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Area forecast discussion 
National Weather Service Taunton Massachusetts
716 PM EST Monday Nov 30 2015

high pressure will continue to move offshore tonight and early
Tuesday. A strong upper low pressure area approaching the Great
Lakes will spawn a couple of weak surface low pressure areas over
the northeast. One system will pass near Cape Cod Tuesday
evening...and there is a low risk of freezing rain at the onset
in northwest Massachusetts. Another wave of low pressure tracks
over the area Wednesday afternoon and night yielding a second round of
rain...which may be heavy at times. This low intensifies Thursday over
the Maritimes bringing blustery and cooler conditions to the area.
High pressure then brings dry and seasonable weather Friday into
the weekend.


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

715 PM update...

Main change to previous forecast was to lower mins where skies
have cleared and temperatures have crashed into the 20s...specifically
interior southeast Massachusetts /tan 27...pym 28/. Where strato-cumulus clouds
break up temperatures plummet into the 20s given light winds and dry
airmass with dew points in the 20s. Amount of cooling overnight will
be critical on threat of freezing rain Tuesday morning across the CT
River Valley especially Massachusetts/CT border northward. Otherwise previous
forecast on track. Earlier discussion below.


Main issue is cloud cover...which in turn impacts temperatures.Although
model blend would suggest clearing...satellite imagery andobservations
depict considerable stratocumulus clouds and suspect alot of that
moisture will remain trapped under an inversion throughat least
early tonight and perhaps even into early Tuesday... gone
with more clouds than guidance would suggest fortonight. Do think
there will be enough breaks for some radiationalcooling later
tonight across northwest Massachusetts where temperatures may reach lowto middle 20s.
Winds should be light tonight.


Short term /6 am Tuesday morning through Tuesday night/...
low amplitude middle level ridge holds through most of morning and slides
to the east. This opens the way for overrunning moisture.Models
fairly insistent on surface low pressure passing near or across southeast New
England during this period in SW upper flow well ahead of
vigorous trough moving east across Great Lakes region. The critical
question is timing of the onset of precipitation and whether there
remains any leftover subfreezing surface temperatures at the
outset. There does look to be some risk in our western
zones...mainly Hampshire and Franklin County where there is a
chance of some light freezing rain middle to late Tuesday morning
before temperatures rise above above 32f. It is likely to be a
race between onset of rain and temperatures rising above freezing. Not
sufficiently confident to issue an advisory but believe enough
risk of pockets of light freezing rain to issue a Special Weather
Statement. Otherwise...sufficient model consensus to be confident
of likely to categorical probability of precipitation Tuesday afternoon into Tuesday night. May
see a break toward Wednesday morning as initial weak short wave trough
and surface wave slides off to the NE. Anticipate temperatures to
drop only very slightly Tuesday night and to remain above freezing
throughout the forecast area.


Long term /Wednesday through Monday/...

Highlights ...

* showers with heavy rain Wednesday/Wednesday night
* drying trend begins Thursday and likely continues into the weekend
* seasonably cool Thursday through next weekend

Wednesday ... may see the coastal plain /esp Rhode Island and southeast Massachusetts/
warm sector with 50+ temperatures as weak short wave ridging builds into
the area behind departing coastal low and next upstream frontal
wave. Both 12z GFS and 12z NAM agree on this which may result in a
bit of a lull in the precipitation Wednesday before picking up again late Wednesday
into Wednesday night as next frontal wave tracks across the area. This
frontal wave will act on a very moist airmass with precipitable waters +2 Standard
above climatology and dew points in the l50s. This combined with frontal
convergence from the approaching wave will likely result in periods
of moderate to heavy rain late Wednesday/Wednesday night. No flood concerns
other than typical nuisance street/Highway flooding.

Thursday ... initally dry slot moves across the region but with
closed low moving from New York state to northern New England...associated
cold pool aloft coupled with cyclonic middle level flow will yield lots
of diurnal clouds and possibly a few showers. By no means a washout.
In fact Thursday will feature a drying trend just a few brief pop-up
diurnal showers possible. Blustery and cooler too with sub 990mb low
over the Maritimes.

Friday through Monday ... split flow regime continues but polar jet
likely remains north of our latitude much of the time. Deterministic
guidance differs on timing and amplitude of individual northern stream
short waves but overall theme suggest any cold air intrusions into
southern New England will be brief/progressive. Thus temperatures this
period should average near or perhaps slightly above normal. As for
precipitation...given streams likely remain separate /no phasing/ not
expecting any big precipitation events this period. Hence lots of dry


Aviation /00z Tuesday 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/

715 PM update...

Not much change from 18z and 21z tafs. Earlier discussion below.


Confidence is high tonight and moderate Tuesday and Tuesday night.

Rest of this afternoon and tonight...VFR conditions expected to prevail
but areas of broken-overcast conditions around 4 thousand feet will persist.
Light winds. Tuesday and Tuesday night...clouds will thicken and lower
during the day. Widespread MVFR ceilings/visibilities developing during Tuesday
afternoon in lightrain and fog. Areas of IFR ceilings/visibilities expected
in rain and fog during Tuesday night.

Kbos terminal ... high confidence. VFR conditions expected through
early Tuesday afternoon...lowering to MVFR conditions in rain and fog
by late Tuesday afternoon.

Kbdl terminal...moderate to high confidence. VFR conditions
tonight intotue morning but lowering to MVFR ceilings/visibilities during Tuesday

Outlook /Wednesday through Saturday/.....High confidence

Wednesday-Wednesday night ... a mix of IFR and LIFR in periods of
rain and drizzle. Rain may be heavy at times late Wednesday into Wednesday

Thursday ... marginal MVFR/VFR ceilings. Northwest winds 20 to 30
knots...strongest wind over Cape Cod and the islands. Other than
a brief spot shower mainly dry weather prevails.

Friday/Sat ... VFR and dry weather likely. Modest northwest wind Friday
diminishing Sat.


forecaster confidence levels...

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

Short term /through Tuesday night/ ... moderate to high

Seas will continue to subside tonight. However...looks like enough
eto southeast gradient ahead of surface low Tuesday afternoon and night to
bring seas over 5 feet in exposed S and southeast facing coastal waters.
Wind gusts may also approach Small Craft Advisory criteria across
the outer S and southeast coastal waters.

Outlook /Wednesday through Saturday/... high confidence

Wednesday ... wave of low pressure tracks over southern New England.
Periods of heavy rain and fog reducing visibility.

Thursday ... low pressure tracks NE into the Maritimes and likely intensifies
into a gale center. Northwest winds 20 to 30 knots with low risk of a few
gusts to 35 knots.

Friday/Sat ... dry weather and good visibility likely with modest northwest winds.


Box watches/warnings/advisories...
Rhode Island...none.
Marine...Small Craft Advisory from 5 PM Tuesday to 11 am EST Wednesday
for anz235-237-254-255.
Small Craft Advisory from 1 PM Tuesday to 11 am EST Wednesday
for anz256.


near term...nocera/Thompson
short term...Thompson
long term...nocera

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