689
FXUS61 KBOX 040613
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
213 AM EDT Fri Sep 4 2026

.WHAT HAS CHANGED...
No significant changes to the forecast.

&&

-  Mainly dry and pleasant today and Saturday with a chance for
   some isolated showers Saturday afternoon.

 - Cooler weather this weekend into early next week gives way
   to a warming trend and the chance for unsettled weather by
   mid week.

-  Dangerous conditions at the beach for the holiday weekend
   with as the rip current risk increases Sunday and Labor Day.

&&

.DISCUSSION...
KEY MESSAGE 1. Mainly dry and pleasant today and Saturday with a
chance for some isolated showers Saturday afternoon.

Looking drier and mild over the next couple of days as broad NW flow
around a closed low advects a lower PWAT airmass into the region.
PWAT values fall below 1.00" by this afternoon into Saturday.
Despite the overall drier airmass, a broad cutoff low over the
Canadian Maritimes will maintain a non-zero chance of isolated
showers today and Saturday. The greatest chance for shower activity
falls on Saturday as an embedded shortwave moves S from Canada. Each
day will see diurnal cumulus as low level lapse rates steepen during
the afternoon. In terms of temperatures, today will be the warmest
day of the whole forecast as a slightly warmer airmass pushes in;
850 mb temps briefly reach ~15C this afternoon before dropping to
~8C Saturday resulting in high temperatures in the low to mid 80s
and low to mid 70s respectively.

KEY MESSAGE 2... Cooler weather this weekend into early next week
gives way to a warming trend and the chance for unsettled weather by
mid week.

The upper air pattern later this weekend into next week evolves from
an amplified omega block into a more zonal configuration. The
changes will come as the persistent closed mid-level low over Nova
Scotia finally pushes away from the eastern CONUS. In its place, 500
mb heights rise as a broad southeast ridge amplifies poleward. What
this translates to at the surface is a benign weather pattern with
somewhat persistent high pressure over the northeast. The next
chance for disturbed weather arrives midweek as a strong shortwave
passes to the N of the region. Guidance shows a somewhat compact and
seasonably strong surface low forming in response to the
aforementioned upper low. Details are still somewhat TBD given the
time to the event but there is a chance for unsettled weather with
this feature around midweek.

Temperatures aloft are cooler Sunday, associated with that mid-level
low east of New England. 925mb temperatures are only around +8C to
+10C, which with boundary layer mixing supports highs in the upper
60s to low 70s. Thus, Sunday will feel very much like autumn, with a
blend of sun and clouds, northerly winds and dew points in the low
50s. While winds won`t be overly strong, the combination of cooler
temperatures and lower dew points will make for a rather crisp day.
Sunday night could feature some decent radiational cooling as high
pressure settles across the region, though this will depend on how
quickly winds diminish. It appears as though the latest NBM has
picked up on this trend for both Saturday night and Sunday night.
The latest run shows widespread 50-55 degree readings with even a
few upper 40s in the higher terrain of northern Massachusetts.
Should see a rebound in temperature readings by early next week as
925mb temperatures climb +14C to +18C, supporting near-seasonable
highs in the upper 70s for Labor Day, then upper 70s to lower 80s
Tuesday into the middle part of next week. Humidity remains
tolerable as well, with dew points generally in the upper 50s to
around 60F. Labor Day itself looks quiet and dry, though there will
be a high risk for rip currents along the ocean beaches.


KEY MESSAGE 3...Dangerous conditions at the beach for the holiday
weekend with as the rip current risk increases Sunday and Labor Day.

Persistent northeast flow, long-period swell, and offshore seas of 4-
7 feet will continue to support an elevated risk for dangerous rip
currents through the Holiday Weekend, especially Sunday into Labor
Day for east-facing ocean beaches. With otherwise quiet weather
expected, those heading to the beach should be mindful that ocean
conditions may still be hazardous. Be sure to check with local beach
staff or lifeguards regarding ocean conditions before entering the
water.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

Update: 06z TAF

Through 12z Friday...Moderate confidence in timing.

Confidence has marginally increased with this update as the
well-advertised areas of marine stratus has pushed over eastern
Massachusetts. An area of marine stratus off the coast of Maine
will advect southwest into eastern Massachusetts overnight,
including KBOS. Expecting this feature to quickly dissipate
around or shortly after 12z as the winds shift more to the W.
Until then wind direction is light and variable at terminals
across southern New England. The light winds, in combination
with wet ground and periods of mostly clear skies, is allowing
for areas of radiation fog and locally lower VISBYs across the
CT River Valley.

Today...Moderate confidence in trends, lower confidence in
timing.

Between 12-15z, conditions improve to VFR for most, with the
exception of the outer Cape and KACK. There, it may take well into
the early afternoon for conditions to improve to VFR. Light north-
northwest winds for most, though a sea breeze develops across
eastern coastal Massachusetts, including KBOS.

Friday Night...High confidence.

VFR. Light northwest winds.

KBOS Terminal...Low confidence.

Areas of stratus and fog continue IFR with MVFR visibilities
roughly through 12z. Some improvement to MVFR is possible
during the morning push, otherwise trending to VFR after 14/15z.
An onshore wind is also anticipated for much of the day today.

KBDL Terminal...Moderate confidence.

Areas of MVFR/IFR conditions contingent upon the development of
low stratus/fog. Any reduced flight categories resolve shortly
after 12z.

Outlook /Saturday Night through Tuesday/...

Saturday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance SHRA.

Sunday: VFR. Breezy.

Sunday Night through Tuesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Saturday Night...

W/NW winds this morning gradually shift the S/SW this evening A
few showers and t-storms may move over the southern waters this
evening then tranquil weather persists. Seas 2-3 ft. Winds shift
to the NE and increase to 10-15 kt Saturday. Seas generally
remain below Small Craft Advisory criteria during the daytime
with an increasing chance later Saturday night.

Outlook /Saturday Night through Tuesday/...

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas.

Sunday Night: Winds less than 25 kt. Areas of rough seas.

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

Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft.

Tuesday: Winds less than 25 kt.

&&

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

&&

$$

DISCUSSION...Dooley/FT
AVIATION...Dooley/FT
MARINE...Dooley/FT