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Area forecast discussion 
National Weather Service Taunton Massachusetts
408 am EDT Friday Jul 11 2014

Synopsis...
tranquil weather today and tomorrow as high pressure settles over
the region. Unsettled weather in the form of showers and
thunderstorms returns late Sunday into early next week. There is
the potential for strong winds and heavy rainfall.

&&

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

430am update....

Rain shield continues to move northeastward and has dropped some
precipitation across mvy early this morning. Believe that ack will also get
clipped within the hour as rain showers continue to move over the
region. Stationary front is still straddling just south of the
Mainland...per surface dewpoint observations. This front will
continue a very slow southward movement through out the day.

Cirrus shield has really limited any radiational cooling early
this morning so believe that min temperatures will remain steady over
the next few hours. Otherwise a pretty quiet night with comfortable
conditions.

Today...

High pressure will build over the region today with the stalled
front still lingering to the south. Although the low levels will be
dry...some increase moisture in the middle to upper levels will produce
some diurnal cumulus this afternoon. Some of the model guidance is still
trying to squeeze out some quantitative precipitation forecast today as upper level jet moves over
the region providing some lift. Because there is a good amount of
dry air in the low levels per soundings...kept a dry forecast.
Temperatures will continue to be cooler then the start of the work
week with highs reaching in the low to middle 80s. Sea breezes will
develop along both coastlines keeping coastal areas in the 70s.

&&

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

Tonight...

High pressure will continue to dominate across southern New England
tonight. This will allow for a weak pressure gradient and with
mostly clear skies could see some radiational cooling. Temperatures will
generally be in the upper 50s with low 60s across the metropolitan regions.
Patchy fog may develop especially across valley regions but have
a lower confidence.

Tomorrow...

High pressure will begin to slide eastward on Saturday. Moisture
will slowly increase as winds will switch to the southwest near the
end of the day. This will allow for more diurnal cumulus to develop.
Still a pretty weak pressure gradient so sea breeze development
looks likely along both coastlines.

Full moon will occur over the weekend allowing for the
astronomical high tides to occur. There could be some minor
splashover across Scituate and p-town Harbor. Otherwise expect
very little impact on the late Saturday high tide.

&&

Long term /Saturday night through Thursday/...

Highlights...

* more humid and breezy Sunday...showers possible late
* strong to severe thunderstorms & heavy rainfall possible Monday/Tuesday
* trend toward drier and less humid weather middle to late next week

Synoptic overview and model preferences...

Guidance continues to simulate an evolving highly anomalous
amplified northern stream this period with a full latitude ridge
developing across the western Continental U.S. Into Canada. Downstream a potent
closed low advects southward into the Great Lakes early next week.
This yields a deep moist SW flow along the eastern Seaboard with an
influx of Gulf and Atlantic moisture into New England. A strong
frontal zone will accompany this closed low and will become the
focus for convection and heavy rainfall early next week across New
England. Anomalous jet dynamics associated with this feature
combined with peak climatological heating will increase the risk for
strong to severe storms here in southern New England. Also given the
deep southwest flow these storms will have the potential of back
building and training over the same area yielding a risk of flash
flooding. As for model guidance...both the 12z gefs and ecens
ensembles along with the 00z deterministic runs of GFS and European model (ecmwf) are
in very good agreement on trough/ridge amplitude and timing of
frontal passage. Thus will blend all data sources for this portion
of the forecast.

Daily details...

Sat night...

Quiet/dry weather as high pressure lingers along the coast. Seasonable
temperatures with lows in the low to middle 60s. Tolerable humidity with dew
points in the u50s to l60s.

Sunday...

Becoming more humid and breezy as low level warm air advection
increases as surface high drifts offshore. Nice weather lingers much
of the day across eastern New England per good model agreement on
warm advection precipitation arriving after 18z across western New England
and probably not until after 00z over Rhode Island and eastern Massachusetts. Thus dry
weather for much of the daylight hours across Rhode Island and eastern Massachusetts.

Early next week...

Warm and muggy conditions ahead of a strong frontal boundary
approaching the region from the west. As middle level flow amplifies
and backs...deep S-SW flow aloft develops along the eastern
Seaboard. This results in a slow moving frontal boundary with an
influx of Gulf and Atlantic moisture. Strong jet dynamics coupled with at
least modest instability increases the risk of strong to severe
storms along and ahead of the approaching front Monday and Tuesday. In
addition the deep S-SW flow aloft will provide an environment
favorable for back building storms and training over the same area.
Thus a risk of flashing flooding.

Middle to late next week...

Ensembles and deterministic guidance suggest a frontal passage
around Wednesday along with middle to upper trough deamplifying as it lifts
NE into Ontario and Quebec. This supports a trend toward drier and
less humid weather middle to late next week.

&&

Aviation /08z Friday through Tuesday/...
forecaster confidence levels...

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

Short term /through Saturday/...high confidence.

Before 12z... VFR for most sites. Patchy fog on ack/mvy and
portions of the cape can drop conditions below VFR. A passing rain
shower across ack may wet the runway.

Today until tomorrow...VFR through the period. Sea breezes once
again likely at near shore terminals for today and tomorrow.
Low confidence on patchy fog across the south coastline.

Kbos taf...high confidence in taf. Sea breeze should start 13-15z
today.

Kbdl taf...high confidence in taf.

Outlook...Saturday night through Tuesday...

Saturday night...high confidence for VFR and dry weather.

Sunday...VFR but low risk of MVFR late in the day western New
England as showers enter this area. High confidence on trends but
lower confidence on exact timing.

Sunday night through Tuesday...low to moderate confidence. Mainly
VFR during the daylight hours but lowering to MVFR/IFR at night in
areas of fog. Also MVFR in scattered showers/tstms.

&&

Marine...
forecaster confidence levels...

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

Short term /today through Saturday/...high confidence.

A cold front will slowly move south of the waters today and
tomorrow. A few isolated showers may occur today but dry weather
should prevail by the afternoon lasting through the period. Winds
and seas will remain below Small Craft Advisory thresholds through
Saturday.

Outlook...Saturday night through Tuesday...

Saturday night...quiet boating weather with light south-southwest winds and dry
weather.

Sunday...south-southwest winds increase as front approaches. Showers/thunderstorms hold
off until Sun night.

Monday and Tuesday...persistent modest south-southwest winds 15-20 knots with higher
gusts. Scattered thunderstorms with heavy rain and strong winds possible. Patchy
dense fog possible especially at night and early morning.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
New Hampshire...none.
Rhode Island...none.
Marine...none.

&&

$$
Synopsis...nocera/dunten
near term...dunten
short term...dunten
long term...nocera
aviation...nocera/dunten
marine...nocera/dunten

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