266
FXUS61 KBOX 031101
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
701 AM EDT Wed Sep 3 2025

.SYNOPSIS...
High pressure remains in control through at least Thursday, bringing
an extended stretch of dry weather and seasonably warm temperatures.
Turns more humid by Friday, with an approaching cold front bringing
showers and a chance of thunderstorms. Warm and humid conditions and
risk for showers linger into Saturday ahead of the cold front, then
cooler and drier weather returns next Sunday and Monday behind the
cold front with slightly below normal temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages:

* Areas of morning fog possible and will give way to a blend of
  sunshine and fair weather clouds.

A very quiet overnight across southern New England with mainly clear
sky cover and generally light wind. Temperatures as a result are on
the decline, falling through the 50s and upper 40s. With most of the
ASOS sites reporting a small T/Td depression it`s possible that fog
redevelops heading towards sunrise, a similar situation to Tuesday.
Any morning fog erodes within two hours of sunrise, then we are left
with another pleasant late summer day with an elongated surface high
pressure stretches majority of the Eastern Seaboard.

Nearly a carbon copy of today, light winds, fair weather clouds, and
warm temperatures. 850mb temperatures are slightly warmer today than
it had been Tuesday, +10C to +12C, thinking highs in the upper 70s
to the low 80s are reasonable. At the coast, there is an on shore
wind component, thus slightly cooler here. But overall comfortable
with the dew point temperature in the 50s.

&&

.SHORT TERM /THURSDAY/...
Key Messages:

* Another cool night with potential redevelopment of fog.

* Becoming breezy with increasing clouds Thursday ahead of an
  approaching cold front, through daylight hours remain dry with
  rain arriving likely overnight.

Surface high shifts east tonight, but will maintain the mostly clear
sky cover with light to calm winds. Should have a similar night as
the past two with effective radiational cooling and fog. Similar low
temperatures in the 50s and isolated areas in the 40s. It is worth a
mention a few of the models have hinted at widespread fog, but think
this is a bit bull-ish, as the higher dew points do not advect into
the region until mid-Thursday morning. Nevertheless, something will
have to monitor, especially for the aviation forecast.

As for Thursday, in general it is quiet. To the west a potent 500mb
low centered over the northern Great Lakes. Shortwave energy pivots
across the Great Lake region with a subtle trough and surface cold
front. Back in southern New England the area of high pressure that
has given us a few great days weather-wise will shift east and off
shore. Wind direction becomes southerly and advects higher humidity,
while it`s not oppressive, it will be noticeable considering how it
has felt like early fall the last few days.

WAA aloft, though mixing will be limited to 925mb, temperatures are
+18C to +21C and should result with highs well into the upper 70s
and lower 80s. And with the southerly winds, expect lower
temperatures at the south coast in the middle 70s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Key Messages:

* Rain chances increase Friday into Saturday with chance for
  embedded thunderstorms mainly on Saturday.

* A cold front Saturday night will usher in a drier and cooler
  airmass to start next week.

A large trough over much of the eastern U.S. will be the primary
driver of the weather through the weekend before some drier air and
weak mid level ridging returns late weekend into next week. After a
quiet and seasonable Thursday under the influence of high pressure
centered just to the east we`ll see an increasingly warm and moist
airmass advected north ahead of our next shortwave. The broader
trough will see a series of disturbances moving through, serving as
lift that will act on a moist airmass (PWATs >1.5" by Fri) to bring
scattered rain showers. Difficult to time exact periods of rainfall
but generally anytime between Thursday night and Saturday night
looks to feature a chance for rain; perhaps best chances being Thu
night into early Fri and Saturday afternoon/evening. As for
thunderstorms, instability looks quite marginal Friday with no
source of lift to speak of either so thunder is not a given (SREF
paints a small area of 5% t-storm chance in SNE) but possible;
however severe weather is unlikely. Saturday brings the better
chance of some severe storms as instability increases and lift
arrives in the form of a cold front. Details will ride on exact
timing and strength of this front, how unstable we can get ahead of
it, etc.

Beyond the front a much drier and cooler airmass is ushered into the
region under rising mid level heights. After WAA leads to highs in
the mid 80s by Saturday, they drop back into the low to mid 70s
behind the front Sunday-Tuesday.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

Today... High Confidence.

VFR. East to southeast wind up to 8-12 knots across eastern MA
terminals. South to south/southwest wind elsewhere 5-8 knots.

Tonight... Moderate Confidence.

VFR and calm winds, though this combination lends to radiational fog
to develop, and could lead to areas of IFR/LIFR. Do have moderate
confidence in fog developing, after 06z/08z, but confidence is lower
with respect to how widespread the fog or low stratus will become.

Thursday... High Confidence.

VFR. Increasing mid-level clouds, west to east during the afternoon
ahead of a cold front. South wind 8-12 knots, gusts up to 20 knots
are possible. Any SHRA arrives to western areas after 00z Friday.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

VFR. But, a low risk of late night patchy fog after 08z.

Outlook /Thursday Night through Sunday/...

Thursday Night: Mainly VFR, with areas IFR possible. Breezy.
Widespread FG, chance SHRA.

Friday: Mainly VFR, with local IFR possible. Breezy. Widespread
FG, slight chance SHRA.

Friday Night: Mainly VFR, with areas IFR possible. Breezy.
Widespread FG, slight chance SHRA.

Saturday: Mainly VFR, with local IFR possible. Breezy.
Widespread FG, slight chance SHRA, slight chance TSRA.

Saturday Night: Mainly VFR, with areas IFR possible. Breezy.
Widespread FG, chance SHRA.

Sunday: VFR. Widespread FG, slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Thursday... High Confidence.

Area of high pressure is in control, providing tranquil boating
conditions today, but somewhat gustier conditions can be expected on
Thursday, although still quiet weatherwise. Thursday night into
Friday a cold front will approach bringing gusty winds and scattered
storms. Until then, dry conditions for today and Thursday.

Wind remains relatively light, for the southern waters the direction
is out of the ESE to SE, while the eastern and northern waters are
from the SSE to SE. Northeastern waters off the coast of Cape Ann
could gusts up to 20 knots this afternoon. Overnight into Thursday
the direction becomes southerly for all waters with increasing
speeds of 10 to 15 knots, gusting 20 to 25 knots. Seas during this
period are between 2-4 feet. A Small Craft Advisory may become
needed for marginal wind gusts Thursday afternoon.

Outlook /Thursday Night through Sunday/...

Thursday Night: Winds less than 25 kt. Patchy fog. Local
visibility 1 nm or less.

Friday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Seas locally approaching 5 ft. Patchy fog. Local
visibility 1 nm or less.

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of seas approaching 5 ft. Patchy fog.
Local visibility 1 nm or less.

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Slight
chance of rain showers, patchy fog. Local visibility 1 nm or
less.

Saturday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, patchy fog. Local
visibility 1 nm or less.

Sunday: Winds less than 25 kt. Chance of rain showers, patchy
fog.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...BW/Dooley
NEAR TERM...Dooley
SHORT TERM...Dooley
LONG TERM...BW
AVIATION...BW/Dooley
MARINE...Dooley