765
FXUS61 KBOX 221111
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
711 AM EDT Tue Sep 22 2026

.WHAT HAS CHANGED...

Gale watches have been expanded and upgraded to Gale Warnings.
Small craft advisories have also been issued for our northern
waters today into Thursday. Confidence in an impactful coastal
storm for Friday into the weekend is increasing.

&&

.KEY MESSAGES...

- Dry, cool, and breezy conditions continue through Thursday.

- Probabilities are increasing for a strong coastal low pressure
  system to bring impacts to southern New England in the form of
  rain, rough seas, strong winds, and coastal erosion late week
  into the weekend.

&&

.DISCUSSION...

KEY MESSAGE 1...Dry, cool, and breezy conditions continue through
Thursday.

Over the next several days southern New England will see a
persistence forecast without much change. Basically, cooler than
average temperatures under persistent northeast flow will be the
story of the week thanks to our placement south of a broad area of
high pressure over eastern Canada. As this high pressure continues
to sit and even expand, a coastal low pressure system will slowly be
meandering up the eastern seaboard. While this will likely bring
more direct impacts to the region at the end of the week, we`ll
begin to feel the impacts of the ever tightening pressure gradient
as early as Tuesday. Those breezy northeast winds will be even
moreso on Wednesday. While the strongest gusts will be over the
waters where Gale Warnings are in effect, locations along the coast
and especially the Cape and Islands are increasingly likely to see
wind gusts 25 to 35 mph each day through Thursday. This, while high
temperatures struggle to get out of the low 60s so together it will
feel much cooler than the normal low 70s we`d expect this time of
year.

KEY MESSAGE 2...Probabilities are increasing for a strong coastal
low pressure system to bring impacts to southern New England in the
form of rain, rough seas, strong winds, and coastal erosion late
week into the weekend.

Thursday onward is where uncertainty ramps up considerably, owing to
the significant spread amongst the guidance as to how this coastal
low evolves in its track up the coast. That being said, the last few
runs of GFS guidance have trended toward the ECMWF solution showing
a retrograding back to the west, meandering with little forward
motion through the weekend. Of course, this is only one
deterministic run, but it is so far a trend for a few run and GEFS
ensemble guidance has also evolved to show a stronger, more western
low track with the 00z run. Should this be the solution that pans
out, there`s a good chance we`ll be dealing with storm force wind
gusts on the waters and wind advisory conditions at least for
coastal locations by Friday. Additionally, the many days of
persistent and increasing NE flow will lead to high seas and
potential for significant coastal erosion on the east coast,
especially given astronomically high tides. It doesn`t appear that
the low is likely to finally exit east until at least early next
week but again, confidence in specifics is low Friday onward.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...

Forecaster Confidence Levels...

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

12z TAF Update...

Today...High confidence.

VFR after any marginal MVFR cigs depart the coastal plain by mid
to late morning. NE winds 7-15 knots with gusts along the
coastal plain of 20 to 25 knots.

Tonight...High confidence.

Mainly VFR. NE winds of 5 to 15 knots tonight with 20-25 knot
gusts at times across the southeast New England coast and 25-30
knots for Nantucket.

Wednesday...High confidence.

Mainly VFR. NE winds of 10 to 20 knots with gusts of 20 to 30
knots...strongest towards the southeast New England coast.
Gusts near 35 knots for Nantucket.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: VFR. Windy with gusts up to 35 kt.

Thursday: VFR. Strong winds with local gusts up to 40 kt.

Thursday Night: VFR. Strong winds with local gusts up to 40 kt.
Slight chance SHRA.

Friday: VFR. Strong winds with gusts up to 45 kt. Chance SHRA.

Friday Night through Saturday: Mainly VFR, with local MVFR
possible. Strong winds with gusts up to 45 kt. SHRA likely.

&&

.MARINE...

Forecaster Confidence Levels...

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

Through Wednesday Night...High Confidence.

NE winds 15-20 kt with gusts up to 25 kt at times will
continue, as strong 1030+ mb high pressure over southeast
Ontario moves eastward into Quebec. This northeast fetch will
yield rough seas on the ocean waters. Dry weather and good vsby
prevail. Potential for gale force gusts appear to hold off until
Wed and beyond. Seas 4-7 ft on Tuesday increase to 6-13ft by
Wednesday and Wednesday night.

Outlook /Wednesday Night through Saturday/...

Thursday: Moderate risk for gale force winds with areas of
gusts up to 45 kt. Rough seas up to 15 ft. Slight chance of
rain showers.

Thursday Night: gale force winds with areas of gusts up to
45 kt. Rough seas up to 17 ft. Chance of rain showers.

Friday: gale force winds with gusts up to 45 kt. Rough seas up
to 19 ft. Rain showers likely. Local visibility 1 to 3 nm.

Friday Night through Saturday: gale force winds with gusts up
to 45 kt. Rough seas up to 20 ft. Rain showers likely, slight
chance of thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents through this evening for MAZ007-015-016-
     019>024.
RI...High Risk for Rip Currents through this evening for RIZ002-004>008.
MARINE...Small Craft Advisory until 8 PM EDT Thursday for ANZ230-250-
     251.
     Gale Warning from 8 PM Wednesday to 8 PM EDT Thursday for
     ANZ231-254.
     Gale Warning from 5 AM Wednesday to 8 PM EDT Thursday for
     ANZ232>235-237-281.
     Small Craft Advisory from 5 AM Wednesday to 8 PM EDT Thursday
     for ANZ236.
     Gale Warning from 2 AM Wednesday to 8 PM EDT Thursday for
     ANZ255-256-282-283.

&&

$$

DISCUSSION...BW
AVIATION...Frank/BW
MARINE...BW