048
FXUS61 KBOX 151938
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
338 PM EDT Sat Aug 15 2026

.WHAT HAS CHANGED...
Small Craft Advisories have been issued for Monday night
through Tuesday. Higher chances for Rips Currents Monday and
Tuesday, but forecast conditions will need to be monitored.

&&

.KEY MESSAGES...

- Seasonable temperatures and pleasant weather linger through
  the weekend.

- Rain chances return late Sunday into Monday, followed by
  quieter weather through late-week. Unsettled weather returns
  late-week.

&&

.DISCUSSION...
KEY MESSAGE 1...Seasonable temperatures and pleasant weather
linger through the weekend.

Fair weather cumulus today provides some pockets of shade today
as temperatures peak in the upper 70s to low 80s, seasonable
for late summer in southern New England. Seabreezes will keep
the coastline slightly cooler before kicking out around sunset.
There remains a low chance for isolated showers, mainly across
eastern and southeastern MA, late this afternoon as a shortwave
moves through the region. If any showers do form, they are
likely to be brief with light rain as opposed to heavier
downpours.

Much like last night, skies will clear and winds will calm,
allowing for good radiational cooling and chances for valley fog
to develop. Temperatures tonight likely bottom out in the low
to mid 50s, near 60 for urban areas.

KEY MESSAGE 2...Rain chances return late Sunday into Monday,
followed by quieter weather through late-week. Unsettled weather
returns late-week.

A mid-level shortwave trough moves through the flow late Sunday
into Monday with a surface low developing and tracking
offshore. This will support our next shot at rainfall. Most of
Sunday is likely to stay dry with most model guidance showing
arrival of showers Sunday night-early Monday AM. Batches of rain
continue through the day Monday. There is still uncertainty in
the details of this system, mainly with respect to the
development/track of a surface low pressure tracking near
southern New England and how it interacts with the low pressure
tracking across New England. This will lead to lower confidence
in expected rain amounts with this system. A stronger, closer
positioned surface low to southern New England would provide
more forcing for more moderate to heavy rainfall. With PWATs
1.5-1.8" and marginal instability, embedded showers/storms with
heavier rain rates are supported, especially where there will be
that additional forcing with the surface low. In terms of flash
flooding potential, mid-level winds will be strong enough to
keep any heavier showers or storms moving reducing widespread
flash flood threat. At this point, given the potential for some
heavier showers, can`t rule out isolated instances of flash
flood impacts in poor drainage/urban areas. This will become
more clear as we get a better idea on the finer details of the
system. The WPC ERO as a Marginal Risk (Level 1 of 4) which
aligns well with the potential for localized heavier downpours.
For total amounts, ensemble guidance shows a range of 0.25" to
0.60" across southern New England though locally heavier amounts
possible, especially beneath any downpours. Ensemble
probabilities for greater than 1.0" are lower (< 30%), but do
show the lower end potential for higher amounts if the surface
low were to track closer to the south coast of southern New
England.

A cold front moves through the region by Tuesday with a drier
airmass advecting into southern New England behind it.
Conditions remain generally dry Tuesday and Wednesday with zonal
flow aloft. Temperatures will likely be in seasonable ranges in
the upper 70s to low 80s. Ensemble guidance signals at
transition to a more unsettled weather pattern Wednesday night
into late-week with chances for rain returning to the forecast.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

18z TAF Update...

Today...High confidence.

VFR. NW winds 5 to 10 kt. Sea breeze kicks out around sunset.

Tonight...High confidence.

VFR outside some touch of very localized ground fog possible
near daybreak in typically most prone low-lying locations. Calm-
light NW winds.

Sunday...High confidence.

VFR. S-SW winds 7-12 kt...except for a period of localized sea
breezes on the very immediate eastern MA coast.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Monday through Thursday/...

Monday: MVFR/IFR conditions possible. Breezy. SHRA likely,
slight chance TSRA.

Monday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

Tuesday through Wednesday: VFR.

Wednesday Night: VFR. Chance SHRA, slight chance TSRA.

Thursday: VFR. 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.

High pressure dominates through the weekend before a low
pressure system pushes through Sunday night into Monday.
Generally light north winds today turn southerly Sunday and
become breezy 15 to 20 kts Sunday night. Relatively calm seas
through the weekend under the high pressure, but will begin to
build to 5-8 ft by early Monday morning as the low approaches.
Small Craft Advisories have been issued for Monday night through
Tuesday.

Chances for rip currents increase Monday for south facing
beaches and Tuesday for eastern facing beaches as rougher seas
and long-period swells settle in with the passage of the low.

Outlook /Monday through Thursday/...

Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. Rain showers likely, slight
chance of thunderstorms.

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

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

Tuesday Night through Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Slight chance of rain
showers.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 8 AM to 11 PM EDT Monday for ANZ231-
     232-250-251-254.
     Small Craft Advisory from 2 AM Monday to 2 AM EDT Tuesday for
     ANZ233>235-237-255-256.

&&

$$

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