecast soundings climb to over 1.5 to near 2 inches
in some areas by Sunday afternoon. 0-6km bulk shear is around
30-40 knots Sunday afternoon, so any storms that do develop should
move along and not stall over the region. Some brief locally heavy
rainfall may be possible with any storms that do develop.
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.SHORT TERM /7 PM THIS EVENING THROUGH MONDAY NIGHT/...
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 include 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
.LONG TERM /TUESDAY THROUGH SATURDAY/...
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
.AVIATION /06Z Sunday THROUGH Thursday/...
-- Changed Discussion --Through 00Z Monday...mainly VFR through the period.
Expecting cumulus clouds over the Adirondacks and Green Mountains
to dissipate shortly then expecting a gradual increase 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 00Z Monday through Thursday...
00Z Monday through Thursday...mainly VFR through the period with
high pressure. Scattered showers and brief MVFR conditions
possible Tuesday afternoon/Wednesday with weak trough passages.
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