Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 271145
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
745 AM EDT SAT AUG 27 2016

.SYNOPSIS...
High pressure builds over Northern New England, bringing dry
weather for much of this weekend. A cold front will bring the
threat for showers and thunderstorms Sunday night into Monday.
Weak high pressure brings dry and mild conditions on Tuesday,
followed by another cold front for mid week. This will bring
another chance for showers and thunderstorms. Large high pressure
from north central Canada will likely bring dry conditions and
more seasonable temperatures by late this week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

735 AM Update...

Other than a few patches of fog that developed in some of the
normally susceptible locations, skies were mainly clear early this
morning. Temperatures bottomed out in the mid-upper 50s across the
central and northern CT valley as well as portions of interior E
Mass, ranging to around 70 in the urban centers. Dewpts have
lowered some after the early morning frontal passage with light
N-NW or calm winds in place.

Near term forecast was on track, but did update temps, dewpts and
winds to bring conditions current. Still expect sea breezes to
develop as high pressure ridge builds across the region.

Previous Discussion...
Dew points around 60 degrees will be more common today, which is
about a 10 degree drop from Friday. Max temperatures will be a
little cooler, too. The lower temperatures will be more noticable
toward the coasts, where sea breezes will develop later this
morning.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
The center of the high pressure shifts east tonight into Sunday.
Expecting mainly clear skies and light winds to prevail through
this portion of the forecast. Once the high pressure reaches the
Maritimes late Sunday, there is a small possibility for a mid
level shortwave to bring isolated showers to northwest MA late in
the day.

Temperatures expected to be slightly above normal, despite
seabreezes along both coasts Sunday.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Highlights...

* Scattered showers and thunderstorms possible Sunday night into
  Monday
* Dry and mild conditions briefly return Tuesday
* Another cold front brings the chance for brief wet weather
  Tuesday night into Wednesday
* Large high pressure sweeps out of north central Canada with
  more dry conditions and near seasonable temperatures late this
  week

Overview and model preferences...

Medium range model and ensemble suite continues to signal
generally warm conditions with brief periods of showers/
thunderstorms across the northern tier states with weak mid
level short waves in the nearly zonal steering flow through mid
week. All models showing changes working into the overall North
American flow as high amplitude ridge builds into north central
Canada, across Nunavut and the NW Territories toward the Arctic
Circle by mid week. This will bring a NW flow aloft into the
northeast U.S. Large surface high pressure will shift SE late
this week out of central Canada with more dry conditions as
temperatures become seasonal. Only noting two weak fronts that
will cross the region, with just a few showers and/or
thunderstorms, so the long term dryness looks to continue into
the holiday weekend.

Used a blend of available guidance through Wednesday as models did
show pretty good continuity, then blended over to ensemble guidance
with the pattern change noted later this week though the 00Z
operations runs of the GFS, GGEM and ECMWF remain in rather good
agreement with the evolving North American pattern.

Details...

Sunday night-Monday...High pressure moves offshore with a SW wind
flow in place at the surface and aloft. Cold front works SE,
bringing the chance for showers/thunderstorms, with the best shot
across N Mass around the Route 2 region, possibly as far south as
the Mass Pike through Sunday night into Monday morning.  As the
front moves across the region, the H5 short wave associated with it
pushes quickly E by midday Monday. With the lack of energy as well
as limited moisture, the precipitation weakens as it shifts SE. The
front continues to slowly cross the region, but as a dry passage.
Winds shift to W-NW during Monday afternoon as skies become partly
cloudy.  Warm air lingers across the region, with highs mainly in
the lower-mid 80s, with a couple of spots possibly touching 90.

Tuesday...As the front pushes offshore, it stalls south of the
region early Tuesday. Weak high pressure will build across, so
expect another dry day. Temperatures remain mild, though, but
dewpts do drop a few degrees so it will be less humid.

Tuesday night-Wednesday...Another front will bring a few showers/
thunderstorms late Tuesday night and Wednesday. The front will
steadily move through, pushing offshore Wednesday night. Will see
best shot for precipitation across the CT valley to the E slopes of
the Berkshires. Temperatures will continue to run above seasonal
normals.

Thursday night-Friday...Expect dry conditions as large high pressure
works southeastward out of north central Canada to the Great Lakes
during this timeframe. Temperatures will slowly lower to near or
even below seasonal normals by Friday.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels.

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short Term /through Sunday/...

Today...High Confidence.
VFR. Light N-NE winds. Sea breezes will develop along both
coasts.

Tonight...High Confidence.
VFR. Light and variable wind. Patchy fog after midnight in the
usually prone locations, mainly in the CT River Valley, with
IFR/LIFR cigs/vsbys through sunrise.

Sunday...
VFR with winds turning S and increasing. Increasing mid and high
clouds across the region, with the possibility of a few SHRA N/W
late in the day.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday night...Moderate confidence. Mainly VFR. May see patchy
MVFR conditions in widely scattered -SHRA/-TSRA mainly near and N
of the Mass Pike, best chance near and N of Route 2. Patchy fog
with local MVFR-IFR VSBYs after midnight.

Monday...Moderate to high confidence. Mainly VFR. Slight chance
of SHRA/TSRA over central and N Mass through midday. W winds shift
to NW, may gust up to 20 kt on the S coast.

Tuesday...Moderate to high confidence. VFR. Light W-NW winds back
to SW as high pressure shifts S of the region.

Tuesday night-Wednesday...Moderate confidence. Mainly VFR. Local
MVFR-IFR in scattered SHRA/isolated TSRA. SW winds gusting to
15-20 kt along S coast, shifting to W-NW Wednesday night.

&&

.MARINE...
Forecaster Confidence Levels.

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short Term /through Sunday/...High confidence.

Winds and seas expected to remain relatively light through
Sunday. Sea breezes near shore expected both today and Sunday.
Seas increase across the outer coastal waters Sunday in response
to arriving southeast swell from distant Tropical Storm Gaston.

Outlook /Sunday Night through Wednesday/...

Sunday night...High confidence. High pressure pushes offshore.
Expect S-SW winds gusting to 20 kt across the eastern outer
waters. Seas will remain below 5 ft, but may see a few higher
swells on the eastern outer waters due to Gaston. Scattered
showers/thunderstorms from Cape Cod northward with local
visibility restrictions, along with patchy fog after midnight.

Monday...Moderate to high confidence. SW winds shift to NW as
cold front passes. Gusts up to 20 kt on the eastern outer waters
Monday afternoon/evening. May see isolated showers/thunderstorms
across the northern waters into Monday afternoon with brief
visibility restrictions.

Monday night-Tuesday...High confidence. NW winds shift to NE on
Tuesday as high pressure builds across. SE Swells up to 5-6 feet
reach the outer waters from Gaston.

Tuesday night-Wednesday...Moderate confidence. Winds shift to
S-SW as cold front approaches. Gusts up to 20 kt possible on the
eastern outer waters Wednesday afternoon. May see local visibility
restrictions Wednesday afternoon in isolated showers/
thunderstorms. Leftover 5 foot swells early Tuesday night will
subside after midnight.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$
SYNOPSIS...Belk/EVT
NEAR TERM...Belk/EVT
SHORT TERM...Belk
LONG TERM...EVT
AVIATION...Belk/EVT
MARINE...Belk/EVT



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