-- Discussion containing changed information from previous version are highlighted. --
724
FXUS61 KBOX 280749
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
349 AM EDT Sat Jun 28 2025

.SYNOPSIS...
High pressure begins to move further east of the Gulf of Maine
heading into Saturday morning, diminishing onshore breezes. A
warm front lifts north Saturday along with a risk for showers
and thunderstorms. Seasonably warm and dry for Sunday.
Temperatures then warm up into the mid to upper 80s again early
next week. Primary chance for precipitation next week falls on
Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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Key Messages:

* Few showers and fog this morning. Will have a dry afternoon for
  the most part with partial sunshine west and mostly cloudy skies
  east.

* Slightly below normal temperatures this afternoon.

* Isolated severe weather threat late this afternoon across western
  parts of MA and CT.

Location of the warm front early this morning is southwest of us and
it is anticipated to move northeast towards southern New England by
sunrise. Front lifts with WAA showers the first-half of the morning.
Front settles to the north in central New England with our area well
inside of the warm sector. Anticipate winds from the south/southwest
and milder temperatures. Used a blend of the high-res guidance, such
as the HREF, CONSShort, and HRRR to derive todays max temperatures.
Despite good amount of cloud cover, will warm into the 70s for most
and the lower Connecticut River Valley closes in on 80F.

There will be low stratus and patchy areas of fog/drizzle as higher
dew points advect in from the south, nearing 70F. Areas that have
the greatest chance for patchy fog will be the south coast and those
across eastern CT, RI, and eastern MA. As temperatures increase late
this morning will see improvements, but they are subtle. Today is
not a washout, much of this afternoon is expected to be dry, with
more breaks in the clouds across southwestern New England, which
could ended up becoming a mixture of sun and clouds. While the
further east you are located, more in the way of clouds and only a
few breaks of sunshine. A cold/cool front approaches late today and
brings a few more showers and thunderstorms post sunset.

Bottom line, not expecting widespread severe storms this afternoon
across southern New England. What we do anticipate isolated severe
thunderstorms with primary hazard of damaging straight-lined winds.
Which is highlighted by the Marginal Risk from SPC, expanded into
far western MA and northern Connecticut, west of the CT River. Thus
the area greatest risk is the Connecticut River Valley and areas to
the west. Suspect the Hudson Valley region of New York to have the
better chance for storms, as there will be better destabilization
with clearing skies. Nevertheless, mean CAPE ~ 1,500 J/kg and shear
of 30 knots across western MA and northern CT, based on the 00z run
of the HREF. The lacking factor, best forcing doesn`t arrive until
00z/8pm or just after sunset. CAMs do show a line of storms firing
off after 21z/5pm across eastern New York, but the overall theme is
for the line to decay as it reaches western areas of southern New
England.

We will continue to monitor developments throughout the day but do
want to take a moment to echo the importance of being weather aware
and a thunderstorm doesn`t need to become severe to be deadly as
lightning can occur without a storm reaching severe limits, also if
you can hear thunder you are close enough to be struck by lightning.

Cold front moves east overnight, showers and few rumbles of thunder
are possible, though the severe threat has ended. Wind shifts from
the southwest to northwest, bringing in a drier airmass and clearing
skies. Tonight low temperatures settle in the upper 60s. As the
front is slow to clear the coastal plain, fog redevelops overnight.
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&&

.SHORT TERM /SUNDAY/...
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Key Messages:

* Gorgeous conditions on tap for Sunday, plenty of sunshine, and
  seasonably warm temperatures.

Fairly quiet weather for Sunday as the cold front shifts off shore
and northwest flow ushers in a drier albeit warmer airmass. Surface
high pressure begins to build into the northeast, which will remain
in the area through Monday. Have subtle mid-level height increases
as well, leading to a dry and mostly sunny afternoon. With the 925mb
temperatures on either side of +20C, maximum temperatures will
reach the lower and middle 80s. Dew points are manageable in the
upper 50s across the interior, while the coastal plain are in the
lower and middle 60s.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Key Messages:

* Summertime Warmth for most of the week
* Showers and thunderstorms Tuesday

Large scale zonal flow across the northeast will be in place for
much of the week. A short wave embedded in the flow will move across
the region on Tuesday. That will be the primary opportunity for
precipitation for the week.

Warm temperatures:  850mb temperatures will fluctuate between 15-18C
for most of the week, and these values are roughly 2-5C above
normal. That translates to warmer than normal temperatures with
daily highs well into the 80s, with some lower 90s in the mix as
well. Although this heat will be nowhere near what we experienced
earlier this week. Currently Monday is showing the highest chance of
exceeding 90F, with most inland areas (except the higher elevations)
likely topping out in the lower 90s. Winds look light enough for a
sea breeze to form along the immediate east and south coastal areas
to temper the heat a bit. Temperatures aloft are higher on Tuesday,
but more clouds and showers/t-storms should keep highs a few degrees
cooler, though on the other hand, dewpoints will be highest this day
(push 70F), so it will feel several degrees warmer because of that.
Dewpoints drop for Wednesday and Thursday after a "cool" front moves
through, but with sunny skies, we will remain warm. NBM
probabilities of seeing 90F or higher range from 50-85% across
interior lower elevations both days, so barring significant pattern
change, I`d think our max temperature forecasts will trend slightly
upward in the coming days.  Luckily dewpoints will be on the lower
side, so it won`t feel overly humid. Friday has a bit more
uncertainty, some suggestions that heights aloft decrease a bit
and along with that, temperatures also lower. Probability of
seeing 90F+ on Friday decrease to 20-50% across the interior.

Tuesday Thunderstorms: Global models are in general agreement with
swinging a shortwave across the region, and generating surface CAPE
over 1000 J/kg, with about 20% of the members having over 2000 J/kg
of CAPE. That`s pretty decent. GFS has about 30kt of 0-6km shear as
well. Just based on those quick looks, it would seem that there is a
possibility of stronger t-storms Tuesday. 00z CSU Machine Learning
guidance paints in about a 10% chance of severe weather Tuesday. Of
course, the devil is going to be in all of the details, including
timing of the shortwave, and with this being 4 days out, it`s far
too early to decide on any specific details, but we will monitor
trends in guidance in the coming days. Additionally, precipitable
water values should be reaching over 2.0", and that suggests the
potential for some local heavy rain as well.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
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Forecaster Confidence Levels...

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

Through 12... Moderate Confidence.

Generally VFR across the region, although MVFR ceilings will begin
to develop across CT sometime in the 06-08z timeframe and spread
northeast. Believe by 10-12z, those lower ceilings will have reached
BOS. Could see some light showers develop closer to 12z.

Today... Moderate Confidence.

Expecting widespread MVFR to IFR conditions with spotty light
showers. Much of the guidance suggests IFR ceiling and visibilities
pretty much everywhere the entire day, but continue to believe that
guidance is too pessimistic and conditions will improve to MVFR in
the 17-19z timeframe. Could even be a few spots with VFR. Late in
the day, generally after 22z, scattered TSRA are expected to move
into far western New England. Have included a PROB30 at BDL and BAF
for that potential. Quite a bit of uncertainty with regard to timing.

Tonight... Moderate Confidence.

Any TSRA should dissipate as they move eastward, and believe any
threat of precipitation will basically come to an end 05-07z. A weak
front will also be pushing through the region, and that will produce
a wind shift to the W/NW and conditions IFR/MVFR begins to improve
to VFR from west to east.

Sunday... High Confidence.

Early morning MVFR/IFR may linger cross the Cape and Islands through
13-15z, otherwise, VFR. Northwest wind 8 to 12 knots, winds aloft
are weaker, could lead to a sea breeze for eastern MA terminals, ie,
BOS. Cape Cod and Islands remain with a WSW wind 10 to 15 knots.

KBOS Terminal...Moderate confidence in TAF. MVFR/IFR much of
Saturday, but the afternoon may end up with far better conditions
than currently in the TAF.

KBDL Terminal...Moderate confidence in TAF. Expect conditions to
improve to VFR for mid-afternoon, although timing of any TSRA late
in the day is still rather uncertain.

Outlook /Sunday Night through Wednesday/...

Sunday Night through Monday: VFR.

Monday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, isolated TSRA.

Tuesday: Mainly VFR, with areas MVFR possible. Breezy. Chance
SHRA, isolated TSRA.

Tuesday Night: VFR. Breezy. Chance SHRA, isolated TSRA.

Wednesday: 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.

Today and Tonight... High Confidence.

A warm front lifts across the waters this morning with increasing
southerly winds, gusts remain below 20 knots and seas are 3 to 4
feet, thus no Small Craft Advisory will be needed. As the front
lifts north this morning, higher humidity will lead to areas of
marine stratus and fog, leading to patchy areas of reduced
visibilities. Tonight into Sunday morning a cold front will push
across the waters with hit-or-miss showers and thunderstorms. The
front slowly clear the eastern waters Sunday morning, but areas of
marine fog could remain until the front completely clears the
coast.

Sunday... High Confidence.

High pressure builds in for Sunday with northwest winds across the
eastern waters and west/southwest winds across the southern waters.
Cannot rule out a seabreeze, easterly wind, developing on Sunday for
the eastern coast of Massachusetts.

Outlook /Sunday Night through Wednesday/...

Sunday Night through Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Slight chance of rain
showers, isolated thunderstorms.

Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Chance of rain
showers, isolated thunderstorms.

Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers, isolated thunderstorms.

Wednesday: Winds less than 25 kt. Areas of seas approaching
5 ft.
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&&

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

&&

$$

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