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Area forecast discussion 
National Weather Service Taunton Massachusetts
657 am EDT Wednesday Jul 30 2014

mainly dry/pleasant weather today other than perhaps a brief passing
sprinkle. A few showers and perhaps a thunderstorm or two are
possible Thursday and Friday...but most of the time will feature dry
weather. Confidence is increasing in a period of steady rain
sometime this weekend as low pressure tracks close to the coast.


Near term /until 6 PM this evening/...
7 am update...temperatures dropped well into the 50s this morning
but are slowly starting to warm with the sunrise. Patchy fog
across the region should also start to dissipate as the sun comes
up. Made some minor adjustments to temperatures and sky cover to
account for latest trends.

A moisture starved shortwave will result in a fair amount of middle
level cloudiness today...although still expect peeks of sunshine.
Much of the day will be dry...but the shortwave could result in a
few passing sprinkles. Very little forcing/instability is available
for much more than that. Anomalous upper level trough will continue
to result in low humidity with temperatures a bit below normal for late
July. High will top out in the 70s to near 80.


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

A weak ridge of high pressure will result in light winds along with
partly cloudy skies. The relatively dry airmass should allow lows
to fall back into the 50s to lower 60s in most locations.


Potent shortwave will be lifting into northern New England on
Thursday. Marginal instability will develop across our northern and
western zones with convective available potential energy on the order of 500 to 1000 j/kg. 0 to 6
km shear will be around 40 knots along with 500 temperatures around
-15c...which is quite cold for this time of year.

All in all...the best dynamics will be to our north.
However...enough parameters are in place for a few hit and miss
showers/thunderstorms across the interior and especially in
northwest Massachusetts/southwest New Hampshire. While instability is very
marginal...cold pool aloft/good shear may result in a few strong
storms producing small hail and gusty winds. Best shot of that is
in our far northwest zones. High temperatures will be in the upper 70s to
lower 80s under a mixture of clouds and sunshine.


Long term /Thursday night through Tuesday/...
* a few showers possible on Friday
* steady rain likely sometime this weekend
* showers and thunderstorms possible early next week

The models are in fairly good agreement through the long term.
There are differences in the details of course but overall the
synoptic scale pattern is fairly well modeled. Used a blend of
available guidance for much of the forecast. The high amplitude
upper level trough across the eastern U.S. Is the dominant feature
through the early part of the long term.

Thursday night and Friday...the combination of a shortwave and
abnormally cold air at 500mb may be enough to spark some showers and
perhaps a thunderstorm on Friday...but much of the day should be

Saturday and Sunday...the trough shifts a bit to the west over the
weekend allowing for subtropical moisture to move up the East Coast.
This allows a stationary front off the coast to shift west over
southern New England. Combined with the moisture...expect a fairly
steady rainfall across at least a portion of southern New England
through part of the weekend. There are some differences in the
models both in the westward extent of the front and in the timing so
this could occur Saturday...Sunday...or a portion of both days.

Monday and Tuesday...stationary front slowly shifts back offshore
bringing an end to the steady rainfall. However...low pressure
moving through Quebec will bring a cold front towards southern New
England. Expect the possibility for showers and thunderstorms


Aviation /12z Wednesday through Sunday/...
forecaster confidence levels...

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

Short through Thursday...

Today...high confidence. VFR conditions despite scattered to broken
deck of middle level cloudiness. Sea breezes develop this afternoon
along portions of the immediate coast.

Tonight and Thursday...high confidence. Mainly VFR conditions. A
few hit and miss showers/thunderstorms are expected during the day
Thursday across the interior...which may result in briefly lower

Kbos taf...high confidence in taf. Sea breezes are expected to
develop by early afternoon.

Kbdl taf...high confidence in taf.

Outlook...Thursday night through Sunday...

Thursday night through Friday...high confidence. Mainly VFR. Low
probability of a brief period of MVFR conditions in -shra.

Saturday and Sunday...moderate confidence. Mainly VFR northwest...chance
for MVFR ceilings/visibilities in scattered showers. MVFR conditions more
probable towards eastern Massachusetts/Rhode Island in -shra.


forecaster confidence levels...

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

Short through Thursday...

High confidence. Winds/seas should generally remain below Small Craft Advisory
levels today through Thursday along with good visibilities. Low risk
of marginal 5 foot swell reaching into the southern and eastern
Atlantic waters tonight and Thursday with distant low pressure.
However...based on most wave guidance capped seas at 4 feet for now
but later shifts will have to re-evaluate.

Outlook...Thursday night through Sunday...

Thursday night through Friday...high confidence. Quiet boating
weather expected with high pressure over the waters.

Saturday and Sunday...moderate confidence. Winds and seas are
forecast to remain below Small Craft Advisory criteria.
However...more unsettled weather is likely with a stationary front
wavering over the waters.


Box watches/warnings/advisories...
New Hampshire...none.
Rhode Island...none.


near term...Frank/rlg
short term...Frank
long term...rlg

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