FXUS61 KBTV 121440
Area Forecast Discussion
National Weather Service Burlington VT
1040 AM EDT Sat Aug 12 2017
Scattered to numerous showers and thunderstorms will develop
this afternoon and evening across much of the North Country.
Some of the thunderstorms will have the potential to produce
gusty winds and small hail...especially across the northern
Adirondacks...the Champlain Valley... and remainder of Vermont.
Cooler and drier weather moves into the region on Sunday...but
there may still be a few showers over the higher terrain. An
extended period of dry weather is expected for much of next week
with temperatures right around seasonal normals.
.NEAR TERM /THROUGH SUNDAY/...
As of 1039 AM EDT Saturday...Previous showers have exited the
region, with only a small shower moving east across northern
Clinton County. Minor updates to temperatures this morning
mainly in southeast Vermont where thick cloud cover is slowing
temperature rises this morning. Otherwise no changes.
LAPS surface based CAPES over 1,000 j/kg in the St. Lawrence
Valley, and radar showing a narrow line of showers and
thunderstorms further west over western NY coming off lake Erie.
Expect continued destabilization and rest of forecast discussion
below remains valid.
Threat for stronger storms this afternoon and evening still
exists. Optimal time will be from 200 pm to 800 pm. The area of
interest will be the northern Adirondacks between 200 pm and 400
pm where storms are expected to form over the higher terrain
and in the vicinity of a weak surface boundary. The atmosphere
over this area and points east will sufficiently destabilize
this afternoon with temperatures in the 75 to 80 degree range
and dew points in the lower to mid 60s. This should result in
convective available potential energy...CAPE... values in the
800-1200 J/kg range. The destabilization process will be aided
by the development of steep mid level lapse rates. Deep layer
shear will be increasing over the area...but will not be strong.
It will not be weak either and should be sufficient to have
storms become more organized and have the potential to produce
gusty winds...40 to 50 mph..and small hail. The strong storms
will move into the Champlain Valley in the 400 pm to 700 pm time
period and between 500 pm and 800 pm for areas east of the
Green Mountains. Going forecast already has the enhanced wording
and will continue to maintain in the forecast. The Saint
Lawrence Valley...which has seen a couple of rounds of showers
and thunderstorms early this morning will be too far west this
afternoon and threat for stronger storms will be lower in this
area. However...still looking for some showers or storms late in
the day to affect the area.
Any convection should come to an end between 800 pm and midnight
tonight...but there may be a few showers lingering around
overnight as upper trough axis looks like it coming into the
region a little sooner. This should help to keep Sunday drier
and really looking at the possibility of a few showers over the
northern Adirondacks and scattered showers from the Green
Mountains eastward during the mid-morning to late afternoon time
period before drier air moves in and showers come to an end.
Highs on Sunday will generally be in the 70s.
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 356 AM EDT Saturday...With shortwave energy exiting to
our east and surface high pressure building in from the west,
the end of the weekend and beginning of next week looks dry and
seasonal. While high pressure builds in at the surface, aloft
the North Country will be dominated by cyclonic flow associated
with an upper low centered east of James Bay. The only resulting
weather will be periods of clouds, otherwise temps will be
seasonal in the 50s for lows and upper 70s to low 80s for highs.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 356 AM EDT Saturday...Long term period picks up where the
short term left off with high pressure continuing to dominate
at the surface while upper level low pressure east of James Bay
slowly shifts southeastward to the Gulf of St. Lawrence by
Wednesday evening. For the most part the region remains dry,
though some isolated to scattered showers will be possible
Tuesday afternoon as weak shortwave energy traverses the region.
An upper level ridge follows for Wednesday night through
Thursday night continuing the dry stretch, before our next
potential system moves in for Friday and Saturday. While it`s 7
days out, there`s good consensus amongst the GFS and ECMWF for
widespread precipitation these 2 days, with PWATS possibly near
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Through 12Z Sunday...Area of showers east of KMSS and north of
KSLK will move northeast this morning and have little affect on
the TAF sites. Expect all areas to have VFR/MVFR conditions
through much of the period. Not much in the way of weather is
expected through about 19z. After 19z expect scattered showers
and thunderstorms to form over the northern Adirondacks of New
York and move east across the Champlain Valley and remainder of
Vermont through 00z. Thus all TAF sites with the exception of
KMSS should see brief periods of MVFR and localized IFR
conditions in any showers or thunderstorms. There could also be
gusty winds and small hail with any of the storms as well. All
locations go to VFR after 00z and any showers and storms move
east of the area. Light winds through 14z...then south to
southwest winds with gusts in the 10 to 20 knot range before
turning more southwest and west after 00z and decreasing in
Sunday: VFR. Slight Chance SHRA.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Slight Chance SHRA.
Tuesday Night: VFR. Slight Chance SHRA.
Wednesday: VFR. Slight Chance SHRA.