Lexington Weather

Lexington, Massachusetts, USA

76°F

8/26/2026 7:16pm

Lexington Conditions: Overcast
Temperature: 76.1°F / 24.5°C
Dew Point: 64.8°F
Relative Humidity: 68%
Wind: Calm, 10-min avg: Calm, gust: 1 mph
Barometer: 29.96 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 251936
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
336 PM EDT Tue Aug 25 2026

.WHAT HAS CHANGED...
Small Craft Advisory canceled.

&&

.KEY MESSAGES...

- Mostly quiet through Wednesday night with a stray 
  shower or t-storm Tuesday afternoon. 

- A round or two of scattered showers & thunderstorms possible Thu 
  afternoon into Fri along with summerlike humidity as well.

- Mainly dry and seasonable weather follows for the weekend.
  Temps may trend above normal early next week.  

&&

.DISCUSSION...

KEY MESSAGE 1...Mostly quiet through Wednesday night with a stray 
shower or t-storm Tuesday afternoon. 

Surface high pressure continues to influence southern New England's 
weather as it builds in from the Ohio valley this afternoon. Even 
so, a lingering mid level trough/cold pool aloft is leading to a 
smattering of diurnal cumulus and hit-and-miss showers over 
western/central areas. Mesoanalysis shows ~1000 J/kg of CAPE which, 
in the absence of any real bulk shear may lead to a stray 
thunderstorm or two at most. With sunset these showers will 
dissipate and cloudcover quickly recede. Tonight expect clear skies 
with light winds and patchy fog in the interior where dewpoint 
depressions may be near 0. Wednesday is dry and sunny with mid level 
ridging building in. As this happens, the low/mid level flow backs 
to the SW 850mb temps bump up from ~11C to 12-13C pushing high 
temperatures a few degrees warmer on Wednesday, into the upper 
70s/low 80s with cooler temps along the coast. 

KEY MESSAGE 2...A round or two of scattered showers & thunderstorms 
possible Thu afternoon into Fri along with summerlike humidity as well.

The model guidance is in fairly good agreement in an approaching 
shortwave trough/cold front late in the work week. Out ahead of this 
disturbance...S-SW flow will result in the return of low level 
moisture and summerlike humidity. While specific timing remains 
uncertain...the potential exists for a round or two of scattered 
showers and thunderstorms sometime Thu afternoon/night into Fri. The 
CSU machine learning probabilities also indicate a low risk for 
severe weather/heavy rainfall. That is basically climatology for an 
approaching shortwave this time of year. But the question remains 
does the forcing/instability lineup favorably for that potential to 
be realized along with various mesoscale processes. It is just too 
early to determine that at this time. Nonetheless...certainly 
something to watch over the next day or two.

KEY MESSAGE 3...Mainly dry and seasonable weather follows for the 
weekend. Temps may trend above normal early next week. 

High pressure builds in behind the departing shortwave/cold front 
for the upcoming weekend. The result will be mainly dry and 
seasonable weather Sat into Sun. Ensembles indicating upper level 
flow may become more westerly early next week allowing for temps to 
trend above normal. 

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

18Z Update...

This afternoon...High confidence.

VFR. Mostly dry with a few spot showers during the afternoon. W
winds 6-12 knots, except some 20+ knot gusts possible towards 
the upper Cape. 

Tonight...High confidence. 

VFR. Calm/Light WNW winds. Patchy fog possible. 

Wednesday...High confidence.

VFR. Light west winds, with local seabreezes towards the coast.

Wednesday night...High confidence. 

VFR. Winds light and variable. Patchy fog possible. 

KBOS Terminal...High confidence in TAF.

We think pressure gradient remains just strong enough to result
in mainly W winds today. However, the low probability exists for 
a few hours of sea breeze. This risk/duration too limited to 
insert into the TAF at this time. 

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Sunday/...

Thursday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Thursday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA, slight chance TSRA.

Friday: VFR. Chance SHRA, chance TSRA.

Friday Night: Mainly VFR, with local IFR possible. Chance SHRA.

Saturday through Sunday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Wednesday night...High confidence.

Fairly quiet boating conditions through the first half of this 
week as high pressure develops across the Midwest before 
expanding toward the waters off the coast of southern New 
England. Gusty southwest flow develops today, with gusts around
20 kt. Conditions improve overnight into early Wednesday 
morning as winds shift to the northwest.

Outlook /Wednesday Night through Sunday/...

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

Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, slight chance of
thunderstorms. 

Friday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers, slight chance of thunderstorms. 

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers, slight chance of thunderstorms. 

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

Saturday Night through Sunday: Winds less than 25 kt. 

&&

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

&&

$$

DISCUSSION...Frank/BW
AVIATION...Frank/BW
MARINE...Frank/BW