Lexington Weather

Lexington, Massachusetts, USA

60°F

9/20/2026 8:51pm

Lexington Conditions: Overcast
Temperature: 59.9°F / 15.5°C
Dew Point: 56.7°F
Relative Humidity: 89%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.95 in Steady
Visibility: 9 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 150553
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
153 AM EDT Tue Sep 15 2026

.WHAT HAS CHANGED...
No significant changes to the forecast.

&&

.KEY MESSAGES...

- Dry with below normal temperatures through Tuesday night.

- Above normal temps return Wed through the end of the week with
  high temps mainly in the 70s to near 80. A few showers possible
  sometime late Thu into early Fri...But dry weather dominates.

- Possible return for unsettled weather towards the back half 
  of the upcoming weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Dry with below normal temperatures through
Tuesday night.

A large high pressure arrives from the west tonight. Gusty winds
subside around sunset, then become light and variable late this
evening. Expecting decent radiational cooling conditions,
leading to low temperatures about 5-10 degrees below normal. The
cooler conditions continue into Tuesday night with light E to SE
winds. This high pressure should be over the North Atlantic
Tuesday night, shifting winds more from the S to SW. 

KEY MESSAGE 2...Above normal temperatures return midweek and 
last through the end of the week. Dry weather dominates, though 
a few showers are possible sometime in the late Thursday-early 
Friday timeframe.

High pressure continues to dominate this week's pattern, keeping 
generally dry conditions in place for southern New England. A strong 
upper level ridge set up across the southeast US will build partly 
into the northeastern US midweek before flattening out on its 
northern tier Thursday into Friday. A trough remains well to our 
north in Canada, and between these two large features, surface high 
pressure remains affixed over much of the northern and northeastern 
US. With a surge in warmer mid level air coming in from the west 
during this period, more above-normal temperatures make a return 
across southern New England; highs climb back up into the 70s and 
may creep into the low 80s.

High pressure loosens its grip over the region slightly late 
Thursday into Friday as a shortwave tracks toward the region. NAEFS 
guidance signaled a return of more anomalous moisture with the 
westerly flow, indicating PWATs about a standard deviation or two 
above normal for this time of year. Ahead of any possible showers 
with the incoming shortwave/frontal system, it may feel a bit more 
humid on Thursday. Guidance currently favors showers moving through 
the region late Thursday into Friday morning, though timing may 
fluctuate slightly between now and then. Dry conditions follow as 
drier air aloft is advected in, though the higher than normal 
temperatures may remain Friday afternoon before cooler temperatures 
take hold for Saturday.

KEY MESSAGE 3...Possible return for unsettled weather towards
the back half of the upcoming weekend.

The ridge to our south appears to break down a bit going into the 
weekend, which may introduce increased chances for more unsettled 
conditions. Latest ensemble guidance hints at the second half of the 
weekend as the likely timeframe with strong low pressure tracking 
towards the region from the Plains and Great Lakes. Given how
far out this event is, much will likely change over future
updates.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

06z TAF Update...

Through 12Z...High confidence.

VFR. Light N/NNE winds. Occasional gusts to 18 kts possible for
Cape terminals through 08Z (HYA/ACK).  

Tuesday...High confidence.

VFR. NNE winds this morning shifting to the NE at 5-10 kts. Interior
terminals shift likely shift to the S/SSE early afternoon while
coastal terminals shift to E/ESE in the afternoon then shift to
the S/SSE 00-03Z. 

Tuesday night...High confidence.

VFR. Winds becoming light S to SW. Patchy fog possible in
valleys. 

KBOS Terminal...High confidence in TAF. NNE winds shift to NE
this morning then shift E/ESE 16-18Z at 5-10 kts. Winds shift
toward the SSE/S around 00Z becoming S/SSW by 03Z.  

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday through Wednesday Night: VFR. 

Thursday: Mainly VFR, with local MVFR possible. 

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

Friday through Friday Night: Mainly VFR, with local MVFR
possible. 

Saturday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

High pressure moves over the waters late Tuesday, then offshore
Tuesday night. Gusty NW to N winds diminish towards sunset
tonight. Expecting relatively light winds and seas through
Tuesday night. Marginal Small Craft Advisory conditions will end
later this afternoon. The existing headlines may be canceled
early. Will continue to monitor through this afternoon.

Outlook /Wednesday through Saturday/...

Wednesday through Thursday: Winds less than 25 kt. 

Thursday Night: Winds less than 25 kt. Chance of rain showers,
slight chance of thunderstorms. 

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

Friday Night through Saturday: Winds less than 25 kt. 

&&

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

&&

$$

DISCUSSION...Belk/Hrencecin
AVIATION...Mensch
MARINE...Belk/Hrencecin