122
FXUS61 KBOX 261046
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
646 AM EDT Sun Apr 26 2026

.WHAT HAS CHANGED...

Added small craft advisories for the waters adjacent to Cape Cod and
Nantucket tonight into Monday as northeast winds and seas build
up. Otherwise, no significant changes.

&&

.KEY MESSAGES...

- Overcast early with rain showers limited to the South Coast,
  Cape and Islands. Although still cloudy and cool for the Cape
  and Islands, decreasing cloudiness and more sunshine north and
  west by the afternoon.

- Clear and dry Monday and Tuesday, but with northeast onshore
  breezes for the Cape and Islands.

- Increasing clouds and light rain from the ocean waters Tuesday
  night and Wednesday, but more active, unsettled weather
  develops around Wednesday night into Thursday with much-needed
  rainfall.

&&

.DISCUSSION...

KEY MESSAGE 1...Overcast early with rain showers limited to the
South Coast, Cape and Islands. Although still cloudy and cool for
the Cape and Islands, decreasing cloudiness and more sunshine north
and west by the afternoon.

Overcast skies blanket Southern New England early this morning.
Though radar imagery shows echoes across a large portion of Southern
New England, drier air below cloud base is limiting the spatial
coverage of steadier light showers to a rough Chicopee-Willimantic-
Newport line southward and westward. This cloud cover and areas of
rain are being driven by a positively-tilted shortwave trough over
eastern NY and an organizing surface cyclone just off the Delmarva
Peninsula. One of the more significant changes compared to yesterday
in terms of how these synoptic features evolve is that while the NAM-
based guidance closed off this midlevel shortwave trough sooner,
there is now consensus across the NWP suite in this shortwave not
closing off until later this afternoon in eastern/southeast New
England. This is a more optimistic outcome, especially as it
pertains to the weather for today into Monday, as the surface
cyclone near the Delmarva moves off towards the ENE today and passes
far enough southeast of Nantucket to mitigate a longer-duration of
rain showers, overcast and onshore winds that the NAM was offering
yesterday.

Current area of rain showers should continue to shift southward and
expanding southeastward through this morning. While this means
decreasing rains in CT and western MA, it will lead to lowering
cloud bases and at least intermittent rain showers for Block Island,
the South Coast and the Cape and Islands. At least modest NE winds
will accompany those showers, but rain showers probably won`t end up
being persistent and total QPF amts are up to a few hundredths.
Temperatures are coolest for those locations today, and could
struggle to reach the low 50s. Further north and west, we should see
mid-level overcast persist this morning but with decreasing
cloudiness late this morning to the afternoon, leading to the
warmest temperatures in the upper 50s to even some lower 60s in the
CT and Merrimack Valleys. Eastern coastal MA will be contending with
modest onshore breezes so these areas will still be running quite a
bit cooler, in the upper 40s to lower 50s.

For tonight, high pressure to our northeast ridges back in, leading
to clear skies and light northeast to northerly winds winning out
for most of Southern New England. Meanwhile, low pressure southeast
of Cape Cod will lead to increasing NE breezes and still partly to
even mostly cloudy skies as moisture wraps around in the low`s cold-
conveyor-belt region. This creates a challenging low temperature
forecast, as areas away from Cape Cod should radiate quite well
after sundown with mid 30s to near 40, with a low risk for
mist/fog especially in those locations in CT/RI/western MA
where it rained early this morning. For the Cape and Islands,
lows end up more in the low to mid 40s meaning little overall
change from daytime highs, with NE winds around 10-15 mph.

KEY MESSAGE 2...Clear and dry Monday and Tuesday, but with
northeast onshore breezes for the Cape and Islands.

Monday and Tuesday are shaping up to be absolutely spectacular,
chamber-of-commerce days as amplified shortwave ridging aloft
develops and dry high pressure rebuilds back in. A bit breezy for
the Cape and Islands both days, and onshore flow will keep eastern
MA several degrees cooler too - lower 50s. Away from the eastern
coast though, deep mixing and full sun should push highs into the
60s on both days, and some spot 70 degree readings could occur in
the CT Valley. Winds are very light through a deep depth of
atmosphere away from the east coast, and expect dewpoints to plummet
into the upper 20s to mid 30s. Cool nights too, milder near the Cape
and Islands (upper 30s-mid 40s lows) but in the mid 30s to low 40s
away from the Cape.

KEY MESSAGE 3...Increasing clouds and light rain from the ocean
waters Tuesday night and Wednesday, but more active/unsettled
weather develops around Wednesday night into Thursday with much-
needed rainfall.

The clear and dry weather pattern breaks down potentially as soon as
Tuesday night as moisture wraps back westward and brings at least
expanding cloud cover and perhaps some light rain showers and
mist/drizzle. Overcast with intermittent showers Wednesday, but the
better chance for welcomed rains occurs later Wednesday night and
into Thursday as a shortwave trough over the Gt Lakes swings a cold
front and possible secondary low pressure along it near the ME/NH
coast Wednesday night into Thursday. Could even be a rumble or two
of thunder with the front too. Ensemble 24-hr QPF probs with this
frontal passage show high (70-90%) chances for at least a tenth of
an inch, moderate (40-60%) chances for a half inch, with low
(less than 30%) probs of an inch or more of rain. Thus mid to
late in the week looks to offer our next chance at more active
weather.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...

Forecaster Confidence Levels...

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

12z TAF Update...High confidence.

Mainly VFR conditions today and tonight. Some very light
showers/sprinkles from a mid level cloud deck graze parts of
the Cape through mid-morning. Showers more steady across the
Islands through mid-morning...where we may have some brief MVFR
conditions on ACK. Otherwise...VFR conditions persist with
perhaps a touch of very localized patchy ground fog in the
typically prone locations very late tonight. Winds generally
become ENE at 6 to 13 knots today...diminishing tonight except
across parts of the Cape and Nantucket.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Monday through Thursday/...

Monday through Tuesday: VFR. Breezy.

Tuesday Night through Wednesday: Mainly VFR, with local IFR
possible. Slight chance SHRA.

Wednesday Night: Mainly VFR, with local IFR possible. SHRA
likely.

Thursday: Mainly VFR, with local IFR possible. SHRA likely,
slight chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Other than offshore seas building up to around 5 ft today on the
far southern waters, winds and seas should remain below SCA
criterion through today. NE/E winds increase to around 10-15 kt,
with gusts around 20 kt. Seas 3-5 ft, higher in the southern
waters. Periods of showers over the southern waters thru this
afternoon reducing visbys to around 4 miles in steadier rain.

NE winds then increase tonight and into Monday near and
southeast of Cape Cod and Nantucket. NE winds should increase to
around 20-25 kt in gusts overnight into Monday, with seas
becoming around 4-6 ft, which prompted issuance of SCAs.
Elsewhere, NE/N winds around 10 kt and seas less than 3 ft.

Outlook /Monday through Thursday/...

Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft.

Monday Night through Tuesday: Winds less than 25 kt. Local
rough seas.

Tuesday Night through Wednesday: Winds less than 25 kt. Areas
of rough seas. Slight chance of rain showers.

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

Thursday: Winds less than 25 kt. Areas of rough seas. Rain
showers likely, slight chance of thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 2 AM to 8 PM EDT Monday for ANZ232-
     254-255.
     Small Craft Advisory until 8 AM EDT Monday for ANZ256.

&&

$$

DISCUSSION...Loconto
AVIATION...Frank/Loconto
MARINE...Loconto