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Area forecast discussion 
National Weather Service Taunton Massachusetts
724 am EDT Monday Jul 6 2015

Synopsis...
dry and above-seasonable conditions prevail beneath high pressure
into Tuesday morning. A series of fronts will bring scattered
showers and thunderstorms Tuesday and Wednesday. Dry weather
should prevail into next weekend...although a stalled front south
of New England may trigger a few showers from time to time.

&&

Near term /until 6 PM this evening/...
7 am update...
some scattered cirrus to start the morning leftover from convective activity
well to the SW associated with tomorrows warm front. Aside from
this and a few cumulus later...mainly sunny skies with a chance run at
the middle-upper 80s away from the coastlines. Would not be shocked
to find a 90 by the end of the day but these are likely to be
mainly few and far between. Thankfully...mixing should keep the
dewpoints at Bay a bit today...mainly the upper 50s and 60s so the
more uncomfortable humidity should hold off until tomorrow. All-
in-all...forecast looks on track so only changes were to bring
current conditions up to speed.

Previous discussion...

Continued influence of high pressure...with some thin...high
clouds late. Light winds expected once more...leading to seabreeze
development once more. Expecting slightly higher temperatures
today than Sunday due to the slightly higher starting point. A few
locations across the interior could approach 90 degrees. Cooler
along the immediate coasts.

&&

Short term /6 PM this evening through 6 PM Tuesday/...
high pressure moves southeast of New England tonight. This will
place our region into a favorable area for isentropic lift. This
will mean thicker clouds later tonight. A warm front should
approach the South Coast late tonight. Despite the surface
humidity...drier air aloft should keep rainfall chances at a
minimum. Another night of patchy dense fog not out of the
question.

Warm front lifts moves through Tuesday. Marginal instability
during the morning hours...so thinking chances for thunderstorms
will be small. Once we get into the warm sector though...we should
see cape values between 700-1200 j/kg during the afternoon across
the interior. 0-6 km shear remains weak...so the severe weather
threat is low. However...that should be enough instability for
scattered thunderstorms. Projected storm motions could be quite
slow. With precipitable water values approaching 2.0 inches...
there is potential for localized heavy rainfall...leading to a
risk for localized flooding.

&&

Long term /Tuesday night through Sunday/...
highlights...

* showers/storms Wednesday
* high uncertainty later in week but mainly dry

Overview and model preferences...
little chance in the synoptic scale pattern amongst operational
and ensemble guidance at 00z. Amplified ridging gives way to zonal
flow beneath deep cutoff low pressure across central Canada. This
zonal flow is what leads to the uncertainty in timing of any
potential shortwaves/mesoscale convective system impacting southern New England. With a stalled
baroclinic conduit to the south it/S a battle between the
anticyclonic shear across New England. Agree with the previous
forecasters assessment that this is likely to lend to mainly dry
weather at the end of the week following the frontal passage on Wednesday.
However...will need to watch mainly upstream convective
development for their potential impact on the region. Models
continue to indicate the remnants of an mesoscale convective system moving through at some
point. With the east shift in the northern vortex late next week...a
transition toward a more definite unsettled pattern is possible
beginning early next week. Will continue with the ensemble blend
proposed earlier.

Details...

Tuesday night into Wednesday...
warm front lifts north overnight allowing southern New England to fully
enter the warm sector. The combination of this increased
warmth/moisture may lead to overnight fog/stratus
development...the extent of which may define conditions for Wednesday.
The cold front...which will pass through late day Wednesday will provide
a focus for another round of convection. Instability will be
dependent on the leftover stratus/fog. Lapse rates and shear is
marginal at best while precipitable waters remain high...nearly 2 Standard deviations
above normal. With sunny breaks...which are possible...surface cape
values could reach or exceed 1500j/kg particularly if dewpoints reach
the low 70s in spots as potential forecast. In any case...thunder
is likely assuming lifting of the early day low clouds...with
heavy rain the most likely threat...severe threat is low given the
lacking shear/enhanced lapse rates...but will need to monitor over
the next 48 hours. Highs will be dependent on how quickly any
clouds clear...if they do...some temperatures in the upper 80s to near 90
are possible as 850 mb temperatures approach +17c.

Thursday into Friday..
cold front stalls offshore as upper level steering flow becomes
more zonal. This will provide a focus for lift within the vicinity
and a conduit for upstream convection or the remnants there to
follow as low level waves develop. The bulk of the instability will
remain to the S...so some steering to the S is likely as well.
Therefore...will maintain lower probability of precipitation especially focused on the southern
half of the region where the better lift/moisture resides...but
will need to watch upstream during this period in spite of the low
end probability of precipitation and mainly dry wording. Temperatures near to possibly below
normal.

Sat and sun...
a weak ridge will build east as the cutoff low pressure to the northwest moves
east. The cold front will continue a shift offshore. Therefore...will
begin to lean drier for the weekend at this time...but this is
still a low certainty forecast given the zonal flow and upstream
cutoff. 850 mb temperatures of +12c to +14c suggest temperatures near seasonal
normals.

Early next week...
as mentioned above...with the upper level cutoff shifting east and
most guidance showing a slight bagginess to middle-upper level heights
across the region...will be seeing a shift toward wet/unsetteled
conditions. Timing will be better defined once the kicker wave
that shifts the cutoff east is better sampled.

&&

Aviation /12z Monday through Friday/...
forecaster confidence levels...

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

Short term...through Tuesday...

Today...high confidence.
VFR. Mainly light winds shifting southerly through the day. Sea
breezes begin middle morning.

Tonight...moderate confidence.
Mainly VFR for much of the night. Some lower ceilings may work their
way into SW Massachusetts/CT with MVFR conditions possible mainly after 08z.
Some fog at typically prone airports.

Tomorrow...high confidence.
Lower ceilings/fog give way to mainly VFR. Sea breezes are
likely...but with a slightly later starting time.

Kbos terminal...high confidence in taf. Sea breeze expected
around by 15z today.

Kbdl terminal...high confidence in taf. Patchy fog 08-11z.

Outlook /Tuesday night through Friday/...

Tuesday night into Wednesday...moderate confidence.
MVFR/IFR in scattered showers/tstms...otherwise VFR. Patchy fog at
night.

Thursday and Friday...low confidence.
Mainly VFR. But occasional showers/fog may lead to lower
categories periodically.

&&

Marine...
forecaster confidence levels...

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

Short-term /through Tuesday/...high confidence.

Quiet boating weather. Seas continue to diminish beneath high
pressure. Winds turn south today into tonight with any gusts
remaining below 20 kts. Light winds will lead to local seabreezes
today. Patchy dense fog possible tonight.

Outlook /Tuesday night through Friday/...

No change with the overnight forecast...mainly quiet boating
weather prevails with the slight chance of Small Craft Advisory
conditions late Wednesday into Thursday.

Previous discussion follows...

Moderate confidence. Mainly light winds and flat seas as a series of
weak fronts cross waters...but could see 4-5 feet seas on southern
waters S of islands by Wednesday or Thursday due to building swell.

Main concern is for scattered showers/storms Tuesday and Wednesday...as well
as patchy late night/early morning fog.

&&

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

&&

$$
Synopsis...Belk/doody
near term...Belk/doody
short term...Belk
long term...doody
aviation...Belk/doody
marine...Belk/doody

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