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Area forecast discussion 
National Weather Service Taunton Massachusetts
712 PM EST Tuesday Nov 24 2015

large high pressure remains an influence across New England through
the end of the week during which time temperatures gradually warm as
the high moves offshore. A cold front from Canada will cross the
region Friday night into Saturday. High pressure then brings dry
weather later Sat into sun. Then forecast uncertainty increases
Sunday night into early next week when unsettled weather may impact
the region.


Near term /until 6 am Wednesday morning/...

715 PM update...

Main change to the forecast was to lower mins tonight as 7 PM
temperatures already in the 20s where winds have decoupled. Have followed
the 12z mavmos which was the coldest guidance available. Thus
expect many locations outside of the urban areas to dip into 20s
/even a few upper teens possible northwest Massachusetts/ including Cape Cod
and the islands. This is courtsey of 1040 mb high building into
the region coupled with mainly clear skies/light winds and a dry
airmass. Otherwise forecast remains on track. Earlier discussion


Noting 500 mb short wave pushing into the Gulf of Maine on latest
water vapor satellite imagery. Northwest flow aloft has brought drier air
across the region...though still noting low clouds moving across
central and West New York into PA on visible satellite loop along with some
showers moving off Lake Ontario.

The clouds and showers should generally dissipate within a couple
of hours of sunset...though some clouds may linger there. they try to move east toward the region...being in the
center of the large high pressure center...subsidence will take over
and any clouds should dissipate. Expecting mainly mostly clear
conditions overnight.

With the mainly clear skies and light/variable or calm winds...should
see excellent radiational cooling taking place especially for the
normally colder locations across interior east Massachusetts as well as north
central Massachusetts and across most of the CT valley overnight.

Due to the cold temperatures and readings looking at the this morning/S
lows /16 at kowd...17 at ktan...19 at kbed...and 20 at kpym/...
went close to or a bit lower than mavmos guidance which was the
coldest on the 12z package. Not quite as low as this morning...but
could go below again with the long night in play. Expect lows
generally in the 20s except a few upper teens in the colder
spots...ranging to 30-35 along the immediate coast.


Short term /6 am Wednesday morning through Wednesday night/...
Wednesday and Wednesday night...
high pressure will remains in control as it crosses overhead
during Wednesday. Will see light north-NE winds in place mainly across east
coastal areas.

As the ridge axis moves offshore Wednesday afternoon...winds
shift to east-southeast though they are light. With the low sun angle along
with subsidence inversion setting up as seen on BUFKIT soundings
and rising 850 mb temperatures. So...looks like low level moisture will push
onshore as noted on both NAM and GFS h925 moisture fields.

Will start to see low clouds move in off the ocean during the
afternoon...starting on the S coast then heading further inland
and along the East Coast during Wednesday night. May even see a low chance
for spotty drizzle developing along the immediate coast. Not
enough to mention at this time...but something to keep an eye on.
May see overnight patchy fog develop as well.

Daytime highs on Wednesday will reach into the 40s...getting close to
seasonal normals. On Wednesday night...temperatures will fall back to the upper
20s and 30s...mildest along the S coast.


Long term /Thursday through Tuesday/...


* much warmer than normal Friday west/highs l60s
* scattered showers Friday night/early Sat
* uncertainty Sun night into early next week


Forecast fairly straight forward into Sat with subtropical ridge
from the Gulf states to the southern New England coast providing
moderating temperatures Thanksgiving and then much warmer than
normal Friday with highs in the u50s and l60s. Then northern stream
trough moves across Ontario...Quebec and northern New
England...eroding the subtropical ridge at our latitude. This
transition will be accompanied by a frontal passage and showers Friday
night into early Sat. Behind the frontal passage...a trend toward
drier and seasonably cool temperatures later Sat into Sunday.

However thereafter forecast uncertainty increases as the upper air
pattern is dominant by split flow...which typically offers low model
predictability. Features in question this period are the depth of
the northern stream trough over southeast Canada this weekend. Will
the trough have sufficient amplitude to shunt southern stream
moisture south of New England /per GFS and gefs/...or will the
trough be of lower amplitude /ec and ecens/ and allow southern
stream moisture to overrun marginally cold airmass across southern
New England for a wintry mix inland Sun night/early mon? High
uncertainty continues into next week as both ensembles /gefs and
ecens/ showing lots of spread on how quickly western closed low
ejects eastward.

Daily details...

Thursday...much milder with low level warm air advection boosting 925 mb temperatures to about
+4c/+5c. However model soundings suggest blyr mixing limited to only
950 mb due to subsidence inversion from 1042 mb surface pressure overhead.
In addition model cross sections reveal lots of low level moisture
likely in the form of strato-cumulus clouds. These two factors will limit
highs in the mu50s. Although these values are 5-10 degrees warmer than
normal and noticeably milder than the previous 2 days. Dry weather
should prevail but can/T rule out some spotty drizzle at night given
low level moisture trapped beneath inversion. NAM and nmm suggest
spotty light drizzle during the day but given cloud bases appear to
be around 2 kft...prefer the drier GFS/European model (ecmwf) and sref solutions.

Friday...strong low level warm air advection ahead of approaching cold front. Model
cross sections continue to show lots of low clouds persisting. Thus
not much sunshine expected. Nevertheless strong low level warm air advection will
boost temperatures in the u50s and l60s...possibly middle 60s if some sunshine
develops. See record highs Friday in climate section. Becoming a bit
breezy with SW winds 10 to 20 miles per hour. Any showers should hold off until
after dark with highest risk across northwest Massachusetts. Scattered showers
are expected Friday night.

Weekend...frontal passage sometime late Friday night or early Sat
morning. Thus showers may spill into very early Sat morning along
the South Coast including cape and islands. Column dries quickly
with frontal passage so expecting a drying trend Sat with at
least some sunshine likely. Good low level cold air advection behind the front
with 925 mb temperatures falling from +10c Friday night to -2c Sat afternoon.
This will only yield highs in the 40s...which is fairly close to
normal or just below normal. Chilly Sat night with 1030 mb high
overhead. Dry weather lingers into sun and continued cool with
highs only 40-45. As mentioned above will have to watch southern
stream moisture approaching southern New England from the south
Sun night. May be enough cold air over inland areas for potential
wintry mix or precipitation may remain south of the region. 12z runs have
become warmer and with precipitation either staying south or holding off
until early next week. Worth watching given all the returning
Holiday travel Sun night.

Early next week...lots of uncertainty this time period but 12z
models have trended toward middle level low and surface circulation
tracking into the Great Lakes...suggesting a warmer and wet scenario
for southern New England.


Aviation /00z Wednesday through Sunday/...
forecaster confidence levels...

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

715 PM update...

No changes from 18z or 21z taf updates. Earlier discussion below.


Short term /through Wednesday night/...

Through 00z...high confidence. VFR. Mainly clear or patchy high
thin clouds. West winds diminish...becoming light SW or calm by

Tonight through Wednesday...high confidence. VFR. Expect
generally light/variable winds as high pressure passes across the region
tonight. Winds become southeast-S Wednesday as high moves offshore...but remain
10 knots or less.

Wednesday night...moderate confidence. Mainly VFR. Low clouds at
around 3500 feet begin to move onto S coast after 02z-04z on light
S-southeast winds. Will push inland overnight. May see MVFR ceilings develop
along the coast. May also see patchy fog and local MVFR-IFR visibilities
after midnight.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook /Thursday through Sunday/...

Thursday and Friday...mainly MVFR and dry. Although can/T rule out spotty
light drizzle Thursday night into Friday am. Scattered showers likely Friday

Sat and sun...VFR and dry weather likely. Low risk of a few leftover
showers and MVFR ceilings early Sat and then again Sun night.


forecaster confidence levels...

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

Short term /through Wednesday night/...high confidence.

Tonight...have continued small craft advisories on the outer
waters for leftover 5-6 foot swells into late tonight. They should
subside during the overnight hours.

Wednesday and Wednesday night...winds and seas remain below small
craft criteria. Winds shift from light NE to southeast Wednesday afternoon...
then around to S Wednesday night. The wind will increase overnight
Wednesday...gusting up to 20 knots on the outer waters.

Outlook /Thursday through Sunday/...

Thursday and Friday...increasing south-southwest winds possibly reaching 25 knots late
Friday/Friday night. Risk of showers Friday night then a wind shift to the
north-northeast with the frontal passage late Friday night.

Sat and sun...generally light winds as high pressure passes overhead.
However a brief period north-northeast winds up to 20 knots or so is possible Sat
morning immediately behind the cold front.


record highs Friday 11/27...


Record high mins Friday 11/27...



Box watches/warnings/advisories...
Rhode Island...none.


near term...nocera/evt
short term...evt
long term...nocera

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