Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Clear
Temperature: 35.1°F / 1.7°C
Dew Point: 32.4°F
Relative Humidity: 90%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.00 in Falling Slowly
Visibility: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 210627
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
227 AM EDT Wed Oct 21 2026

.WHAT HAS CHANGED...
There have been no significant changes to the expected track of the 
offshore nor'easter. However, uncertainty remains in rainfall 
amounts across the Cape and Islands due to the potential for a 
narrow band of enhanced precipitation. Gale Warnings have been 
extended through Thursday evening across the ocean waters, and a 
Gale Watch has been issued for the northeastern coastal waters from 
Thursday evening into early Friday afternoon as the nor'easter 
tracks northeast.

&&

.KEY MESSAGES...

- A slow-moving nor'easter remains offshore through Thursday.
  Most of southern New England stays dry, but locally heavier
  rainfall is possible across the Cape and Islands. Gusty
  northeast winds and dangerous marine conditions remain the
  primary concerns.

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

&&

.DISCUSSION...
KEY MESSAGE 1...A slow-moving nor'easter remains offshore through 
Thursday. Most of southern New England stays dry, but locally 
heavier rainfall is possible across the Cape and Islands. Gusty 
northeast winds and dangerous marine conditions remain the primary 
concerns.

There have been no significant changes to the overall track of the 
nor'easter, which remains several hundred miles south-southeast of 
southern New England. The system continues to meander over the warm 
waters of the Gulf Stream and is expected to make little progress 
over the next 12 to 18 hours before eventually tracking northeast 
and out to sea. As previously discussed, the National Hurricane 
Center continues to monitor this system for potential subtropical 
development, with the latest outlook indicating a 40 percent chance 
of development over the next seven days. However, the low remains 
associated with frontal boundaries. Even if the system were to 
acquire subtropical characteristics and receive a name, no 
meaningful changes to the expected impacts across southern New 
England are anticipated.

Meanwhile, gusty northeast winds continue to be one of the more 
noticeable impacts from this offshore nor'easter. The pressure 
gradient between strong high pressure to our north and the nearly 
stationary low pressure system offshore will maintain breezy to 
gusty conditions through today. The strongest winds will remain 
focused along the eastern Massachusetts coastline, Cape Cod, and the 
Islands, where gusts of 30 to 40 mph are possible. Farther inland, 
northeast wind gusts of 20 to 30 mph are expected, particularly 
across eastern portions of southern New England. Gusty conditions 
will persist into tonight and Thursday, with the strongest winds 
remaining near the immediate coast. While winds gradually diminish 
across most inland locations, the northeastward movement of the 
nor'easter may bring another period of stronger winds across the 
northeastern coastal waters Thursday night into Friday.

The nor'easter is expected to make its closest approach 
overnight/early Thursday morning, with the greatest precipitation 
chances remaining across the Cape and Islands. One interesting 
feature worth watching is a sharp thermal gradient aloft, which 
could support enhanced frontogenesis and the development of a narrow 
band of heavier precipitation. There continues to be considerable 
spread in forecast rainfall amounts, particularly across the outer 
Cape and Nantucket. Much of this uncertainty appears tied to the 
exact placement and intensity of the frontogenetic forcing and how 
far west the associated precipitation band extends. For QPF, 
utilized a blend of NERFC and WPC guidance, with the highest 
rainfall amounts expected across Nantucket, where storm totals 
around 0.50 inches are forecast. Across Cape Cod, rainfall amounts 
generally range from 0.20 to 0.30 inches. However, ensemble guidance 
suggests a higher-end scenario of an inch or more across Nantucket, 
with probabilities of storm-total rainfall exceeding one inch 
ranging from 30 to 50 percent. While confidence remains lower in 
precisely where the heaviest precipitation will occur, the greater 
likelihood is that the enhanced precipitation band remains primarily 
offshore. As a result, most of southern New England should remain 
dry, with the greatest potential for measurable rainfall confined to 
the Cape and Islands.

Nevertheless, while this will not be the quintessential nor'easter 
for those on land, it certainly will be for the marine community. 
Large waves and gale-force northeast winds will continue to create 
hazardous conditions across the coastal waters. While astronomical 
tides are low, persistent wind and wave action may lead to beach 
erosion, particularly along east and northeast-facing beaches. 
Additional details can be found in the marine discussion.

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 the nor'easter gradually pulls away from southern New England, 
high pressure builds into the region for the upcoming weekend. One 
feature worth mentioning is a northern-stream shortwave and 
associated mid-level cold pool passing east of southern New England 
on Friday. Compared to 24 hours ago, the latest guidance has shifted 
these features farther east, increasing confidence in dry conditions 
across the region. An isolated shower cannot be ruled out over the 
eastern coastal waters, but otherwise dry conditions are expected 
across southern New England.

Despite the eastward shift in the cold pool, northerly flow aloft 
will continue to advect colder air into southern New England. Thus, 
Friday remains the coolest day of the period, with highs mainly in 
the lower 50s. 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. Otherwise, high 
pressure promotes subsidence and generally quiet weather through the 
weekend and into Monday. Temperatures gradually moderate Saturday 
through Monday, with both daytime highs 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 or move through southern New England sometime during the 
day. However, uncertainty remains regarding the timing and strength 
of this frontal passage, and it is still too early to provide much 
detail on any associated sensible weather impacts.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

06Z TAF Update:

Through 12Z...High confidence.

VFR for most terminals. Ceilings begin lowering to MVFR across Cape 
Cod and the Islands between 10Z and 14Z. ENE wind gusts of 25 to 35 
kt across the Cape and Islands, with localized gusts up to 40 kt 
possible at ACK. Farther inland, wind gusts of 20 to 25 kt.

Today and Tonight...High confidence overall, though moderate 
confidence in shower coverage across southeastern New England.

Low clouds, generally VFR to marginal MVFR, and scattered showers 
across Cape Cod and the Islands through this afternoon. Showers may 
be intermittent, with dry periods in between. A better chance for 
more persistent showers develops overnight into early Thursday 
morning, accompanied by MVFR to IFR ceilings and visibilities of 3 
to 5 SM.

Away from the Cape and Islands, SCT-BKN VFR cloud decks extend 
westward toward I-95, with decreasing cloud cover farther inland. NE 
wind gusts of 25 to 35 kt across the Cape and Islands, and 20 to 25 
kt farther inland. Gusts gradually diminish this evening, 
particularly across inland terminals, while breezy conditions 
persist closer to the coast.

Thursday...High confidence.

MVFR ceilings across Cape Cod and the Islands improve to VFR between 
14Z and 18Z. Winds shift to the north, with gusts gradually 
diminishing from west to east through the day.

KBOS Terminal...High confidence in TAF. 

VFR throughout the TAF period, with increasing cloud cover and 
ceilings around 5 kft this afternoon into tonight. NE wind gusts of 
25 to 30 kt expected through this afternoon, diminishing this 
evening. Winds gradually turn northerly overnight.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday: VFR. Windy with gusts up to 35 kt. 

Thursday Night: VFR. Windy with gusts up to 35 kt. Patchy
frost.

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

Friday Night: VFR. Breezy. 

Saturday through Sunday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Thursday...High confidence.

Dangerous marine conditions will persist through the end of the 
workweek as a slow-moving nor'easter remains offshore of southern 
New England. Strong high pressure to the north, combined with the 
offshore low, will maintain a tight pressure gradient across the 
coastal waters, resulting in persistent northeast winds and large 
seas. Gale Warnings have been extended through Thursday evening 
across the ocean waters, where northeast wind gusts of 30 to 40 
knots are expected, with locally stronger gusts possible across the 
outer waters. Seas will remain rough, potentially approaching 15 
feet across portions of the outer waters.

As the nor'easter begins tracking northeast Thursday evening into 
Friday, the potential for gale-force winds increases across the 
northeastern coastal waters, including Massachusetts Bay and the 
waters south of the Merrimack River. As a result, a Gale Watch has 
been issued for these waters from Thursday evening into early Friday 
afternoon. While confidence is high in continued hazardous marine 
conditions, uncertainty remains regarding the magnitude of the 
strongest wind gusts as the low passes offshore.

Conditions should gradually improve later Friday and into the 
weekend as the nor'easter pulls farther away from southern New 
England.

Outlook /Thursday through Sunday/...

Thursday: Moderate risk for gale force winds with gusts up to
45 kt. Rough seas up to 14 ft. Rain showers. 

Thursday Night: Strong winds with gusts up to 40 kt. Rough seas
up to 13 ft. 

Friday: Strong winds with gusts up to 35 kt. Rough seas up to
13 ft. 

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 13 ft. 

Saturday: Winds less than 25 kt. Rough seas up to 10 ft. 

Saturday Night through Sunday: Winds less than 25 kt. Areas of
rough seas. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for ANZ230-236.
     Gale Warning until 8 AM EDT Thursday for ANZ231>235-237.
     Small Craft Advisory until 5 PM EDT Thursday for ANZ250-251.
     Gale Watch from Thursday afternoon through Friday afternoon 
     for ANZ250-251-280.
     Gale Warning until 8 PM EDT Thursday for ANZ254>256-281>283.

&&

$$
Dooley