Snow Squall Warning 3, NWS Boston/Norton, MA

Area Forecast Discussion
National Weather Service Boston/Norton MA
634 AM EST Thu Jan 1 2026

.WHAT HAS CHANGED...
Winter Weather Advisory canceled across Franklin and Hampshire
Counties, which are now behind an arctic front. Expecting Winter
Weather Advisories will likely be canceled early as this arctic
front moves by. Gale Warnings downgraded to Small Craft
Advisories for Boston Harbor and narragansett Bay.

&&

.KEY MESSAGES...

- Light to moderate snowfall this morning, possibly ending with
  a snow squall due to an incoming arctic cold front.

- High pressure brings dry conditions and continued cold
  temperatures through most of the weekend.

- Increasing chance for snow showers on Sunday.

- Light to moderate freezing spray over the waters is possible
  into this weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Light to moderate snowfall this morning,
possibly ending with a snow squall due to an incoming arctic
cold front.

Latest guidance continued to tweak critical forecast parameters,
mainly temperatures and total precipitation. The last few runs
of the HRRR, along with the 00Z HREF, appeared to have a rather
good handle on the snowfall timing this morning. This included
the possibility of a snow squall along an arctic cold front
crossing our region later today.

Temperatures were slightly higher and total projected
precipitation was slightly less. This combination leads to
slightly lower snowfall. Made changes to the Winter Weather
Advisory this morning where it is no longer expected that 3 or
more inches of snowfall will accumulate.

Timing-wise, expecting the steadiest snowfall to be over for
most of southern New England by 7 AM, and finally clearing
eastern MA by about 10 AM. It will take a little longer for this
snow to move past the coastal waters.

Strong cold advection will mean temperatures not changing much
this morning, and likely falling from late morning through this
afternoon.

KEY MESSAGE 2...High pressure brings dry conditions and
continued cold temperatures through most of the weekend.

By Friday, high pressure will begin to dominate across southern
New England and a dry pattern will emerge. High pressure
combined with 925 mb temperatures between -10C and -15C will
allow for high temperatures through Monday to remain relatively
stable, in the mid 20s to lower 30s. Overnight lows are likely
to be slightly more variable, in the mid teens through the first
half of this weekend, then dropping to single digits to lower
teens by Sunday night.

Some guidance is indicating southern New England could see
another round of snow on Monday. However, uncertainty on timing,
placement, and snow amounts remains high. Something to keep an
eye on through this weekend.

KEY MESSAGE 3...Increasing chance for snow showers on Sunday.

00z guidance has begun to narrow in on the possibility of
southern New England seeing another round of Snow on Sunday.
General consensus indicates a northern stream disturbance and a
more diffuse disturbance along the southern jet. Thinking these
two systems will be separated by a weak low, and the southern
system should remain offshore with the northern system bringing
the snow impacts. However, uncertainty remains high on snowfall
totals at this time.

KEY MESSAGE 4...Light to moderate freezing spray over the waters
is likely into this weekend.

A lengthy period of cold air over the warmer waters will give
rise to the likelihood of freezing spray becoming a concern for
mariners through at least Saturday, and possibly into early next
week as well. There is potential for moderate freezing spray
late tonight into early Friday, therefore a Freezing Spray
Advisory has been issued for the waters off of Cape Ann,
Buzzards Bay, Vineyard Sound, and Nantucket Sound.

&&

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

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

This morning...High confidence.

IFR to briefly LIFR conditions under snow showers this morning
across southeast MA. VFR elsewhere. Steadier snow should be
departing southeast MA by 13z. A brief, secondary round of snow
is likely to move through from west to east with a cold front
between 12-16Z with brief MVFR conditions. Westerly winds with
gusts of 25-35 knots developing this morning behind this arctic
front.

This afternoon and Tonight...High confidence.

VFR conditions. WNW wind gusts of 25 to 35 knots this afternoon
gradually diminish tonight and become more westerly.

Friday...High confidence.

VFR with gusty W winds.

KBOS Terminal...High confidence in TAF. Snow continues until
about 10z/11z. A brief round of scattered snow showers, and
perhaps a localized snow squall, will then be possible with the
cold frontal passage through about 15z.

KBDL Terminal...High confidence.

High confidence in TAF. Snow continues until about 08z/09z. A
brief round of scattered snow showers and perhaps a localized
snow squall will then be possible with the cold frontal passage
through about 13z/14z.

Outlook /Friday Night through Monday/...

Friday Night through Saturday: VFR. Breezy.

Saturday Night through Sunday: VFR. Slight chance SN.

Sunday Night: VFR. Breezy.

Monday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

* Northwest Gale Force Winds through Friday morning along with
  the threat of moderate freezing spray for some waters.

Through Tonight...High Confidence.

Southwest flow early this morning shifts west by mid morning. An
arctic front moving past the waters by early afternoon then
shifts winds to the northwest with Gale Force gusts through
tonight for most waters. Easing wind by Friday morning.

Threat for moderate freezing spray for waters north of Cape Ann
to the Merrimack River, as well as Buzzards Bay, Vineyard Sound,
and Nantucket Sound between this evening and Friday morning.

Outlook /Friday Night through Monday/...

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. Freezing spray.

Saturday: Winds less than 25 kt. Areas of seas approaching
5 ft.

Saturday Night through Sunday: Winds less than 25 kt. Slight
chance of snow.

Sunday Night: Winds less than 25 kt. Freezing spray likely.

Monday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 1 PM EST this afternoon for
     CTZ003-004.
MA...Winter Weather Advisory until 1 PM EST this afternoon for
     MAZ004-012-017>022-026.
RI...Winter Weather Advisory until 1 PM EST this afternoon for
     RIZ001>007.
MARINE...Small Craft Advisory until 1 AM EST Friday for ANZ230-236.
     Gale Warning until 4 AM EST Friday for ANZ231>235-237-251.
     Freezing Spray Advisory from 10 PM this evening to 1 PM EST
     Friday for ANZ232>234-250-251.
     Gale Warning until 7 AM EST Friday for ANZ250-254-255.
     Gale Warning until 7 AM EST Friday for ANZ256.

&&

DISCUSSION...Belk/McMinn
AVIATION...Belk/McMinn
MARINE...Belk/McMinn