Lexington Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 220640
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
240 AM EDT Thu Oct 22 2026

.WHAT HAS CHANGED...
The offshore coastal storm has been classified as Subtropical Storm 
Josephine, though expected impacts across southern New England 
remain largely unchanged. Brief storm-force gusts are possible 
across the outer southeastern waters today, but confidence remains 
too low to upgrade Gale Warnings. Small Craft Advisories will likely 
be needed as Gale Warnings expire from west to east tonight into 
Friday.

&&

.KEY MESSAGES...

- Subtropical Storm Josephine brings showers to far 
  southeastern Massachusetts, along with dangerous marine 
  conditions and gusty winds.

- Fairly cool on Friday with a very low chance of an early
  morning shower over the eastern waters. Otherwise, moderating
  temperatures and dry conditions are expected for the weekend
  into early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Subtropical Storm Josephine brings showers to far 
southeastern Massachusetts, along with dangerous marine conditions 
and gusty winds.

The coastal storm we've been monitoring this week acquired 
subtropical characteristics Wednesday afternoon and was classified 
as Subtropical Storm Josephine by the National Hurricane Center 
(NHC). The storm remains roughly 250 to 300 miles south-southeast of 
Nantucket over the warm waters of the Gulf Stream. So, what does 
this mean for southern New England? Simply put, the change in 
classification does not alter our expected impacts. As discussed 
last night, our forecast and messaging remain largely unchanged. In 
fact, the NHC anticipates Josephine will transition to a post-
tropical cyclone later today.

Dangerous to life-threatening marine conditions remain the primary 
concern, particularly across the ocean waters southeast of 
Nantucket. Gale Warnings remain in effect across the coastal waters. 
There is potential for a brief period of storm-force gusts of 50 kt 
or greater across the outer southeastern waters this morning into 
early afternoon. However, confidence in the coverage and duration of 
these stronger gusts remains too low to warrant an upgrade to Storm 
Warnings at this time.

On land, north to northeast wind gusts of 20 to 30 mph are expected 
across the interior, with 35 to 45 mph along the coastal plain, 
strongest across Cape Cod and the Islands. Beach erosion also 
remains possible along east-facing shorelines due to persistent 
northeast winds and large waves.

As of early this morning, KBOX radar returns show a shield of 
precipitation pivoting westward toward Cape Cod and the Islands. 
However, much of this precipitation is struggling to reach the 
ground due to dry air near the surface associated with high pressure 
to our north. Most of southern New England will remain dry, although 
a few light showers could extend as far west as southeastern 
Massachusetts, generally east of a New Bedford to Plymouth line. The 
greatest chances for measurable rainfall remain from Nantucket to 
Chatham through the first half of today.

Farther west, sunshine will allow temperatures to reach the middle 
60s, while persistent cloud cover across eastern portions of the 
region will keep highs in the upper 50s to lower 60s. Northeast 
winds gradually diminish from west to east this afternoon as 
Josephine tracks northeast into the North Atlantic, aided by an 
approaching northern-stream shortwave and associated trough.

KEY MESSAGE 2...Fairly cool on Friday with a very low chance of an 
early morning shower over the eastern waters. Otherwise, moderating 
temperatures and dry conditions are expected for the weekend into 
early next week.

As Josephine transitions to a post-tropical cyclone and departs into 
the North Atlantic, surface high pressure builds into southern New 
England from the west. A northerly breeze will likely persist 
Friday, although winds will be considerably lighter than the past 
few days as the pressure gradient relaxes. Despite abundant 
sunshine, northerly flow will maintain a cooler air mass, with highs 
mainly in the lower to middle 50s. An isolated shower cannot be 
ruled out over the eastern coastal waters early Friday, but 
otherwise dry conditions are expected.

Depending on how quickly winds decouple Friday night, Saturday 
morning could feature a frosty start across portions of the 
interior, with lows in the upper 20s to middle 30s. Similar 
overnight temperatures are possible Sunday morning as well.

Otherwise, high pressure promotes subsidence and generally quiet 
weather through the weekend and into early next week. Temperatures 
gradually moderate, with daytime highs returning to the lower and 
middle 60s and overnight lows increasing a few degrees each day as 
warmer air advects into the region aloft.

Looking ahead to Tuesday, guidance suggests a cold front may 
approach southern New England. However, the front will be situated 
between two strong areas of high pressure, limiting available 
moisture and potentially slowing its southward progression. High 
pressure may even suppress the front, allowing dry conditions to 
persist into Wednesday. Uncertainty remains regarding the timing and 
strength of any frontal passage, so it is still too early to provide 
much detail on associated sensible weather impacts.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

06Z TAF Update:

Today...High confidence in trends, though moderate confidence in 
shower coverage.

VFR conditions prevail at terminals north and west of I-95. The 
greatest potential for SHRA and MVFR ceilings remains across Cape 
Cod and the Islands. Showers should end between 12Z and 14Z across 
Cape Cod and Martha's Vineyard, and between 16Z and 19Z at ACK. 
Ceilings improve to VFR between 16Z and 19Z. NE winds of 15 to 25 kt 
along the eastern and southeastern coast, with gusts of 25 to 40 kt. 
Strongest gusts expected at ACK, with lower gusts along the coastal 
plain. Farther inland, N winds of 10 to 14 kt with gusts of 20 to 25 
kt.

Tonight...High confidence.

VFR. N to NNW winds gradually diminish from west to east, with 
inland wind speeds decreasing to 6 to 10 kt and gusts subsiding. 
Stronger winds persist along the eastern and southeastern coast, 
with sustained speeds of 10 to 15 kt and gusts of 20 to 30 kt.

Friday...High confidence.

VFR. Light northerly winds across much of the region, though winds 
remain elevated east of I-95, with sustained speeds of 8 to 12 kt 
and gusts of 20 to 25 kt.

KBOS Terminal...High confidence in TAF.

VFR. Gusty northerly winds continue today, with sustained speeds of 
10 to 14 kt and gusts of 25 to 30 kt.

KBDL Terminal...High confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: VFR. Breezy. Areas frost.

Saturday: VFR. 

Saturday Night: VFR. Areas frost.

Sunday through Monday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Friday...High confidence in hazardous marine conditions, 
though lower confidence in the potential for storm-force gusts 
across the outer southeastern waters.

Dangerous to life-threatening marine conditions continue as 
Subtropical Storm Josephine remains offshore of southern New 
England. Strong high pressure to the north, combined with Josephine 
to the southeast, maintains a tight pressure gradient across the 
coastal waters, resulting in persistent northeast winds and large 
seas.

Gale Warnings remain in effect across all coastal waters through at 
least 8 PM this evening, with northeast wind gusts generally ranging 
from 30 to 45 kt. However, there is potential for a brief period of 
storm-force gusts of 50 kt or greater across the outer southeastern 
waters this morning into early afternoon. Given lower confidence in 
the coverage and duration of these stronger gusts, opted to maintain 
Gale Warnings rather than upgrade to Storm Warnings. Seas remain 
rough, potentially reaching 15 to 16 feet across portions of the 
outer waters.

As Josephine tracks northeast into the North Atlantic, winds 
gradually diminish from west to east this evening. Gale Warnings 
across the waters west of Nantucket and Martha's Vineyard are 
expected to expire at 8 PM, with Small Craft Advisories needed 
thereafter for lingering gusty winds and elevated seas. Farther 
east, gale-force gusts will persist longer, with Gale Warnings 
continuing through early Friday afternoon. Once these warnings 
expire, Small Craft Advisories will likely be needed as winds 
gradually subside but seas remain elevated.

Marine conditions continue to improve Friday night and into the 
weekend as Josephine pulls farther away and high pressure builds 
into southern New England. However, elevated seas may linger beyond 
the strongest winds.

Outlook /Friday Night through Monday/...

Friday Night: Winds less than 25 kt. Areas of rough seas. 

Saturday: Winds less than 25 kt. Local rough seas. 

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

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

Sunday Night: Winds less than 25 kt. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Friday for ANZ230.
     Gale Warning until 2 PM EDT Friday for ANZ231>234-250-251-254-
     255-280>282.
     Gale Warning until 8 PM EDT this evening for ANZ235-237-256-
     283.
     Small Craft Advisory until 8 PM EDT this evening for ANZ236.

&&

$$
Dooley