385
FXUS61 KBOX 242329
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
729 PM EDT Mon Aug 24 2026

.WHAT HAS CHANGED...

A marginal Small Craft Advisory issued for Buzzards Bay and
Vineyard Sound for Tuesday afternoon.

&&

.KEY MESSAGES...

- Mainly dry and seasonable conditions, outside of a stray
  shower this afternoon and Tuesday afternoon.

- Main risk for a round of scattered showers and a few
  thunderstorms will be sometime late Thu/Thu night into Fri
  with summerlike humidity. Mainly dry & seasonable weather
  favored for the weekend.

&&

.DISCUSSION...

KEY MESSAGE 1...Mainly dry and seasonable conditions, outside of a
stray shower this afternoon and Tuesday afternoon.

The synoptic setup for the next several days is as follows. A mid-
level low, which is easily seen on GOES water vapor imagery across
northern New York, will move into northern New England before
drifting east into the Canadian Maritimes by Wednesday. Locally,
Wednesday brings a subtle shortwave ridge. In general, expect benign
conditions through the first half of Thursday as surface high
pressure expands into the Northeast from the Midwest. However, a
stray pop-up shower or thunderstorm remains possible this afternoon
and Tuesday afternoon due to cyclonic flow, which will promote
diurnal cu development amid steep low-level lapse rates (greater
than 8C/km) along a trough. No severe weather is expected, as mid-
level lapse rates remain poor (less than 6C/km). Areas with the best
chance of experiencing a brief shower or storm (less than a 25 PoP)
through this afternoon are west of KIJD, KORH, and KFIT, associated
with the passage of a weak surface trough. Thereafter, cannot
discredit a shower farther east along the Boston-to-Providence
corridor. Similar conditions are expected again Tuesday. Wednesday
into Thursday, the mid-level shortwave ridge moves through,
providing another dry day Wednesday. However, the ridge shifts east
by Thursday ahead of an approaching trough, which has the potential
to bring numerous showers late Thursday into Friday. More on that in
KEY MESSAGE 2.

As for temperatures, expect a seasonable week, with afternoon highs
in the lower 80s and higher-terrain communities in the northern
Worcester Hills and eastern Berkshires remaining in the middle to
upper 70s. Nightly lows will be a touch cooler as clear skies and
light winds allow for radiational cooling, with temperatures
slipping back into the 50s while urban areas remain near 60 degrees.
This setup may allow for another night of low stratus or fog.
Confidence in how widespread it becomes remains low; however, it
does not appear this round of fog will be as prevalent as last
night.


KEY MESSAGE 2...Main risk for a round of scattered showers and a few
thunderstorms will be sometime late Thu/Thu night into Fri with
summerlike humidity. Mainly dry & seasonable weather favored for the
weekend.

The next shortwave trough approaches from the west by late in the
work week. Ahead of this approaching shortwave...summerlike humidity
will return Thu into Fri. Timing quite uncertain this far out in the
forecast...But appears there will be the potential for a round of
scattered showers and a few thunderstorms sometime in the late
Thu/Thu night into Fri time frame. CSU machine learning probs do
indicate some low probs for severe weather/heavy rainfall
potential...But that is really just climo for an approaching
shortwave this time of year. So not much more we can say at this
point. Current guidance does indicate that drier/seasonable weather
is favored to return for the upcoming weekend.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

00z TAF Update...

Tonight...High confidence.

Isolated showers dissipate by mid-late evening. Otherwise...VFR
conditions tonight outside of localized patchy ground fog
possible toward daybreak in the typically prone locations.
Greatest risk will be those low-lying spots in southeast
MA/Cape...where higher dewpoints reside. Winds becoming
calm/light WSW.

Tuesday...High confidence.

VFR outside a few spot showers during the afternoon. W winds
6-12 knots except some 20+ knot gusts possible in the afternoon
towards the upper-Cape.

Tuesday Night...High confidence.

VFR. Calm/Light WNW winds.

KBOS Terminal...High confidence in TAF.

We think pressure gradient remains just strong enough to result
in mainly W winds on Tue. However...the low probability exists for a
few hours of sea breeze but risk/duration too limited to insert
into the TAF at this time.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday through Wednesday Night: VFR.

Thursday: VFR. Breezy. Chance SHRA, chance TSRA.

Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, slight chance TSRA.

Friday: VFR. Chance SHRA, slight chance TSRA.

Friday Night through Saturday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday Night...High confidence.

Fairly quiet boating conditions through the first half of this week
as high pressure develops across the Midwest before expanding toward
the waters off the coast of southern New England. Gusty southwest
flow develops Tuesday, with gusts around 20 kt. However, Vineyard
Sound and Buzzards Bay are oriented roughly parallel to the wind,
allowing for a localized enhancement from funneling. Have opted to
issue a marginal Small Craft Advisory for gusts up to 25 kt Tuesday
afternoon. Conditions improve overnight into early Wednesday morning
as winds shift to the northwest.

Swell periods of 11-12 seconds are expected off the coasts of
Martha`s Vineyard and Nantucket, which will lead to a higher risk of
rip currents along south-facing beaches there, warranting expansion
of the Rip Current Statement over the Vineyard. A moderate risk for
rip currents extends along SE MA and RI beaches due to swells as
well.

Outlook /Wednesday through Saturday/...

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

Wednesday Night through Thursday: Winds less than 25 kt.

Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, slight chance of
thunderstorms.

Friday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers.

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 11 AM to 8 PM EDT Tuesday for ANZ233-
     234.

&&

$$

DISCUSSION...Dooley/Frank
AVIATION...Frank
MARINE...Dooley/Frank