129 
FXUS61 KBOX 152345
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
745 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 /00Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

00z TAF Update...

Tonight...High confidence.

VFR outside some touch of very localized ground fog possible 
near daybreak in typically most prone low-lying locations. Calm-
light N/NW winds after 21Z.

Sunday...High confidence.

VFR. Light northerly winds become S/SSW for most terminals.
ESE sea breeze sets up at BOS/east coast terminals 13-15Z 8-12
kts, eventually shifting to S/SSW after. 

Sunday Night...High confidence in trends. 

VFR ceilings to start. Scattered showers arrive from west to 
east mainly after 03Z along with MVFR ceilings. 


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