FXUS61 KBTV 182309
Area Forecast Discussion
National Weather Service Burlington VT
709 PM EDT Fri Aug 18 2017
The weekend will feature slightly unsettled weather Saturday
and Saturday night with a few light showers. Sunday will be
mostly sunny, dry and warm. That sunny and warm weather will
continue Monday, allowing for perfect conditions to view the
solar eclipse. Increasing chances for showers and thunderstorms
return for late Tuesday and into Wednesday.
.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 709 PM EDT Friday...High dewpoints (upper 60s-lower 70s),
continue this evening as temperatures gradually cool. CAPE
values in excess of 1500J/kg continue across northeastern NY in
response to the high dewpoints in the low levels. With both mid-
level and low-level GOES 16 water vapor imagery showing
extremely dry airmass across the North Country, expect only a
few showers/isolated thunderstorm during the evening.
Dewpoints will remain in the mid-upper 60s tonight, so thats
about as cold as it will get and it will feel muggy. With the
high humidity, we may see a light fog/haze develop in most areas
overnight. Perhaps a few patches of denser fog in eastern
Saturday: Another day that will be on the slightly warm and
humid side, but not an uncommon mid-summer day. At upper levels,
there will be a trough off to our west, putting us in deep
southwest flow. However the mid/upper levels will still be
relatively dry, so this will limit the potential for convective
activity. Hi-res models do indicate a few hit or miss (but
mostly miss) showers developing during the day. As such, have
some 20-35% PoPs, highest across the higher terrain of northern
Vermont. High temperatures will be a few degrees above normal,
with upper 70s to lower 80s.
Saturday Night: models all indicate the upper trough will be
passing overhead, and this passage will be accompanied by clouds
and a few light showers. Kept PoPs in the 25-35% range.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 350 PM EDT Friday...If you love outdoor summer activities,
Sunday will definitely be a day to take advantage of it. Plenty
of sunshine, temperatures in the mid 70s to lower 80s, and most
importantly lower dewpoints -- all thanks to high pressure
ridging and a west/northwest flow bringing in the drier air.
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 350 PM EDT Friday...First... ECLIPSE. Partial for
CWA...basically 58-65 percent. Sky conditions looking very
favorable. Partial begins at BTV around 1725 UTC and ends around
1953 UTC according to NASA Eclipse sight.
Zonal flow across area on Monday with surface high south of
area, this will eventually allow for some increased humidity and
clouds but really not til Tuesday. A pretty nice eclipse day
with Highs in the 80s and sunshine.
The next system has been delayed as its awaiting a sharp, deep
shortwave from central Canada to drop across the Northern Plains
Tuesday and then rotate across the Great Lakes Tuesday night
and lift NE into Ontario/Quebec on Wednesday. The timing looking
like more of a Tue ngt-Wed feature. However...surface temps in
the M-U80s with rich dewpoints in the 60s and PWATs approaching
1.75 inches should produce SFC based CAPES in the 1000-1500
range at least. Also...despite the main dynamics and surface
front still across the Great Lakes, there are falling
heights...diffluent flow aloft and indications of some pre-
frontal trof, thus chance for t-storms will increase toward
evening...esp NY and Intl border. Wind dynamics don`t look too
favorable and timing may just be too late but still worth
watching as they will increase Tue ngt.
Leading, strong shortwave and surface front move through Tue
ngt- midday Wed. By Wed aftn...front should be just east of CWA.
Trof axis still west of CWA Wed ngt-Thu with surface high still
west as well. Therefore, some unstable flow but PWATs fall to
around 0.50 inches on Thu. Current thinking is largely mountain
upslope shower/sprinkle. Highs on Thu L-M70s.
Thu ngt-Fri deep trof axis passes area with surface high
pressure building into region thus primarily dry and cooler
temperatures. Highs in U60s-L-M70s. A cool start with lows in
the 40s/50s and some possible upper 30s. Friday ngt-Sat morning
should be as cool or cooler.
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
Through 18Z Saturday...a mix of conditions across the region,
with VFR across most of northern NY, and MVFR across
eastern/southern Vermont. A few showers are also near RUT as I
type. Trends should be toward VFR, except eastern Vermont where
MVFR ceilings will likely hang on. During the evening we expect
scattered showers to redevelop and move across the region.
However the confidence in exact timing and location are such
that "VCSH" is the best that can be placed into the TAFs right
now. Expect MVFR ceilings to also redevelop across much of the
area, along with at least a "light" (4-6sm) fog. Guidance
suggests that IFR due to visibilities of 1-2sm and ceilings
under 1000ft will develop in locations east of the Green
Mountains (eg: MPV), with some as well across the `Dacks.
Conditions will start to improve after 13z Saturday.
Saturday Night: VFR. Chance SHRA.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Chance SHRA...Slight Chance TSRA.
Tuesday Night: VFR. Chance SHRA...Slight Chance TSRA.
Wednesday: VFR/MVFR. Likely SHRA.