743
FXUS61 KBOX 020740
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
240 AM EST Tue Dec 2 2025

.SYNOPSIS...
Monday brings the return to drier, colder and blustery weather. Low
pressure tracking south of New England brings accumulating snow to
interior portions of CT and MA Tuesday and Tuesday night, with rain
most likely in the lower elevations. Beyond that high pressure
brings dry weather to end the week except for a moisture starved
front Thursday.

&&

.NEAR TERM /THROUGH 6 AM WEDNESDAY/...
Key Messages:

* Coastal storm system still on track to bring accumulating snow to
  higher elevations, rain to lower elevations in southern New England

* Wet, dense snow in the interior will make for difficult travel
  during the afternoon and evening commute. Significant
  accumulations of wet snow in higher terrain could lead to tree and
  powerline damage

* Mainly rain expected for the majority of the event across lower
  elevations with totals ranging from 1-1.5", possibly approaching
  2" for some spots on the Cape and Islands

Details...

Latest guidance has trended a bit warmer since the last forecast,
however the general track and timing of the coastal storm system
remain unchanged; precipitation should start sometime in the mid-
morning to early afternoon hours, continuing through the evening
commute and ending during the overnight period. Headlines also
remain unchanged as a result.

Guidance remains in agreement that the low will track ENE along the
East Coast into New England later this afternoon before shifting
into Nova Scotia late Tuesday night. The latest model runs have
continued to have the center pass just within the 40N/70W benchmark,
which continues to favor easterly winds advecting in temperatures
above freezing for the lower elevations in eastern MA, RI, which
will keep precipitation there as mostly rain. High-resolution
guidance also continued to keep these areas above freezing through
the afternoon and evening hours (highs should be in the upper 30s
and low 40s, though higher over the Cape and Islands). Temperatures
will not get below freezing there until the overnight period. 925 mb
temperatures over the interior are expected to be generally around -
5C, with the highest elevations dipping slightly lower; surface
temperatures in these areas are generally around freezing at the
surface as well during the afternoon and evening hours, though they
are still marginal. In the highest elevations, downed powerlines and
trees may become a concern due to higher accumulations of wet snow.
Some guidance also indicated low probabilities for a snow band or
two with 1" an hour rates moving over these areas as well. Over the
highest elevations, 6-9" of wet snow with localized higher totals
can be expected, while lower parts of the interior can expect totals
within Winter Weather Advisory criteria: between 3-6". For much of
eastern MA, RI, and eastern CT, rainfall totals are expected to
range between 1-1.5". Higher totals closer to 2" are a possibility
over Cape Cod and the Islands due to the system`s forecasted track.

As the system continues to move ENE, wrap-around snow bands in the
overnight hours may lead to some snow showers in northern CT and up
into NE MA and Metrowest after seeing rain during the day. This
period is when the highest chance for some accumulating snow in
those areas is expected, though it should remain within Advisory-
level criteria. This remains favorable as temperatures there also
fall below freezing overnight. Lows tonight are expected to dip into
the teens across the interior, with the rest of the region in the
20s and low 30s.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Messages:

* High pressure builds in following the exit of the coastal storm,
  leading to cooler, drier weather

The low responsible for the active weather to start the week exits
heading into Wednesday morning and high pressure moves in behind it.
High temperatures are not expected to get higher than the low 40s
and mid 30s for the region, with some spots in the higher elevations
struggling to get above freezing. NW winds weaken and shift slightly
more to the W and SW as the day progresses.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages:

* Scattered snow showers possible Thursday.

* Arctic airmass in place Thursday night-Saturday bringing well
  below normal temperatures.

Details...

After a brief period of weak high pressure, a shortwave trough moves
through the region on Thursday accompanied by a strong cold front.
The wave is fairly moisture starved with precipitable water values
0.4-0.6". There should be a brief window with some mid-level
moisture advecting into the region. With the help of the
approaching front, this will provide lift for a few snow
showers during the day Thursday. Ensembles show low-moderate
probabilities for light QPF amounts. With marginal instability
present and approaching arctic front/airmass, global guidance
also hint at snow squall potential. Given limited moisture and
uncertainty in the details of the frontal passage, this will be
lower probability for now. A few convective showers/segments
that may be capable of a localized brief "burst" of higher snow
rates. Overall deterministic/ensemble guidance keeps totals
trace to light if anything given the localized nature of the
showers.

An arctic airmass will push in behind the front Thursday night.
850mb temperatures range -15 to -20C with mainly clear skies.
Despite breezy conditions (at least to start the night),
temperatures will likely plummet into the single digits for the
interior and teens along the coast. These are the coldest
temperatures of the season so far. As mentioned, winds may be
elevated to start the night which will bring wind chill values into
the negative single digits for the higher terrain and single digits
elsewhere. The arctic airmass remains in place for Friday support
high temperatures 10-15 degrees below normal. Highs struggle to
reach 30 degrees, with the exception of SE MA and the south coast in
the mid 30s.

Ensemble guidance shows a consensus for a transition to a more
active pattern heading into the weekend. There is a signal for a
coastal system to brush the region sometime late Friday-Saturday.
Details still less certain this far out, but this could bring
another round of precipitation to southern New England. Once timing
and track become more clear, we will get a better idea of precip
type (snow or mix/rain event).

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

06Z update...

Through 12Z...High Confidence.

VFR conditions. Ceilings developing after 09Z. Light winds.

Tuesday...Moderate Confidence (precipitation type)

Ceilings drop to IFR-LIFR as precip overspreads the region this
morning, 12-15z in west and 15-18z in the east. Ptype rain for
coastal terminals. Snow to start for BAF and ORH, with chance
for RA to mix in the afternoon. SN to RASN mix or potentially a
period of RA at BED and BDL. Lower confidence for precipitation
type due to uncertainty in location of rain-snow line. E-NE
wind 5-15 kt. Minor accumulations for BDL/BED. Light
accumulations for BAF (< 5"). 2-6" possible depending on where
RA- SN line positions. Snowfall rates less than 0.5"/hour for
terminals.

Tuesday night...Moderate confidence.

Widespread IFR-LIFR improving to VFR late from west to east
after 06Z. Light SN for interior terminals in evening. Change
over to a period of light RA/SN or light SN possible along the
I-95 corridor, including BOS and PVD for a short period. Timing
of change over is lower confidence, but would be after 03Z.
Minor accum (Trace-0.5") possible at BOS. NE wind becoming N-NNW
with gusts to 25 kt developing, with 30-40 kt gusts possible
for Cape/Islands.

Wednesday...High Confidence.

VFR. NW winds with gusts up to 22 kts (up to 25 kts for
Cape/Islands) in the morning decreasing in the afternoon.

KBOS Terminal...Moderate confidence in TAF.
Changeover to -RASN or -SN possible Tuesday night. Exact timing
lower confidence, more likely between 03-07z.


KBDL Terminal...Moderate confidence in TAF. Lower confidence in
timing of ptype changes.

Outlook /Thursday through Saturday/...

Thursday: VFR. Windy with areas of gusts up to 30 kt. Slight
chance SN.

Thursday Night: VFR. Windy with gusts up to 30 kt.

Friday: VFR.

Friday Night: VFR. Slight chance SN.

Saturday: VFR. Chance RA, slight chance SN.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Tuesday Night... High confidence.

Rain overspreads the waters and SSE winds early increase and
turn out of the east then northeast late as a low pressure
system crosses the southern waters. Gusts to 30-35 kts become
possible tonight over the eastern waters, and around 25- 30 kts
for the southern waters. Seas become rough as well, approaching
8-9 ft. Gale Warning starting 7 PM tonight through the
overnight hours for the eastern waters, while a Small Craft
Advisory is issued for the southern waters.

Seas and winds begin to diminish heading into Wednesday as high
pressure moves in over the waters.

Outlook /Thursday through Saturday/...

Thursday: Low risk for gale force winds with gusts up to 35 kt.
Areas of rough seas.

Thursday Night: Low risk for gale force winds with gusts up to
40 kt. Rough seas up to 10 ft.

Friday: Winds less than 25 kt. Seas locally approaching 5 ft.

Friday Night: Winds less than 25 kt. Slight chance of rain.

Saturday: Winds less than 25 kt. Chance of rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Storm Warning from 7 AM this morning to 7 AM EST
     Wednesday for Maz005>004-008-009-026.
     Winter Weather Advisory from 4 PM this afternoon to 7 AM EST
     Wednesday for Maz005-006.
     Winter Weather Advisory from 7 AM this morning to 7 AM EST
     Wednesday for Maz020>012.
RI...None.
MARINE...Gale Warning from 7 PM this evening to 7 AM EST Wednesday for
     Anz236.
     Gale Warning from 7 PM this evening to 1 PM EST Wednesday for
     Anz236-232-250-251-254-255.
     Small Craft Advisory from 4 PM this afternoon to 7 PM EST
     Wednesday for Anz236>235-237.
     Small Craft Advisory from 4 PM this afternoon to 7 AM EST
     Wednesday for Anz236.
     Small Craft Advisory from 4 PM this afternoon to 1 AM EST
     Thursday for Anz236.

&&

$$

SYNOPSIS...Hrencecin/Mensch
NEAR TERM...Hrencecin
SHORT TERM...Hrencecin
LONG TERM...Mensch
AVIATION...Hrencecin/Mensch
MARINE...Hrencecin/Mensch