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Area forecast discussion 
National Weather Service Taunton Massachusetts
316 PM EDT Tue Oct 25 2016

some cold unstable air will bring areas of clouds and unseasonably
cool temperatures through Wednesday. Low pressure approaches from
the Great Lakes Thursday, then redevelops closer to the coast and
moves across our area Thursday night and early Friday. This will
bring a cold rain...possibly heavy at times and gusty winds along
the coast. A period of snow and sleet is likely at the onset
across the interior. A drying trend develops Fri in the wake of
the low, but blustery northwest winds develop. Another round of
showers is possible sometime over the weekend.


Near term /until 6 am Wednesday morning/...
through evening...

Upper shortwave overhead with cold pool and cold pool moisture
generating clouds. The air is dry beneath these clouds, with dew
point depressions of 20-25f, so any attempt at showers should dry
up on the way down. Daytime heating by the sun is creating a mixed
layer up to near 850 mb. Winds in the mixed layer are 20-25 knots,
so expect wind gusts in this range. Temps aloft around -5c which
will support Max temps in the upper 40s and lower 50s.


***freeze warning expanded a little in Rhode Island and southeast ma***

High pressure axis remains centered to the west. North-northwest
winds continue at night but the winds and diurnal sky cover will
diminish with sunset.

The northwest flow has been transporting colder air into the
region. With this cold air in place, we expect temperatures to
fall below freezing away from the coast and the mid 30s to around
40 near the coast. With these values, we expect freezing conditions
in the interior including several areas that have not yet experienced
a killing freeze.

The freeze warning continues where previously issued. We have
added southeast Providence co. And eastern Kent co. In Rhode Island where places
outside the urban core will be at risk. We have also added
southern Bristol co. And southern Plymouth co. In Massachusetts for areas
away from the immediate shoreline.

Temps aloft around -5c to -6c with ocean temps 14-15c. This
20-degree differential with sustained winds 12 knots or higher
will favor bands of ocean effect clouds, possibly a shower. But
the direction will favor an offshore fetch that may clip
Provincetown and parts of the Outer Cape.


Short term /6 am Wednesday morning through Wednesday night/...

High pressure builds over the region. This should bring subsidence
and mainly clear skies. Winds over the ocean will continue at
10-14 knots sustained, turning more from the north. This may keep
some ocean clouds over Cape Cod, especially Hyannis and points

Sunshine will work on -6c temps aloft to bring Max temps in the
mid 40s to around 50.

Wednesday night...

High pressure ridge will be in place surface and aloft through the
night. This should provide mainly clear skies and light winds.
Depending on specifics of the ridge axis, the north wind over Cape
Cod could back around from the northeast, drawing ocean clouds
farther west to the Cape Cod canal.

Great Lakes shortwave and associated surface low over the Midwest
will approach overnight. Moisture fields show increasing potential
for mid and high clouds during the night, but the lower thicker
clouds hold off until near sunrise.

Based on the light wind prevailing fair skies, we have stayed
close to the existing min temp forecast. The coldest temps may
actually be reached a couple of hours earlier than normal, with
steady or slowly rising temps late at night as the clouds build

With the dry low level air expected, the lack of any source of
lift, and no forecast of measureable pcpn by this system east of
the New York border... we will show nil pops through 12z Thursday.


Long term /Thursday through Tuesday/...
updated at 423 am...


* cold rain and wind Thu/Thu ngt W/snow and sleet likely at the
onset across the interior

* blustery with a drying trend Fri

Thursday into Friday...

Interesting setup with cold airmass lingering over the region early
Thu in response to 1035 mb high over Quebec. Meanwhile robust
northern stream short wave energy diving southeast into the Great
Lakes/Ohio Valley. Differences in deterministic guidance with 00z ec
colder than 00z GFS on the front end with airmass over the region
early Thu. This results in the ec driving the baroclinic zone/storm
track farther southward. In addition ec is stronger with jet energy
diving into the Great Lakes/Ohio Valley and also mergers energy
quicker than GFS...although not as robust as its prior 12z run. This
results in mid level flow digging farther southward to our
latitude...which would delay warming in the mid levels. In addition
this also results in cyclogenesis developing farther south than the
GFS...with ec forming secondary low along the South Coast. This
scenario would linger low level cold air longer across the interior.
Both gefs and eps ensembles provide support for the deeper/colder
solution of the European model (ecmwf). Thus will blend the stronger/colder European model (ecmwf)
solution into this forecast. However not expecting a high impact
event here given system is progressive and doesn/T really intensify
until it moves northeast of the region into coastal ME and Gulf of
ME. So for now expecting a period of snow and sleet Thu at the onset
across northwest CT/MA...possibly as far east as the Worcester Hills
with a risk of a minor accumulation across the higher terrain of the
east slopes of the Berkshires.

Otherwise...with mid level low tracking west-northwest of the region
mid level warming overspreads the entire region with a changeover to
all rain by late in the day. For the remainder of the region a cold
rain is expected and possibly heavy at times given strong jet
dynamics and moisture advection. Could also have a period of brief
strong onshore winds Thu ngt across coastal eastern Massachusetts as secondary
low intensifies over Rhode Island/southeast Massachusetts before exiting into Gulf of ME.

System is fairly progressive so should see a drying trend Fri along
with brisk northwest winds on the backside of the low.

Weekend... models differ on next bundle of northern stream energy.
Good agreement that there will be a period of showers sometime this
weekend. GFS is of lower amplitude with progressive system and risk
of showers late Sat into Sat night. European model (ecmwf) more dynamic with risk of
showers Sat night thru Sun night.

Early next week...uncertainty on timing of departing system sun/Mon.
However thereafter both deterministic and ensemble guid suggest
pattern deamplifying next week...suggesting not as cold as this week.


Aviation /19z Tuesday through Sunday/...
forecaster confidence levels.

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

Through evening...

VFR. Scattered to broken sky cover from diurnal clouds, but with
bases 5000-6000 feet. These should diminish with sunset. Winds in
the mixed layer reach 20-25 knots, thus surface winds will gust at
times to these speeds. Winds diminish after sunset.

Tonight...high confidence.

VFR. Diminishing northwest winds. Ocean effect clouds may linger on the
Outer Cape. Low risk of showers in this area.

Wednesday...high confidence.

VFR. Winds turn a little from the north but with gusts a little
lighter than we had today.

Wednesday night...high confidence.

VFR. Ocean effect clouds may linger on parts of Cape Cod,
especially if surface winds turn north-NE overnight.

Kbos taf...high confidence in taf.

Kbdl taf...high confidence in taf.

Outlook /Thursday through Sunday/...moderate confidence.

Updated 423 am...

Thursday into Friday...

IFR-LIFR likely. Initial snow/ice pellets possible with potential accompanying
low level wind shear transitioning to -ra/rain with embedded +ra, possible thunderstorms and rain mostly
S/se. Blustery S/southeast winds. Gusts up to 30 kts along the immediate
shoreline terminals. Improving Friday with winds turning out of the


Brief period of VFR before conditions return low-end VFR to MVFR
with another chance of -ra/ra.


forecaster confidence levels.

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

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

Through tonight...

Northwest winds will gradually diminish tonight. Small craft advisories
will end piece by piece over the inner waters during the night.
Seas will remain up to 5-6 ft on the outer waters, so small crafts
will remain in effect there overnight.


High pressure builds over the waters. Winds and seas continue to
diminish. Seas remain around 5 feet on the outer waters through
Wednesday. Continue small crafts in those areas.

Wednesday night...

North winds diminish. Widely scattered ocean effect rain showers
east of Cape Cod.

Outlook /Thursday through Sunday/...moderate confidence.

Thursday into Friday...

Rain on the increase through Thursday, moderate to heavy at times
with the possibility of thunderstorms. S/southeast winds strengthening
ahead of a deepening area of low pressure across the region. Seas
building 8 to 10 feet the height of which will be on Friday, slowly
dropping off thereafter as winds turn out of the west behind a cold
front but remain breezy.


Breezy west winds continue as there is a brief lull in the weather.
Seas remain above 5 feet on a good chunk of the waters as winds
increase once again along with wet-weather late Saturday into
Saturday night.


Box watches/warnings/advisories...
CT...freeze warning from 2 am to 9 am EDT Wednesday for ctz003.
Massachusetts...freeze warning from 2 am to 9 am EDT Wednesday for maz006-007-
Rhode Island...freeze warning from 2 am to 9 am EDT Wednesday for riz001-003-
Marine...Small Craft Advisory until 2 am EDT Wednesday for anz232.
Small Craft Advisory until 8 PM EDT this evening for anz230-
Small Craft Advisory until noon EDT Wednesday for anz231.
Small Craft Advisory until 1 am EDT Wednesday for anz237.
Small Craft Advisory until 9 am EDT Wednesday for anz235.
Small Craft Advisory until 6 PM EDT Wednesday for anz250-254-
Small Craft Advisory until 8 am EDT Wednesday for anz251.
Small Craft Advisory until 2 PM EDT Wednesday for anz256.


near term...wtb/nocera
short term...wtb
long term...nocera

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