Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 202333
Area Forecast Discussion
National Weather Service Burlington VT
733 PM EDT Thu Apr 20 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 /THROUGH FRIDAY NIGHT/...
As of 700 PM EDT Thursday...Generally quiet conditions this
evening with weak sfc ridge in place across srn Quebec.
Subsidence inversion has generally locked in low clouds, but
have seen a few breaks along the intl border with some partial
sunshine this evening.
Timing is still on track for best low-level WAA and strong UVV
during the 05-10Z tonight (pre-dawn hrs), bringing periods of
steady light to moderate rainfall. Strong speed convergence and
deformation is driving current widespread rain shower activity
across sern Ontario into wrn NY at 23Z. This activity will lift
newd into our region, reaching St. Lawrence Co. around 03Z, and
into the Champlain Valley by 05-06Z. Only minor adjustments to
total QPF...generally 0.5-0.75", but orographic enhancement is
possible on S-SW facing slopes, with rainfall near 1" possible
srn Greens and portions of the Adirondacks high peaks.
Will see some gusty S-SE winds around daybreak, 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
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 /SATURDAY 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 /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --Through 00Z Saturday...A mix of VFR and MVFR ceilings across
the region at this time. Conditions will trend lower to
IFR/MVFR in rain and low ceilings by 06Z continuing through 18Z
Friday. Also, expecting mainly southerly gusty surface winds,
with gusts at or above 20 knots developing after 06Z Friday and
continuing through 18Z Friday. Gusty northeast surface winds
will be over the Saint Lawrence valley in northern New York.
Friday Night: VFR/MVFR. Slight Chance SHRA.
Saturday: VFR/MVFR. Slight Chance SHRA.
Saturday Night: VFR. 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.
-- End Changed Discussion --
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.