864
FXUS61 KBOX 050702
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
302 AM EDT Sun Oct 5 2025

.SYNOPSIS...
A ridge of high pressure in control of our weather will continue to
bring dry and unseasonably warm afternoon temperatures through
Tuesday. A cold front moves through Southern New England Tuesday
night into Wednesday, bringing rain and much cooler/drier
weather for Thursday and Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
250 AM Update:

Key Messages:

* Another very warm day with seabreezes near the coasts.

* Highs in the low to mid 80s inland, and in the mid 70s for the
  eastern and southern coasts.

Details:

High pressure remains parked over the mid-Atlantic coastal waters,
while the axis of an amplified mid-upper level ridge extends from VA
northward up to western NY. Thus the main drivers for our weather
pattern for today are little changed compared to yesterday. Winds
are essentially nil with current temps running rather mild for an
early October evening, in the lower 50s to around 60. In
addition...while still tolerable, dewpoints have started to rise
into the 50s (to spot 60 degree readings along the immediate
southeast coast).

Offered a persistence forecast for today with not much overall
change to the weather pattern from 24 hrs ago. We are again
expecting another warm and dry day with plenty of sun, leading to
well above normal temperatures. Weak pressure gradient and boundary
layer winds will favor seabreezes on the southern and eastern
coasts, keeping these areas slightly cooler compared to inland.
Highs in the mid 70s along the coasts, with inland highs in the low
to mid 80s. As was the case yesterday, have to watch for a late-day
high along the eastern MA coast once the seabreeze shuts off and
becomes a landbreeze.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
250 AM Update:

Key Messages:

* Mostly clear for most tonight thru Mon, but have to watch for
  fog/low clouds overnight tonight in southeast New England. If it
  develops, it may linger into a good part of Mon along the
  immediate south coast.

* Highs again in the lower 80s Mon, but in the lower 70s along the
  south coast.

Details:

Tonight:

Dry weather and mostly clear skies are again expected for tonight
for a large portion if not all of Southern New England. Where there
is now some uncertainty in the forecast is along the South Coast,
Cape and Islands and possibly into portions of CT. Dewpoints come up
a bit (into the lower 60s) on a light SW wind, and the NAM-based
guidance in particular hits these areas hard with fog and stratus
for the overnight, as this shallow layer of moisture becomes trapped
under the strong subsidence inversion. The GFS on the other hand is
clear and dry. NAM has a tendency (a bias) to overdo shallow moist
layers so it`s tough to place much faith in that outcome; but I did
side the forecast that way by introducing patchy fog and partly
cloudy skies for parts of CT-RI-SE MA. While not likely a major
issue for the overnight...if it does develop, it would cast some
question on the forecast for these same areas for Monday. Otherwise,
it`s another rather mild night with lows in the 50s to near 60.

Monday and Monday Night:

SWly winds start to pick up further on Mon, and we expect another
day of above normal temperatures under full sun for a large portion
of Southern New England. Mixing looks shallow so that should limit
gusts to no more than 20 mph but with sustained SW winds around 10
mph. The uncertainty in the forecast revolves around how quickly
might stratus and fog in southeast/southern-coastal New England
disperses, if it indeed developed overnight tonight. That this
moisture is trapped underneath an inversion suggests it may be
slower to scour out and/or retreat to the cooler ocean waters. These
areas probably end up cooler than further inland anyway given the SW
breeze, but raw 2-m AGL temperature output from the NAM/NAM-3km show
areas such as New Bedford, Newport and the Cape struggling to reach
70 degrees. Though we`re looking at low to mid 80s high temps away
from the southern for most; for southeast New England I kept a
mention of partial cloud cover and opted for highs in the lower 70s,
with eyes toward bumping these back up a few degrees if low clouds
scatter out sooner.

Remains mild for the evening too, especially with the continued
southerly breeze. We`ll have to monitor if south-coastal fog/stratus
re-develops toward the coast, but its extent could be more limited
by stronger SW breezes. Lows mid 50s to the lower 60s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Key Messages:

* Above normal temps and breezy for Tue, though not as warm as prior
  days.

* Much needed rains Tue night into Wed as a cold front moves in,
  though not enough to break the drought.

* Cooler, dry and blustery Wed night, with cooler temps for Thurs.

* Modifying temps Fri into the weekend, but drier weather generally
  prevails.

Details:

Tuesday:

Tuesday still looks to be another day with above-normal temperatures
particularly inland, but may end up slightly cooler than prior days
as cloud cover begins to increase during the afternoon ahead of a
cold front. It also turns rather breezy with SWly gusts in the 20 to
as much as 30 mph range. Though RHs are on the high side, that we`ve
had several days of antecedent dryness could still support fire
weather concerns on Tue. Highs mainly in the 70s to a few lower 80s.

Tuesday Night and Wednesday:

A cold front will be slowly traversing through Southern New England
Tue night into Wed, bringing a much-needed rainfall to our area. The
exact timing of the front is still a little uncertain, though the
current indications indicate rain beginning as soon as the pre-dawn
hrs in far western MA/CT and mainly during the daytime hours Wed.
Global ensemble QPF probabilities remain less bullish on rainfall
than the deterministic guidance does, but the odds for a wetting
rainfall are increasing. Thunder could be possible but the
unfavorable time-of-day could limit any thunder potential to a weak
mid-level instability burst and not likely be supportive of strong
storms. This front looks to take most of Wed to reach the coastline,
before rapid drying takes place to go along with strong CAA and
increasing NWly gusts. Mild lows Tue night with overcast and SW
breezes in the upper 50s to the mid 60s, then only climbing a few
degrees (mid 60s to near 70) Wed before temps rapidly cool off late
in the day.

Wednesday Night through Thursday:

Much cooler temperatures and drier weather then settles in for late
in the week, as a strong 1030+ mb high pressure area builds into New
England. Strongest cold advection takes place Wed night (our 925 mb
temps plummet to around +2 to +4C by Thu AM), supporting a rather
chilly night but seems that northerly breezes prevail for most areas
and that could preclude frost from developing. While sunny, Thurs is
a cooler day with decreasing northerly winds, with highs in the 50s
to lower 60s. Though our low-level temps modify into Thurs night,
strongest radiational cooling takes place then, and temps could
support a frost in some areas in mid 30s to lower 40s.

Friday into Next Weekend:

Gradually modifying temps into Fri as high pressure maintains
itself. Some uncertainty for next weekend as some global ensemble
members show some developing troughing over the waters, and
potential for clouds and light showers for the weekend, but this
outcome seems to be in the minority compared to an otherwise drier
model-consensus.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

06z TAF Update:

Through 12z Sunday: High confidence.

VFR for most; IFR-LIFR fog at ACK and perhaps into the remainder
of the Cape airports from the overnight hours should disperse
with sunrise. Light/calm winds.

Today: High confidence.

VFR. Light S/SW winds, with seabreezes at BOS and PVD.

Tonight thru Monday: High confidence overall, but is moderate
for southeast New England.

VFR prevails away from the south coast through Monday. Near and
southeast of I-95, fog and stratus at MVFR-LIFR levels could
develop tonight, and it may take until mid-morning to early
afternoon Monday to scatter to VFR in these areas if it were to
develop. SW winds around 5-10 kt, becoming around 10 kt Mon with
occasional gusts to near 20 kt.

Monday Night: High confidence overall, but moderate for
southeast New England.

Mainly VFR, though have to watch for returning fog/stratus along
the south coast. SW winds around 10 kt.

KBOS Terminal...High confidence in TAF. Seabreeze looks to
develop around 14-15z Sun, continuing through 22-23z.

KBDL Terminal...High confidence in TAF.

VFR. Light southerly winds

Outlook /Tuesday through Thursday/...

Tuesday: VFR. Breezy.

Tuesday Night: MVFR/IFR conditions possible. Breezy. Chance
SHRA.

Wednesday: Mainly VFR, with local IFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Wednesday Night: VFR. Breezy. Slight chance SHRA.

Thursday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Monday Night: High confidence.

Winds and seas below small craft advisory levels. Light
southerly winds today, increasing to around 10 kt tonight, then
increase to around 15-20 kt Mon. Seas mainly 3 ft or less all
waters. Areas of marine fog possible tonight which could reduce
visbys to one-half mile, and may be slower to disperse into Mon.

Outlook /Tuesday through Thursday/...

Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas locally approaching 5 ft.

Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers.

Wednesday: Winds less than 25 kt. Seas up to 5 ft. Rain
showers. Local visibility 1 to 3 nm.

Wednesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas. Chance of rain
showers.

Thursday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas.

&&

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

&&

$$

SYNOPSIS...Loconto
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...Loconto
AVIATION...Loconto
MARINE...Loconto