Lexington Weather

Lexington, Massachusetts, USA

79°F

7/17/2026 1:02pm

Lexington Conditions: Clear
Temperature: 78.6°F / 25.9°C
Dew Point: 54.3°F
Relative Humidity: 43%
Wind: Calm, 10-min avg: Calm, gust: 2 mph
Barometer: 29.94 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 110016
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
816 PM EDT Fri Jul 10 2026

.WHAT HAS CHANGED...
No changes to the forecast for this update cycle. Isolated
showers and thunderstorms across Southern Massachusetts continue
to move southward offshore and over Martha's Vineyard and 
Nantucket. Rain chances will quickly diminish this evening and
overnight.

&&

.KEY MESSAGES...

- A few showers and thunderstorms are possible through this
  evening.

- Dry and seasonable weather with low humidity levels this
  weekend into Monday.

- Heat and humidity return by midweek.

&&

.DISCUSSION...
KEY MESSAGE 1...A few showers and thunderstorms are possible
through this evening.
 
A cold front will slowly sag south across southern New England 
through this evening. A warm and humid airmass resides across the 
region resulting in heat indices in the upper 80s to low 90s. 
Regional radar shows a line of widely scattered showers from the 
Hudson Valley to the NH seacoast, with another area of showers on 
the Upper Cape this afternoon. Instability has increased to 500-1000 
J/Kg with weak shear across the forecast area. The showers are 
expected to slowly sag southward across MA before dissipating this 
evening. An isolated thunderstorm is possible, mainly across the sea 
breeze near the Cape where higher dewpoints and low-level 
convergence are located. 

The cold front will move south of the region tonight with patchy fog 
possible in valleys. Dry weather is expected across the region.


KEY MESSAGE 2...Dry and seasonable weather with low humidity
levels this weekend into Monday.

In the wake of a cold front, surface high pressure will build
across the region this weekend and become centered over New 
England Sunday into Monday. This will bring comfortable 
temperatures in the mid 80s and low humidity with dew points in 
the upper 50s/low 60s. A much drier air mass will keep rain 
chances to near zero before moisture returns later in the week. 

KEY MESSAGE 3...Heat and humidity return by midweek. 

Mid-level high pressure ridging will remain over the Central
U.S., stretching across into the Mid Atlantic through much of 
next week, bringing mostly hot and dry weather across the 
Northeast. Hot temperatures in the low to mid 90s will return
mid week with 850mb temperatures ranging from +18 to +22C. We
may need to consider a period of heat headlines with dew points
rising into the mid to upper 60s again.

Rain chances through the period will generally remain low with a
better chance on Tuesday into Wednesday with a possible shortwave
trough moving through Northern New England. Southerly return 
flow at the surface will be short lived prior to this 
perturbation moving through, so moisture depth will remain 
shallow. Models are showing possible deeper upper-level 
troughing toward the end of the week, so we may start to see 
increasing rain chances and slightly cooler temperatures if 
that trend continues.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

Through Friday Night: Moderate confidence. 

Showers and a few thunderstorms are expected to dissipate this 
evening from north to south, with a low chance of MVFR
visibilities with ongoing convection moving southward near ACK.
Winds may become calm overnight, with patchy fog and low
ceilings developing at some locations in the early morning 
hours.

Saturday: High confidence.

MVFR/IFR at ACK will improve to VFR Saturday morning.

Elsewhere VFR. Light E to NE winds.

KBOS Terminal...Moderate confidence. Light southerly winds
should reestablish out of the northeast and become light 
overnight. Lighter winds expected on Saturday with possibly an 
isolated shower with the seabreeze, but have decided to keep any
mention out of the TAF at this time.

KBDL Terminal...High confidence. VFR with light winds.

Outlook /Sunday through Wednesday/...

Sunday through Sunday Night: VFR. 

Monday through Monday Night: VFR. Breezy. 

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

Tuesday Night through Wednesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Saturday Night...High confidence.

Mostly tranquil boating conditions continue into next weak. A weak 
cold front should cross the waters tonight. A risk for scattered 
showers or thunderstorms tonight, especially the waters around the 
Cape and islands. Mainly dry weather Sat into next Wed.

Outlook /Sunday through Wednesday/...

Sunday through Monday: Winds less than 25 kt. 

Monday Night: Low risk for Small Craft Advisory winds with
local gusts up to 30 kt. Seas locally approaching 5 ft. 

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. 

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

Wednesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas.

&&

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

&&

$$

DISCUSSION...HK/CB
AVIATION...CB
MARINE...HK