Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 301920
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
320 PM EDT MON MAY 30 2016

.SYNOPSIS...
A cold front over New York will swing across Southern New England
tonight. Scattered thunderstorms over Eastern New York will affect
Western MA and CT before weakening. Another batch of showers
moving up the front may graze the South Coast overnight. High
pressure then builds over New England with dry weather for the
middle of the week. Another cold front may bring unsettled
weather by the end of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Through 8 pm...

There was sufficient heating over NY and PA to generate a few
thunderstorms during the afternoon. These showers/storms are
moving east into favorable instability over Eastern NY and the
Berkshire/Litchfield Hills. The favorable instability then
diminishes farther east. This means a chance for showers and a few
tstms to cross into Western MA and NW CT around 530-600 pm.
Movement father east will be increasingly difficult. Note that the
13Z HRRR was showing showers into the CT Valley around 6 pm and
weakening over the Worcester Hills 7-8 pm.

Tonight...

Lingering convection should fall apart with the loss of daytime
heating. The cold front will slowly cross New England during the
night. Model data suggests the front may be able to pull some of
the showers off the South Coast back to the north. This would
mean another period of showers in this area overnight with light
amounts expected.

Dew points will be in the upper 50s and lower 60s overnight. This
suggests min temps in the low to mid 60s. With temps and dew
points nearly equal and winds light, expect more patches of fog
overnight especially in areas that received a soaking during the
day.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...

There may be some lingering showers along the South Coast early
Tuesday. But with high pressure building in, the trend will be for
showers tapering off and sky cover diminishing. Drier air will
work into New England with dew points falling through the 50s.

A weak cold front dips south over the region late Tuesday. The
main effect of this front will be to turn winds out of the north
Tuesday night. This may bring dew points a little lower, roughly
upper 40s to mid 50s.

Sunshine Tuesday will create mixing to at least 850 mb, possibly
higher. Temps at the top of the mixed layer will support max
surface temps in the low to mid 80s. The lower dew points will
allow min temps to be a little lower than tonight, generally in
the 50s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights...

  * Mainly dry with above normal temperatures Tue/Wed
  * Unsettled weather may return toward next weekend

Medium range models are in good agreement on the overall synoptic
pattern. A mid-level ridge will move offshore Wednesday. Mid-
level troughing then moves into Quebec towards the end of the work
week and starts influencing our weather with several shortwaves
working around the base of the trough. This will result in more
unsettled weather towards the end of the week.

Wednesday...A back door cold front arrives on Wednesday.
Temperatures will be above normal, especially across the western
zones. Onshore flow will result in more seasonable temperatures
along the east coast.

Thursday through Sunday...Mid-level trough moves into Quebec
allowing several shortwaves rotating through the base of the trough
to move through southern New England.  This will result in periods
of showers, particularly Friday and Saturday.  Due to the difficulty
in pinpointing when and where these showers will occur, have kept
chance PoPs in the forecast for much of this period.  However, not
expecting rain to be widespread, nor for the entire period.
Temperatures will be around normal for much of the time.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels.

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

Short Term /through Tuesday Night/...

Through 00z... Showers and a few tstms may cross into Western MA
and CT around 21Z. These would bring potential MVFR cigs/vsbys
during the evening before dissipating.

Tonight...Moderate confidence. Lingering IFR cigs and vsbys in fog
and showers along the south coast. Mixed VFR/MVFR farther north.
Local IFR/LIFR is possible in these areas overnight due to patchy
dense ground fog.

Tuesday and Tuesday night...High confidence. VFR.

KBOS TAF...Moderate confidence in TAF.

KBDL TAF...Moderate confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday...Moderate confidence. VFR.

Thursday...Moderate confidence.  Mainly VFR conditions expected.
Increasing clouds with diminishing conditions through the night,
particularly along the south coast.

Friday...Moderate confidence.  Mainly VFR conditions expected. Brief
MVFR conditions are possible in SCT -SHRA at times.

&&

.MARINE...
Forecaster Confidence Levels.

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

Short Term /through Tuesday Night/...High confidence.

Tonight...Moderate confidence.

Poor visibility due to dense fog. Best chance for this will be
across the southern waters from Block Island to Nantucket. Winds
will remain below 20 knots. Seas will remain below 5 feet.

Tuesday and Tuesday night...Moderate confidence.

A south swell builds into the southern waters Tuesday. Expect the
swell to reach 4 feet during the day, with potential for 4-5 foot
swell Tuesday night. Southwest wind Tuesday shifts from the North
Tuesday night, but remains below 20 knots.

Outlook /Wednesday through Saturday/...

Wednesday...Moderate confidence.  Northeasterly winds and seas will
remain below Small Craft Advisory criteria.

Thursday...Moderate confidence.  Easterly winds and seas increase.
Seas may rise above 5 feet, especially on the outer waters.

Friday...Moderate confidence.  Easterly winds are expected to remain
below 15 kts.  Seas decrease through the period.

&&

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

&&

$$
SYNOPSIS...WTB/RLG
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...RLG
AVIATION...WTB/RLG
MARINE...WTB/RLG



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