529
FXUS61 KBOX 301110
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
610 AM EST Sun Nov 30 2025

.SYNOPSIS...
A warm front brings a period of rain and wind late this morning into
this evening, with rain moderate to heavy at times, along with
milder conditions. A cold front ushers in a return to drier and
colder conditions Monday. Low pressure tracking south of New England
likely brings accumulating snow to interior portions of CT and MA.
However, details regarding the rain/snow line and specific
accumulations are still quite uncertain.

&&

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

* Low pressure brings rain later Sunday into Sunday night.

* Milder, with highs in the 40s to lower 50s in SE MA

* Becoming breezy with south winds 15-25 mph

Cloudcover has overspread southern New England early this morning as
a warm front approaches our doorstep from the south. Isentropic lift
will increase through the day as does moisture with a plume of
0.75+" PWATs over southeast MA/RI. This is where the focus for the
bullseye of rainfall totals will be over the next 12-24 hours as the
peak moisture plume aligns with the core of the LLJ. The parent low
is transient so rain arrives after noon and is fully offshore by
midnight; up to a half inch of rain expected over southeast MA with
lesser amounts north and west. This moist southerly flow is also
quite mild, pushing temps into the mid 40s to low 50s. This
afternoon winds pick up, gusting 20-30 mph in spots.

The cold front swings through between 7pm and 1am ushering in a
drier NW flow and shutting off the rain showers.

&&

.SHORT TERM /MONDAY/...
Key Messages...

* Dry and seasonable.

Cool NW flow persists on Monday keeping skies clear and temperatures
in the upper 30s/low 40s. This is several degrees below average for
early December as is, but it will also feel even colder (20s/low
30s) thanks to breezy NW winds the first half of the day. High
pressure briefly becomes centered overhead Monday evening.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Key Messages

* A coastal low-pressure system will bring substantial precipitation
  to southern New England Tuesday into Tuesday Night, with the
  potential for a plowable/shovelable snow for interior southern New
  England

* Mainly colder and drier Wednesday into Friday, with next chance
  for precipitation Friday night into Saturday

Winter Storm Tuesday and Tuesday Night...

Significant detail differences continue to impact the forecast for a
low pressure passing by our region Tuesday into Tuesday night. Some
of the latest guidance suite notably the GFS and Canadian, have
trended their tracks farther north. This time being inside of the
40N/70W benchmark. Meanwhile, other members continued to linger near
or south of that point. With no blocking high over Quebec to trap
low level cold air across southern New England, the track and timing
details will greatly impact temperatures. Minor changes to
temperatures around freezing will have a major impact on
precipitation type, and ultimately snowfall accumulations.

The latest NationalBlend data continued to show some mixed messages,
highlighting the remaining uncertainty. While uncertainty decreased
across portions of central and western MA and northern CT,
uncertainty increased across eastern MA. The 50 percent confidence
interval for 24-hour snowfall ending 7 AM Wednesday lowered to 4-5
inches, while across eastern MA it increased to 10-14 inches.
Expecting changes almost up to the last minute with this
particular event.

Continue to have the greatest confidence in accumulating snowfall
across the higher terrain of the northern Worcester Hills and east
slopes of the Berkshires. Still no certainty on the amounts.
However, there are moderate probabilites (50-70%) for at least 3
inches of snowfall, and about a 30-45% chance for 6 or more inches
of snowfall. The probabilities only go down from there towards the
I-95 corridor between Boston and Providence, about 30-45% for at
least 3 inches of snowfall and 15-25% for at least 6 inches of
snowfall.

Late this week...

Low pressure is expected to depart for the Maritimes Wednesday. A
high pressure should then move from the Ohio Valley into the central
Appalachians. This positioning should send much colder air our way,
that peaks around Thursday night into Friday. Slight warmup
thereafter, but still cold enough to likely support some more
snowfall Friday night into Saturday away from the coastal influence.
Water temperatures are still in the 40s and 50s, and that is a lot
to overcome.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

12Z update...

Today...High confidence on trends, moderate on timing.

VFR to start the day, but rain and MVFR conditions quickly
overspread CT/MA/RI between 16z-19z from west to east. Then a
period of IFR/LIFR possible 20z-02z from west to east, in
moderate to heavy rain, low cigs and areas of fog. Winds light
SE in the morning, S 15-25 KT afternoon and evening with gusts
up to 30 kt along the south coast. This should minimize LLWS,
however the core of the low level jet may yield marginal LLWS
21z Sun to 03z Mon over southeast MA, WS020/18045KT.

Tonight...high confidence on trends, moderate on timing.

MVFR/IFR at 00z quickly improving to VFR with FROPA and the
wind shift to the west 15-25 kt.

Monday...High Confidence.

VFR. NW wind 5-10 kts gusting 20-25 kts, diminishing late
afternoon.

KBOS Terminal...High confidence in TAF through Sunday morning.

KBDL Terminal...High confidence in TAF through 12z Sunday, then some
uncertainty on exact timing details.

Outlook /Monday Night through Thursday/...

Monday Night: VFR.

Tuesday: Mainly IFR, with areas MVFR possible. Breezy. RA,
chance SN.

Tuesday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SN, chance RA.

Wednesday through Wednesday Night: VFR. Breezy.

Thursday: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 30 kt.

&&

.MARINE...
Forecaster Confidence Levels...

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

Sunday through Monday...High confidence.

Dry weather and good vsby prevail through this morning, then a warm
front brings rain late Sunday morning into Sunday evening, with fog
limiting vsby to 1-3 miles at times. Light SE winds this morning
become south in the afternoon and evening, increasing with gusts up
to 30 kt. Then a cold front sweeps across the RI/MA waters later
tonight, ushering in dry weather and a wind shift to the west, with
speeds 15-25 kt. Monday winds are NW 10-15 kts gusting 20-25 kts.

Seas of 2-4 ft this morning increase to 4-6 ft by this evening and 6-
8 ft on southern waters tonight. Seas decrease through the day on
Monday.

Outlook /Monday Night through Thursday/...

Monday Night: Winds less than 25 kt.

Tuesday: Winds less than 25 kt. Chance of rain. Areas of
visibility 1 to 3 nm.

Tuesday Night: Strong winds with gusts up to 35 kt. Areas of
rough seas. Chance of rain.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 11 ft.

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

Thursday: Strong winds with gusts up to 40 kt. Areas of rough
seas.

&&

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

&&

$$

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