Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 210539
Area Forecast Discussion
National Weather Service Burlington VT
139 AM EDT Fri Apr 21 2017
A low pressure area and a warm front will approach the North
Country overnight and will bring moderate rain to the region,
mainly during the pre-dawn hours. Rain will continue into
Friday, before tapering off to showers Friday afternoon and
Friday night. A ridge of high pressure will build into the
region Sunday and will remain over the North Country through
early next week.
.NEAR TERM /UNTIL 2 PM THIS AFTERNOON/...
As of 1123 PM EDT Thursday...Forecast remains on track. Broad
region of 850-700mb warm advection across sern Ontario into
central NY will shift newd into nrn NY and VT during the
remainder of the overnight hrs...in advance of low pressure
across nrn lower Michigan. It appears convective instability
driving tstm activity across s-central NY and PA will remain
south of our region. However, strong synoptic ascent will move
across the North Country between 06-09Z, bringing steady
moderate rainfall to most locations for several hrs. Only minor
adjustments to total QPF...generally 0.5-0.75" expected, but
orographic enhancement is possible on S-SW facing slopes, with
rainfall near 1" possible srn Greens and portions of the
Adirondacks high peaks.
Winds are light and variable late this evening. However, will
see some gusty S-SE winds around daybreak with increasing
p-gradient, with gusts 20-30 mph once the steady rain ends, and
gusts locally to 30-40 mph along the immediate wrn slopes of
the Green Mtns with downslope effects.
Rain will continue into Friday morning before tapering off to
showers Friday afternoon as best synoptic forcing shifts to our
east. A slight chance of showers will continue into Friday
night. Expecting low temperatures to be mainly in the 40s
overnight. High on Friday from the upper 40s to lower 50s. Lows
Friday night from the upper 30s to lower 40s.
.SHORT TERM /2 PM THIS AFTERNOON THROUGH SUNDAY NIGHT/...
As of 345 PM EDT Thursday...Weakening complex surface low
pressure system will affect the North Country for the first half
of the weekend. Surface low pressure to the north in Quebec
will weaken and allow coastal low to become primary surface low.
Meanwhile, 500mb trough will move across the region through
Sunday morning. Expect low level moisture in north to northwest
flow to keep slight chance of showers and low clouds over the
area til building ridge of high pressure at the surface and
aloft brings drier air early Sunday.
Late Sunday into Sunday night, weakening front extending for
surface low east of Hudsons Bay will bring more clouds and only
a slight chance of showers to the international border.
Saturday max temps limited to the 40s to low 50s under the
overcast skies. Saturday night temperatures generally in the 30s
as skies begin to slowly clear. Temperatures expected to be
warmer Sunday with increasing sunshine throughout the day and
maxes in the 50s to around 60. Sunday night temperatures
generally in the 30s again.
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 345 PM EDT Thursday...Beginning of the work week looks to
be quiet as high pressure is over the region through Monday
night. The high slides east, putting the North Country in
southerly flow on Tuesday beginning an influx of warmer air.
Late Tuesday into Tuesday night, the North Country will be
sandwiched between 2 low pressure systems - one to the north and
one to the south. Southerly low becomes coastal Tuesday night
and moves northward, attempting to bring some showers to eastern
VT on Wednesday. GFS keeps associated energy aloft further off
the coast and is also weaker, limiting the impact on the North
Country. The northerly low looks to have a warm front across
Quebec Wednesday and closed surface low over the Great Lakes
region. This low may bring some showers Wednesday night into
Thursday. Still some uncertainty with regard to these systems as
12Z ECMWF and GFS differ on evolution of said systems.
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --Through 06Z Saturday...Conditions will largely be a mix of VFR
and MVFR over the next 24 hours with steady rainfall through
about 12-15Z reducing vsby to MVFR and cigs a mix of VFR/MVFR.
Thereafter scattered showers may briefly reduce vsby at times,
but cigs should lift to VFR area-wide until later in the evening
after 22-24Z when a gradual lowering back to MVFR is expected.
Winds mainly SSE becoming increasingly gusty by dawn with gusts
in the 20-30kt range especially at KBTV through the daylight
hours, abating after sunset.
Saturday: VFR/MVFR. Slight Chance SHRA.
Saturday Night: VFR/MVFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Slight Chance SHRA.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
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As of 401 PM EDT Thursday...No major issues are expected on
area rivers and streams but we should see some modest rises on
Friday with basin average QPF in the 0.50-0.90" range (occurring
late tonight into Friday AM). Concerns still exist on Lake
Champlain with gusty southerly winds developing late tonight and
Friday morning. This will likely cause rises across the
northern portion of Lake Champlain, where Rouses Point could
rise slightly above flood stage on Friday. This will be closely
monitored over the next 12-24 hours.