Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 192000
AFDBOX

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

.SYNOPSIS...
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. Another cold front may bring more showers Saturday
followed by blustery and colder weather next Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Monday...

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.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Highlights...

* Dry conditions and blustery NW winds Monday
* Moderating temperatures Tuesday into early Wednesday
* Dry but chilly for Thanksgiving day and Friday

Overview...

Overall progressive mid level pattern continues across North
America through most of the long term period, with a few fast
moving H5 short waves in the northern stream flow. There may be
scattered showers with milder temperatures ahead of the short
wave and surface frontal passages, followed by colder temps and
some gusty winds especially on Monday. May see some
amplification of the mid level flow across the eastern half of
the U.S. around mid week, which continues to show some signs of
model solution spread giving a bit lower confidence in timing
the surface front through. Models in better agreement in
bringing some southern stream moisture up the eastern seaboard
as cold front approaches around the Wednesday timeframe. The
front remains progressive, and should push offshore Wed night,
just in time for dry but cooler conditions for the Thanksgiving
day HS football games. Temps look to remain on the cool side at
the end of the week.

Details...

Monday into Tuesday...High confidence.
Another weak disturbance in the W-NW flow should remain dry but
will bring colder air across the region as it moves through the
northern extent of the large high pressure are settling across
the southern Appalachians and SE U.S. on Monday.

May see some lake effect snow shower streamers try to cross the
Berkshires into western areas, mainly near the E slopes and the
northern CT Valley especially late morning into the early
evening hours. At this point, should see only light activity.

Not expecting temps to recover much during the day with W-NW
winds gusting up to 30-40 mph, highest across the higher terrain
and east coastal areas through midday, then should slowly
diminish. Excellent cold air advection with H85 temps down to
-10C to -12C through midday with little change in the afternoon.
Expect highs only in the lower-mid 30s across the higher
terrain ranging to the lower 40s along the immediate coast.

NW flow early Tuesday will back to SW as the large high
pressure center shifts E during the day. Will see return of
milder temps as readings top off in the mid 40s to mid 50s, with
a few upper 50 degree readings possible across S coastal areas.
A cold front will approach late in the day but will remain dry.

Tuesday night and Wednesday...Moderate confidence.
Expect the cold front to push quickly across, but most of the
energy and moisture will remain across northern New England into
southern Quebec. Good pressure gradient sets up between the
high exiting to the E and the approaching front. Plus, models
continue to signal moisture working up the eastern seaboard from
developing southern stream mid level system across S GA/FL into
the eastern Gulf of Mexico.

Still some timing issues amongst the model suite, but showing a
bit better continuity in bringing precip across most areas
except N central and NW Mass Tue night, then will push E Wed.
May see a decent shot of QPF amounts during Wed as the moisture
feed moves across eastern areas with 0.2 to 0.3 inches possible
before ending. Kept CHC POPs going, with best chances across S
coastal areas. High temps Wed will top off a few degrees either
side of seasonal normals.

Winds shift to W as the front exits late Wed into Wed night,
bringing yet another shot of colder air from central Canada.

Thanksgiving and Friday...Moderate to high confidence.
High pressure sets up from New England southwestward through
the Ohio Valley into the mid Mississippi Valley by midday
Thanksgiving day, then slowly shifts S Thu night and Friday.
Models trying to bring another low toward the region from
Manitoba and western Ontario late Friday, but model solution
spread on timing and track of this system. Have kept a dry but
cold forecast going through Black Friday.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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.

Through 00z...VFR. Any lingering MVFR on the Cape/ACK will
quickly improve to VFR as skies clear. W/NW gusts 30-40 kt.
Gusts to 45 kt possible higher elevations.

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: VFR. Windy with local gusts to 30 kt. Chance
SHRA.

Wednesday: VFR. Chance SHRA.

Wednesday Night: VFR. Breezy.

Thanksgiving Day: VFR.

&&

.MARINE...
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/...

Moderate to high confidence.

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

Tuesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas. Chance of rain
showers.

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

Wednesday Night through Thanksgiving Day: Winds less than
25 kt. Areas of seas approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 8 PM EST this evening for CTZ002>004.
MA...Wind Advisory until 8 PM EST this evening for MAZ002>024-026.
RI...Wind Advisory until 8 PM EST this evening for RIZ001>008.
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.

&&

$$
SYNOPSIS...KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...EVT
AVIATION...KJC/EVT
MARINE...KJC/EVT


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