Lexington Weather

Lexington, Massachusetts, USA

31°F

4/21/2026 7:30am

Lexington Conditions: Clear
Temperature: 30.7°F / -0.7°C
Dew Point: 23.7°F
Relative Humidity: 75%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.33 in Steady
Visibility: 10 miles
Snow Today: 0.0 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 160637
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
237 AM EDT Thu Apr 16 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...

- Backdoor front returns once again, making it cooler near the
  coast with continued warmth inland through Friday. Next chance
  for showers and thunderstorms tonight.

- Strong cold front moves through on Sunday bringing showers, 
  perhaps ending as brief snow showers but of no impact. 
  Blustery and anomalously cool temperatures for early to mid 
  next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Backdoor front returns once again, making it 
cooler near the coast with continued warmth inland through 
Friday. Next chance for showers and thunderstorms tonight.

Unseasonably warm temperatures aloft persist through the latter half 
of this week, and a stronger shortwave approaches later tonight. The 
backdoor front that has been lingering around the region will dip 
back down again today, cooling the coast and ushering in more 
onshore flow. This front may make it as far inland as Worcester 
today, with temperatures further inland remaining much warmer. Highs 
in the low to mid 80s are possible once more out in the CT Valley, 
parts of RI, and western MA. Closer to the coast, highs will likely 
top out in the 50s, increasing up to the low 70s as you move inland. 
This backdoor front should exit the region as its associated low 
moves offshore through the day Friday, and flow shifts more W 
initially as a separate front pushes through the region, then 
shifts more onshore for the afternoon/evening.

With regards to the approaching shortwave, rain showers with 
embedded thunderstorms are possible once again tonight after sunset. 
The latest forecast soundings have not changed much, still 
indicating 0-6 km bulk shear at and above 40 knots, and mid-level 
lapse rates around 6 C/km. The greatest instability remains over 
western MA and CT with MLCAPE values around 1000-1500 J/kg with a 
window of surface-based CAPE in the late afternoon/early evening 
possibly overcoming CIN. Generally, though, most instability will be 
more elevated. So, the severe risk remains low, especially with LCL 
heights remaining above 1000 km. This area is still under a Marginal 
(level 1 out of 5) risk for severe weather today, so remain weather 
aware this evening.


KEY MESSAGE 2... Strong cold front moves through on Sunday 
bringing showers, perhaps ending as brief snow showers but of no
impact. Blustery and anomalously cool temperatures for early to
mid next week.

A strong cold front will be working its way through the Northeast on 
Sunday, acting on a narrow but moist (PWATs around 1.2-1.4") warm 
sector. Showers, perhaps with a rumble or two of thunder, are likely 
with the front, which moves through during the daytime hours. The 
main story is what lies behind it: an anomalously cool airmass with 
925 mb temps dropping to near 0C and 850 mb temps 0 to -5C by Sun 
night. Global models show the potential for backside snow showers as 
the front moves offshore; the airmass is just that cold where it is 
possible, but it remains to be seen if there is enough lingering 
precip as the colder air surges in behind the front to allow for 
snowflakes to mix in. No impacts with those snow showers were they 
to develop though. 

While dry, Monday looks blustery and anomalously cool for mid-April, 
with 925 mb temps around 0 to -2C, with northwest winds around 10-15 
mph and gusts 25-30 mph. High temps in/around the high terrain in 
the low to mid 40s, with mid to upper 40s for eastern MA and RI. 
Winds decrease later in the day with clear skies, light winds 
setting stage for a pretty chilly night with subfreezing lows in 
most areas away from the cities. Anomalously cold air then begins to 
briefly recover starting Tuesday, though some indication for another 
weak disturbance in NW flow to reinforce another shot of cool air 
around midweek.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

06Z Update...Moderate confidence.

Today and Tonight:

Scattered showers with embedded thunderstorms continue to move
east across the region this morning amidst a mix of LIFR to VFR
ceilings. VFR to MVFR ceilings possible in any RA/TSRA that
moves through with visbys to IFR not ruled out in any heavier
showers/storms. The main line pushing through should exit the
region in the next 2 hours or so. Another line of showers
following it will progress through over the next few hours as
well.

For the day today, improvement to VFR expected for most 
terminals, aside from western MA and central CT. Some may remain
MVFR through much of the day, but periods of more scattered
ceilings may give way to VFR midday in any areas where
persistent MVFR is possible. SW winds today with E/NE winds to 
start closer to the coast. More scattered showers and storms
possible again tonight.

Friday:

VFR with periods MVFR. Showers and thunderstorms possible. Winds
shifting from the W/NW to NE as the day goes on.

KBOS Terminal... Moderate confidence in TAF. Though MVFR 
possible though most of today, periods of VFR possible if 
ceilings end up more SCT than BKN.

KBDL Terminal... High confidence in TAF.

Outlook /Friday Night through Monday/...

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

Saturday Night: Mainly VFR, with areas IFR possible. Breezy.
Slight chance SHRA.

Sunday: Mainly VFR, with local IFR possible. Breezy. SHRA
likely.

Sunday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA, slight chance SHSN.

Monday: VFR. Breezy. Slight chance SHRA, slight chance SHSN.

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence through the weekend.

Backdoor front meandering over southern New England through Fri AM 
will maintain light winds and calm seas, though there will be wind 
shifts from SW to NE from time to time on eastern MA waters along 
with showers and embedded thunderstorms. Brief periods of marginal 
Small Craft Advisory seas possible late tonight/early Fri AM over 
the southern outer waters, though not expected to be widespread.
 
Passage of stronger cold Front Sun should bring SCA conditions to at 
least outer waters Sun into Mon.

Outlook /Friday Night through Monday/...

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

Saturday through Saturday Night: Winds less than 25 kt. 

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Rain showers likely. 

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain showers. 

Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers, slight chance of snow showers. 

&&

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

&&

$$

DISCUSSION...Loconto/Hrencecin
AVIATION...Loconto/Hrencecin
MARINE...Loconto/Hrencecin