Lexington Weather

Lexington, Massachusetts, USA

79°F

7/17/2026 1:12pm

Lexington Conditions: Clear
Temperature: 79.2°F / 26.2°C
Dew Point: 54.1°F
Relative Humidity: 42%
Wind: Calm, 10-min avg: Calm, gust: 2 mph
Barometer: 29.93 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 101815
AFDBOX

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

.WHAT HAS CHANGED...
No changes to the forecast for this update cycle.

&&

.KEY MESSAGES...

- Another warm and humid day today with a chance for isolated 
showers and storms. 

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

- Heat and humidity return by midweek.

&&

.DISCUSSION...
KEY MESSAGE 1...Another warm and humid day today with a chance
for isolated showers and storms. 
 
Cold front drops S from northern New England, crossing through 
northern MA this morning before slowing S of the Mass Pike by
the afternoon. Front acts as a focus for showers and isolated 
thunderstorms along and S of the Mass Pike as the column dries 
out significantly behind the front. General risks with any 
limited thunder activity will be limited to lightning and 
locally heavy rain as lingering cloud cover limits CAPE values 
to >1000 J/kg. Could see locally higher shower and storm 
coverage on the east coast of MA with a sea breeze acting as a 
mesoscale lifting mechanism. Thus, have POPs around 20-35% this 
afternoon in those areas. The other story today will be hot and 
humid conditions as highs warm into the upper 80s to near 90 for
much of the CWA. Highest heat index values will be along and S 
of the Mass Pike where dew point values will likely be near or 
above 70 degrees. 


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

Surface high pressure from Canada builds southward under
cyclonic flow aloft. NW flow aloft will cool 850 mb temps to 
+13-15C, which translates to highs in the mid 70s to low to mid 
80s. Should feel quite a bit more comfortable than what we've 
experienced over the last few weeks with low humidity levels and
dry weather Saturday through Monday. Other than some cooler 
seabreezes near the eastern coast, it's shaping up to be a great
weekend weatherwise. 

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

A sprawling 594dm ridge over the central CONUS builds east
through midweek. By Tuesday and especially Wednesday,
temperatures become quite hot as 850 mb temps soar again into
the +18 to +22C range. These values are similar (somewhat cooler 
by comparison) to our last extended spell of high heat/humidity.
The potential could exist for temperatures in the 90s with high
humidity levels perhaps necessitating a period of heat 
headlines for midweek. The risk for thunderstorms looks limited,
with a better chance on Wednesday as NW flow aloft increases 
and a plume of elevated mid-level lapse rates builds in favoring
stronger instability.

&&

.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...FT
AVIATION...HK
MARINE...Belk