559
FXUS61 KBOX 090802
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
302 AM EST Tue Dec 9 2025

.SYNOPSIS...

After a frigid start early this morning...a ridge of high pressure
will result in dry weather but high temperatures still well below
normal today. A moisture starved shortwave crosses the region
tonight with a period of mainly scattered light snow showers. A more
significant disturbance brings much milder temperatures and a period
of mainly rain Wednesday afternoon and evening with any snow
confined to the highest terrain of the Berkshires and northern
Worcester Hills. A cold front crosses the region later Wednesday
night...bringing mainly dry, but blustery and cold weather returning
Thursday into Friday. Low pressure may bring snow with even some
ice/rain to the region Saturday night into Sunday depending on its
track. This will be followed by another shot of arctic air and well
below normal temperatures early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

Key Messages...

* Dry & unseasonably cold today

Details...

Today...

A cold albeit quiet and dry day setting up for Tuesday. A clear cold
start will give way to increasing mid and high level clouds as a
weak mid-level disturbance begins to approach from the Great Lakes.
Arctic high pressure moves offshore resulting in an increasing
return flow and mid-level warming. Guidance shows 850mb temps
increasing from -15C in the morning to -9C or so by the afternoon.
Will be a cold day with temps rising from the single digits to the
teens and lower 20s by the afternoon.  Winds will become southerly
then eventually southwesterly by the afternoon as WAA increases.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...

Key Messages...

* Scattered light snow showers tonight with accumulations mainly
  a dusting to less than 1 inch

* Stronger disturbance arrives from the Great Lakes Wednesday
  afternoon w/ rain and accumulating elevation snow possible.

Tonight...

Increasing mid-level frontogenesis under an upper level impulse will
bring a brief period of showery precipitation from west to east
between 02-06z. Expecting negligible snow totals (dusting to an
inch) across the interior as the precipitation will have to overcome
a fairly deep layer of drier air. Rain showers more likely S of I-95
as temps warm near or above freezing. Overall a low impact event
that will last for only a few hours. Still, there could be slick
spots as partial clearing cools temps down a few degrees late
Tuesday night.

Wednesday...

A stronger clipper disturbance approaches from the Great Lakes
Wednesday morning. Precip should start as a period of snow between
14-16z north of route 202 in northern Massachusetts. Elsewhere, the
temperatures will likely yield rain as the region finds itself in
the system`s warm sector. Temperatures may actually be somewhat mild
SE of I-95 as highs approach 50. Expecting generally light QPF with
the NBM advertising up to 0.5". Best chance for accumulating snow
will be in the elevated terrain of northern Mass where event totals
1-3 inches are possible. Widespread precipitation shuts down later
Wednesday afternoon as a dry slot develops. A few lingering rain
showers in the Berkshires change back over to snow behind a cold
front Wednesday night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

Key Messages...

* Lingering showers/highest terrain snow showers depart Wed evening

* Cold and windy Thu with continued cold weather Fri...Highs in the
  upper 20s/30s with dry weather outside a brief spot snow shower

* Low pressure may bring snow or even some ice/rain to the region
  Sat night into Sun depending on its track which remains uncertain

* Another shot of arctic air Mon into Tue with unseasonably
  cold highs in the 20s to the lower 30s and mainly dry weather

Details...

Wednesday night...

Intensifying low pressure moves eastward along the northern New
England and Quebec border Wednesday night...dragging a cold front
across our region. Lingering rain showers with any snow showers
confined to the highest terrain of the Berks/northern Worcester
Hills will come to an end Wednesday evening. It will turn rather
blustery behind this cold front later Wednesday night with
increasing west winds. Overnight low temps should mainly be in the
25 to 35 degree range with the mildest of those readings near and
southeast of the I-95 corridor.

Thursday...

Windy and colder weather returns to the region on Thursday. Strong
cold advection will result in 850T dropping to between -13C/-14c.
This should result in steady or slowly falling temperatures with
afternoon temperatures mainly in the upper 20s to the middle 30s.
Bufkit indicates excellent mixing which should yield westerly wind
gusts of 25 to 40 mph. This will result in afternoon wind chill
values mainly in the teens to the lower 20s.

Dry weather should generally prevail...but given cold westerly flow
some remnant lake effect moisture may result in a brief spot snow
shower/flurry or two.

Thursday night and Friday...

Strong low pressure just east of the Canadian Maritimes will
continue to generate a blustery westerly flow of dry but cold air
into southern New England. Lows Thu night will mainly be in the
teens to the middle 20s with highs Fri in the upper 20s and middle
30s.

This Weekend...

The forecast becomes rather complex this weekend. Low pressure
developing in the Tennessee Valley will be lifting northeast towards
the mid-Atlantic states. At the same time...northern stream energy
will be dropping another shot of arctic air into the Great Lakes.
The timing and amplitude of this shortwave energy will determine the
track of the low pressure system. FWIW the latest 00z guidance has
trended north with this low pressure system...particularly some of
the EPS/CMC ensembles. That being said...there was still significant
spread though among many of the individual ensembles. While plenty
of uncertainty remains...the trend was towards a greater risk for a
period of snow Sat night into Sun. However...the potential for more
northern solutions also introduces the risk for some ice/rain
getting involved especially south of I-90. We will need a few more
days to have a better idea on this potential...but certainly
something to watch in the next few days.

Monday and Tuesday...

Regardless of what happens this weekend...it appears that another
shot of arctic air with well below normal temperatures will move
into the region early next week. Highs probably will only be in the
20s to the lower 30s and perhaps even colder than that if the latest
00z ECMWF verifies.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...

Forecaster Confidence Levels...

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

06z TAF Update...

Tonight through Tuesday... High Confidence.

Light northerly wind tonight becoming calm. Wind direction on
Tuesday starts out of the west less than 5 knots, becoming south-
southwest 8-12 knots after 15z. Lowering ceilings but still solidly
VFR thru the day.

Tuesday Night... Moderate Confidence.

VFR, lowering to MVFR/IFR, isolated to scattered snow and/or rain
showers possible after 00z through 06z, with minor accumulation on
runways less than an inch, especially across northern areas. Wind
from the southwest are gusting up to 15 knots over land and 25-30
knots over the coastal terminals.

Wednesday... Moderate Confidence.

Widespread precipitation arrives from W-E between 14 and 16z.
MVFR/IFR, perhaps areas of LIFR across interior MA. Areas of SN and
SHSN to start, turning to rain for most terminals by the afternoon.
Possible LLWS across interior and western MA by the afternoon.

KBOS Terminal...High Confidence in TAF.

KBDL Terminal...High Confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly IFR, with local MVFR possible. Windy
with gusts up to 35 kt. Chance SHRA, slight chance SHSN.

Thursday through Thursday Night: VFR. Windy with gusts up to
30 kt. Slight chance SHSN.

Friday: VFR. Windy with gusts up to 30 kt.

Friday Night: VFR. Breezy. Slight chance SHSN.

Saturday: VFR. Breezy. Chance SHRA, slight chance SHSN.

&&

.MARINE...

Forecaster Confidence Levels...

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

Today through Wednesday...High confidence.

Winds shift to the southwest this afternoon as high pressure
moves east of the region. Strong LLJ allows for SW wind gusts of
35 knots to develop late tonight with another round on
Wednesday. Therefore...Gale Watches have been issued for all
open waters late tonight into Wednesday. Long southwest fetch
should allow seas to build to between 6 and 12 feet across our
southern waters.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Low risk for gale force winds with gusts up to
35 kt. Areas of rough seas. Chance of rain showers. Areas of
visibility 1 to 3 nm.

Thursday: Moderate risk for gale force winds with gusts up to
35 kt. Areas of rough seas. Local visibility 1 to 3 nm.

Thursday Night: Moderate risk for gale force winds with gusts
up to 40 kt. Areas of rough seas. Slight chance of snow
showers.

Friday: Moderate risk for gale force winds with gusts up to
35 kt. Local rough seas.

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of seas approaching 5 ft. Slight
chance of rain showers, slight chance of snow showers.

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. Chance of rain showers,
chance of snow showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 10 PM this evening to 7 PM EST
     Wednesday for ANZ230-236.
     Gale Watch from late tonight through Wednesday evening for
     ANZ231>235-237-250-251-254>256.

&&

$$

SYNOPSIS...Frank
NEAR TERM...FT
SHORT TERM...FT
LONG TERM...Frank
AVIATION...FT/Frank
MARINE...FT/Frank