Area Forecast Discussion
Issued by NWS Boston, MA

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877
FXUS61 KBOX 231209
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
709 AM EST Thu Nov 23 2017

.SYNOPSIS...
Quiet weather through Friday with dry and cool conditions.
Milder air returns Saturday ahead of a cold front, but will
have to watch a coastal storm to the southeast. Blustery and
cooler weather follows Sunday into Monday, then dry and milder
conditions again Tuesday into Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

No major changes to the forecast this morning. Brought the
forecast back in line with observed trends.

Previous Discussion....

Chilly start to Thanksgiving as high pressure from the Great
Lakes builds into the Mid-Atlantic. This will lead to dry
weather and sunny skies to start the day. Northwest winds will
begin to back to the west as flow aloft because a bit more
zonal. This will warm 925mb temps closer to -1 to -2 C compared
to the -5C we are starting out with this morning. This will help
push temps into the upper 30s to low 40s.

Weak shortwave aloft will increase cloud cover during the later
half of the day. Moisture associated with this wave is meager
enough to lead the forecast dry. Cross sections also support
this with just high level clouds passing through. Overall, a
chilly but dry Turkey day as temperatures will remain 5 to 10
degrees below normal.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Trough axis will push through the region this evening and slide
to the north tonight. Mid to high level clouds will stream
through as guidance continues to show some moisture for the
first half of the night. 925mb jet will be on the increase along
the passing wave resulting in a few gusts during the overnight
hours. Best location is along the shoreline where waters will
help increase the mixing. While the jet could limit radiational
cooling, expect overnight inversion to limit the mixing across
the interior.

Aside from the cloud cover, dry weather will prevail. Expect
temperatures in the mid 20s with metro region in the low 30s.

High pressure will allow for dry weather once again on Friday.
Developing ridge aloft will result in a more southerly flow. This
will help push temps to be warmer than today. Highs should reach
into the upper 40s to low 50s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Highlights...

* Warming Sat with a low risk of showers
* Blustery and cooler Sun/Mon
* Turning mild again Tue/Wed with mainly dry conditions

Overview...
23/00Z guidance suite is in good overall agreement through
Saturday, then the detail differences start to become
significant early next week. It will likely be a few more days
before these differences resolve, when the energy involved gets
better sampled by moving over North America. Have only moderate
confidence in the details after Sunday.

In general, expecting a variable temperature pattern, with near
normal temperatures Saturday and the middle of next week. In
between, below normal temperatures are anticipated.

Mainly dry weather through this portion of the forecast. Low
risk for some showers late Saturday into Saturday night as a
cold front moves across southern New England. Moisture will be
the main limitation, but thinking the greater risk will be
towards the coast, where proximity to the ocean and interaction
with an offshore low pressure may be enough to increase shower
coverage.

The forecast for the middle of next week remains uncertain.
Current indications suggest a period of drier and warmer
weather. However, large disagreements in the handling of a
significant trough moving into the Pacific northwest Monday
complicate the forecast through Wednesday. The resulting timing
differences will mean the difference between a warm and dry
Wednesday, or a cooler and wetter day.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

Short Term /through Friday/...High confidence.

Today and tonight...VFR with W to NW winds through the period.

Friday...VFR with winds backing to the south, but remaining
light.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: VFR. Breezy.

Saturday: VFR. Breezy. Slight chance SHRA.

Saturday Night: VFR. Chance SHRA.

Sunday through Monday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Friday/...

Decided to cancel the Small Craft Advisory for Cape Cod Bay as
recent observations indicate wind gusts are less than 25 kt.
Buoy in the bay also showed wave heights less than 5 feet.

Previous Discussion...

Winds shift to the W, with gusts generally remaining below 20 kt
after sunrise. Seas however will take some time to fully
diminish, and will require small craft advisories to linger
much of the day. Winds will shift to a more southerly direction
on Friday and will begin to increase during the evening.
Advisories for the ocean waters have been extended for the outer
waters into tomorrow given 5 ft lingering swells are expected.

Outlook /Friday Night through Monday/...

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.

Saturday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.

Saturday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.

Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Local rough seas. Slight chance of rain showers.

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft.

Monday: Winds less than 25 kt. Seas locally approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ235-
     237.
     Small Craft Advisory until 7 AM EST Friday for ANZ250.
     Small Craft Advisory until 1 PM EST Friday for ANZ254>256.

&&

$$
SYNOPSIS...Belk/Dunten
NEAR TERM...Belk/Dunten
SHORT TERM...Dunten
LONG TERM...Belk
AVIATION...Belk/Dunten
MARINE...Belk/Dunten



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