Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 210032
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
832 PM EDT Thu Jul 20 2017

.SYNOPSIS...
A few showers and thunderstorms around the region this
afternoon. Friday will remain relatively dry, but an isolated
afternoon shower or two is not out of the question. Saturday
into the first part of Sunday will see more dry and seasonable
weather under high pressure. Sunday evening into Monday brings
the next chance of showers and thunderstorms as an upper level
trough of low pressure moves in.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 721 PM EDT Thursday...Showers and thunderstorms have moved
out of the area. Rest of the evening should be quiet with skies
becoming mostly clear. Gradient should preclude any dense fog
formation. Previous discussion follows.

The region will be in west to northwest flow aloft with little
in the way of any larger scale forcing. The hi-res models have
picked up on some very isolated shower and thunderstorm activity
across the northern counties and some lake breeze convection on
western side of Lake Champlain. Convection so far is isolated
in nature and should remain so for the next few hours. Models
also indicate isolated pockets of CAPE 500-2000 J/kg which have
been lining up so far with the activity to this point. If things
hold, the instability should drop off in a few hours and the
activity along with it. Quiet and dry weather is expected
tonight and for most of Friday. There will be a trough moving
across eastern Canada and we should see some increase in dynamic
support and combined with additional forcing from the higher
terrain and sufficient instability. Because of that cannot rule
out the possibility of some very isolated showers or
thunderstorms, mainly over the northern Adirondacks and the
Northern third of Vermont. Again this activity would be weak and
disorganized. Overnight Friday, high pressure takes hold again
leading to another dry and quiet night.

High temperatures today and Friday will generally be in the
upper 70s to mid 80s while lows for Thursday and Friday will be
in the mid 50s to mid 60s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 314 PM EDT Thursday...Looking for a relatively dry day on
Saturday with west-northwesterly mid-level flow and weak sfc
high pressure in place across NY and New England. Low-level wind
fields are quite weak with flat p-gradient, so winds areawide
should be less than 10 mph. The 850mb temps per 12z GFS/ECMWF
are near +13C at BTV at 18Z Saturday, and with partly to mostly
sunny conditions, should see daytime highs in the low-mid 80s.
Can`t completely rule out a terrain driven shower/isold
tstm...especially vcnty of the nrn Adirondacks. There is a
slight chance mention (PoPs 15-20%) in the official forecast
during the mid aftn thru early evening period as a result.

Low pressure tracking ewd across the srn Great Lakes region will
be associated with ewd extending frontal zone, with developing
zone of 850-700mb warm advection across the srn half of the
forecast area during Saturday night. Some NWP differences with
12Z GFS showing associated showers and WAA further north across
our region, with 12z ECMWF suppressed further south. At this
point, included 30-40% PoPs mainly late Saturday night for
showers and chance for an embedded elevated thunderstorm.

Will see continued chances for showers and isold thunderstorms
on Sunday into Sunday night, generally 20-40% PoPs Sunday and
50-60% PoPs Sunday night with highest PoPs across the srn half
of our forecast area. During this time frame, E-W baroclinic
zone will be situated across central NY into central New
England, with weak sfc low tracking ewd along the frontal zone.
It appears that better upper level support arrives Sunday night
into Monday with shortwave trough approaching from sern Ontario.
12Z GFS model soundings at KRUT Sunday night indicate elevated
instability around 500 J/kg, so maintained slight chance
thunderstorms thru the overnight period. Should see high temps
mid-upr 70s Sunday, and upr 50s to around 60F for Sunday night
with mostly cloudy skies expected.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 314 PM EDT Thursday...Mid-level shortwave trough tracks
ewd thru the area Monday into Monday night, with continued
chances for showers. Abundant clouds likely Monday, keeping
daytime highs in the low-mid 70s. Should trend toward cooler and
drier weather mid-week as shortwave trough moves east of our
longitude later Monday night or Tuesday. Should see highs in the
mid 70s Tue/Wed. Kept lingering 30% PoPs Tuesday and down 10%
or less into Wed/Thu.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...Last vis imagery of the evening shows
mainly clear skies across our taf sites...as much drier air
advects into the region on northwest winds. Surface dwpts have
dropped into the upper 50s to lower 60s...which combined with
975mb to 900mb winds of 10 to 20 knots overnight will keep
atmosphere mixed and limit fog/br development. Have utilized
tempo btwn 08-11 for mvfr in br at mpv and mvfr cigs at slk
toward sunrise. Otherwise...vfr conditions prevail at all sites
with northwest winds 3 to 8 knots...becoming light and variable
overnight.

Outlook...
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Slight Chance SHRA.
Sunday: VFR. Chance SHRA...Slight Chance TSRA.
Sunday Night: VFR. Chance SHRA...Slight Chance TSRA.
Monday: VFR/MVFR. Chance SHRA...Chance TSRA.
Monday Night: VFR/MVFR. Chance SHRA.
Tuesday: VFR/MVFR. Chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Verasamy
NEAR TERM...Neiles/Verasamy
SHORT TERM...Banacos
LONG TERM...Banacos
AVIATION...Taber



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