929
FXUS61 KBOX 081126
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
626 AM EST Sat Nov 8 2025

.SYNOPSIS...
Stationary frontal boundary draped over Southern New England
will continue to focus cloud cover and light rain through early
this afternoon before improving late. Brief clearing tonight,
but a warm front brings another period of overcast and light
rains for Sunday, trending to areas of drizzle and misty
overcast for Sunday evening. Area of low pressure and cold front
bring a round of rain and gusty southerly winds into early
Monday, followed by much chillier weather later Monday and
especially by Tuesday. Slight improvements in temperatures
Wednesday before a reinforcing trough arrives later next week.

&&

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

Key Messages:

* Overcast with light, nuisance-type rains for most this morning,
  although some heavier showers and possible morning lightning
  strikes for the Cape and Islands.

* Decreasing clouds west to east through afternoon. Mild temps in
  the mid 50s to near 60, but not much warming anticipated.

Details:

What has now turned into a quasi-stationary frontal boundary bisects
Southern New England early this morning, trailing from about NYC on
northeast through Boston, bringing mostly light rain showers along
its extent. This boundary has stalled in response to a deamplifying
midlevel shortwave disturbance evident in water vapor imagery near
the Cincinnati/Louisville area. This stalled frontal boundary will
be the biggest forecast challenge regarding the forecast for today.
SE of this stalled boundary, in a weakly-unstable elevated-
instability environment offshore of Long Island into our southern
coastal waters, regional radar is showing deeper convective showers
and even a few thunderstorms with radar-estimated cloud tops around
20-25kft, which have prompted some MWSs for the waters. This
activity is developing in a weakly unstable airmass (MLCapes per
SPC`s mesoanalysis around 100-300 J/kg) in a theta-e ridge over the
waters. The SPC mesoanalysis forecast off the RAP shows this narrow
ribbon of instability translating eastward through the next 4 to 6
hours, which will favor additional shower and thunderstorm activity
to continue to develop and move rather quickly off towards the
northeast, primarily impacting the Cape and Islands and the adjacent
waters. Although severe weather is not expected, a few cloud to
ground lightning strikes and perhaps graupel could result in the
most intense of storms. Otherwise, due to the cloud cover and
continued SWly breezes, temperatures are well above normal for a mid-
November early morning with current readings in the lower to mid
50s.

As mentioned, the main forecast challenge for today revolves around
when this stationary boundary and its clouds/rain finally exits
stage right. The rain showers aligned along the stationary
front are light. Still, continued light rains can be expected
from the Hartford- Worcester-Boston corridor on south/east into
late this morning until the shortwave aloft over Cincinnati
vicinity gives the front its added push offshore. Further north
and west from the Merrimack Valley into the Berkshires/Pioneer
Valley, showers are expected to be more intermittent with more
drier periods in the morning than not. So the message for the
first part of the day over the southeastern half of the CWA is
that we`ll see periods of light rain showers which are more of a
nuisance than necessarily impactful. Obviously with the
overcast, diabatic warming will be at a minimum too, so
wouldn`t expect temps to go much further than the mid to upper
50s through the morning, and those will most likely serve as
today`s calendar-day highs in most if not all areas.

By afternoon, a few more peeks of sun are anticipated, sooner in
western New England and not until later in the day for eastern MA
and RI. Winds to turn light westerly with falling dewpoints.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
315 AM Update:

Key Messages:

* Mostly clear and chilly tonight, but with increasing clouds and
  slowly-warming temps before sunrise.

* Turns overcast with another round of light, nuisance rains later
  in the morning, becoming overcast and drizzly late in the
  day/early tonight. Potential for a raw Sunday with highs in the
  40s to lower 50s.

Details:

Tonight:

Sfc ridge of high pressure noses in from the NW early tonight, which
will bring decreased west winds which eventually flip a light
northerly to northeast drainage flow around midnight-ish. Strong
nighttime cooling is likely before the pre-dawn hrs.

We then enter in a period of low-level warm advection with rather
complex sea level pressure pattern for the 2nd half of the night.
Mid-level warm front, associated with a primary but occluding sfc
cyclone progged near northern Indiana early Sunday morning, spreads
a canopy of midlevel clouds over interior New England. Backed off on
populated NBM low-chance PoPs overnight for western New England as
it`s simply still too dry for precip to develop. You`d be really
digging deep into the toolbox (seeder-feeder mechanism?) to
justify showing any PoP there and I just don`t see it. Meanwhile,
secondary bagginess to isobars/possible weak low near the lower
mid- Atlantic region takes shape toward early morning, and this
should turn winds toward the SE and allow for temps to slowly
warm over eastern/southeast coastal areas from nighttime lows.

Opted for lows around freezing NW MA, to the mid/upper 30s for the
rest of SNE, but temps should be gradually trending upward prior to
sunrise with the SE flow developing.

Sunday:

Increasing clouds from SW to NE on Sun, as initial complex frontal
system traverses NE through New England. While the primary sfc wave
treks from IN/OH NE through western NY, weak secondary low pressure
and its associated warm front move northward through NY/LI into
Southern New England late in the morning to the mid-afternoon. The
timing of this warm front/related light rains is still a little
uncertain and will affect the temps. QPF amts are light, a quarter
inch or less.

Present indications are that rains approach the southern coast just
before noontime and spreads quickly N/NE through the rest of
Southern New England during the afternoon, tapering off to an
overcast/drizzly/dry-slot aloft kind of look late in the day to
early Sun night. If warm frontal rains develop sooner, say towards
mid-morning as offered by more progressive solutions, then a slower
rise to temps driven by thermal warm advection would be more likely.

I sided highs to the mid 40s NW MA to lower-mid 50s eastern and
southeast MA and CT, which is on the cooler end of outcomes in
case the light rains do come in early in the day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Key Messages:

* System brings a period of rain and breezy winds Monday.

* Trending cooler early next week, with below normal temperatures.

* Gusty winds Tuesday. 30-35 mph, locally up to 40 mph.

* Isolated shower/sprinkle or flurry over the higher terrain and
  some ocean effect showers for Cape/Islands. Round of showers
  possible later Wednesday.

Details...

Monday:

A deep upper level low and trough moves across the Great Lakes
toward the region Monday, eventually pushing in a cool airmass into
southern New England. An increasing number of global ensembles
develop a secondary area of low pressure on Monday.  Overall, not
expecting high impacts from the system as the majority of ensemble
MSLP members from the GFS and ECMWF have minimum MSLP values >995mb.
In terms of impacts, Monday should feature showers with a greater
chance for steadier rain towards the Cape and Islands. Models show a
significant frontal inversion on Monday with 925mb temps climbing to
10-15C, especially across the Cape and Islands. If these temps mixed
to the surface, we`d be looking at highs in the upper 60s for much
of southeast Massachusetts. Unfortunately, dense clouds won`t allow
for much in the way of mixing and so highs will be stuck in the 50s
for much of the region. Some colder air may seep far enough south to
keep it in the upper 40s across the higher terrain of the interior.

Tuesday-Friday:

Strong cold air advection into Tuesday as the deep upper trough
shifts eastward bringing the core of the coldest air into the
region. This will likely bring in the coldest air of the season so
far with 850mb temperatures anomalies showing well below normal
temperatures (-7 to -10C). This will support chilly temperatures
with upper 30s for the higher terrain and 40s elsewhere. NW flow
aloft with 850mb winds 40-50 kts. With CAA and ample mixing, higher
winds should be able transfer down to the surface with gusts 30-35
mph possible, potentially up to 40 mph. This will make it feel even
chillier, with it feeling like upper 20s across the higher terrain
and 30s elsewhere. Can`t rule out a few lake effect showers to
survive the trek over the Berkshires which would bring sprinkles,
perhaps a flurry for the higher spots. Ocean effect showers will be
possible with some potentially brushing the Cape and Islands in the
WNW flow.

Temperatures moderate slightly Wednesday as the core of the coldest
air shifts eastward with the upper trough. It will still be on the
cooler side with highs in the 40s for the higher terrain and low 50s
elsewhere. Parade of shortwaves continues next Thursday bringing
scattered rain and snow showers to much of New England. Can`t rule
out a lake effect shower earlier in the day to again make it to the
east slope of the Berkshires, potentially as a flurry or very light
shower. Colder airmass  works back in for the end of the week with
below normal temperatures returning to the forecast and chances for
some ocean-effect showers and a isolated remnant lake-effect shower
out west.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

12Z TAF Update:

Today: High confidence in trends but moderate on timing.

Quasi-stationary front from NYC to BOS with off-and-on periods
of P6SM -SHRA and VFR/MVFR boderline ceilings for BOS, PVD, BDL
through 16z. MVFR for the Cape and Islands with steadier light
rains. Improvement ~15-21z from west to east, with windshift to
WNW around 10 kt accompanying that improvement.

Tonight: High confidence.

VFR. Winds assume a clockwise turn NW to NE under 10 kt through
04-06z, though may trend E/ESE for the Cape and Islands with
lowering ceilings.

Sunday: Moderate confidence.

Early VFR, although conditions trend MVFR/intervals IFR ceilings
with 4-6 SM light rains with approaching warm front. Timing is
still unclear but thinking onset of sub-VFR from 14-16z south
coast to 16-18z northern MA. Categories probably deteriorate
more after the warm front lifts through, with IFR-LIFR cigs and
mist/drizzle. SE winds increase to around 10 kt near the coast,
but could trend NE to N under 10 kt for interior.

KBOS Terminal...Moderate confidence in TAF. VFR/boderline-MVFR
bases with off-and-on periods -SHRA thru 15z, drying out 16-17z
with west windshift. Winds become NW/N tonight then NE/ENE by
the pre-dawn hrs Sun.

KBDL Terminal...High confidence in TAF. BKN/OVC VFR decks,
scattering out thru the day. Winds become W then NW/N tonight.

Outlook /Sunday Night through Wednesday/...

Sunday Night: MVFR/IFR conditions possible. Breezy. RA likely.

Monday: Mainly VFR, with areas IFR possible. Breezy. Chance RA.

Monday Night: VFR. Breezy. Slight chance RA.

Veterans Day: VFR. Windy with gusts up to 35 kt. Slight chance
RA.

Tuesday Night: VFR. Windy with gusts up to 35 kt.

Wednesday: Mainly VFR, with local MVFR possible. Windy with
gusts up to 35 kt. Slight chance RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

SCAs remain in effect for most waters due to continued SW winds
around 25-30 kt and offshore seas 5-8 ft. In addition, a risk
for heavy showers and embedded lightning strikes will exist for
mariners over the southern/southeast waters, which could prompt
periodic MWSs thru mid-morning. Winds turning light W and
decreasing seas into late-day today.

Sub-SCA conditions tonight into first part of Sunday but
increasig SE winds to around 15-25 kt could support reissuing
SCAs for Sunday afternoon into evening. Another period of light
rains for Sunday as well from south to north.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Rain likely, isolated
thunderstorms. Local visibility 1 nm or less.

Monday: Winds less than 25 kt. Local rough seas. Chance of
rain.

Monday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Slight chance of rain.

Veterans Day: Strong winds with gusts up to 40 kt. Rough seas
up to 13 ft. Chance of rain.

Tuesday Night: Strong winds with gusts up to 45 kt. Rough seas
up to 14 ft. Slight chance of rain.

Wednesday: Strong winds with gusts up to 35 kt. Rough seas up
to 14 ft. Slight chance of rain.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides are still running high coming out of the full
moon from late in the week, but are slowly decreasing each high
tide cycle through the next couple days. Will have to monitor
the high tides Sunday and Monday mornings at Nantucket for
possible minor coastal flooding, with Stevens Institute
supporting about a 1 ft storm surge. Monday may offer a somewhat
better chance at getting close to minor flood stage as winds
turn more W to WNW into the harbor. Will reassess this potential
over the next day/two for possible coastal flood headlines but
significant flooding is not expected.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 AM EST this morning for ANZ230-
     236.
     Small Craft Advisory until 10 AM EST this morning for
     ANZ231>234-250-251.
     Small Craft Advisory until 7 PM EST this evening for ANZ235-
     237.
     Small Craft Advisory until 10 PM EST this evening for ANZ254.
     Small Craft Advisory until 4 AM EST Sunday for ANZ255-256.

&&

$$

SYNOPSIS...Loconto/FT
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...FT
AVIATION...Loconto/FT
MARINE...Loconto/FT
TIDES/COASTAL FLOODING...Loconto