Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 192337

Area Forecast Discussion
National Weather Service Taunton MA
637 PM EST Sun Nov 19 2017

Blustery and cold conditions will prevail tonight into Monday.
Winds shift to southwest with milder temperatures on Tuesday,
followed by a cold front sweeping across the region that will
bring showers late Tuesday night and Wednesday morning. Dry and
colder conditions expected late Wednesday through the end of the
week. Well below average temperatures will spill into the
region this weekend.



700 PM Update...

Wind advisory has been expired as gusts across southern New
England have been below criteria over the past hour or two. Many
spots are still gusting around 30-33 kts but conditions should
begin to subside over the next few hours. Breezy westerly winds
will remain during the overnight hours which will limit temps
from radiating out.

Aside from the wind, cloud cover is advancing eastward ahead of
the secondary trough. Went ahead and increased cloud cover for
the overnight period. Otherwise the bulk of the forecast remains
on track for tonight.

Previous Discussion...

Secondary mid level trough and shortwave moves into New Eng
tonight with cooling temps aloft. 500 mb temps down to -35C by
12z Mon. This combined with some moistening of the column in
the low and mid levels may result in a few flurries or snow
showers, mainly western MA and northern CT where some lake
effect moisture may spill into the region. Hi-res guidance just
showing some spotty light QPF so continued slight chc pops in
the west.

While peak of the wind will be diminishing tonight, it will
remain blustery with gusts 25-30 mph at times as cold advection
continues. Lows mid 20s to lower 30s but the wind will make it
feel considerably colder.



Mid level trough exits the region with high pres building south
of New Eng. It will be a dry day, but area of low and mid level
moisture moving through will result in sct-bkn cu developing.
850 mb temps starting out -10 to -12C with some moderation in
the afternoon. Chilly day with highs ranging from mid 30s
interior high terrain to lower 40s coastal plain. Strong
pressure gradient remains in place so it will be another windy
day. Soundings are well mixed in the lower levels and suggest
potential for gusts 30-40 mph at times, especially through 18z.
Strongest gusts expected over interior northern MA.

Monday night...

High pres moves off mid Atlc coast with area of mid level
moisture lifting to the north so expect mostly clear skies.
Winds will be diminishing and backing to the SW and there will
still be enough gradient so not as cold as it otherwise would
be if winds were calm. Generally followed a blend of MOS
guidance for min temps. Temps will likely slowly rise
overnight along the south coast and Cape/Islands.



* Warm but windy for Tuesday
* Cold frontal passage on Wednesday will drop temps through the
  day with showers.
* Dry but chilly for Thanksgiving day

Pattern Overview/Confidence...

Building high pressure over Baja California will push the ridge into
the Western CONUS for next week. This in combination of the blocking
high over northeastern Canada and Greenland will favor East Coast
troughing through the period. 12z Models and their ensembles are in
good agreement on the large scale pattern. However, some differences
will remain on timing and amplitude of each wave. Overall trend in
the forecast for southern New England will be wet weather for
Wednesday with drying trend into the end of the week. Will have to
continue to watch the weekend as with offshore low to the east and
approaching system from the West and how those two systems will
impact each other. Otherwise temperatures will trend below average
for the week.


Tuesday into Wednesday...High confidence.

Mid-level ridge will build over the region on Tuesday as winds
switch to the SW and WAA returns. Temperatures will warm within this
southwesterly wind as 50`s return back to the region. A few sites
may be near 60F depending on how much mixing occurs. Approaching
cold front from the west will result in a developing LLJ with 925mb
winds reaching 40-45 kts. Once again another windy day on Tuesday.

Cold front from the Great Lakes will pass through the region on
Wednesday. A coastal low off the coast of the Carolinas appears to
ride along or out ahead of the front. Latest guidance continues to
trend this low closer to the region, thus allowing for more moisture
in the mid-levels. The GFS appears to be on the slow end of the
developing low, thus not capturing enough moisture when the front
moves through. Therefore trended with the EC/UKMET/NAM for this
portion of the forecast. Precip will begin to overspread the region
overnight and result in widespread rainfall Wed morning. Highest
confidence is south and east of I-95, closer to the mid-level
moisture. Regardless appears that most of the region will see some
rainfall, which highest amounts closer to SE MA.

One thing we will have to watch on Wednesday is the available
moisture and timing of the CAA. Some guidance indicates that a few
flakes can fly on the backside of the front. Uncertain on if there
will be moisture. Regardless, trend is only trace to less than if it
does accumulate on the roads.

Thanksgiving into Friday...High confidence.

Behind the front on Wednesday, CAA will move back into the region
for Thursday. High pressure will move south of the region resulting
in a chilly but dry day for Thanksgiving.

Passing shortwave to the north Friday morning may bring in some
clouds, but another dry but more seasonable day.

The weekend...Low confidence.

High pressure and mid-level ridge Friday night will lead to a
warming trend on Saturday. Winds will back to the southwest as
another front from the west approaches. Behind this system
anomolous cold air will spill into the region putting temps well
below average. While a few waves will move through this period,
overall precip looks light.


Forecaster Confidence Levels...

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

Short Term /through Monday Night/...High confidence.

Tonight...VFR with sct-bkn cigs 040-050 developing. A few lake
effect snow showers may spill into western MA and northern CT
tonight. W/NW winds diminishing but remaining gusty with 25-30
kt gusts.

Monday...VFR. Sct-bkn cigs 050-060. West gusts 25-35 kt.

Monday night...VFR. Diminishing wind.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday: VFR. Windy with gusts to 30 kt.

Tuesday Night: Mainly VFR, with areas MVFR possible. Windy with
gusts to 35 kt. Chance SHRA.

Wednesday: Mainly VFR, with areas MVFR possible. Breezy. SHRA

Wednesday Night: VFR. Breezy.

Thanksgiving Day through Friday: VFR.


Forecaster Confidence Levels...

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

Short Term /through Monday Night/...

Near gale force gusts will continue tonight. Winds may diminish
below gale for a time tonight but another surge of stronger
winds expected by Mon morning. As a result we extended the gales
into Monday for most of the waters. Winds gradually diminish
Mon night to near 25 kt.

Outlook /Tuesday through Friday/...

Tuesday: Low risk for gale force winds with gusts up to 35 kt.
Areas of rough seas.

Tuesday Night: Low risk for gale force winds with gusts up to
35 kt. Areas of rough seas. Rain showers likely.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Local rough seas. Rain showers likely.

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas.

Thanksgiving Day: Winds less than 25 kt. Areas of rough seas.

Thursday Night through Friday: Winds less than 25 kt. Seas up
to 5 ft.


MARINE...Gale Warning until 2 PM EST Monday for ANZ232>235-255-256.
     Gale Warning until 10 PM EST this evening for ANZ230-236-237.
     Gale Warning until 6 PM EST Monday for ANZ231-250-251-254.


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