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Area forecast discussion 
National Weather Service Taunton Massachusetts
327 am EST Thursday Nov 26 2015


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 and Saturday. High pressure then brings dry
and cooler weather Sunday and Monday. A storm coming out of the
western USA will bring rain to New England late Tuesday into


Near term /until 6 PM this evening/...

High pressure remains in control with accompanying dry-subsidence
inversion beneath which return S-flow continues to pool maritime-
origin moisture. A scattered to broken low cloud deck is likely to
maintain throughout the day mainly across The Heart of S New England
around the CT-River Valley ... perhaps broken up more so by boundary-
layer mixing. Will also have to contend with some thin high cloud
pushing in from the west. Subsequently warmest temperatures may remain
over east/southeast interior S New England near 60-degrees with highs around
the middle- to upper-50s elsewhere. Breezy S/se-winds along the shores
with gusts up to 20 miles per hour.


Short term /6 PM this evening through 6 PM Friday/...

Tonight ...

Continued anticyclonic flow round the stronger area of high pressure
to the east coupled with overnight cooling ... expecting the low cloud
deck to thicken and lower. More moisture in the air as dewpoints
keep rising with the onshore flow. Values around the low-40s similar
to soil temperatures within the first 5 cm. Greater indications of a
shallow uniform moist profile yielding either drizzle and/or patchy
dense fog. There is the potential for soupy conditions as both the
NAM and GFS BUFKIT soundings suggest ... but not entirely sold as
there would be higher confidence if dewpoints were higher rather
than similar to soil temperatures. Mav / met guidance does suggest
some visibility issues over the CT-River Valley. Mixed guidance so
will not lean pessimistic with fog and/or drizzle and rather focus
on the low cloud decks overall which seemingly look to remain an
issue around central and western portions of S New England. Will
likely continue to see some high decks filter in from the west as
well. Winds diminish as they back out of the SW.

Friday ...

Expectation is for the cloud deck to erode by two means: entrainment
of low-level dry air ahead of an approaching weather system from the
west ... and subsequent boundary-layer mixing as sunshine becomes more
abundant and temperatures warm into the low-60s. Looking like a
fantastic day overall after some morning cloudiness. Record high
temperatures are at the bottom of this discussion ... and present
thinking is that we will come close to record highs at all climate
sites noted except Boston. Breezy SW-winds with gusts up to 25 miles per hour


Long term /Friday night through Wednesday/...

Big picture...

Rex block over the western USA this weekend will break down late
Sunday into Monday. This will eject an upper low into the plains
that reaches New England during midweek.

Model behavior is similar through midweek next week. The European model (ecmwf) has
had a history of racing well ahead of the other models with the
ejecting western low. But with this model package the timing
differences are greatly reduced...and trend toward the slower
models. The forecast trends toward this consensus which continues to
favor precipitation onset several hours slower than model probability of precipitation would indicate.

The dailies...

Friday night-Saturday...cold front across northern New England and
central New York moves southeast across southern New England late
Friday night or early Saturday morning. Best dynamics remain to our
north but sufficient low level convergence to support low-end chance
probability of precipitation with the frontal passage. High pressure and north wind will bring drier
air and clearing skies Saturday afternoon and night.

Sunday-Monday... another northern stream shortwave breezes through
on Sunday but with limited lift and moisture. This would bring winds
around to west during Sunday followed by a shift to north or
northeast after frontal passage. But little or no precipitation with the surface front.
High pressure builds over northern New England Monday. Maximum temperatures
will be a few degrees less cold on Sunday...then cooler Monday
behind the front...but generally in the 40s both days. Min temperatures in
the 20s inland and 30s along the coast.

Tuesday-Wednesday... the ejecting upper low from the west will move
across the central USA Monday and generates a surface low over the
Mississippi Valley Monday. Long-range models are similar in bringing
the difluent zone in the upper flow over New England during the
afternoon/evening Tuesday. At this same time surface high pressure
shifts well offshore. A 40-knot low level jet moves up across New
England by Tuesday night with increasing and deepening
moisture...and the best combination of low-level lift and upper
venting taking place late Tuesday and Tuesday night.

Timing may vary a little over the next few model runs but currently
Tuesday night looks to be the focus of precipitation...diminishing Wednesday
after a cold front swings through.


Aviation /08z Thursday through Monday/...

Forecaster confidence levels...

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

Short term /through Friday/... high confidence.

Through Thanksgiving day ...

VFR. Scattered-broken 3-4 kft ceilings persisting intermixed with some MVFR.
East/se-onshore flow increasing with 20 knots gusts towards the end of
the period along the coasts.

Thursday night ...

MVFR ceilings especially for west New England with the low possibility
of IFR. Possible patchy dense fog and/or -dz but low confidence at
this time. S-winds remaining breezy.

Friday ...

Improving VFR. Low ceilings erode to scattered 3-4 kft. Breezy S/SW-flow
with gusts up around 25 kts especially for coastal terminals.

Kbos terminal...high confidence in VFR.

Kbdl terminal...scattered MVFR ceilings into midday Thursday.

Outlook /Friday night through Monday/.....Moderate confidence.

Friday night-Saturday... VFR much of the time. Cold front moves
through late night and Saturday morning. A few showers possible
Friday night and Saturday morning with brief MVFR cigs/vsbys. Patchy
fog overnight may bring local IFR cigs/vsbys.

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



Forecaster confidence levels...

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

Short term /through Friday/... high confidence.

Increasing S/se-winds will generate wave stress especially along
the east-waters resulting in 5-foot waves. Combined with the potential
for gusts up to 25 kts ... small craft advisories continue.

Winds are forecast to diminish during the overnight period as they
shift out of the SW. This will result in a lull of activity. But
during Friday winds will kick-up with gust potential in excess of
25 kts ahead of an approaching cold front. Small-craft-advisories
will likely be needed for the east-waters especially.

Outlook /Friday night through Monday/...

Friday night-Saturday...moderate-high confidence.

A cold front moves across the waters late Friday night or Saturday
morning and producing scattered showers. Southwest winds ahead of
the front will gust to 20 knots...with seas of 5-6 feet on the
exposed waters. Winds will shift behind the front to north with
gusts around 20 knots. Seas will linger around 5-7 feet
Saturday...mostly in the outer waters. Small Craft Advisory may be
needed for some of the waters during this period.

Saturday night-Sunday-Monday...moderate confidence.

A weak cold front sweeps through on Sunday bringing shifting wind
directions from north to west...and back to north again. North to
northeast winds behind the front Sunday night/Monday may reach 20-25
knots. Seas subside below 5 feet by Sunday...then build again to 5-7
feet behind the front Sunday night/Monday. Small craft advisorys
may be needed for some of the waters at that time.



Record highs Friday 11/27...

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

Record high mins Friday 11/27...

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


Box watches/warnings/advisories...

Rhode Island...none.
Marine...Small Craft Advisory from 7 am this morning to 1 am EST Friday
for anz250.
Small Craft Advisory from 7 am this morning to 7 PM EST this
evening for anz251.



near term...sipprell
short term...sipprell
long term...wtb
marine...wtb/sipprell forecast office box staff

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