Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Taunton Massachusetts
1041 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/...
1030 am update...
little change to current forecast. Increasingly moist southeast
flow led to early morning cloudiness...but mixing has caused the
low clouds to break apart in most areas. Overcast high cloudiness
was covering western Massachusetts and western CT. So...overall expect a
partly sunny afternoon. Winds were 20 knots at 2000 feet and 28 knots at
3000 feet above Boston and Providence...which explains why we are
beginning to see gusty winds at the surface. Winds were gusting to
20 knots at fmh this hour 22 knots at Newport...and 23 knots at Boston
buoy. Have increased wind gusts in grids in eastern sections to
reflect these speeds. No changes to small craft advisories.
Temperatures exactly on track... for highs east/southeast interior S New
England near 60-degrees and highs around the middle to upper 50s


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

Continued anticycl breezy S/se-winds along the shores with gusts up to 20
miles per hour.Onic 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 /15z 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 this afternoon ...

VFR. Scattered-broken 3-4 kft ceilings with isolated pockets of MVFR. Southeast wind
gusts to around 22 knots along the Rhode Island and Massachusetts coasts.


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.


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.

Southeast winds 20 kts along the coast this afternoon...with up to 25 knots
mainly over the eastern waters. Seas were near 5 feet at buoy 44098
to the east of Cape Ann... so will continue the small craft
advisories mainly from mass Bay northward.

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 until 1 am EST Friday for anz250.
Small Craft Advisory until 7 PM EST this evening for anz251.


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

National Weather Service Glossary of Abbreviations