Area Forecast Discussion
Issued by NWS Boston, MA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS61 KBOX 220753

Area Forecast Discussion
National Weather Service Taunton MA
353 AM EDT Sat Oct 22 2016

A strong upper level disturbance moving into New Eng will bring
numerous showers today. In addition, strong west winds will
develop late today and continue into Sunday as a strong storm
settles over the Maritimes. A cold front may bring a few more
showers Sunday night, then dry but cool conditions persist into
mid week.


Potent negative tilt trof and mid level low will move NE across
New Eng this afternoon and evening. Deepening moisture ahead of
the trof combined with strong QG forcing will result in numerous
showers moving east across the region this morning into early
afternoon. The showers should then become more focused across the
interior late this afternoon as a dry slot tries to move up along
the coastal plain. Impressive mid level cooling will add an
element of instability so brief heavy rain is possible in some
showers and can`t rule out an isold rumble of thunder. In fact,
much of the hi-res guidance is suggesting localized rainfall of
0.50 to 1 inch is possible in the interior.

As cold front moves across the region, expect falling temps in
western New Eng through the 50s and into the 40s this afternoon.
In the coastal plain, temps will be in the 60s this morning before
dropping through the 50s through the afternoon.

Increasing west winds will develop from south to north late
afternoon with gusts 25-35 mph developing, especially south of the
Mass pike.


As mid level low lifts into northern New Eng, comma head moisture
will rotate into SNE with additional shower activity possible,
especially in the interior where deeper moisture is present. Strong
gusty winds will be the main concern tonight as low pres deepens
as it moves north into the Maritimes. Soundings support gusts to
40 mph at times so we will issue a wind advisory for MA/RI as
trees are still close to fully foliated making it easier to
sustain tree damage. The wind advisory will likely be expanded to
include CT in later forecasts. Low temps will range from upper
30s to mid 40s.

Some clouds will linger into the first part of the morning, but
clearing will quickly develop from SW to NE as excellent mid level
drying moves in leading to a mosunny day. Strong winds will
continue to be a concern with a secondary surge from excellent
mixing. Soundings support gusts to 35-45 mph with up to 50 mph
gusts possible over higher elevation in central and western MA.
Highs will be in the mid/upper 50s, cooler higher terrain.



* Cooler and dry Sun into mid week.

Overview and model preferences...
Have reasonably high confidence in overall trends through the mid
term, and much of the extended term as the 00Z guidance update
continues to show good agreement.  Labrador cutoff will slowly
deamplify and shift to the northern Atlantic, but the attendant trof
remains in place across the region yielding a draw of CP air across
the area.  This suggests a mainly dry but cool period through much
of the week, with the dryness thanks to building ridge upstream.  A
lee low pres and trof (clipper-type system) will move off the
Rockies during the late week period, and models disagree on its
interaction with the aforementioned ridge.  Therefore, although
there will be a risk for more unsettled weather by Fri or the
weekend, the timing and ultimate impacts are a question-mark at this
time.  Given there is reasonably good agreement between models, a
blend of deterministic guidance with persistence will be used for
this update.


Sun night into Mon...
Reinforcing, fast moving shortwave, will be sliding quickly across
the region early Mon morning.  There is a risk for a few shra with
this passage as low lvls from the sfc to about H7 do saturate and
feature modest lapse rates thanks to cold advection aloft.   Pops
will be caped at low end chance.  Otherwise, isallobaric couplet
shifts backing the winds to the NW, so the breezy conditions are
expected to continue into Monday.  H92 temps drop to near +2C by
late Mon, so highs will remain in the 50s.  Sun night mins will
remain higher than they could be due to the continued strong pres
gradient, looking at mainly upper 30s to mid 40s.

Mon night into Tue...
Radiational cooling expected Mon night as H92 temps continue to drop
below 0C.  Will likely see widespread temps in the low-mid 30s and
even a few upper 20s possible in the NW valleys.  Will need to
monitor for some frost/freeze headlines where the growing season
continues.  The fall-like conditions continue Tue, although less
windy with highs mainly in the upper 40s to mid 50s.

Wed and Thu...
Dry wx lingers as high pres moves across the region, but as it
approaches, winds continue to back to the N and possibly even NE.
Therefore, could be a caveat to the dry conditions for the
Cape/Islands and southern Plymouth county.  Noting H85 temps
averaging about -6C with SSTs remain near +15C, yielding a delta-T
of 21C or more.  Therefore, will need to watch for ocean effect
clouds and showers across these areas.  Otherwise, cool mins in the
30s with highs in the 50s are expected each day, combined with
diurnal cloudiness.

Fri and Sat...
Overall forecast becomes more uncertain due to interaction of a trof
from the lee of the Rockies and its interaction with ridging across
the northeast.  Periods of rain, or at least more unsettled weather
are possible, but timing and final totals will take more time to
nail down, especially since the trof that triggers the weather has
yet to even form at this time.


Forecaster Confidence Levels.

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

Short Term /through Sunday/...

Through 12z...Widespread IFR/LIFR cigs with areas of fog. Showers
may reach CT valley by 12z.

Today...Moderate confidence. Improving cigs to MVFR through the
morning with improving vsbys. Numerous showers, some briefly
heavy, will move across SNE during the morning into the afternoon
then become more focused across western MA and CT late afternoon.
Mainly MVFR cigs this afternoon with brief lower vsbys in heavier
showers. Low prob of an isold t-storm. Increasing W winds
mid/late afternoon with gusts 25-35 kt developing, especially
south of the Mass Pike.

Tonight...High confidence. MVFR cigs improving to VFR. Sct showers
continuing, mainly western New Eng and focused over higher
terrain. West wind gusts to 35 kt.

Sunday...High confidence. VFR cigs clearing in the afternoon. West
wind gusts 30-40 kt, strongest higher terrain.

KBOS TAF...High confidence in trends but lower confidence in

KBDL TAF...High confidence in trends but lower confidence in

Outlook /Sunday Night through Wednesday/...

Sun night through Tue...High confidence.
VFR.  W winds remain elevated (shifting somewhat to the NW Tue).
Daylight winds gust 20-30 kt at times and then subside during the
overnight hours except at terminals along the immediate coast.

Wed and Thu...Moderate confidence.
Mainly VFR, although some MVFR conditions possible mainly over the
Cape/Islands and southeastern Massachusetts.


Forecaster Confidence Levels.

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

Short Term /through Sunday/...High confidence.

Gale force westerly winds will develop mid/late afternoon southern
waters expanding across the rest of the waters by early evening.
Gusts to 35-40 kt expected which will persist into Sunday. Gale
warnings continue. Vsbys will improve later this morning and early

Outlook /Sunday Night through Wednesday/...

Sun night...High confidence.
Remnant westerly gale force winds will recede to between 25-30 kt.
So Gale warnings will give way to small craft advisories.  Seas
remain elevated 5-7 ft.

Mon through Tue...High confidence.
Persistent W winds with gusts 25-30 kt and seas 5-6ft.  Small craft
advisories likely last both days.

Wed and Thu...Moderate confidence.
Winds shift to the NW then N.  Some gusts, especially late Wed night
into Thu may approach small craft advisory thresholds.  Seas may
briefly dip below 5 ft but secondary swells may exceed 5 ft by Thu.


MA...Wind Advisory from 8 PM this evening to 2 PM EDT Sunday for
     Wind Advisory from 8 PM this evening to 6 PM EDT Sunday for
RI...Wind Advisory from 8 PM this evening to 2 PM EDT Sunday for
MARINE...Gale Warning from 2 PM this afternoon to 6 PM EDT Sunday for
     Gale Warning from 5 PM this afternoon to 6 PM EDT Sunday for


MARINE...KJC/Doody is the U.S. government's official web portal to all federal, state and local government web resources and services.