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Area forecast discussion 
National Weather Service Taunton Massachusetts
335 PM EDT Monday Apr 27 2015


Cooler conditions mixed in with bouts of wet weather prevail into
the early part of the week. A brief lull Wednesday under high
pressure and warmer conditions is quickly replaced by a return of
cooler and wetter conditions into the end of the week. The weekend
looks better with seasonable and dry conditions.


Near term /until 6 am Tuesday morning/...

Till this evening...

Focus upon a rain-band pushing S out of Maine along a back-door
cold front. Have high confidence in hrrr trends as we go into
evening. Likely to high categorical probability of precipitation mainly east of the CT-River
Valley. Punch of colder air S/SW as winds turn blustery out of the
N/NE. More details in the /tonight/ discussion below.


Back-door cold front continuing to push S through the region. Shower
activity continuing along and ahead though struggling against drier
air across the region /see 12z soundings from around S New England/.
Nevertheless strong forcing of available moisture per middle-level
impulse to the back-building nearly-stacked low into the Gulf of
Maine should yield activity. In its wake expect cold-air advection
to proceed within the low-levels allowing a steepening boundary-
layer profile /see 12z upstream soundings over Newfoundland/ that
allows for the mix-down of faster momentum and drier air to the

So will see decent rain chances that continue into midnight. Likely
or higher probability of precipitation. Low confidence with respect to thunder. Northwest-flow
backs out of the north/NE and becomes blustery behind the front with
gusts around 20 miles per hour...strongest across the mass East-Shore especially
Cape Ann / Cape Cod / islands. Gusts in these locations could get as
high as 35 miles per hour if conditions are just right. Upstream observations
would suggest potential outcomes. The S push of a colder airmass
drops temperatures to lows around the low-40s.


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


Conditions improve behind the cold front. In its wake expect a well-
mixed profile with a continued cold-pool aloft enhanced by abundant
sunshine and daytime heating. Anticipate blustery north-winds with gusts
around 20-25 miles per hour and drier air with relative humidity values falling
down to 30-percent. Some elevated fire weather potential concerns...
but in collaboration with other forecast offices and fire-weather
state liaisons...feel the threat is marginal and will not be
going with any headlines.

Overall a dry forecast as better forcing of available moisture
stays to the east. Clouds continue to be an issue across east New
England along the west-periphery of the nearly-stacked low continuing
to spin across the waters southeast of Canada. Highs into the upper-50s
to low-60s. But combined with winds... could feel 5-degrees
cooler. Slightly below average conditions making it feel

Tuesday night...

Remaining quiet and dry as northwest-flow diminishes. Clouds continue to
linger along the west-periphery of the low southeast of Canada. It is possible
some locations could radiate out should winds become light enough.
Confidence is within sheltered valley regimes. Lows around the upper-
30s to low-40s.


Long term /Wednesday through Monday/...


* pick of the week is Wednesday with dry weather and normal to above
normal temperatures
* unsettled weather returns for Thursday and Friday
* improvement expected for the weekend

The models have come into better agreement regarding the track and
strength of the low pressure developing off the North Carolina
coast. However...they continue to struggle with the timing and how
quickly the low pulls away from southern New England late in the
week. These discrepancies then affect the timing of
features through the remainder of the model run.

Wednesday...should be the pick of the week. Dry weather and
temperatures in the normal to above normal range are expected.

Thursday and Friday...low pressure moves away from the North
Carolina coast and starts tracking northeastward towards southern
New England. Right now...the track looks to keep it well outside
the benchmark with limited impact on our land zones...but
significant impact on the marine zones. Main impact to the land
will be overcast skies and possibly a bit of rain close to the
coast. However...this is highly dependent upon the eventual track
of the low. Model runs do seem to be coming into better agreement
on keeping the low fairly progressive but this is a new trend so
will keep an eye on this over the next couple of days.

Saturday through Monday...there is potential for a very nice weekend
with southerly flow bringing in warmer temperatures and pleasant...
dry weather. Rain showers look to move into southern New England
sometime Sunday into Monday. This as a result of low pressure
moving through Quebec and dragging a cold front through southern New
England. The timing of this will largely be based on how Thursday
and Friday turn out.


Aviation /20z Monday through Saturday/...

Forecaster confidence levels...

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

Short-term /till 0z Wednesday/...

18z update...

Into tonight...high confidence. Low-end VFR ceilings. MVFR ceilings/visibilities
with -shra...across east Massachusetts / Rhode Island...improvement by 6z. Low-risk IFR
for cape. Northwest-winds backing north-NE becoming blustery with gusts
upwards of 30-35 kts across east Massachusetts coast including cape.

Tuesday...high confidence. Low-end VFR ceilings becoming scattered. Broken
decks across east Massachusetts. Though not as blustery...N-winds with gusts
around 20-25 kts...especially across the high terrain and East-Coast Massachusetts.

Tuesday night...high confidence. Low-end VFR ceilings lingering across
east-coastal Massachusetts. Otherwise sky clear. Northwest-flow diminishing.

Kbos taf...high confidence in taf. North-wind gusts intensifying
towards midnight...diminishing towards the morning hours. Feel the
northwest-winds will be pronounced to keep sea-breeze offshore Tuesday.

Kbdl taf...high confidence in taf.

Outlook /Wednesday through Saturday/...

Wednesday...high confidence. VFR.

Thursday and Friday...low confidence. Mainly VFR with a low
probability of MVFR/IFR conditions near the coast.

Saturday...moderate confidence. VFR.



Forecaster confidence levels...

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

Short-term /till Tuesday evening/...

130 PM update...

Gusty winds across the interior...but a weak sea-breeze boundary
remains along the coast lending to some variance in the wind at
times. Nevertheless the dominant flow will be northwest with gusts up to
20 kts. Seas likely to enhance...especially towards evening as a
cold frontal boundary drops S along which showers are expected.
With passage...wind gusts increase out of the north with the potential
for gales. These winds continue into morning diminishing through
Tuesday. Small-crafts continue...gales forecast to be short-lived
so will emphasize threat in the Small-Craft Advisory. Waves
building around 6-8 feet on the east-outer waters...subsiding into
Tuesday night.

Outlook /Wednesday through Saturday/...

Wednesday...high confidence. Quiet boating weather.

Thursday through Saturday...high confidence in trends...lower
confidence in duration and magnitude of trends. Winds and seas will
increase in response to a strong low pressure system passing east of
the coastal waters. Small craft advisories will be necessary with
gale warnings possible.


Box watches/warnings/advisories...

Rhode Island...none.
Marine...Small Craft Advisory from 10 PM this evening to 5 PM EDT
Tuesday for anz231-232.
Small Craft Advisory from midnight tonight to 2 PM EDT Tuesday
for anz233-234.
Small Craft Advisory from 10 PM this evening to 2 PM EDT
Tuesday for anz230.
Small Craft Advisory from 2 am to 2 PM EDT Tuesday for anz235-
Small Craft Advisory from 10 PM this evening to 8 am EDT
Wednesday for anz250.
Small Craft Advisory from 10 PM this evening to 8 PM EDT
Tuesday for anz251.
Small Craft Advisory from midnight tonight to 8 am EDT
Wednesday for anz254.
Small Craft Advisory from 2 am Tuesday to 8 am EDT Wednesday
for anz255.



near term...sipprell
short term...sipprell
long term...rlg

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