Lexington Weather

Lexington, Massachusetts, USA

80°F

7/17/2026 1:55pm

Lexington Conditions: Clear
Temperature: 80.1°F / 26.7°C
Dew Point: 52.9°F
Relative Humidity: 39%
Wind: Calm, 10-min avg: Calm, gust: 1 mph
Barometer: 29.93 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 101908
AFDBOX

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

.WHAT HAS CHANGED...

Introduced a low chance of showers across most of the forecast area 
this afternoon. 

&&

.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 /18Z FRIDAY 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. 

Widely scattered showers stretch from the Hudson Valley to the NH 
Seacoast, with another area of showers along a sea breeze 
across the Upper Cape this afternoon. Main concern is if any of 
these showers reach the terminals. Due to the scattered 
coverage, kept them out of the northern terminals including BOS
and BDL. Added a TEMPO into the southeast coast terminals. 

Showers are expected to dissipate this evening, with a low chance of 
showers along the southern coast. MVFR ceilings and vsbys are 
possible at ACK overnight. 

Saturday: High confidence.

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

Elsewhere VFR. Light E to NE winds.

KBOS Terminal...Moderate confidence. E seabreeze is expected to develop
between 19-20z. Most SHRA/TSRA expected to remain outside of 
the terminal, but there is a low risk 18-23Z.

KBDL Terminal...Moderate confidence. Low risk for an isolated 
SHRA/TSRA this afternoon. Not enough confidence to include in 
the TAF.

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...HK
MARINE...HK