Lexington Weather

Lexington, Massachusetts, USA

46°F

4/19/2026 8:02am

Lexington Conditions: Mist, Overcast
Temperature: 46.4°F / 8.0°C
Dew Point: 45.0°F
Relative Humidity: 95%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.73 in Falling Slowly
Visibility: 1½ miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 170540
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
140 AM EDT Fri Apr 17 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...

- Scattered shower and a few thunderstorms possible tonight. 

- Strong cold front will bring a round of widespread showers
  late Sat night into Sunday, then drying out and turning 
  colder Sun night.

- Mainly dry and unseasonably cool Mon-Tue, then moderating
  temperatures toward midweek. Next chance of showers will be
  Tue night into early Wed.

&&

.DISCUSSION...
KEY MESSAGE 1...Scattered Showers and few thunderstorms possible 
tonight. Few showers possible late Friday afternoon, low probability 
(< 20%) for an isolated thunderstorm. 

Ample warming this afternoon in western and central southern New 
England. Satellite imagery this afternoon shows cumulus starting to 
develop across those areas. A sign that at least marginal 
instability is present. Something to keep tabs on given that we have 
potential for scattered showers and thunderstorms in the forecast 
tonight in response to a shortwave trough. Winds aloft increase this 
evening which will bring in better bulk shear values. All that being 
said, we can still see a risk for scattered thunderstorms generally 
after sunset. Where higher instability and sufficient shear overlap 
in far west/NW MA, can't rule out a strong to severe storm. Overall 
CAMs show limited coverages of storms as they develop and move 
eastward after sunset. A round or two of scattered showers are also 
possible overnight and into early Friday morning. 

Cooler day Friday compared the Thursday, especially for the 
locations that were well into the 80s in western southern New 
England on Thursday. Highs range in the 60s and 70s in west, central 
southern new england and mid 50s to lower 60s further east. 
Isolated showers are possible, although lower confidence on 
exact location of the showers given the lower coverage. 
Instability will be marginal, but enough to support an isolated 
storm in the afternoon. 

KEY MESSAGE 2...Strong cold front will bring a round of widespread 
showers late Sat night into Sunday, then drying out and turning 
colder Sun night.

Surface ridging in control on Sat will provide dry weather with 
temps more seasonable for mid April as onshore flow will prevail. 
Then a fairly robust upper trough will approach from the Gt Lakes 
with the attendant strong cold front moving through SNE during 
Sunday. A plume of PWATs 1.25-1.5" move into SNE in the pre-frontal 
environment Sat night into Sunday. Decent forcing for ascent ahead 
of the upper trough acting on this moisture will result in an area 
of widespread showers moving through the region late Sat night into 
Sunday which may be enhanced along and just ahead of the front. 
There is some elevated instability so can't rule out a few t-storms 
as well. 

The front will move through western New Eng by midday and eastern MA 
during the afternoon. The column cools rapidly behind the front and 
there may be enough lingering moisture for showers to end as some 
snow showers in western MA, especially over the higher terrain but 
if it happens not expecting any accumulation. PWATs drop quickly 
from W to E late Sun and Sun night which will bring clearing skies 
and turning much colder in the strong cold advection pattern. Temps 
by Mon morning will drop to the low-mid 30s, with upper 20s over the 
higher elevations. Brisk W-NW winds will result in wind chills in 
the 20s around daybreak Mon.

KEY MESSAGE 3...Mainly dry and unseasonably cool Mon-Tue, then 
moderating temperatures toward midweek. Next chance of showers will 
be Tue night into early Wed.

Upper trough and core of coldest air aloft move through Mon into Mon 
night so it will be unseasonably cool during this period. 850 mb 
temps bottom out around -10C Mon night. Expect diurnal cu to develop 
Mon but dry weather with highs mostly in the 40s to near 50 in the 
coastal plain. Gusty W-NW winds will make it feel even cooler. Lows 
will drop into the 20s Mon night with diminishing wind as high pres 
builds into the region. Temps moderate slightly Tue but still chilly 
with below normal temps, then temps get back to seasonable normals 
Wed and Thu. Another northern stream shortwave may bring a few 
showers Tue night into early Wed, otherwise mainly dry weather 
through Thursday.

&&

.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: Moderate confidence. 

Mix of ceilings across southern New England this morning.
Periods of LIFR/IFR possible even amidst VFR due to BR and
periodic lower clouds. Exact timing uncertain. SHRA with some
embedded TS moving into the region as of the time writing this.
These showers will continue tracking NE this morning, most
likely impacting BDL and ORH, and possibly BED and BOS.

Today: Moderate confidence. 

MVFR-IFR along the immediate coast, otherwise conditions 
lowering to MVFR elsewhere and eventually to IFR eastern MA and
RI during the afternoon. Scattered showers and a few t-storms
developing. Exact spatial extent still a bit uncertain. North 
to northeast winds 5-10 kt.

Tonight through Saturday...Moderate confidence.

Any lingering showers should dry up heading into tonight. Light
N to NE winds continue, then increase to around 10 kt during the
day Saturday. Periods of IFR/MVFR possible, especially heading 
into Sat.

KBOS Terminal...Moderate confidence in TAF. LIFR fog and stratus
this morning. Low clouds continue, but IFR/LIFR ceilings may
break briefly in periods this morning. IFR likely persists
through much of today. Scattered showers and possibly a t-storm
developing around midday and into the afternoon.

KBDL Terminal...High confidence in TAF. Showers with embedded TS
moving through terminal over the next hour or so (06-07z).

Outlook /Saturday through Tuesday/...

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.

Monday Night through Tuesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence through the weekend.

Seas 2-5 ft and winds less than 25 kts. SW winds shift to NE
later Friday. 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 /Saturday through Tuesday/...

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. 

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

&&

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

&&

$$

DISCUSSION...Loconto/Hrencecin
AVIATION...KJC/Loconto/Hrencecin/Mensch
MARINE...Loconto/Hrencecin