Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 231145
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
645 AM EST Sat Feb 23 2019

.SYNOPSIS...
High pressure over the Great Lakes builds into New England
today, then moves offshore this evening. This will bring a
period of dry and seasonably cool weather to the region. Low
pressure then tracks along the coast Sunday with a wind-swept
rain, except freezing rain/ice for the interior Sunday morning.
Strong to damaging winds develop Sunday night, peaking around
Monday, then gradually diminishing into Tuesday. A mostly quiet
week thereafter, watching a potential storm for next weekend.

&&

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

645 am update...

Forecast on track. Adjusted temperatures down a bit to account
for more radiative cooling over the northern portions of
forecast areas where high clouds were less widespread. Satellite
showes cirrus clouds continuing to spill over the ridge ahead of
tonights system...these should continue through the day; better
chance for clouds over the southern portion of the CWA, with
more clearing likely to the north.

Previous Discussion...

High pressure moving across southern New England today will
result in rather light winds. Other than some higher level
clouds at times, dry weather will continue. Near normal high
temperatures.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Looking at another round of wintry mess late tonight into
Sunday. the biggest threat will be from freezing rain, although
there could be some light snow or sleet at times, too. Have
posted a Winter Weather Advisory where we have the greatest
confidence in light icing. Most areas should see up to a tenth
inch of icing, but could see up to two tenths towards NW MA,
where icing should persist longer. It`s possible this advisory
could be expanded, should confidence in freezing rain increase
farther south and east.

Eventually warm air will win out, transitioning all
precipitation to simple rain across all of southern New England.
This rain should then persist though most of Sunday morning,
then gradually end from SW to NE during Sunday afternoon.

Winds increase late tonight into Sunday as a secondary low
pressure passes by. Gusty winds should be confined to the
immediate coast, including the Cape and islands, through Sunday.

With lots of clouds and an increasing SE to SW flow,
temperatures should remain above normal through this period.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
*/ Highlights ...

- Strong, damaging winds starting Sun night, peaking Mon
- Low confidence in wet weather potential mid week & next
  weekend

Sunday night through Tuesday...

Strong and potentially damaging winds move in starting Sunday
night, peaking during the day Monday, and diminishing through
the day Tuesday. As the low strengthens over southeast Canada
it drags a cold front through southern New England late Sunday
as the mid level trough and cold pool moves overhead. Post-
frontal winds turn out of the WNW and begin to increase as the
pressure gradient tightens on the back side of the low. Between
the deepening low and incoming high pressure this gradient
tightens bringing sustained winds up mainly after midnight and
peaking Monday afternoon 25-35 mph. At the same time good CAA
aloft will promote very efficient mixing up to 700-800 mb
depending on the guidance. Either way model soundings indicate
potential for damaging wind gusts to mix down from a 55-60 kt
850mb jet. Expecting fairly widespread Wind Advisory criteria
with gusts of 50-55 mph. Certainly possible we could reach High
Wind Warning criteria in the Berkshires and along the coastline
with gusts approaching 60 mph. A Gale Watch is in effect over
the waters, but it may well be upgraded to a Storm Watch soon.
Potential impacts include power outages and downed limbs/trees.
After Monday afternoon/evening winds decrease through the night
into Tuesday but will still be gusty given continued efficient
mixing; likely we`ll see gusts 35-40 mph through Tuesday
afternoon. High temperatures drop ~10 F on Tuesday, into the
upper 20s which, with gusty winds will feel like teens to single
digits.

Wednesday through Friday...

Mid level flow remains rather zonal across the CONUS for much of
late week. While models show little agreement in details beyond
Friday, no very big or impactful storms are likely. High
pressure crests on or about Wednesday with dry weather
persisting. Beyond that the GFS brings a weak clipper-like
system through Wednesday night while the EC keeps any wet
systems out of SNE through the rest of the week, so trending the
forecast to a drier EPS solution. Focus then shifts to late next
weekend and another potential wet system.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

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

Today...VFR. Light NW winds becoming variable during the
morning as high pres moves overhead.

Tonight...VFR with dry weather through this evening, then
becoming MVFR with precipitation after midnight from west to
east. Mainly rain, except for a period of wintry mix across the
interior. LLWS likely toward 12z Sunday morning along the south
coast, including Cape Cod and Islands.

Sunday...MVFR/IFR conditions. Windy with areas of gusts up to
30 kt. RA ending, with some FZRA possible in the early morning
across the interior. LLWS likely.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR. Strong winds with gusts up to 45 kt. Slight
chance RA.

Monday: VFR. Strong winds with gusts up to 50 kt.

Monday Night: VFR. Strong winds with gusts up to 45 kt.

Tuesday: VFR. Windy with gusts up to 35 kt.

Tuesday Night: VFR. Windy with gusts up to 30 kt.

Wednesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

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

High pressure builds across the waters today, then moves east
of the waters tonight. SE winds increase as a secondary low
pressure moves across southern New England on Sunday. Vsby
lowering in rain late tonight through Sunday morning. Some
improvement in visibility in the afternoon, although winds
likely to remain gusty. Could see gale force gusts across the
eastern coastal waters Sunday.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Moderate risk for gale force winds with gusts up
to 45 kt. Rough seas up to 15 ft.

Monday: Moderate risk for storm force winds with gusts up to
50 kt. Rough seas up to 17 ft.

Monday Night: Moderate risk for gale force winds with gusts up
to 45 kt. Rough seas up to 15 ft. Chance of freezing spray.

Tuesday: Moderate risk for gale force winds with gusts up to
35 kt. Rough seas up to 11 ft. Chance of freezing spray.

Tuesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas. Chance of freezing
spray, slight chance of snow.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Seas locally approaching 5 ft. Chance of freezing
spray, slight chance of snow.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Weather Advisory from 1 AM to 6 AM EST Sunday for
     MAZ010>012.
     Winter Weather Advisory from 1 AM to 9 AM EST Sunday for
     MAZ004-005-008-009-026.
     High Wind Watch from Sunday evening through Monday evening for
     MAZ002-008-009.
     Winter Weather Advisory from 1 AM to 11 AM EST Sunday for
     MAZ002-003.
RI...None.
MARINE...Storm Watch from late Sunday night through Monday evening for
     ANZ231>235-237-254>256.
     Gale Watch from late Sunday night through late Monday night
     for ANZ230-236.
     Storm Watch from Monday morning through late Monday night for
     ANZ250-251.

&&

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


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