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739
FXUS61 KBOX 310704
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
304 AM EDT Fri May 31 2024

.SYNOPSIS...

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Expanding high pressure brings sunny and warm conditions both
Friday and Saturday, although a few showers are possible Sunday
afternoon and evening in the west. Mainly dry and warm weather
is expected through mid to late next week as high pressure is in
control. Rain chances return late in the week.
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&&

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

* Warm, mostly sunny, with a breezy northwest wind.

Gorgeous day ahead, mid-level ridging off to our west with a surface
high pressure expanding across the Ohio River Valley. Starting of
cool if not chilly for some. While many spots are in the low 50s and
upper 40s, parts of far northwest MA are nearing 40 degrees. Outside
of a few clouds, a mainly clear start with widely isolated radiation
fog in typical areas - no real impact to the morning commute.

Trough exits east of New England this afternoon, weak shortwave with
it and PWATs around 0.6 and 0.8 should be enough to develop some
cloud cover, but do not expect to be a "cloudy" type of day. There
is a VERY low chance for an isolated shower, but given how high the
cloud bases are, around 10k ft, these should produce nothing more
than a light shower focuses mainly from Cape Ann to Cape Cod and the
Islands.

Deep mixing of the boundary layer today, some guidance in BUFKIT
suggests the boundary layer extending 800mb/700mb. This taps into
the drier air and mixes down lower dewpoints. Dewpoints are in the
upper 30s to low 40s. This leads to a warm afternoon with no
humidity, highs are expected to be in the lower to middle 70s, with
the CT River Valley in the upper 70s. NW winds this afternoon are
breezy, gusts 15 to 20 MPH.

Whether a seabreeze develops or not is tough, have opt to hold back
on this across eastern MA given BUFKIT profile soundings do not
really support the flip over along the eastern coast. Could see more
of a SW wind develop along the south coast of MA and RI, leading to
more of a seabreeze. Areas from Westerly to Newport likely are tad
cooler around 70 to 72 degrees.

But over all, a stunner of a Fri-Yay!
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...

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Tonight: Winds ease overnight with high pressure firmly in control
along with clearing of those afternoon clouds. Winds should remain
steady enough overnight, precluding any radiational cooling. Lows
are generally in the low and middle 50s, higher terrain of NW MA in
the low and middle 40s. Will say, if winds trend weaker overnight
could have a similar night to the previous with lows more towards
the 40s and low 50s.

Saturday: The mid-level ridge shifts east, centered over northern
New York and surface high pressure to our southwest. The flow aloft
is northwest and should promote mainly sunny conditions, downsloping
and warmer temperatures for the afternoon. Highs are in the upper
70s to low 80s, likely a few degrees cooler from the tip of Cape Ann
and Cape Cod with a NNW wind. Still fairly low dewpoints, a tad
higher than Friday, but still comfortable in the mid 40s to 50
degrees. Winds are around 10 to 15 MPH.
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&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
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Key Points...

* High pressure supports warm/dry weather through mid to late next
  week

* Low chance for some afternoon showers across western MA/CT Sunday
  afternoon

Details...

Quiet and mostly dry weather is the story for most of the extended
forecast period thanks to expansive mid level ridging over southern
New England on Sunday which rebuilds on Tuesday/Wednesday. This
broad ridge and associated surface high will keep widespread rain
chances out of the forecast through at least mid week. The one
exception will be Sunday night into Monday as a weak shortwave drops
into the northeast bringing a plume of moisture and associated rain
showers with it. Thinking continues to be that high pressure will
steer this disturbance southwest of the region, so the best rain
chances will be over CT and coastal RI. Beyond that, our next
widespread rain chances come around Thursday or Friday as the ridge
begins to break down with the arrival of a trough which digs into
the Great Lakes during the latter half of the week. Confidence on
when this rain arrives and who sees the most is low at this distance
in time. Temperature-wise the airmass overhead will remain
essentially unchanged with 850mb temps on either side of 10C which
will correlate to highs in the upper 70s/low 80s and lows in the
50s.
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&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
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Forecast Confidence Levels:

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

06Z TAF Update: Overall high confidence, with low confidence in
development of seabreeze this afternoon

Today... High confidence.

VFR and dry. NNW winds 8-12 kts, gusts 18-22kts between 17z and
23z.

Tonight... High confidence.

VFR. Low chance of radiational fog to development for prone sites.
Light NW wind overnight, some site becoming calm.

Saturday... High confidence.

VFR and dry. NNW winds less than 10 knots. Could see a seabreeze
develop along the coast.

KBOS TAF... Overall high confidence, with low confidence in the
development of a seabreeze today. Overnight guidance suggests winds
aloft will be strong enough to preclude the development of the
seabreeze. Otherwise, VFR and dry for the TAF period. Period of
gusty NNW wind between 16z and 21z.

KBDL TAF... VFR, dry, breezy NW winds.

Outlook /Saturday Night through Tuesday/...

Saturday Night through Sunday: VFR.

Sunday Night: VFR. Slight chance SHRA.

Monday through Tuesday: VFR.
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&&

.MARINE...
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Forecaster Confidence Levels:

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

Friday into Saturday...

Tranquil boating conditions with surface high pressure building over
the waters into Saturday. There remains a very low risk for a widely
isolated shower this afternoon, otherwise dry conditions prevail.
Winds are light and from the north, but become southwest, for a time,
as weak surface trough moves over the waters. Winds return to
northwest direction tonight. Saturday the wind over the southern
waters are west/southwest while eastern waters are west/northwest.
Wind speeds and waves remain below SCA criteria, winds are 10-15
knots with localized gusts near shore to 20 knots, seas are 1-2ft
near shore and 2-3ft off shore.

Outlook /Saturday Night through Tuesday/...

Saturday Night through Sunday: Winds less than 25 kt.

Sunday Night: Winds less than 25 kt. Slight chance of rain
showers.

Monday through Tuesday: Winds less than 25 kt.
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&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...BW/Dooley
NEAR TERM...Dooley
SHORT TERM...Dooley
LONG TERM...BW
AVIATION...BW/Dooley
MARINE...BW/Dooley