Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 150321

Area Forecast Discussion
National Weather Service Taunton MA
1021 PM EST Tue Feb 14 2017


Quiet and dry weather tonight. Another storm center develops
Wednesday into Wednesday night across the Gulf of Maine, bringing
a period of rain and/or snow to much of the region. The low will
be in the Canadian Maritimes Thursday and Friday, bringing mainly
dry but blustery and cold weather to the region. Dry weather
continues this weekend, but with a significant moderation in
temperatures especially by Sunday when much of the region may
see highs exceeding 50.



10 pm update...

Clouds thickening ahead of both N and S stream energy as light S
winds prevail. Low level moistening per increasing SW-fetch with
a warm-nose intrusion around H925 ahead of increasing QG-forcing
and diffluence aloft, growing values of omega within the mid- to
upper-levels. However the breadth of the column remains fairly
dry while the magnitude and depth of omega (lift) is in question.
Better forcing mechanisms, such as the cold front associated
with the N-stream impulse, reside to the W by daybreak. Yet
there is some indication of some low-level convergence per
H925-85 S/SW winds. Can`t rule out a spot shower but believe
it`ll be quiet and dry through daybreak.

As for temperatures, clouds, light S winds, not much opportunity
for radiational cooling as we saw last night. Lean warmer to the
W with mid to upper 20s, while cooler N/E with low 20s to teens
given the synoptic setup. Lows reached around midnight and then
holding steady into morning as all of S New England should be
beneath a blanket of clouds with increasing onshore S/SW winds.



Wednesday and Wednesday night...Moderate confidence.

A lot of questions in play during this timeframe. Models have
varying solutions in handling development of secondary low
pressure tracking NE out of the Carolinas to the E coast during

Noting decent short wave in the southern stream flow moving off
the Carolinas, hooking up with a strong northern stream H5
short wave. Models starting to merge the two waves as they move
off the New England coast. In the meantime, surface low moves
near or just S of the 40N/70W benchmark by around 00Z Thu. With
this low moving NE, rounding the developing cutoff H5 low, looks
like an inverted trough may try to set up somewhere across the
region. Each model in the suite has its own solution, anywhere
from across E Mass/SE NH to the SW Maine coast early Wed night.
Noting the surface low moves to the Gulf of Maine and deepens
rapidly overnight.

Big question at this point will be whether the inverted trough
tries to wrap around this developing low SW of Nova Scotia back
into NE and N Central Mass, bringing some more decent snowfall
late Wed and Wed night, or if the low will continue to track
into the Maritimes.

At this point, will see best chance for precip during the day
Wed, but milder air will work in on southerly winds, temps will
top off in the upper 30s to lower 40s across the coastal plain
allowing any snow will change to rain. Across inland areas, will
see snow and/or rain, especially across the higher terrain.
With lowering rain/snow ratios, only expecting light snow
accumulations. As the low moves offshore, winds shift to W and
colder air will cause the precip to change back to snow but
again, should be light amounts depending upon the ultimate
solution to this weather scenario.

Have carried best chance for precip near and N of the Mass Pike
Wed night, leaning toward a bit further N solution with the
inverted trough set up, for now. Winds will shift to W and
increase as strong low level jet passes. Could see gusts up to
around 25 kt across the higher inland terrain mainly after
midnight, and possibly up to 30- 35 kt across Cape Cod and the
islands. Expect temps to fall back through the 20s to around 30.




* A few snow showers possible Thu...otherwise dry into Mon
* Blustery and cold Thu into Fri
* Moderating temps Sat and unseasonably mild by Sun
* Above normal temps continue into early next week



Rapidly intensifying low pressure will be already lifting into
the Canadian Maritimes Thursday morning. While the inverted
trough axis extending back from the storm will have weakened,
left over low level moisture coupled with shortwave energy/cold
pool aloft may result in a few snow showers. Highest risk will
be in northern and eastern MA, where better low level moisture
will exist.

Otherwise, the majority of the day will be dry but strong cold
advection behind the system will keep highs in the 30s.
Northwest wind gusts of 25 to 35 mph are also expected with good
mixing in the cold air advection pattern.

Thursday night and Friday...

Strong low pressure over the Canadian Maritimes will only
slowly lift northeast as a weak ridge of high pressure
approaches from this midwest. This should result in mainly dry
but cold and blustery weather across the region Thu night/Fri.
Low temps Thu night mainly in the teens to lower 20s. Highs on
Thu generally in the lower to middle 30s.

Saturday and Sunday...

Upper trough moves northeast of the region allowing for rising
height fields and more zonal flow. So while it will remain dry,
the result will be much milder air overspreading the region from
the west. High temps should recover into the upper 30s to lower
40s on Saturday, but by Sunday expect highs to break 50 across
much of the region.

Monday and Tuesday...

A backdoor cold front will bring a bit cooler temperatures on
Monday, but highs will still probably reach well into the 40s
with above normal temps continuing into early next week. A
shortwave may bring a few showers to the region Tuesday
afternoon/night, but best forcing/dynamics will probably pass to
our north and west.



Forecaster Confidence Levels...

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

Short Range /through Wednesday night/...

Tonight...Moderate confidence.
VFR with increasing low-end VFR cigs. MVFR may arrive into W
terminals close to daybreak. Will keep it dry. Increasing S/SW

Wednesday...Moderate confidence.
MVFR-IFR. Areas of -RA and/or -SN. Best chance IFR with -SN
across central/N/NE MA with mainly -RA elsewhere, especially
over S/SE MA and RI. Precipitation beginning around 16-18z. S
winds initially with gusts 20-25 kts over Cape and Islands prior
to shifting W afternoon into evening.

Wednesday night...Moderate confidence.
Precip changes to -SN before tapering off across N CT / RI / SE MA.
-SN lingering near and N of the MA Pike, especially NE MA extending
to the outer Cape. Areas of MVFR-IFR with -SN into morning. W winds
gusting to around 30 kt across Cape Cod and the islands around or
after midnight.

KBOS TAF...Moderate confidence in TAF.

KBDL TAF...Moderate confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday...Moderate confidence.  Some MVFR ceiling along with a few
snow showers remain possible particularly across northern and eastern
MA into Thu afternoon.  Otherwise, northwest wind gusts of 20 to 30
knots expected.

Friday through Sunday...High confidence in mainly VFR



Forecaster Confidence Levels...

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

Short Range /through Wednesday night/...

Moderate to high confidence.

Tonight...Expect W-SW winds around 10 kt, backing to S after
midnight. Seas remain at or above 5 ft across the eastern open
waters to S of Nantucket where small crafts continue. May see
local visibility restrictions toward daybreak in patchy light

Wednesday...S-SE winds gusting up to 25 kt by mid-late morning,
strongest across the eastern waters. Winds shift to W across
the southern waters during the afternoon. Seas build up to 6-10
ft by midday. Visibility restrictions in light rain and/or snow.

Wednesday night...Winds shift to W in the evening on the
eastern waters. Winds gusting up to 25-35 kt around or after
midnight. Have issued Gale Watch on the outer waters as well as
Cape Cod Bay, Rhode Island/Block Island and Nantucket sounds.
Visibility restrictions in lingering light snow mainly across
the eastern waters to Cape Cod.

Outlook /Thursday through Sunday/...

Thursday and Thursday night...Moderate to high confidence.  Cold
advection will result in northwest wind gusts of 30 to 35 knots Thu
into Thu night so Gale Watches will be issued. The airmass will
be cold enough to support some light freezing spray late Thu

Friday...Moderate to high confidence.  While pressure gradient
weakens a bit, still expect northwest wind gusts of 20 to 30 knots
and small craft headlines will be needed for most waters.

Saturday and Sunday...Moderate to high confidence.  Weak pressure
gradient should keep winds and seas generally below small craft
advisory thresholds.



MARINE...Gale Watch from late Wednesday night through Thursday morning
     for ANZ231-232.
     Small Craft Advisory until 6 PM EST Wednesday for ANZ231-250-
     Gale Watch from late Wednesday night through Thursday evening
     for ANZ235-237.
     Gale Watch from Wednesday evening through Thursday evening for



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