625
FXUS61 KBOX 101851
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
251 PM EDT Sun Aug 10 2025

.SYNOPSIS...
High pressure off the coast will bring increasing heat and humidity
through mid week, but it will not be as oppressive as it was earlier
in the summer. An isolated thunderstorm is possible late Wednesday
across western portions of MA and CT. Then not as hot Thursday,
along with scattered showers or thunderstorms, as a cold front moves
through. Drier weather follows Friday into next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
130 PM update...

Key Messages:

* Warmer this afternoon with some 90 degree highs inland

Rest of Today...

Beautiful summer afternoon in progress, with temps warming thru the
80s, except 70s along the immediate coast and islands, in response
to cooler onshore flow. Some inland locations will approach 90 later
this afternoon, with temps aloft of +23C at 925 mb and +17C at 850
mb. Humidity levels are tolerable for this time of year, with dew
pts in the upper 50s to low/mid 60s.

Tonight will feature clear skies once again, with patchy fog in
valleys and near Cape Cod/Islands. Some low clouds may impact the
outer Cape and islands at times overnight. Given the radiational
cooling conditions, the lower MOS mins look more reasonable than the
NBM. Also, given the modest dew pts, still cool-ish tonight with
lows mainly in the 60s, upper 50s in the cooler inland valleys and
closer to 70 in Boston.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
130 PM update...

Key Messages:

* Increasing heat and humidity Monday, but probably just shy of Heat
  Advisory criteria

Monday...

Upper ridge continues to dominate yielding abundant sunshine.
Increasing SW flow brings somewhat more humid air into region, but
not as oppressive as what we experienced earlier in summer. Also,
with solar summer behind us (90 days of highest sun angle from early
May to early Aug), the heat is not as intense as June and July. In
addition, gradient remains weak enough to allow for some relief
along both coasts, in the form of afternoon sea breezes. Thus,
despite the combination of highs in low to mid 90s inland and
dewpoints climbing into mid 60s, the heat index likely remains
headline criteria. Therefore, given the marginal heat conditions and
other factors mentioned above, we will hold off on heat headlines
for now. Better chance looks to be Tue and especially Wed, when
humidity increases further.

Monday night...deep layer ridge continues to provide quiet/tranquil
weather conditions. Slightly higher dew pts may yield a bit more
patchy fog and low clouds, especially coming onshore to the south
coast. Seasonably mild with lows in the 60s, a few upper 50s
northwest MA and around 70 in Boston. Winds light and variable.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Key Messages:

* Heat with moderate humidity peaks Wednesday

* Possible showers/storms in the evening Thursday associated with
  passing cold front

* Cooler Friday into the weekend

An upper level ridge`s influence continues through at least
Wednesday along with SW flow, maintaining the elevated heat over
southern New England. It still appears we will remain marginal for
Heat Advisory criteria at this time, as highs in some spots in
the valleys reach 95F Tuesday and Wednesday. Dew points are not
expected to be as oppressive as they were earlier in the summer;
only reaching the 60s rather than climbing into the 70s.

Heat is expected to peak on Wednesday ahead of a cold front passing
through the region. Increasing cloud cover and the chance for
some showers and storms will move in heading into the evening
hours, especially over western MA into CT. Chances for scattered
showers and storms will remain through Thursday as this front
moves through. Timing for any precipitation remains in a broad
window looking at the ensembles, and there is still quite a bit
of disagreement across the deterministic guidance, too. Temps
will be cooler post-frontal passage for Friday heading into the
weekend and dry conditions will make a return as surface high
pressure and upper level ridging build back in.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

18z TAF Update: High confidence.

VFR, aside from local MVFR/IFR vsbys possible due to patchy fog
across interior valleys and near Cape Cod and Islands late
tonight. Light S/SW winds expected with sea breezes along both
coasts today and Mon.

KBOS terminal...High confidence in TAF.

KBDL terminal...High confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday through Tuesday Night: VFR.

Wednesday: VFR. Breezy. Slight chance SHRA.

Wednesday Night through Thursday: VFR. Breezy. Chance SHRA,
slight chance TSRA.

Thursday Night: VFR. Slight chance SHRA.

Friday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

130 PM update...

High confidence through the period.

Weak gradient will allow for sea breezes near shore through at least
Monday night, before high pressure offshore brings SW flow
thereafter. Winds and seas should remain below SCA levels.
Patchy fog may limit visibility later at night and early in
morning.

Outlook /Tuesday through Friday/...

Tuesday through Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Seas locally
approaching 5 ft. Slight chance of rain showers.

Thursday: Winds less than 25 kt. Chance of rain showers.

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

Friday: Winds less than 25 kt.

&&

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

&&

$$

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