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Area forecast discussion 
National Weather Service Taunton Massachusetts
701 PM EST Wednesday Dec 24 2014

strong low pressure tracking across the Great Lakes will bring
heavy rainfall and gusty winds through Christmas. Dry weather
with above normal temperatures will follow from Christmas
afternoon into Saturday. A cold front may bring a few rain or
snow showers Sunday. Another storm may affect US late Monday into


Near term /until 6 am Thursday morning/...
700 PM update...

Made some minor tweaks to bring the forecast for the next few
hours back into line with observed trends. The biggest change was
to temperatures. Still observing light northerly winds across most
of southern New England. This left a warm front draped between
Boston and Marshfield Massachusetts...between Norwood and Taunton...then
between Providence and Newport...before it stretched west across
southern CT.

Southerly winds have increased south of this front...and we now
expect this front to make better progress north this evening.
Minimum temperatures should be about now...then slowly rise

Previous discussion...

Moderate to high confidence...lower with respect to wind

Bulk of precipitation will continue to stream up the coast with
increasing precipitable waters . Kept precipitation totals on order of 1-2 inches...but
could see locally higher amounts mainly across NE CT/RI/se Massachusetts.

Warm front appears to be sitting across S coastal areas. Still
having a tough time moving north with light north-NE winds in place with
just enough drainage and cold air damming. Noting pressure falls of
3-4 mb/3 hour /to 21z/ with fastest falls across East New York into west Vermont.
Cold front across central Ohio/western WV and east Kentucky at 21z will
eventually shift east...which should push the warm front northward
overnight. As cold front approaches overnight...some question as
to whether there will be a fine line associated with it. If this
does develop...will need to monitor for brief strong wind gusts as
it crosses the region. Also...pretty good instability starting to
move in with Li/S from zero to -2 and k indices in the Lower-Middle
30s. May see isolated thunderstorms develop ahead of the cold front

Strong influx of milder temperatures move in with the warm front temperatures to rise through the night into the 50s...and
possibly to the lower 60s across portions of east Massachusetts before sunrise.
This will approach record levels /see listing in climate section

Still some question as to how much wind will mix down. Noting
little if any mixing below 900 hpa so will be tough to mix down
the strong jet associated with this system...on order of 50-60 knots
at h9 and 850 mb. If fine line mentioned above does materialize...
might see it. Something to monitor closely. For now...have
mentioned wind gusts up to 30-35 knots for most areas...and could
reach around 40 knots across Rhode Island/southeast Massachusetts where some mixing will start to
work in ahead of cold front after midnight as the core of the 900
and 850 hpa jets move across eastern areas.


Short term /6 am Thursday morning through Thursday night/...
Christmas day...high confidence.
Short range models in very good agreement in pushing front
offshore by middle morning with leftover showers moving offshore as
dry slot works in. Winds shift to west-SW with drier air working in.
Lapse rates steepen especially from 900 hpa and below which will
allow good mixing to work in. Question is how strong will the
gusts be. At this point...continued to see wind gusts just below
Wind Advisory criteria...though could be some marginal gusts to
criteria mainly along the S coast...Cape Cod and the islands Thursday
afternoon. Might also see some higher gusts across the higher
inland terrain of the Worcester Hills and Monadnocks as well as
the east slopes of the Berkshires. Kept advisory through late morning
across Rhode Island/southeast Massachusetts...but may need to extend into the afternoon.

With general overall middle level steering currents from W-E...not
much cold air to transport into the region. Temperatures will hold in the
50s during the morning before starting to slowly fall back Thursday
afternoon with the increasing wind.

Christmas night...high confidence.
High pressure ridge begins to build east out of the Appalachians. Winds
will shift to W-NW. Winds will remain gusty early Thursday night...then
will diminish overnight with dry conditions. Colder air remains north
of the region. With generally mostly clear skies in place...though
some clouds linger across northwest Massachusetts...temperatures will fall back to the
upper 20s across north central and west Massachusetts to the upper 30s on the Outer
Cape and Nantucket. These readings are around 10 degrees above
seasonal normals for late December.


Long term /Friday through Wednesday/...
* clearing...windy and mild Christmas day.
* Remaining dry with above normal temperatures Friday and Sat.
* Potential for some rain or snow early next week.

Friday and Saturday...high confidence.

High pressure builds to the middle Atlantic coast. Dry weather will
prevail with lighter winds. Temperatures will remain above average
with highs in 40s both days and lows mainly in 30s.

Sunday through Wednesday...low confidence.

Models drop a weak cold front through southern New England Sunday.
Moisture appears to be limited and convergence rather
only expecting widely scattered rain showers as it moves through.
Temperature profiles may be cold enough for some wet snow to mix
in across higher terrain in western Massachusetts.

24/12z models continue to struggle with the details of the
synoptic pattern next week. There are some signs the solutions are
starting to converge...with the 12z European model (ecmwf) coming into line with
the 12z GFS. That said...ensembles still showing 100-140 dam spread
in the 500 mb heights...which does not inspire much confidence in
the forecast details.

Latest deterministic and ensemble mean guidance establish a fairly
zonal flow into southern New England Monday into Wednesday. This
would steer any storms either to our north...or too our south...
depending on where it originated.

Leaned toward a consensus model blend to help Iron out these
differences for now. This would bring a chance for precipitation
to southern New England during this time period. Thermal profiles
suggest the possibility for light snow across much of southern New
England...with rain more likely closer to the South Coast.

This is several days away...with low confidence in the details. Low
level temperatures look a bit warm for any significant
accumulations...especially from the Mass Pike to the South Coast.
We need to see how larger scale features will be resolved over the
next few days.


Aviation /00z Thursday through Monday/...
forecaster confidence levels...

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

Short term /through Thursday night/...

Tonight...moderate confidence. Expecting widespread IFR/LIFR
conditions in rain...heavy at times...along with isolated thunderstorms.
Visibilities improve to MVFR-low end VFR in heavier rain mainly after
midnight. Ceilings may improve across CT valley after 09z as rain
begins to shift east. S-southeast surface wind gusts up to 25-30 knots. Low level wind shear on
S winds at 40-60 knots at 2 kft. Any thunderstorm may cause brief wind gusts
up to 40 knots...greatest risk across Rhode Island/southeast Massachusetts late tonight.

Thursday...moderate confidence.
IFR-LIFR ceilings/MVFR-VFR visibilities improve to VFR from west-east as rain
moves offshore. SW winds gusting up to 25-30 knots...shifting to west
by midday. Low chance for gusts up to 40 knots across the higher
interior terrain.

Thursday night...high confidence.
VFR. West winds gusting to 25-30 knots early...highest along coast...
then diminishing after midnight.

Kbos terminal...high confidence in taf trends. Moderate confidence
in timing a warm front to move north of the terminal this

Kbdl terminal...high confidence in taf.

Outlook...Friday through Monday...

Friday and Saturday...high confidence VFR.

Sunday...moderate confidence. MVFR possible in isolated rain

Monday...moderate confidence. Mainly VFR. Lower conditions south
of New England. Low probability these lower conditions move
farther north into southern New England.


forecaster confidence levels...

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

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

Tonight...strong S-southeast low level jet passes across the waters
through tonight. Low level inversion in place through 900 hpa so
will be tough to mix the bulk down. Will see gusts up to 25-30 knots
on the outer waters...increasing to 35 knots S and east of Nantucket
toward daybreak. Have issued gales for the outer waters. Marginal
conditions for gales on Narragansett Bay so backed off the strong
small craft. Visibilities reduced in patchy fog and rain. Isolated thunderstorms
possible overnight.

Thursday...cold front moves offshore by midday. Winds shift to
west-SW and increase...gusts up to 40 knots on the outer waters. Have
converted gale watches for southern bays and sounds to warnings
with gusts to 35 knots. Remaining waters have small crafts.

Thursday night...gale force west winds early Thursday night will diminish
to small craft criteria overnight. Small craft winds on Boston
Harbor/Narragansett Bay will diminish overnight.

Outlook...Friday through Monday...moderate confidence.

Winds gradually diminish Friday...with seas also slowly subsiding
into Saturday as a high pressure builds over the Middle Atlantic
States. A weakening cold front may bring an isolated shower or two
as it drops through New England Sunday. Winds and seas should
remain below Small Craft Advisory levels across all but the
outermost coastal waters from midday Saturday into Monday.
Moderate probability of 5 foot seas across the outermost coastal
waters...particularly south and east of Nantucket.


record highs for today / Christmas day

Bos...61 in 1996 / 65 in 1889
pvd...60 in 1990 / 63 in 1964
bdl...59 in 1996 / 64 in 1964
orh...57 in 1996 / 60 in 1964


Box watches/warnings/advisories...
CT...Flood Watch through Thursday morning for ctz002>004.
Massachusetts...Flood Watch through Thursday morning for maz002>022-026.
Wind Advisory from 10 PM this evening to 7 am EST Thursday for
Wind Advisory from 1 am to 9 am EST Thursday for maz022>024.
Rhode Island...Flood Watch through Thursday morning for riz001>007.
Wind Advisory from 10 PM this evening to 7 am EST Thursday for
Marine...Gale Warning from 10 am to 9 PM EST Thursday for anz232>234.
Small Craft Advisory from midnight tonight to midnight EST
Thursday night for anz230.
Small Craft Advisory until 5 am EST Friday for anz231.
Small Craft Advisory from 10 PM this evening to midnight EST
Thursday night for anz236.
Gale Warning from 9 am to 9 PM EST Thursday for anz235-237.
Gale Warning from 9 am Thursday to midnight EST Thursday night
for anz250.
Small Craft Advisory until 4 am EST Friday for anz251.
Gale Warning from 6 am Thursday to midnight EST Thursday night
for anz254>256.


near term...Belk/evt
short term...evt
long term...Belk

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