Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Partly cloudy
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 041721
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
121 PM EDT Fri Sep 4 2026

.WHAT HAS CHANGED...
No significant changes to the forecast.

&&

.KEY MESSAGES...

- Mainly dry and pleasant today and Saturday with a chance for 
 some isolated showers Saturday afternoon.

- Cooler weather this weekend into early next week gives way to
  a warming trend and the chance for unsettled weather by mid 
  week. 

- Dangerous conditions at the beach for the holiday weekend 
  with as the rip current risk increases Sunday and Labor Day.

&&

.DISCUSSION...
KEY MESSAGE 1. Mainly dry and pleasant today and Saturday with a 
chance for some isolated showers Saturday afternoon.

Looking drier and mild over the next couple of days as broad NW flow 
around a closed low advects a lower PWAT airmass into the region. 
PWAT values fall below 1.00" by this afternoon into Saturday. 
Despite the overall drier airmass, a broad cutoff low over the 
Canadian Maritimes will maintain a non-zero chance of isolated 
showers today and Saturday. The greatest chance for shower activity 
falls on Saturday as an embedded shortwave moves S from Canada. Each 
day will see diurnal cumulus as low level lapse rates steepen during 
the afternoon. In terms of temperatures, today will be the warmest 
day of the whole forecast as a slightly warmer airmass pushes in; 
850 mb temps briefly reach ~15C this afternoon before dropping to 
~8C Saturday resulting in high temperatures in the low to mid 80s 
and low to mid 70s respectively. 

KEY MESSAGE 2... Cooler weather this weekend into early next week 
gives way to a warming trend and the chance for unsettled weather by 
mid week. 

The upper air pattern later this weekend into next week evolves from 
an amplified omega block into a more zonal configuration. The 
changes will come as the persistent closed mid-level low over Nova 
Scotia finally pushes away from the eastern CONUS. In its place, 500 
mb heights rise as a broad southeast ridge amplifies poleward. What 
this translates to at the surface is a benign weather pattern with 
somewhat persistent high pressure over the northeast. The next 
chance for disturbed weather arrives midweek as a strong shortwave 
passes to the N of the region. Guidance shows a somewhat compact and 
seasonably strong surface low forming in response to the 
aforementioned upper low. Details are still somewhat TBD given the 
time to the event but there is a chance for unsettled weather with 
this feature around midweek. 

Temperatures aloft are cooler Sunday, associated with that mid-level 
low east of New England. 925mb temperatures are only around +8C to 
+10C, which with boundary layer mixing supports highs in the upper 
60s to low 70s. Thus, Sunday will feel very much like autumn, with a 
blend of sun and clouds, northerly winds and dew points in the low 
50s. While winds won't be overly strong, the combination of cooler 
temperatures and lower dew points will make for a rather crisp day. 
Sunday night could feature some decent radiational cooling as high 
pressure settles across the region, though this will depend on how 
quickly winds diminish. It appears as though the latest NBM has 
picked up on this trend for both Saturday night and Sunday night. 
The latest run shows widespread 50-55 degree readings with even a 
few upper 40s in the higher terrain of northern Massachusetts. 
Should see a rebound in temperature readings by early next week as 
925mb temperatures climb +14C to +18C, supporting near-seasonable 
highs in the upper 70s for Labor Day, then upper 70s to lower 80s 
Tuesday into the middle part of next week. Humidity remains 
tolerable as well, with dew points generally in the upper 50s to 
around 60F. Labor Day itself looks quiet and dry, though there will 
be a high risk for rip currents along the ocean beaches.


KEY MESSAGE 3...Dangerous conditions at the beach for the holiday 
weekend with as the rip current risk increases Sunday and Labor Day.

Persistent northeast flow, long-period swell, and offshore seas of 4-
7 feet will continue to support an elevated risk for dangerous rip 
currents through the Holiday Weekend, especially Sunday into Labor 
Day for east-facing ocean beaches. With otherwise quiet weather 
expected, those heading to the beach should be mindful that ocean 
conditions may still be hazardous. Be sure to check with local beach 
staff or lifeguards regarding ocean conditions before entering the 
water.

&&

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

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

18z Update...

This afternoon...High confidence. 

Light north- northwest winds for most, though a sea breeze 
continues across eastern coastal Massachusetts, including KBOS.

Tonight...High confidence.

VFR. Light northwest winds.

Saturday...High confidence. 

VFR. N/NE winds 10-15 kts. Isolated SHRA/TSRA. 

Saturday night...High confidence. 

VFR. Winds light and variable. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF. 

Outlook /Saturday Night through Wednesday/...

Sunday: VFR. Breezy. 

Sunday Night through Tuesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Saturday Night...

W/NW winds this morning gradually shift the S/SW this evening A
few showers and t-storms may move over the southern waters this
evening then tranquil weather persists. Seas 2-3 ft. Winds shift
to the NE and increase to 10-15 kt Saturday. Seas generally
remain below Small Craft Advisory criteria during the daytime
with an increasing chance later Saturday night. 

Outlook /Saturday Night through Wednesday/...

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. 

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. 

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

Labor Day: Winds less than 25 kt. Areas of seas approaching
5 ft. 

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

Tuesday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Dooley/FT
AVIATION...BW/Dooley/FT
MARINE...Dooley/FT