Lexington Weather

Lexington, Massachusetts, USA

76°F

8/26/2026 7:18pm

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 231744
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
144 PM EDT Sun Aug 23 2026

.WHAT HAS CHANGED...

No significant changes to the forecast.

&&

.KEY MESSAGES...

- Showers and storms around today, especially towards the CT 
  River Valley where an isolated strong to severe thunderstorm 
  or two is possible.

- Drier and warmer next week before rain chances make a return
  sometime Thursday/Friday.

&&

.DISCUSSION...

KEY MESSAGE 1...Showers and storms around today, especially towards 
the CT River Valley where an isolated strong to severe thunderstorm 
or two is possible.

Weak low pressure just off to our northeast continues to aid in 
continued NE low level flow this morning, keeping overcast skies 
over southern New England. Chances for spotty showers continue 
primarily towards Nantucket and the outer Cape where showers are 
just offshore and continuing to move off to the northeast. Aside 
from these, misty and foggier conditions continue this morning 
across the region.

The main thing to keep an eye out for today will be the chances for 
some showers and storms towards the afternoon. Showers tracking 
across New York associated with the approaching cold front will 
approach western MA and CT towards the late morning/early afternoon 
hours. The low pressure to our northeast loosens its grip over 
southern New England as more southerly winds take hold in the late 
morning/early afternoon hours, advecting in dewpoints in the 70s. 
Increased humidity along with diurnal instability may enhance the 
risk for storms in the interior turning strong to severe. Even with 
cloudier skies inhibiting instability a bit, model soundings and CAM 
guidance have MUCAPE values around 1500-1800 J/kg over the CT Valley 
in the afternoon, and MLCAPE values to around 1200-1300 J/kg with 
limited capping in the soundings. Effective bulk shear values around 
40 kt will also aid in development of an isolated stronger to severe 
storm or two, with the main risk of these storms being damaging 
winds. PWAT values still around 1.25-1.5" in the afternoon ahead of 
the front will also keep the risk for some torrential downpours in 
play. The interior remains in a Marginal (1/5) risk for severe 
weather today considering this environment.

Outside of this risk of showers and storms, the rest of the region 
can expect to remain mostly dry, albeit dreary. Humid conditions 
prevail with highs in the upper 70s.

KEY MESSAGE 2...Drier and warmer next week before rain chances make 
a return sometime Thursday/Friday.

The cold front to our west passes through the region heading into 
Monday, clearing skies quickly in its wake. Drier post-frontal air 
flows into the region, noted by dew points falling into the 50s and 
low 60s and PWATs to an inch and lower. Temperatures return to more 
seasonable levels in the 70s and 80s, though it should feel more 
comfortable than today given the reduced humidity. High pressure 
steadily builds in through Tuesday into Wednesday as ridging takes 
place of the troughing from Quebec that will continue to shift off 
to the east. Clear skies and dry weather prevail through this period.

Greater uncertainty reenters the forecast towards Thursday and 
Friday with the approach and development of another shortwave over 
the Great Lakes. Ensemble and deterministic guidance does hint at 
the return of elevated moisture towards this time period, along with 
rain showers. Latest ensemble guidance has PWAT values returning to 
around 1.5" Thursday afternoon into Friday, along with more 
southerly flow towards the surface. Inconsistencies remain among the 
ensembles, though, regarding the track of the low associated with 
the shortwave. This also leads to discrepancies regarding the timing 
of any showers.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...

Forecaster Confidence Levels...

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

18z TAF Update...

This afternoon through tonight...Moderate confidence in trends
but lower confidence in specific timing. 

The main cluster of showers and an occasional rumble of thunder
or two will be exiting eastern MA by mid afternoon. 
Otherwise...a few additional showers and perhaps an isolated 
t-storm will be possible into mid evening with the focus across
interior southern New England and particularly areas near and 
west of the CT River Valley.

IFR/LIFR conditions will be improving to mainly MVFR-VFR by 
early-mid evening in most locations although the process will be
slowest across the Cape/Islands. However...a wet ground, light 
winds and dewpoints still in the 60s will likely result in areas
of fog developing in the typically prone locations. Some of 
that fog may become locally dense overnight...while areas like 
KBOS end up going VFR. So a wide variety of conditions possible 
toward daybreak. Winds become calm/light SW tonight. 

Monday and Monday night...High confidence. 

Any leftover ground fog quickly burns off after sunrise Mon.
Otherwise...VFR with SW winds of 7-13 knots. Mainly VFR 
conditions continue Mon night outside of any localized patches 
of ground fog that develop in those typically prone locations. 
Winds become calm/light SW Mon night. 

KBOS Terminal...Moderate confidence in trends but lower
confidence in specific timing. 

KBDL Terminal...Moderate confidence in trends but lower
confidence in specific timing. 

Outlook /Tuesday through Friday/...

Tuesday: VFR. Breezy. 

Tuesday Night: VFR. 

Wednesday: VFR. Breezy. 

Wednesday Night: VFR. 

Thursday: VFR. Slight chance SHRA.

&&

.MARINE...

Forecaster Confidence Levels...

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

Through Monday...High confidence.

Winds and seas are expected to remain below Small Craft Advisory
criteria through tonight. However, gusts could get close to this 
criteria during the day Monday following the cold front passing 
through tonight. Patchy fog over the waters tonight will clear 
following the front as well.

Seas remain between 2-4 ft with 5 ft seas possible tonight in
the far ocean waters. Winds shift more S to SW today, continuing
through Monday.

Outlook /Monday Night through Friday/...

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

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

Wednesday through Thursday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents from Monday morning through Monday 
     afternoon for MAZ024.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Hrencecin
AVIATION...Frank
MARINE...Hrencecin