014
FXUS61 KBOX 191808
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
108 PM EST Fri Dec 19 2025

.WHAT HAS CHANGED...
Strong to damaging wind gusts have been experienced across parts of
southern New England, these winds are expected to continue into the
early afternoon. A shift in wind direction from south to west occurs
there after with wind gusts this evening and overnight between 35
and 50 MPH, prompting the extension of the Wind Advisory into early
Saturday morning.

&&

.KEY MESSAGES...

- Damaging southerly gusts through this afternoon as a powerful
  low-level jet and cold front push across the region. Drying
  conditions late today with strong post frontal westerly winds.

- Quiet conditions Saturday and Monday, with Sunday featuring
  the potential for additional strong wind gusts.

- Shortwave brings a period of gusty winds and much colder air
  Sunday night into Monday.

- Weak disturbance may bring a period of light snow Tuesday
  afternoon.

&&

.DISCUSSION...
KEY MESSAGE 1...Damaging southerly gusts through this afternoon
as a powerful low- level jet and cold front push across the
region. Drying conditions late today with strong post frontal
westerly winds.

A mighty low-level jet has brought damaging southerly gusts across
the region late this morning and these conditions will continue into
early afternoon. Wind gusts have ranged between 45 and 65 MPH across
much of southern New England. But a few notable gusts include; the
Blue Hill Observatory with a gust of 72 MPH and a gust of 82 MPH at
the Southeast Lighthouse on Block Island. This system is quickly
exiting the region, the core of the jet shifting east of Cape Cod
between 2 PM and 4 PM this afternoon. High Wind Warnings for coastal
areas of RI/MA and the coastal plain remain in effect through early
this afternoon. Areas under the warning will convert to an advisory
for post frontal winds that are driven by strong cold air advection.

BUFKIT forecast soundings indicate deep mixing of the boundary layer
which could extend to 850mb, where winds are 35 to 45 knots. With
the steep low-level lapse rates, should be able to transfer a fair
amount of the energy to the surface this evening through sunrise on
Saturday morning, winds quickly diminish there after. Have extend
the Wind Advisory through due to the ongoing wind threat. Gusts for
tonight will not be as intense, but are still blowing 35 to 50 MPH
from the west. That said, gusts up to 60 MPH are possible for the
highest terrain of eastern Berkshires and northern Worcester Hills,
but didn`t have enough confidence to issues a High Wind Warning
here.

As for precipitation, this is wrapping up early this afternoon with
a brief change over to snow showers possible as the CAA develops.
Otherwise, drying conditions overnight, PWATs fall from 1.3" to less
than 0.3". And as for temperatures, fall from the 50s this afternoon
through the 20s overnight. Given the strong winds overnight, this
should help to dry out the ground and limit any formation of black
ice.

KEY MESSAGE 2...Quiet conditions Saturday and Monday, with
Sunday featuring the potential for additional strong wind gusts.

High-pressure briefly returns Saturday with easing winds, sunshine,
and seasonable temperatures. While dry conditions likely continue on
Sunday, a developing low pressure system moves across Quebec and the
trailing cold front extending into southern New England. Another day
with gusty winds, starting from the southwest and going northwest.
Winds aloft are 40 to 60 knots, don`t think as much wind transfers
to the surface on the southwest wind direction, but when wind shift
to northwest with the CAA, gusts should develop between 35 and 45
MPH. Mainly dry period, outside of an upslope snow shower across the
far western areas of MA. Monday, 1035mb high-pressure sets up to the
southwest with dry and chilly conditions expected.

KEY MESSAGE 3... Shortwave brings a period of gusty winds and
much colder air Sunday night into Monday

A mid-level shortwave trough moves through late Saturday into Sunday
bringing scattered rain and snow showers mainly across far northern
Massachusetts. The larger concern will be for another period of
elevated winds especially Sunday night into Monday. Continuing to
see two periods of strong low level winds Sunday and Monday. First
will be early Sunday morning as a southwest low level strengthens to
40-50 mph as warm air advection increases. Limiting factor will
timing as the core of the jet passes through between 06-12z. There
will still be locally better mixing (lapse rates between 4-6 C/km)
at coastal locations and across the elevated terrain. These areas
could winds gust as high as 40-45 mph thru 12z Sun. Another round of
more widespread gusty winds arrives later Sunday behind a strong
cold front. Strong mid and low level cold air advection will help to
mix a 40-55 mph low level jet to the surface. Expecting widespread
gusts of 40-45 mph from 00z-15z Monday.

Additional concern for Monday will be a significantly colder airmass
Monday. Temps at 850mb plunge to around -15C which should translate
to low temperatures ranging from the mid teens in the interior to
the mid 20s for the Cape and Islands. These cold temps paired with
strong NW winds push wind chill temperatures down into the lower
single digits in elevated interior areas and lower to middle teens
elsewhere.

KEY MESSAGE 4... Weak disturbance may bring a period of light
snow Tuesday afternoon.

By Tuesday an upper level disturbance over northeast Quebec helps
form a weak surface low near the international border. Guidance
shows a broad area of warm advection on the southern side of the low
as it moves southeast. Forcing from the warm advection could be
enough for widespread snow showers/light snow Tuesday into Tuesday
afternoon. Latest NBM shows a light event with probabilites of
greater than 1 inch of accumulation Tuesday generally below 30
percent and confined to the higher elevations of Massachusetts.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

18z TAFs: High confidence (60%).

Strongest S winds with gusts to 40-50kt will persist through 21z
before winds shift to W/SW and subside a bit as cold front
approaches. LLWS will remain an issue with 020 winds 40-60kt
except 70-75kt along coastal areas. Another surge of 35-45kt
gusts expected tonight as colder air arrives. W/NW winds
gradually diminish overnight and Sat.

MVFR/IFR conditions persist through late afternoon in -SHRA, and
we may see a change to -SHSN across western/central MA this
evening but no accumulation. VFR later this evening through Sat
night.

KBOS Terminal...High confidence in TAF. Strongest gusts through
21z with LLWS.

KBDL Terminal...High confidence in TAF. Strongest gusts through
21z with LLWS.

Outlook /Sunday through Wednesday/...

Sunday through Monday: VFR. Windy with gusts up to 35 kt.

Monday Night: VFR. Chance SN.

Tuesday: MVFR/IFR conditions possible. Breezy. SN likely,
chance RA.

Tuesday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance RA.

Wednesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Saturday Night...High Confidence.

Storm Warnings are in effect through 3 PM this afternoon, westerly
Gale Force conditions are expected to continue into Saturday morning.

Seas will build to near 15 ft on the outer waters. Winds briefly
drop off later this afternoon as the low level jet moves to the
east, then another pulse of 35-45 kt gusts from the W develops
tonight behind the cold front. Winds will quickly diminish through
the day Saturday with subsiding seas.

Outlook /Sunday through Wednesday/...

Sunday through Sunday Night: Strong winds with gusts up to
35 kt. Rough seas up to 10 ft.

Monday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Areas of rough seas.

Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of snow.

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. Rain likely, chance of
snow. Local visibility 1 to 3 nm.

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

Wednesday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 1 AM EST Saturday for CTZ002>004.
MA...Wind Advisory until 1 AM EST Saturday for MAZ002>006-008>014-
     017-018-026.
     High Wind Warning until 3 PM EST this afternoon for MAZ007-
     015>024.
RI...Wind Advisory until 1 AM EST Saturday for RIZ001>003.
     High Wind Warning until 3 PM EST this afternoon for RIZ002-
     004>008.
MARINE...Storm Warning until 3 PM EST this afternoon for ANZ230>236-251.
     Gale Warning until 7 AM EST Saturday for ANZ237-256.
     Storm Warning until 4 PM EST this afternoon for ANZ250-254-255.

&&

$$

DISCUSSION...Dooley/FT
AVIATION...JWD
MARINE...Dooley/FT