Area Forecast Discussion
Issued by NWS Boston, MA

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067
FXUS61 KBOX 280715
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
315 AM EDT SUN AUG 28 2016

.SYNOPSIS...
High pressure centered over Northern New England brings dry
weather through today. A cold front moves south across New England
tonight and Monday, and may bring a few showers or thunderstorms,
mainly across northern Massachusetts. Weak high pressure brings
dry and less humid conditions late Monday and Tuesday. The risk
for thunderstorms along with warmer and more humid weather returns
Wed, as yet another cold front moves across the area. Canadian
high pressure brings a period of dry and fall-like weather late
next week into the weekend with mild days followed by cool nights.

&&

.NEAR TERM /THROUGH TODAY/...
Not much change from previous thinking. Ridge aloft shifts east
by this evening. High pressure at the surface will move out of the
Maritimes and out to sea. Dry weather still expected though, as
not much lift or moisture to work with during the day. Generally
light south winds today. Seabreezes develop again on both coasts.
Max temperatures similar to Saturday.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
A mid level shortwave from the Plains moves east to Quebec
tonight, then moves south across New England Monday. The best
dynamics, in the form of a 100+ knot upper level jet, still looks
like it will stay mainly to our north. That means most of the
forcing for rainfall will be from a shortwave, a weak cold front,
and whatever convective instability can be generated. Given that
most of this will occur at night into the morning hours, not
expecting strong thunderstorms. These attributes should also keep
areal coverage of any storms isolated or widely scattered. Thus
not a washout expected.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Highlights...

* Temps...Very warm & humid Wed...more pleasant Tue
* Precip...Isolated T-storm Mon...higher risk Wed
* Fall-like weather Thu-Sat with mild days and cool nights

Overview and model preferences...

Northern stream becomes more dominant this period and eventually
erodes the subtropical ridge. Thus trend will be not as warm and
less humid beginning Thu and likely lasting into next Sat. However
this transition will be marked by a very warm and humid day Wed
along with potential convection. Regarding guidance...both GEFS and
EPS ensembles are in very good agreement on the large scale flow
including timing of frontal passage Wed. However as expected at
this time range deterministic guid differing on amplitude and
timing of smaller features. For example 00z EC is slower with
fropa Wed ngt into Thu along with a cooler post frontal airmass
Fri with 850 temps dipping down to +4C! Typical biases (slower and
more amplified) for the EC at this time range. So for this portion
of the forecast there is above average forecast confidence on
trends and avg confidence on details.

Daily details...

Monday Night...Turning much less humid in post frontal airmass.

Tuesday...dry and comfortable humidity as ridging lingers across
New England. Seasonably warm. Seabreezes keep the shoreline
slightly cooler.

Wednesday...next northern stream short wave approaches along with
attending cold front. Warmer and more humid ahead of the
approaching cold front. Temps should surge well into the 80s away
from south coast. In fact with wsw surface winds and ensembles
suggesting +17C at 850mb and +22C at 925 mb...highs of 85-90 are
possible. Heavy rainers possible as PWATs surge to about +1 SD
along with surface dew pts 65 to 70. Modest instability and
marginal shear will yield a low risk for a few strong storms
possible.

Thursday thru Saturday...a touch of fall weather this period
courtsey of 1025 mb Canadian high building across the Great Lakes
into New England. Ensembles suggest 850 temps dropping to about
+8C (about -1 SD) for a number of days. Likely see highs in the
70s and lows in the 40s and 50s! Thus the theme will be for mild
days followed by cool nights. Very pleasant with dry weather and
low humidity.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels.

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

Short Term /through Monday/...High Confidence.

Today...

VFR with light winds increasing out of the south. Some increase in
high thin clouds during the afternoon. Seabreezes redevelop.

Tonight...

VFR. Increasing mid and high clouds. Areas of 5000 foot ceiling
bases with widely scattered MVFR in a shower or thunderstorm.
Patchy fog with local IFR vsbys after midnight.

Monday...

Mainly VFR, with isolated SHRA/TSRA yielding brief MVFR which
shifts into CT/RI and southeast MA during the afternoon.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Tuesday...Moderate to high confidence for VFR and dry weather.
Light winds with local seabreezes likely.

Wednesday...Moderate confidence. Mainly VFR but Local MVFR
possible in scattered SHRA/TSRA.

Thursday...Moderate to high confidence. VFR and dry weather
likely.

&&

.MARINE...
Forecaster Confidence Levels.

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

Short Term /through Monday/...High confidence.

Seabreezes will return late this morning and continue through
this afternoon. Seas trend slowly higher into Monday in response
to southeast swell from distant Hurricane Gaston.

A widely scattered shower or thunderstorm possible late tonight
into Monday as a cold front crosses the waters.

Outlook /Monday Night through Thursday/...

Tuesday...High pres overhead resulting in fine boating weather.
Only issue will be south to southeast swells across the ocean
waters from TS Gaston.

Wed...Another cold front passage in the afternoon/evening along
with risk for T-storms.

Thu...Quiet boating weather should return as high pres builds
into the Great Lakes and eventually the northeast.

&&

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

&&

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



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