Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 261912
Area Forecast Discussion
National Weather Service Burlington VT
312 PM EDT Wed Apr 26 2017
A low pressure area at the surface and aloft along the mid
Atlantic coast will drift slowly northeast today and be near
Cape Cod tonight. A ridge of high pressure will build northward
from the mid Atlantic states northward into northern New York
this afternoon. Expecting rain showers this morning to begin to
taper off by this afternoon, with mostly cloudy skies expected.
A ridge of high pressure will be over the North Country on
Thursday, with highs in the 70s to the lower 80s.
.NEAR TERM /THROUGH THURSDAY/...
As of 1136 AM EDT Wednesday...Updated forecast to integrate
latest trends into the grids and associated forecast. Water
vapor continues to show cyclonic flow with low level upslope
southeast flow impacting our central/eastern vt cwa...while some
drying aloft is occurring across northern NY. We are in the
squeeze play today between drier air associated with building
ridge aloft and subsidence and low level moisture with low pres
along the coast. Thinking some breaks in the overcast develop
this afternoon along and west of the cpv with mostly cloudy
continues prevailing across central/eastern VT. Clouds will have
a big impact on temps with cool maritime airmass in eastern
sections with highs only in the 50s to near 60f...while upper
60s to lower 70s are possible over the SLV. Have trimmed back
the pops as most of the area should remain dry...besides some
light sprinkles/drizzle in the mountains of VT. Rest of fcst in
Previous discussion from 416 AM EDT Wednesday...Radar loop
showing scattered rain shower activity around the region this
morning. Expecting the showers to taper off this afternoon as a
ridge of high pressure aloft builds northward into northern New
York this afternoon. Expecting skies to be mostly cloudy today
and tonight. Highs today will be in the 60s. Lows tonight will
be mainly in the 40s to lower 50s. A ridge of high pressure will
be over the region on Thursday with highs mainly in the 70s to
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
-- Changed Discussion --As of 310 PM EDT Wednesday...Models have come much more into
agreement with timing of a cold front Thursday night. Have used
a blend of hi-res models for better defining the hourly
progression of the front and associated precipitation. Models do
have a minimal amount of instability ahead of the front,
however dynamics are in short supply and with the overnight
timing, we don`t have daytime heating. Thus expect a broken line
of showers to trek eastward fairly quickly. Thinking late
evening in the St Lawrence Valley to about daybreak in the
Champlain Valley then by mid-morning exiting Vermont. Coverage
and intensity of precipitation will be diminishing as the front
moves east, so overall QPF will be less than 1/4". Given the
instability signals, can`t rule out a rumble of thunder, so have
maintained "slight chance" levels of thunder. All the clouds
will keep it very mild. Lots of 50s overnight, perhaps staying
above 60F in the Champlain Valley.
Friday isn`t looking all that bad. Westerly flow develops, with
drier air moving in. 925mb temperatures are still relatively
mild, ranging from about 18C far west to 23C or so far
southeast. This will support above normal highs from the
mid/upper 60s west to upper 70s across the lower CT River Valley
in southeast Vermont.
Friday night, pretty quiet, though clouds will start increasing
ahead of the next cold front, though lows will still be a good
10F degrees above normal.
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.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 310 PM EDT Wednesday...Fairly changeable weather through
the period, however the longer term models are in pretty darn
good agreement. That raises the overall confidence of what is
expected. Taking it day by day...
Saturday: Cold front will be moving across the region during the
day. Not a lot of moisture or instability or dynamics with it,
but enough for a few spotty rain showers. We should still see
above normal temperatures despite the clouds and showers. Looks
like warmest temperatures will be south and east. Clears out for
Saturday night as a weak ridge of high pressure tries to build
in as the front stalls just to our south. Lows will be near
normal, and probably patchy frost around given clear skies and
relatively light winds.
Sunday: Seasonable temperatures, and dry for at least the first
part of the day. Clouds will increase during the afternoon with
initial push of warm air advection aloft associated with a
pretty big low well to the west. Can`t rule out a few spotty
light showers across western sections of northern NY during the
Monday/Tuesday: Looks like southerly flow will strengthen and
push a warm front through and north of the region Monday,
putting us into a mild warm sector. It`s possible we`ll get into
a solid dry slot for Monday afternoon, and if that happens we
could have enough sun to push temperatures well into the 70s.
Not confident enough about that right now, so stuck to model
blend for highs (still mid-upper 60s). Decent southerly jet with
40-45kt at 850mb that develops. Should be breezy in the
Champlain Valley at least. Tried to increase wind gusts a little
from raw model output (which tends to way underdo wind gusts).
Perhaps 25-35mph gusts. A front comes through Monday night into
early Tuesday. Models indicate some weak instability, so went
ahead and tossed in mention of slight chance of thunderstorms.
Should be a widespread rain event, perhaps 1/2" to 1" of rain,
which should not cause any significant hydro problems on rivers.
Residual clouds/showers around on Tuesday in a breezy westerly
flow, though not terribly cold as this storm system originated
in the southern Plains and isn`t really tapping into any very
Wednesday: Still weak troffiness around along with plenty of low
level moisture, so chance level PoPs and at least partly cloudy
skies look good. Flow aloft turns more northwest and does start
to bring in cooler temperatures from Canada, so at this point it
looks like highs will be a few degrees below normal and
primarily in the 50s.
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.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...Very challenging aviation forecast with
low confidence in overall flight categories and potential
impacts on TAFS overnight. Current obs show a wide range of
conditions from ifr at mpv in low clouds to vfr at btv/pbg/slk.
Thinking mainly mvfr/vfr this afternoon with another hour or two
of ifr at mpv. Winds generally light and variable...except
northeast at mss btwn 5 and 10 knots. Tonight...lots of low
level moisture is lingering with surface dwpts in the low to mid
50s...57 currently at slk...thinking with some clearing over
the SLV/northern NY areas...temps will drop below cross over
values with areas of fog/br possible after 04z. Have mention ifr
prevailing with lifr tempo btwn 07-11z at mss/slk.
Meanwhile...thinking southeast flow of low level moisture will
help advect ifr cigs back into MPV by midnight or so. Rest of
taf sites will remain between vfr/mvfr overnight. Winds shift to
the south/southeast on Friday with mvfr trending to vfr at all
sites by 15z.
Thursday Night: VFR. Chance SHRA.
Friday: VFR. Chance SHRA.
Friday Night: VFR. Slight Chance SHRA.
Saturday: VFR. Chance SHRA.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Slight Chance SHRA.
Sunday Night: VFR. Chance SHRA.
Monday: VFR. Chance SHRA.