541
FXUS61 KBOX 221136
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
736 AM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...
Small Craft Advisories extended through tonight (northern
waters) and through Thursday (southern waters).

&&

.KEY MESSAGES...

- Warmer and drier for the most part today with the chance for
  isolated showers and thunderstorms in the afternoon.

- Mainly dry with seasonable temperatures Thursday through the
  weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Warmer and drier for the most part today with
the chance for isolated showers and thunderstorms in the
afternoon.

The high coverage showers and thunderstorms have cleared southern
New England early this morning. However, a second batch will push
into the south coast, far southeast MA/Cape & Islands after 4 AM
continuing through the early morning hours. Other areas will remain
dry; however, residual high dewpoints and recent rainfall have
supported patchy fog this morning. Expect conditions to improve
through the morning with breaks of sun developing from west to east.
Temperatures rise into the low to mid 80s in most spots.

There is still the risk for showers and thunderstorms this
afternoon. A cold front approaches from the west bringing a push of
higher dewpoint air out ahead of it. With the added heating,
instability should likely build through the afternoon with SBCAPE
values 1000-1800 J/kg. Model guidance has been more consistent with
showing clearing early enough to support the building instability.
The moisture and instability are sufficient to support development
of showers and thunderstorms as the cold front progresses eastward.
With 0-6 km shear 30-40 kts, the environment is supportive of
organized convection with potential for an isolated strong to severe
storm or two. Profiles will not be nearly as saturated as last night
with model soundings showing plentiful moisture at the surface, but
also dry air in the mid-levels. In some cases this can limit
convection. The high-res CAMs have generally exhibited isolated
coverage of showers and thunderstorms this afternoon, so most places
will stay dry. Despite this, it is still possible for a strong to
severe storm in the mix given the supportive environment. Main
threat would be locally damaging gusts. Showers and thunderstorms
likely develop mid to late afternoon from west to east with any
lingering showers/storms exiting offshore early tonight.

A cold front sweeps through tonight with winds shifting to the
northwest ushering in drier air and cooler temperatures.

KEY MESSAGE 2...Mainly dry with seasonable temperatures Thursday
through the weekend.

The cold front pushes offshore by Thursday while an upper trough
tracks across the northeast. High pressure gradually builds in from
the west supporting a period of dry conditions. 925mb temperatures
generally range 16-20C support seasonable temperatures in the low to
mid 80s through the weekend. Ensembles lean toward keeping the
region dry through the weekend with a transition to a more unsettled
pattern with rain chances early next week.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

12Z Update...

Today... Moderate confidence.

Tricky ceilings today with most areas MVFR, but pockets of VFR
sporadically across southern New England. IFR/MVFR ceilings
lingering over the Cape/Islands terminals into the afternoon.
Confidence moderate on exact timing of improvements to VFR.
Showers and thunderstorms possible after 18Z, though isolated in
coverage. Due to low coverage and uncertainty in intensity of
showers/storms, kept as PROB30s for TSRA. SW winds 10-15 knots
with gusts 20-25 kts.

Tonight...High Confidence.

Any afternoon SHRA/TSRA wanes after 00Z. VFR conditions
tonight. Winds shift to WNW/NW at 5-10 knots behind a passing
cold front between 22-03Z.

KBOS Terminal...Moderate confidence in TAF.

Lower confidence with the potential for showers/thunderstorms
this afternoon, mainly due to the isolated nature of
showers/storms. Included a PROB30 for now to TSRA with the most
likely timeframe being between 21-01Z.

KBDL Terminal...Moderate confidence in TAF.

Highest chances for TSRA between 21-00Z.

Outlook /Thursday through Sunday/...

Wednesday Night: VFR. Breezy.

Thursday through Sunday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Tonight through Thursday

Small Craft Advisories remain in effect for SW winds 10-20 kts
with gusts 25-30 kts and 6-10 foot seas for the outer coastal
waters and southern waters. Highest waves are expected over the
south coastal waters. Isolated showers and thunderstorms
possible early tonight.

A cold front crosses the waters tonight resulting in a wind
shift to the NW. Winds and seas will slowly decrease overnight
across the northern waters. Seas will be the slower to decrease,
especially across the southern waters. Extended SCAs through
Thursday for south and east coastal waters. They may need to be
extended further (through Fri AM) for southern outer waters
because of 5 ft seas.

Outlook /Thursday through Sunday/...

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 10 ft. Rain showers likely,
patchy fog.

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

Thursday Night: Winds less than 25 kt. Seas up to 5 ft.

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

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

Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 8 PM EDT Thursday for MAZ020>024.
RI...High Surf Advisory until 8 PM EDT Thursday for RIZ006>008.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ231.
     Small Craft Advisory until 2 AM EDT Thursday for ANZ232>234-
     250.
     Small Craft Advisory until 2 PM EDT Thursday for ANZ235-237.
     Small Craft Advisory until 8 PM EDT Thursday for ANZ254>256.

&&

$$

DISCUSSION...Mensch
AVIATION...McMinn
MARINE...Mensch