142
FXUS61 KBOX 061453
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1053 AM EDT Sun Sep 6 2026

.WHAT HAS CHANGED...
Issued a Coastal Flood Advisory for the Cape and Islands for the
threat of minor coastal flooding with this afternoon`s high tide
cycle. Otherwise, the forecast remains on track.

&&

.KEY MESSAGES...

- Early morning showers and cloud cover give way to a mostly
  sunny albeit cooler day. Coastal hazards including the
  potential for minor coastal flooding and rip currents
  continues for east-facing beaches.

- Dry conditions Labor Day through much of Wednesday. Pattern
  becomes more unsettled Wednesday night into late-week with
  periods of showers possible and gusty winds possible Thursday.

&&

.DISCUSSION...
.KEY MESSAGE 1... Early morning showers and cloud cover give way to
a mostly sunny albeit cooler day. Coastal hazards including the
potential for minor coastal flooding and rip currents continues for
east-facing beaches.

Any lingering showers early this morning dissipate by mid to late
morning as an area of subsidence or sinking air moves overhead. The
subsidence will also result in a clearing trend through the day.
Weak cold advection and 925 mb temps of 12-14C  will keep highs in
the upper 60s near the eastern coastline to the lower 70s
elsewhere. Another day of high astronomical tides and an onshore
flow brings the chance for minor coastal flooding back for the
afternoon high tide cycle. As a result, a coastal flood advisory
has been issued for this afternoon`s high tide cycle. The
advisory includes the Cape and Islands from 19-23z. As was the
case with yesterday`s high tide, anticipating minor impacts in
typically more vulnerable spots (Easy Street on Nantucket and
Sesuit Harbor in Dennis). There is also an high risk for rip
currents along east- facing shorelines in eastern MA, as
offshore seas rise to around 4-6 ft overnight into Monday.


KEY MESSAGE 2...Dry conditions Labor Day through much of
Wednesday. Pattern becomes more unsettled Wednesday night into
late-week with periods of showers possible and gusty winds
possible Thursday.

The deeper mid-level trough shifts further eastward through the
day Monday while higher heights advect in as a mid-level ridge
builds to the west. This will bring in warmer temperatures aloft
with 925mb temperatures +15-17C. NW flow and a sufficiently
mixed boundary layer accompanied mainly clear skies should help
yield high temperatures in the the mid to upper 70s for most.
High pressure will support mainly dry conditions Monday with
similar conditions and temperatures likely for Tuesday under the
same pattern.

Ensemble guidance shows a signal for a transition to a more
unsettled pattern mid to late week. Flow aloft becomes more
zonal with a few embedded shortwave troughs moving through late
Wednesday through late-week. This should be accompanied by a
plume of above normal moisture (120-150% of normal) and a jet
positioned to supply lift across the region. This should be
enough to support periods of showers later Wednesday/Wednesday
night into Friday. There is spread across guidance in the finer
details of the timing of the waves which will influence timing
of the showers. Overall, there isn`t a strong signal for flash
flooding at this time. Marginal instability in place may owe to
a storm or downpour depending on the timing.

Another thing we will need to monitor is the potential for a
period of gusty winds Thursday. An 850mb 35-45kt LLJ positions
across southern New England into Thursday. If winds mix down
efficiently, this would support gusty winds. There is a signal
for anomalously gusty winds on the ECMWF EFI (still fairly far
out). Flow looks to become more westerly behind the passage of
the first wave with a signal for CAA. Both things that could
facilitate the mixing down of the higher winds aloft (to some
extent at least). As mentioned, timing of these waves are lower
confidence and this could have influence on when we get the
better mixing and thus the gusty winds. So plenty of details to
be worked out. If things align, ensembles show potential for
gusts in the 30-40 mph range on Thursday across the land and
coastal waters. Still plenty of details to work out in the
pattern before we come into better agreement about the gusts,
but something to watch for now.

Temperatures Wednesday/Thursday lean near to slightly above normal
with temperatures in the mid to upper 70s. A cooler airmass pushes
in sometime later Thursday into Friday with cooler temperatures
arriving by Friday (upper 60s/low 70s).

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

15z TAF Update:

Today: High confidence.

SCT-BKN VFR/MVFR ceilings (020-040 bases) continue as of mid-
morning, with widely SCT light -SHRA around pushing southward.
While showers come to an end shortly, anticipate some lifting
of cloud bases closer to VFR levels by afternoon. Another surge
of moisture comes down now over central Maine could bring an
increase in clouds toward BKN later this afternoon for eastern
terminals. North to northeast winds around 5-10 kt.

Tonight: High confidence.

Mostly VFR as cloud cover decreases. Some risk for patchy fog in
the river valleys prior to sunrise (08-12z) but its development
is uncertain. Winds decrease to light northerly.

Monday and Monday Night: High confidence.

VFR. NW winds increase to around 8-12 kt during the daytime,
easing and becoming WNW with an increase in VFR clouds after
06z Tue.

KBOS Terminal...High confidence in TAF. Mix of SCT-BKN VFR/MVFR
ceilings, but should trend VFR by early afternoon. NE winds
around 5-10 kt. Seabreeze possible but could be late in the
day.

KBDL Terminal...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday Night through Tuesday Night: VFR.

Wednesday: VFR. Breezy.

Wednesday Night: VFR. Windy with gusts up to 30 kt. Chance
SHRA.

Thursday: VFR. Windy with local gusts up to 30 kt. Slight
chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Sunday Night: High confidence.

SCAs remain in effect for the eastern outer waters through
8 pm this evening as seas build to around 4-6 ft. NE gusts
around 15-20 kt through this afternoon, before becoming
northerly the rest of Sunday around 10-15 kt. Off-and-on light
rain showers this morning before clearing this afternoon. but
only minor reductions to visibility, at worst to 4 miles, are
expected. Calmer ocean conditions return overnight as high
pressure builds in. Seas fall to 2-3 feet.

Outlook /Monday Night through Thursday/...

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

Tuesday through Tuesday Night: Winds less than 25 kt.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 30 kt. Seas locally approaching 5 ft.

Wednesday Night: Low risk for gale force winds with gusts up to
35 kt. Rough seas up to 11 ft. Chance of rain showers.

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 11 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 8 PM EDT this evening for MAZ007-
     014>016-019-022>024.
     Coastal Flood Advisory from 3 PM this afternoon to 8 PM EDT
     this evening for MAZ022>024.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ250-
     254-255.

&&

$$

DISCUSSION...Mensch/FT
AVIATION...Loconto
MARINE...Mensch/FT