Lexington Weather

Lexington, Massachusetts, USA

75°F

7/13/2026 11:45pm

Lexington Conditions: Clear
Temperature: 74.5°F / 23.6°C
Dew Point: 62.8°F
Relative Humidity: 67%
Wind: Calm, 10-min avg: Calm, gust: 1 mph
Barometer: 29.99 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Southeast Middlesex County, MA - Heat Advisory
- SEE ALL NEARBY ALERTS -

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 100508
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
108 AM EDT Fri Jul 10 2026

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

&&

.KEY MESSAGES...

- Warm and humid weather will continue through Friday, with a
  low risk of showers and thunderstorms. 

- Dry and seasonable weather with low humidity levels this
  weekend into Monday, but turns hot and humid by midweek.

&&

.DISCUSSION...
KEY MESSAGE 1...Warm and humid weather will continue through Friday, 
with a low risk of showers and thunderstorms. 

Regional radar shows showers and thunderstorms across eastern PA to 
Long Island, with a few showers in southern New England. The 
region is situated between a frontal boundary across the eastern
Great Lakes to northern New England and deep moisture across 
the Mid-Atlantic region. Drier air has limited coverage of 
showers and thunderstorms across the forecast area. The best
chance of additional showers and thunderstorms is west of I-95
through the evening hours.

The frontal boundary will slowly sag into the region Friday 
while moisture increases across the region. Cloud cover and 
patchy fog are expected to increase in coverage tonight. As the 
boundary lies across the forecast area, a weak shortwave trough 
will approach the area Friday. The chance for showers and 
thunderstorms will increase through peak heating hours, however
the risk remains low. Any fog and low clouds will erode early in
the morning with low clouds persisting the longest along the 
southern coast. There will be a low risk of showers Friday
night.

KEY MESSAGE 2...Dry and seasonable weather with low humidity
levels this weekend into Monday, but turns hot and humid by
midweek. 

After Friday evening's cold frontal passage into the southern 
waters, high pressure from Canada builds southward with cyclonic 
flow aloft. This will bring a cooldown toward more seasonable
summer temperatures in the mid 70s to low to mid 80s, with low
humidity levels and dry weather Saturday through Monday. Other 
than some cooler seabreezes near the eastern coast, it's 
otherwise shaping up to be a great weekend. 

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 /06Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

06z TAF Update: 

Through 12z Friday: Moderate confidence. 

Generally VFR but starting to see IFR- LIFR stratus along the 
south coast; potential for MVFR- IFR ceilings as far north as 
PVD to OWD by 09z, but confidence is lower if it slips into 
BOS/BED. SW winds around 7-12 kt, with gusts to 25 kt eastern 
and southeast MA, though gusts subside to sustained SW winds 
5-10 kt overnight. 

Friday: Moderate confidence. 

Main issue for the TAFs Fri is the timing of the cold front 
southward. Current indications are for winds turning NWly under
10 kt for BDL-ORH-BED-BOS between 13-15z with BKN/OVC VFR
ceilings; winds turning NE under 10 kt at BOS early afternoon. 
Thinking area more favored to see SCT SHRA/TS is from HFD to 
PVD south and east after 17z, after overnight stratus disperses.
A slower passage would put more TAFs at risk for SHRA/TS. 

Friday Night: High confidence. 

Lingering SHRA/TS moves offshore early Fri night to VFR
conditions. Outside chance at river valley fog if skies can
clear out. Winds become light northerly overnight.

KBOS Terminal...Moderate confidence. Thinking stratus near south
coast should stay far enough south of the airport. Windshift to
NW under 10 kt by 13-15z Fri, then turning NE under 10 kt with
BKN VFR ceilings. Slower frontal timing will affect timing of
windshifts Fri.

KBDL Terminal...Moderate to high confidence. PROB30 for TSRA
thru 02z Fri, otherwise, VFR should prevail with a windshift to
NW around 13-15z Fri.

Outlook /Saturday through Tuesday/...

Saturday: VFR. Slight chance SHRA.

Saturday Night through Monday Night: VFR. 

Tuesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Friday Night...High confidence.

Mostly tranquil boating conditions this evening. A weak front 
approaches the waters from the NW Friday, but is not likely to
pass the southern coastal waters until late Friday night at 
the earliest. A risk for scattered showers or thunderstorms 
tonight across the southern waters. Some risk for more afternoon
and evening showers and thunderstorms Friday.

Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt. Slight chance of rain showers.

Saturday Night: Winds less than 25 kt. 

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

Tuesday: Low risk for Small Craft Advisory winds with areas of
gusts up to 30 kt. Areas of seas approaching 5 ft.

&&

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

&&

$$

DISCUSSION...Loconto/Guest
AVIATION...Loconto/FT
MARINE...Belk/Loconto