Lexington Weather

Lexington, Massachusetts, USA

39°F

1/8/2026 11:25am

Lexington Conditions: Clear
Temperature: 39.4°F / 4.1°C
Dew Point: 38.3°F
Relative Humidity: 96%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.09 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 050705
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
205 AM EST Mon Jan 5 2026

.WHAT HAS CHANGED...
Increased concern for a period of freezing rain tonight across
portions of RI, northern CT and southeastern MA. Continued
increased confidence in light icing over the higher terrain
across the interior for Tuesday night.

&&

.KEY MESSAGES...

- Light snow accumulations, a coating to 2 inches, expected this
  afternoon into tonight. Could end as a period of freezing rain
  for some. 

- Mixed precipitation expected Tuesday night into Wednesday
  morning. 

- Briefly dry Thursday before an unsettled end to this week.


&&

.DISCUSSION...
KEY MESSAGE 1...Light snow accumulations, a coating to 2 inches,
expected this afternoon into tonight. Could end as a period of
freezing rain for some.

Tricky forecast for the snowfall expected later this afternoon
into tonight. Some critical details remain fuzzy, which could 
have a significant impact on the forecast from only a subtle
change. The questions come after we start off with a period of
light snow from a clipper low moving from W to E this afternoon
into this evening.

The current expectations are that we remain unquestionably 
light snow from about 1-8 PM today. Then some members of the 
latest guidance suite dry out the dendritic growth zone while 
maintaining subfreezing surface temperatures. Others nudge 
temperatures aloft just enough to liquefy the precipitation and
have it fall into the subfreezing surface temperatures. Either 
of these cases is a setup for freezing rain, which could impact 
portions of RI, northern CT as well as southeast MA. There is 
even a muted signal for a period of freezing rain in the 
ensemble solutions such as the NationalBlend and HREF.

Will need to consider Winter Weather Advisories for this
freezing rain later today. However, there is not enough 
confidence yet that freezing rain will develop. With snowfall of
only a coating up to 2 inches, that would not require any 
headlines for the snowfall.

KEY MESSAGE 2...Mixed precipitation expected Tuesday night into  
Wednesday morning.

A shortwave shifts east from the Great Lakes heading into
Tuesday night. As this shortwave and its associated surface low 
pressure move in, warmer, more moist air is advected in over
southern New England. 925 mb temperatures begin to increase to
between 2C and even up to 7C heading into Tuesday night on its
approach, and 850 mb temperatures get to around 3-5C. This is
also reflected in forecast soundings where a distinct warm nose 
can be found across these levels through the overnight hours
Tuesday, particularly in the higher elevations. Aside from the 
higher elevations of the Berkshires and the Worcester Hills, 
temperatures at the surface should get above freezing,
diminishing the chances for any precipitation that is not just
rain. Total flat ice accumulations between 0.01" and 0.05" are 
most likely across the higher elevations where those surface 
temperatures at/below freezing will linger; elsewhere will
likely not see any. Probabilities for accumulations over 0.1" in 
the higher elevations are still low, but totals could approach
0.1" locally. Surface temperatures continue to increase heading 
into Wednesday morning, which will lead to a switch to all rain 
across the region by the mid morning hours and clear towards the
afternoon hours.

KEY MESSAGE 3...Briefly dry Thursday before an unsettled end to 
this week.

Mid-level ridging with surface high pressure briefly return
following Wednesday's event, leading to drier conditions for
Thursday. Behind it, another strong shortwave progresses east
from the central US, bringing with it strong surface low
pressure across the Great Lakes. NAEFS guidance continues to
favor enhanced moisture with this system; PWATs are 2-3 standard 
deviations above average heading into the weekend. Other
ensembles are in agreement, too, with mean PWAT values reaching 
an inch Friday night. Temperatures aloft are also notably warmer
across guidance suites, and ensemble mean highs at the surface 
climb into the 50s behind a warm front. A rain event for
southern New England for the end of the week is what's favored
at this time, but uncertainty remains regarding exact timing,
possible amounts, and track with this system.

&&

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

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

Today...High confidence.

VFR to start, then lowering to MVFR after 19z across central/W 
MA and CT as light snow overspreads the region. Snow may reach
eastern MA/RI after 21z. 

Tonight...Moderate confidence.

MVFR with areas of IFR in snow this evening. Minor accumulations
possible. Snow ending around midnight, possibly as a period of
freezing rain across RI, northern Ct and southeastern MA.
Becoming VFR late towards the south coast and northern CT.

Tuesday...Moderate confidence.

VFR, with areas MVFR across the higher terrain and eastern MA
during the morning. More widespread MVFR expected during the
afternoon.

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday Night through Friday/...

Tuesday Night: MVFR/IFR conditions possible. RA and FZRA 
likely.

Wednesday: Mainly VFR, with local IFR possible. Chance RA.

Wednesday Night: VFR. Breezy. 

Thursday: VFR. 

Thursday Night: VFR. Slight chance RA.

Friday: Mainly VFR, with local MVFR possible. Breezy. Chance
RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday...High Confidence.

Relatively light winds and seas expected during this time.
Reduced visibility at times in light snow tonight, which should
transition to rain across the southern coastal waters after
midnight. Dry conditions expected for Tuesday.

Outlook /Tuesday Night through Friday/...

Tuesday Night: Winds less than 25 kt. Chance of rain. 

Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain. 

Wednesday Night through Thursday: Winds less than 25 kt. Areas
of seas approaching 5 ft. 

Thursday Night: Winds less than 25 kt. Slight chance of rain. 

Friday: Winds less than 25 kt. Chance of rain. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 5 AM EST early this morning for 
     ANZ231-232-250-251-254>256.

&&

$$

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