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Area forecast discussion 
National Weather Service Taunton Massachusetts
631 am EST Friday Nov 27 2015

low clouds and patchy dense fog erode during the morning hours.
Near-record highs follow for today ahead of a cold front which
will sweep the region overnight into Saturday with scattered
showers...briefly stalling S of New England Saturday night before
a second cold front sweeps through on Sunday. High pressure then
brings dry and cooler weather Monday and early Tuesday. A storm
coming out of the western USA will bring rain to New England late
Tuesday into Wednesday.


Near term /until 6 PM this evening/...
630 am update...
areas of fog...some of it with visibilities less than 1/4 mile...lingered
over the region. With sunrise the trend will be toward fog burning
off and visibilities becoming unrestricted. A dense fog advisory
continues through the morning rush hour along the I-95 corridor
through Rhode Island and adjacent southeast mass...but should end during the

Clearing skies beneath a h925 airmass around +10c ... expecting
the mix-down of faster momentum resulting in surface winds to turn
SW with gusts of 20 to 25 miles per hour. With more of a land trajectory ...
temperatures warm into the low- to middle-60s ... near-record highs
and nearly 20-degrees above normal for this time of year.


Short term /6 PM this evening through 6 PM Saturday/...
tonight ...

Increasing clouds as a cold front with anafrontal characteristics
sweeps S across New England exiting offshore by morning. Some middle-
level energy and accompanying jet dynamics ... but overall parallel
flow to the front limits the amount of available lift and thereby
limits the wet-weather potential. Expecting just light showery
weather and a chance of that at best given the synoptic setup. Much
of the wet-weather falling towards the morning hours behind the cold
front. Temperatures dropping with north-flow ... but nothing strong with
a lack of an isallobaric - gradient response to the wind. Lows down
into the middle- to upper-40s.

Saturday ...

Wet-weather slowly slinks S in wake of the cold front. A chance at
best with continued weak forcing. Thinking the activity will still
remain scattered and light ... difficult to nail down where it will
likely occur. Abundance of clouds with continued N-flow...expecting
temperatures to remain near-steady from morning lows. Looking at
highs around the upper-40s to low-50s north to S. Over-all a cool damp


Long term /Saturday night through Thursday/...
big picture...

Rex block over the western USA with split flow...the northern stream
rides over the top of The Block and across Canada while the southern
stream dips across northwest Mexico and then feeds into the central

This starts as a dry pattern for New England early week with just a
shortwave moving through this is mostly aimed at the Maritimes. Once
the Rex block breaks down...the southern stream lifts into the south
central USA and generates surface low which lifts into the Great
Lakes. This aims a moist southwest flow at New England and brings
deep moisture to our area Tuesday-Wednesday. Remnants of Pacific
Hurricane Sandra will be in northern Mexico around the time the Rex
block breaks down. It is possible this may augment rainfall from the
midweek weather system...or the moisture may be shunted eastward.
Stay tuned as this information firms up over the weekend.

Model behavior is similar through early Tuesday...then diverges
during midweek with the GFS more progressive than the European model (ecmwf) and
ggem. We used a blend of model data...but favoring the slower emcwf.

The dailies...

Saturday night... cold front settles south of the region. But upper
jet moves east along and north of the front...crossing southern New
England early in the night. This jet may produce enough lift to
support scattered or widely scattered showers part of the night. But
the overall trend should push the clouds south of New England by
late night. Surface temperatures upstream tonight are in the middle 20s to middle
30s...this looks like a good target for Sat night min temperatures.

Sunday-Monday... northern stream shortwave sweeps into the Maritimes
Sunday. Hard to make out a wind shift in the forecast pressure
field...but relative humidity fields suggest a weak surface frontal passage Sunday night.
High pressure then builds south from Quebec bringing a quick shot of
colder air for Monday. Overall this should be a dry period. Temperatures
in the forecast mixed layer support maximum surface temperatures in the 40s
Sunday...and 35-45 Monday.

Tuesday-Wednesday... high pressure moves east of New England Tuesday
but with plenty of dry air at low levels. Upper jet reaches a
favorable position for generating lift during the afternoon while
the low level jet is more favorable for Tuesday night. Considering
these facts and the overall trend toward the slower
solutions...favor low-end chance probability of precipitation Tuesday afternoon and low-end
likely probability of precipitation Tuesday night. Using the slower trends...surface frontal passage would
occur later on Wednesday with chance probability of precipitation until that time. As noted
above...remnants of Pacific Hurricane Sandra will be drawn north
just as this system starts moving our way. But at this stage it is
possible the extra moisture could pass south of New England rather
than through it. We will need to monitor this.

Thursday... upper low and cold pool will move across the region.
Forecast data suggests 20-40 percent sky cover...but cold pool
instability and forecast cloud-level moisture are a little more
bullish on clouds. We will stay close to model data for this day 7
forecast but monitor as the data firms up.


Aviation /11z Friday through Tuesday/...
forecaster confidence levels...

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

Short term /through Saturday/...

Today ... high confidence.

Areas of MVFR-vlifr clear out during the morning...improving to
VFR as SW-winds increase. Winds will gust around 25 kts in
spots...highest along the S-coast.

Tonight ... moderate confidence.

Mix of MVFR-IFR as scattered rain showers approach the terminal towards morning.
Mainly low ceilings expected with some minor visibility issues.

Saturday ... moderate confidence.

Scattered rain showers throughout much of the day with a mix of MVFR-IFR ceilings.

Kbos terminal ... moderate confidence.

Low ceilings settled in. Overall trend will be IFR or lower. Think
visibilities will go no lower than 3 sm for now with breezy S-winds.

Kbdl terminal ... moderate confidence.

Vlifr fog has enveloped the terminal and will likely continue so
till sunrise. Thereafter should gradually mix-out of VFR.

Outlook /Saturday night through Tuesday/...moderate confidence.

Saturday night...MVFR ceilings/visibilities possible in showers the first part
of the night especially in CT/RI/se mass. Trend overnight will be
for clearing from north to south with VFR most places by morning.
Clearing and light winds may allow some IFR in fog around sunrise.

Sunday-Monday...VFR. Shifting winds Sunday as a weak cold front
moves through. Winds become northeast Monday as high pressure builds
over northern New England.

Tuesday... VFR much of the day but trending to MVFR ceilings/visibilities
possibly late afternoon...then IFR ceilings/visibilities in rain Tuesday


forecaster confidence levels...

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

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

Small-craft-advisories continue. Winds veer out of the SW today
and increase ... gusting around 25 kts even for the inner harbors
sounds and bays. Building seas on the outer water around 5-6 feet.

Cold front sweeps S across New England overnight exiting offshore
Saturday morning. Scattered shower activity as winds back out of
the north remaining blustery with around 20 knots gusts across the east-waters
through Saturday.

Outlook /Saturday night through Tuesday/...

Saturday night-Sunday...moderate to high confidence.

Lingering seas around 5 feet Saturday night but diminishing
winds/seas overnight. Small Craft Advisory may be needed on the
outer waters for the seas.

Sunday night-Monday...moderate confidence.

Cold front moves across the waters early. North winds then increase
to near 25 knots with 5 foot seas mainly on the outer waters. Winds
and seas then diminish on Monday as high pressure moves overhead.
Small Craft Advisory may be needed for some of the waters.

Tuesday...moderate confidence.
Winds and seas will increase out of the southeast especially toward
evening and at night. Poor visibility developing with rain likely Tuesday
night. Small Craft Advisory may be needed Tuesday night.


record highs Friday 11/27...

Bos...72 in 1896
pvd...66 in 1946
bdl...64 in 1976
orh...66 in 1896

Record high min temperatures Friday 11/27...

Bos...57 in 1896
pvd...51 in 1976
bdl...46 in 1927
orh...52 in 1896


Box watches/warnings/advisories...
Massachusetts...dense fog advisory until 9 am EST this morning for maz017.
Rhode Island...dense fog advisory until 9 am EST this morning for riz002>006.
Marine...Small Craft Advisory from 10 am this morning to 6 PM EST this
evening for anz230>234-236-251.
Small Craft Advisory from 1 PM this afternoon to 7 PM EST
Saturday for anz235-237-254>256.
Small Craft Advisory until 7 PM EST Saturday for anz250.


near term...wtb/sipprell
short term...sipprell
long term...wtb

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