492
FXUS61 KBOX 181104
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
604 AM EST Tue Nov 18 2025

.SYNOPSIS...
Breezy and cool again today with mostly sunny skies. High pressure
builds overhead for Wednesday and Thursday bringing relatively light
winds and continued seasonable temperatures. A cold front will bring
a period of unsettled weather Friday which may linger into Saturday,
then high pressure returns next Sunday.

&&

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

* Less windy but cold today with wind chill values in the 30s.

Today

The pressure gradient begins to relax today as high pressure nudges
north from the mid-Atlantic.  As a result, it will be less windy,
with NW gusts around 20-25mph, as opposed to 30-35mph yesterday.
Skies should stay mostly clear with a few diurnal cumulus under
subsidence and dry air aloft.  Even with sunny skies, cold air
advection will keep highs in the low to mid 40s with wind chill
values in the 30s.

Tonight

The wind finally dies off after sunset this evening as high pressure
builds overhead.  A wave of low pressure passes to our south
overnight, but we shouldn`t see anything more than increased cloud
cover, with rain staying well to the south with too much dry air
over SNE.  Low temperatures will drop into the low to mid-20s with
good radiational cooling conditions.

&&

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

* Mainly dry with clearing skies and seasonably cool temperatures.

* Clear and cold overnight.

A positively tilted trough and shortwave ejects off the Mid Atlantic
coast early Wednesday. As mentioned, the region is dry, with the low
risk, less than 20%, of rain across Block Island, Martha`s Vineyard,
and Nantucket. Dry air advects in from the northwest and an area of
high pressure settles in, leading to sunshine Wednesday afternoon. A
seasonably chilly day, with 925mb temperatures +/- 1C, expecting the
afternoon temperatures to only reach the low to middle 40s. Winds
are light, less than 10mph from the northwest. With high pressure in
place Wednesday night, skies remain clear with light winds, this
allows for effective radiational cooling. Waking up Thursday morning
temperatures are largely in the 20s. Slightly cooler across the
higher terrain of western Massachusetts in the teens while immediate
coastal locations are near the middle 30s.

&&

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

* Quiet conditions Thursday, with a few showers possible Friday into
  Saturday morning with frontal passage.

* Near seasonable conditions through early next week.

Surface high pressure provides dry and seasonably cool conditions on
Thursday. On Friday, there is good agreement among the deterministic
models and ensemble members for a robust shortwave to move across
northern New England. Ahead of the front will have southwest flow,
this should help boost temperatures into the lower and middle 50s.
When it comes to available moisture, the GFS and Canadian favor
higher PWATs near 1.0" while the ECMWF is less, around 0.5" and
0.7", notably, ECMWF AIFS is less than 0.5". This does not appear to
be a washout by any means. Timing precipitation is a little uncertain,
but is trending late Friday. With colder arriving overnight a few
snow showers are possible by Saturday morning for western and
northern parts of central Massachusetts.

Saturday through Monday, the 500mb pattern shows somewhat zonal flow
from Pacific Northwest to the northeast, along with surface an area
of high pressure building to the southwest. Don`t see any impactful
systems at this time. And as for temperatures highs are generally in
the upper 40s to 50F and nighttime lows in the 30s.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

12Z TAF Update...

Today... High Confidence.

VFR. Gusty W/WNW winds 20 to 25 knots.

Tonight... High Confidence.

VFR. Gusts diminish, WNW wind less than 10 knots across much of
the region. Wind could become calm at terminals like; KBDL/KBAF
and KBED. Increasing clouds during the second half of the night
with ceilings 040-070 for the south coast of MA & RI.

Wednesday... High Confidence.

VFR. NW to NNW wind less than 8 knots.

KBOS Terminal...High confidence in TAF.

VFR. Gusty NW winds continue through this afternoon up to 25
knots.

KBDL Terminal...High confidence in TAF.

VFR. Gusty NW winds continue through this afternoon up to 20
knots.

Outlook /Thursday through Saturday/...

Thursday: VFR.

Thursday Night: Mainly VFR, with areas MVFR possible. Slight
chance RA.

Friday: Mainly VFR, with local IFR possible. Breezy. Chance RA.

Friday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance RA.

Saturday: VFR. Slight chance RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Wednesday... High Confidence.

Strong area of low pressure near the Canadian Maritimes, but area of
high pressure building across the Mid Atlantic, this leads to gusty
northwest flow today. Pressure gradient slacken with diminishing
winds and lowering seas by tonight, until a Small Craft Advisory
remains in effect. A weak low pressure system passes south of the
waters on Wednesday, a few showers early in the morning are possible
for the waters south of the islands. Seas Wednesday are 2-3 feet
with light northwest winds, gusts less than 15 knots.

Outlook /Thursday through Saturday/...

Thursday through Thursday Night: Winds less than 25 kt.

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

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 1 PM EST this afternoon for
     ANZ230>237-251.
     Small Craft Advisory until 7 PM EST this evening for ANZ250-
     254>256.

&&

$$

SYNOPSIS...Dooley/KP
NEAR TERM...KP
SHORT TERM...Dooley
LONG TERM...Dooley
AVIATION...Dooley/KP
MARINE...Dooley/KP