Area Forecast Discussion
Issued by NWS Boston, MA

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292
FXUS61 KBOX 280544
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
144 AM EDT Tue Mar 28 2017

.SYNOPSIS...
Damp weather continues Tue and Tue night as low pressure tracks
over or near the region. Although Tue should be milder than
Monday. High pressure brings dry but chilly weather Wed and Thu.
More unsettled weather is expected late Fri into Sat. High
pressure builds in Sunday into early next week.

&&

.NEAR TERM /THROUGH TODAY/...
10PM update...
As drier air continues to spill in aloft, noting the widespread
development of fog and low clouds across the region suggesting a
damp and mild night in spite of the drier air trying to spill in
from the N-NW flow behind the exiting frontal wave. Therefore,
generally more of the same for the overnight hours. A mix of
patchy fog/low clouds and temps in the mid to upper 30s. No
major adjustments otherwise. Will hold on any fog headlines at
this point as the aforementioned N-NW flow may limit the ability
for fog to form as dwpts gradually hold or lower through the
overnight hours.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
Tuesday...Over-running with light rain or drizzle. Temps near
50 for highs. Warm front south of Long Island with plenty of
mixture keeps it cloudy and damp. POPs of likely to
categorical, but the key here is for light rain which I was able
to get into the grids.

Not a lot of sunshine anticipated, despite southern New England
getting into the warm sector of a low pressure in southeast
Canada. Max temperatures should be above normal, in the upper
40s and 50s. Could be warmer if clouds and rainfall are delayed
until late in the day. Low risk of a isolated thunderstorm or
two toward the south coast due to elevated instability.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
No significant changes at this time.

Highlights...

* Showers linger Tuesday night as cold front passes through
* Cooler but dry weather for Wed and Thurs
* Unsettled weather returns Friday into Saturday

Pattern Overview...

12z Model consensus continues to show an active weather pattern
for the period. Split flow aloft will continue through the
period with a few shortwaves moving through the flow. Partial
phasing of the two streams will occur across the Great Lakes and
Northeast on Tuesday. This will result in the development of a
low pressure system east of the region late Tuesday into
Wednesday. High pressure and upper level ridge will follow
Thursday into early Friday. The next upper level low/trough
deamplifies as it moves into the mid/upper ridge axis across the
eastern U.S. A coastal low is forecast to develop and quickly
move east in the aforementioned region of this phasing. The
spread has decreased for this timeframe but the still question
in strengthen and location of this system will determine p-types
and qpf amounts.

Details...

Tuesday Night...High confidence.

Weak shortwave will move over the region on Tuesday with surface
low  pressure over Northern New England. Along the cold front,
guidance develops a secondary low pressure system just south of
southern New England by Tuesday night. This wave of low pressure
will bring showery weather Tuesday evening into the overnight
hours. Cannot rule out some isolated thunder with this system as
TT increase above 50 and LI`s drop below 0. This is strongest
in the conservative EC.

Precip chance will quickly come to an end from west to east
during  the overnight hours as CAA takes a hold of the region.

Wednesday into Friday...High confidence.

Trough overhead as upper level low deepens as it moves towards
the  Canadian Maritimes. This puts the region in northwest flow
through the period resulting in dry but breezy conditions.
Clouds may be stubborn on Wed over the Cape and islands given
northerly flow across the waters. In fact could have some ocean
effect rain/snow showers over the outer Cape! Despite cold
advection, the environment should be well mixed, so max
temperatures will be close to normal.

Northwest flow continues on Thursday with an area of high
pressure  building in New England. Anticipate increasing
sunshine and lighter winds. Dry and seasonable conditions should
persist through Friday with high pressure in control.

Friday night into the weekend...Low confidence.

Split flow remains over the region with the next southern stream
wave interacting with the northern stream. Still some model
spread in this system leading to a low confidence forecast. The
EC has become more progressive with this approaching coastal low
developing it over 1-95 while the GFS keeps the system
suppressed. The UKMET is more in between the two systems, but
the GEFS and EPS continue to show the system south of SNE.
Overall a chilly rain with potential for wet snow/sleet at times
on the northern portion of the precip shield. All guidance
suggest system should be or moving offshore by Sunday, thus
drying trend possible second half of the weekend.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

Short Term /through Wednesday/...

Through 18Z today...High confidence.
Mainly IFR/LIFR with CIGS below 800ft (except for some interior
sites which are currently MVFR but will too be dropping this
morning). The IFR/MVFR conditions continue with a mix of
fog/drizzle and low vsbys into the early afternoon hours. Mainly
E flow.

Late today into tonight...High confidence.
Mix of IFR/LIFR continues but with more of a mix of RA/fog
rather than drizzle. Rain tapers off from W to E 03Z-09Z. After
rain ends a period of IFR/LIFR in fog lingers afterwords.

Wed...High confidence.
Improving conditions through sunrise with VFR everywhere by 15Z.
NNW winds. Gusts to 20-25 kt at times.

KBOS TAF...High Confidence. IFR to LIFR through much of the
period.

KBDL TAF...High Confidence. MVFR gives way to IFR and LIFR
through much of the period.

Outlook /Wednesday Night through Saturday/...

Wednesday into Thursday...High confidence. Gusty N/W winds
Wednesday with VFR conditions into Thursday.

Friday...Moderate confidence.  VFR and dry to start but likely
lowering to MVFR or possibly IFR Fri night in rain/wintry precip.

Saturday...Moderate confidence. MVFR or possibly lower in rain/wintry mix.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Wednesday/...Moderate confidence.

Rough seas across the eastern outer coastal waters are more
likely than the southern outer waters. Continued the Small Craft
Advisories for those waters. A few gusts to 25 kt are also
possible this evening.

Tonight...A weak frontal boundary sweeps the waters, with light
west winds developing. This will allow seas to subside and Small
Craft Advisories to conclude.

Tuesday...Light south winds with frontal boundary north of the
region. Vsby reduced at times in rain and fog.

Outlook /Wednesday Night through Saturday/...

Tuesday night...Moderate confidence. winds becoming northeast late
Tue night as front slips south and wave of low pres tracks along the
front south of New England. Vsby reduced at times in rain and fog.

Wednesday into Thursday...High confidence. Gusty north winds near
Wednesday into early Thu then diminishing as high pressure builds
into the area later Thu.

Friday...High confidence. Quiet weather with high pressure over the
area early Fri. However increasing east-southeast winds Fri night as
low pres approaches from the west. Also vsby lowering in rain and
fog Fri night.

&&

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

&&

$$
SYNOPSIS...Belk/Dunten
NEAR TERM...Doody
SHORT TERM...Belk
LONG TERM...Dunten
AVIATION...Doody/NMB
MARINE...Belk/Dunten



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