647
FXUS61 KBOX 272334
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
734 PM EDT Fri Jun 27 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 /UNTIL 6 AM SATURDAY MORNING/...
Key Messages:

* Quiet through tonight with onshore winds

Cloud cover increases tonight as a warm front approaches and the
region falls under its warm sector. Some scattered showers are
possible heading into the morning, but primarily dry conditions
aside from some fog are expected tonight. Winds from the east will
shift more southerly as the warm front moves in. Lows will be in the
upper 50s and low 60s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Key Messages:

* Warm and cloudy with breaks of sunshine across southern New England

* Showers and storms associated with a passing cold front possible
  in the afternoon hours

High pressure that`s been sitting over the Gulf of Maine will shift
off to the east Saturday morning, leading to an end of easterly
winds across the region. A warm front moves up into the region,
introducing southerly flow. This warm front is now expected to sit
just past the northern MA border; temperatures north of this front
are expected to be more in the upper 60s/low 70s, while areas south
of it are expected to be more in the upper 70s/low 80s. If this
front ends up not moving that far north, there`s a chance tomorrow`s
highs across southern New England end up much cooler than expected,
as we will end up still in the airmass that will dominate to our
north.

After sitting in the warm sector, a cold front is expected to move
through the region. Showers and thunderstorms will be possible
as a result. A Marginal risk for severe weather is set over
parts of western MA and CT, but even then, the lower Hudson
Valley is more likely to see severe weather. The window for
storm development is smaller as the primary forcing from the
cold front does not arrive until the late afternoon, but some
stronger storms cannot be ruled out and may end up affecting
outdoor plans. The front will shift winds more to the west
overnight and clear out the stratus from the warm sector heading
into Sunday morning. Lows Saturday night are expected to be in
the lower to mid 60s across the interior and the upper 60s/low
70s east of Worcester and in southern parts of the CT Valley.

&&

.LONG TERM /SUNDAY 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 /00Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

00z Update

Overall moderate confidence.

Tonight - 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 12z, those lower
ceilings will have reached BOS. A few light sprinkles in western
MA through 01z that won`t impact any TAF location. Could see
some light showers develop closer to 12z.

Saturday - no big changes to the previous forecast. 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.

Saturday Night - Any TSRA should disipate 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 improving to VFR.

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 through Wednesday/...

Sunday through Monday: VFR.

Monday Night: VFR. Breezy. Slight chance SHRA, slight chance
TSRA.

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

Tuesday Night: VFR. Breezy. Chance SHRA, slight chance TSRA.

Wednesday: Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Tonight through Saturday Night: Northeast to east wind range
from 15 to 25 knots, with waves 3-5 ft through tonight. The
strongest winds and highest seas over the southern outer waters,
a SCA continues through today on the southern outer waters,
though conditions are somewhat borderline. Mainly dry weather,
although could see some passing showers tonight. Late tonight
wind shifts from the southeast to south with speeds 15 knots and
gusts to 20 knots. Seas are 3 to 4 feet.

Outlook /Sunday through Wednesday/...

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers, patchy fog. Areas of visibility
1 to 3 nm.

Sunday Night through Monday: Winds less than 25 kt. Patchy fog.
Areas of visibility 1 to 3 nm.

Monday Night: Winds less than 25 kt. Slight chance of rain
showers, patchy fog. Areas of visibility 1 to 3 nm.

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas locally approaching 5 ft. Chance of
rain showers, slight chance of thunderstorms, patchy fog. Areas
of visibility 1 to 3 nm.

Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas locally approaching 5 ft. Chance of
rain showers, slight chance of thunderstorms, patchy fog. Local
visibility 1 to 3 nm.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ255-
     256.

&&

$$

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