Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 291402
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
1002 AM EDT Thu Sep 29 2016

.SYNOPSIS...
Onshore winds will bring spotty light rain along with patchy
drizzle and fog across southeast New England through midday, with
a brief break this afternoon. A low pressure wave will pass south
of the region, bringing cloudy, cool conditions with showers
Friday through Saturday which may linger into Sunday. Conditions
will improve somewhat early next week, but still can not rule out
a period of showers.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM Update...Sky cover forecast was challenging with this update
with clearing skies in the west and northeasterly flow keeping
clouds moving in across the eastern zones. Think this trend will
likely continue so have kept broken to overcast conditions in t he
east and partly cloudy to sunny conditions in the west for much of
the day.

Temp/dewpoint spread is enough (7-8 degrees most locations) that
drizzle hasn`t developed along the east coast. Still cool and raw
with temperatures in the mid to upper 50s and northeasterly winds
gusting up to 25 to 30 mph.

Aside from the sky cover forecast, made only minor tweaks to the
forecast to incorporate current trends.

Previous Discussion...

Continued strong pressure gradient between the 1038 hPa high
across southern Quebec and the low to the SW will result in gusty
NE winds especially along the coast. Expect gusts up to 30-35 mph
today, possibly a bit higher along the immediate shore. Temps will
not recover much today, only reaching 60-65 degrees for most areas
under mainly cloudy skies. Could see a few breaks in the clouds
around the Route 2 area of N Mass this afternoon with somewhat
drier air working in there. Will feel really chilly and raw along
the coast with the cool temps and strong winds, though.

Due to the persistent and strong NE winds, have issued a High Surf
Advisory for east facing coastlines of Cape Ann, outer Cape Cod
and Nantucket through 6 PM today. High risk of rip currents as
well as some possible splashover around the time of high tide late
this morning to midday. Also near a new moon phase so somewhat
higher astronomical tides.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Tonight and Friday...

Any breaks in the clouds early tonight across northern areas will
be short lived as mid and high level moisture works N-NW
especially after midnight. Persistent NE winds will keep raw
conditions in place, though gusts will tend to drop off late.
Overnight lows will be close to this morning`s lows, ranging from
the upper 40s across the higher inland terrain to the mid and
upper 50s along the immediate coast.

On Friday, a wave of low pressure will try to push NE, but will
stay offshore. However, a plume of moisture will work northward in
the mid level wind flow. PWATs will increase to 1.9 to 2 inches
across S coastal areas by late in the day. Slug of precip also
looks to shift N, with the best shot for precip across N CT/RI and
SE Mass. QPF amounts could reach 0.3 to 0.5 inches during Friday,
highest along the immediate S coast. The fight between drier low
level air and the higher moisture aloft will make it tough to get
appreciable rainfall north of the Mass Pike, where a tenth of an
inch or less is forecast at this point.

Have carried likely POPs near and south of the Mass Pike for most
of Friday. Expect highs in the mid to upper 50s across the inland
terrain ranging to the lower-mid 60s elsewhere.

&&

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

* Periods of showers and drizzle into Sat with cool afternoons
* Some showers and drizzle may linger into Sunday
* Drier weather Mon-Wed but a period of showers remain possible

Details...

Friday Night and Saturday...

Strong high pressure across eastern Canada will combine with a
low pressure emerging off the mid Atlantic coast to produce a
period of wet weather across most of southern New England.
Although this surface low is not too strong, expecting gusty
northeast winds along the coast, especially across the Cape and
islands.

While measurable rainfall will occur, its uncertain if 1+ inch
amounts will make it into any of our region, or remain to our
south where better low level forcing resides. The most likely
areas to get heavier rainfall should be the Cape and islands,
which will be closer to the low circulation.

Onshore flow, clouds and periods of showers will keep high
temperatures below normal for late September.

Sunday...

The Mid Atlantic low pressure moves farther east, allowing the
pressure gradient to weaken. However, high pressure over the
Maritimes will still still generate a moist, northeast flow.
Depending on the exact timing, some showers and drizzle will
probably linger into Sunday, especially along the eastern MA
coast. High temperatures will likely remain below normal given
lingering low clouds.

Monday through Wednesday...

Another high pressure will build down into eastern Canada and
northern New England early next week. While a shortwave may bring
a period of showers, a good shot at dry weather for a decent
portion of this time frame. Northeast winds at the surface much of
the time will probably continue to hold high temperatures near to
below seasonable levels.

We also will have to keep a close eye on what is expected to become
Hurricane Matthew over the Caribbean. Most model guidance suggests
this system will remain south of our region through Wednesday of
next week.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels.

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

Short Term /through Friday/...

Today...Moderate confidence. Expect mainly MVFR to low end VFR
CIGS with mainly VFR VSBYS for most of today. May see MVFR VSBYS
along the immediate coast near and S of Boston with onshore flow
that may produce -SHRA/-DZ at times through midday. Patchy IFR
CIGS through mid morning across outer Cape Cod and Nantucket
possible. NE winds gusting to 25-30 kt across E Mass, possibly
reaching into RI.

Tonight...Moderate confidence. Mainly VFR tonight near and N of
the Mass Pike. Low end VFR-MVFR CIGS move into southern areas, and
may see IFR CIGS/VSBYS move into S coastal areas after midnight as
sct -SHRA start to move in. Gusty NE winds to 25-30 kt continue
along the east coast.

Friday...Low confidence, mainly for timing. Will see MVFR-IFR CIGS
and/or VSBYS as -SHRA and patchy fog moves in from S-N during the
day. NE wind gusts up to 25 kt continue along the coast.

KBOS TAF...Moderate to high confidence in TAF.

KBDL TAF...Moderate to high confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night through Sunday...High confidence. Mainly MVFR to IFR
conditions in low clouds, periods of showers/drizzle and patchy
fog. Northeast wind gusts of 20 to 30 knots expected along the
coast, and perhaps a bit stronger across Nantucket.

Monday...Low confidence. May see improvement to mainly MVFR
conditions.

&&

.MARINE...
Forecaster Confidence Levels.

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

Short Term /through Friday/...High confidence.

Gale warnings issued for portions of the south coastal waters as
winds gust up to 35 kt late tonight through midday Friday.
Small crafts remain in effect for remaining waters.

Expect NE winds to continue, with general gusts up to 25-30 kt
most waters. Seas up to 8-10 feet, highest over the eastern open
waters. Winds will gradually diminish during Friday, but will
still see gusts to around 25 kt along with seas up to 7-9 ft.

Outlook /Friday Night through Monday/...

Friday Night into Saturday Night...High confidence. Rough seas
expected to continue across the outer coastal waters. Seas
gradually subside as winds diminish Saturday night. Small craft
advisories needed at a minimum during this time. Still a
possibility of gale warnings continuing for some of the southern
coastal waters Friday Night.

Sunday and Monday...Moderate confidence. Pressure gradient
weakens, so expecting winds and seas to remain below small craft
advisory thresholds. Some risk for rough seas to linger across the
outermost eastern coastal waters.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 6 PM EDT this evening for MAZ007-022-
     024.
RI...None.
MARINE...Small Craft Advisory until 6 PM EDT Friday for ANZ231>236-250-
     251-254.
     Small Craft Advisory until 6 PM EDT this evening for ANZ230.
     Gale Warning from 2 AM to 8 PM EDT Friday for ANZ237-256.
     Gale Warning from 8 AM to 8 PM EDT Friday for ANZ255.

&&

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



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