Scientific Forecaster Discussion
fxus61 kbtv 280313
Area forecast discussion
National Weather Service Burlington Vermont
1113 PM EDT Mon Mar 27 2017
surface low pressure system continues to push eastward across
Quebec. Scattered showers redevelop Tuesday as surface front
moves west to east across our area. Wednesday and Thursday will
be drier with ridge of high pressure building south out of
Canada and over the north country. Another storm system looks to
affect the region on Friday.
Near term /until 8 am Tuesday morning/...
as of 1107 PM EDT Monday...the north country is in between mid-
level troughs this evening. The leading shortwave trough - which
brought this morning's precipitation (0.30" at btv since
midnight) - is exiting ewd across nrn Maine and New Brunswick.
There is a weaker shortwave and associated surface trough across
sern Ontario and swrn Quebec, with is maintaining a moist S-southeast
flow across the north country overnight. Not anticipating much
change in wx conditions next 6-12hrs...with temps generally
holding above freezing in the 35-40f range with low overcast in
place. Dewpoint depressions are small, and have seen some
developing fog at mss/Potsdam this evening. With upr 30s
dewpoints over the existing snowpack, could see some additional
patchy dense fog overnight. Deep-layer forcing is limited. In
fact, NAM/rap soundings show mid-level drying thru the remainder
of the overnight...so any lingering precipitation should
primarily be drizzle or perhaps a light orographically induced
rain shower or two. Only change with this update was to include
patchy fog areawide.
Short term /8 am Tuesday morning through Wednesday night/...
as of 330 PM EDT Monday....surface high pressure will build
southward from James Bay Tuesday. Low pressure system tracks
eastward across Quebec dragging a surface front with it across
our County Warning Area. Will have some scattered light rain showers for Tuesday
into the first part of Tuesday night. Region will be solidly in
the warm sector ahead of aforementioned front early in the day
and Max temperatures will reach the upper 40s to around 50.
Strongest shortwave energy stays well south of our County Warning Area Tuesday,
therefore only scattered showers expected with the frontal
passage in the afternoon into Tuesday evening. Showers will
taper off Tuesday overnight, with possible change over to snow
showers with colder air moving into the region on northwesterly
flow. On Wed upper level trough pushes across our area with
surface high pressure building south and east from central
Ontario. Will continue to be some scattered light rain or snow
showers, mainly across the northern high terrain. Wednesday will
be about ten degrees cooler than Tue and back below seasonal
normals once again. Looks to be a breezy day as well with cold
air advection and northwesterly winds gusting up to 25 mph.
Partly sunny skies will develop during the afternoon hours. On
Wednesday night any remaining precipitation comes to an end with
large ridge of surface high pressure ridging into the north
country. Wednesday night will be near normal, temps dropping
back into the 20s with some teens in the dacks.
Long term /Thursday through Monday/...
as of 357 PM EDT Monday...a ridge of high pressure will be over
the north country Thursday through Thursday night with fair and
dry weather expected. A low pressure area over the Ohio Valley
will spread moisture into the region on Friday. GFS and European model (ecmwf)
model showing some timing differences at this time, with the GFS
model holding off precipitation until Friday afternoon, while
the European model (ecmwf) is more aggressive and bring precipitation in earlier
in the day on Friday. Have raised superblend pops to high chance
(50 percent) for Friday across the region, and will have likely
pops for Friday night. Will go with a mention of rain and snow
for Friday and Friday night. Precipitation will linger into
Saturday, so will continue with a chance of rain and snow. Have
stuck with superblend pops for Saturday night and Sunday, and
will have a chance of rain or snow showers. A ridge of high
pressure will build into the north country on Monday for fair
and dry weather.
Aviation /03z Tuesday through Saturday/...
through 00z Wednesday...model guidance showing plenty of deep
layer moisture will be over the region through the period, with
MVFR/IFR/LIFR ceilings expected through 00z Wednesday. Areas of
fog are also expected over northern New York during the overnight
hours, also in the IFR/LIFR range.
Winds will remain light out of the south for all stations at
7 knots or less except kmss which will continue to remain locked
in light northeasterly flow for most of the period.
Outlook 00z Wednesday through Saturday...
00z Wednesday through 12z Wednesday...MVFR/IFR in scattered
rain showers Tuesday, then scattered rain/snow showers Tuesday
12z Wednesday through 12z Thursday...mainly VFR, with some
scattered rain or snow showers mainly over the Adirondacks and
12z Thursday through 18z Friday...VFR, as a ridge of high
pressure will be over Vermont and northern New York.
18z Friday through 00z Sunday...areas of MVFR/IFR in rain and