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 041918
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
218 PM EST Sun Jan 4 2026

.WHAT HAS CHANGED...
Snowfall amounts were increased slightly for late Monday into Monday 
night. Confidence has increased in light icing across the interior 
Tuesday night. 

&&

.KEY MESSAGES...

- Clearing and cold tonight

- Light snow accumulations, a coating to 2 inches, expected Mon 
  afternoon into Monday night 

- Chances increasing for mixed precipitation event Tuesday night 
  into Wednesday.

- A brief period of dry weather on Thursday followed by another
  round of unsettled weather into the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Clearing and cold tonight

Rising heights tonight as mid level trough continues to move east 
and high pres will be building in from the west. NW winds may become 
briefly gusty this evening then diminishing overnight as gradient 
slackens with approach of high pres. With clearing skies expect good 
radiational cooling overnight as winds become light. Lows should 
drop into the single numbers interior MA, with teens elsewhere. 

KEY MESSAGE 2...Light snow accumulations Mon afternoon into Mon night

A modest mid level shortwave will be quickly moving into the region 
Mon afternoon and evening. Ahead of the shortwave a warm front will 
approach from the SW with modest overrunning developing. Synoptic 
scale forcing is not overly impressive but the column does saturate 
through the snow growth region and low levels are quite cold which 
will help to enhance isentropic lift. This should result in a period 
of widespread light snow, starting 1-3 pm in the west and 3-6 pm in 
eastern New Eng. Temps will be in the 20s when snow begins so it 
will stick immediately which will have some impact to the evening 
commute, especially in the west where the snow begins earlier. But 
snowfall rates will be more than manageable at 0.5 inch or less per 
hour.

It's a fairly quick moving system so snow should be tapering off 
before midnight as drier moves in. The snow growth region dries out 
quickly which could lead to snow ending as a period of freezing 
drizzle. QPF amounts are light, generally under 0.2", and expected 
SLR will be 12-15:1. Probably not much more than that as snow growth 
omega is not that strong. Looking at accums of 1-2 inches for much 
of the region, except a coating to an inch closer to the south 
coast. Ptype all snow, but may mix with or change to rain on the 
Islands Mon evening as BL warms with light S flow. 

KEY MESSAGE 3...Chances increasing for mixed precipitation 
event Tuesday night into Wednesday.

A good portion of Tuesday looks to remain dry once the snow showers 
move out in the early to mid-morning. However, another short wave 
and low pressure system look to move into southern New England by 
Tuesday night, bringing chances for a mixed precip event. Excluding 
the NAM, the rest of the models are indicating a warm nose of air 
with 850mb temperatures ranging +2C to +5C. Guidance is beginning to 
hone in on the higher terrain areas of the Berkshires and Worcester 
Hills having a higher likelihood of surface temperatures remaining 
at or below freezing, leading to higher chances of seeing freezing 
rain. Starting to see the latest round of guidance creep up in the 
ice accumulation, bringing consensus to above 0.01" but below 0.1" 
in the higher elevations. Soundings continue to favor this period of 
freezing rain before switching to all rain as surface temperatures 
increase heading into the mid-morning hours on Wednesday.

KEY MESSAGE 4...A brief period of dry weather on Thursday 
followed by another round of unsettled weather into the weekend.

The Tuesday/Wednesday system should make its exit by Wednesday 
night, and a mid-level ridge with a surface high moves in to bring a 
period of dry weather on Thursday. Unfortunately, not expecting the 
dryness to last as another system is projected to push into southern 
New England at some point on Friday. Temperatures Friday and 
Saturday remain above freezing, with ensemble guidance indicating 
surface high temperatures 10-15F above normal, leading to precip 
remaining solely as rain. Given this is still quite a while out, 
uncertainty regarding timing, placement, and precip totals remains 
high.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

18z TAF update...

Through tonight...VFR-MVFR cigs trending all VFR tonight as 
cloud cover decreases. NW wind 5-15 kt becoming light toward
12z. 

Monday...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. 

Monday night...Moderate confidence.

MVFR with areas of IFR in snow in the evening. Minor accums 
possible. Snow ending around midnight. 

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday: Mainly VFR, with local IFR possible. Slight chance RA,
slight chance FZRA.

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

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

Wednesday Night through 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 Monday night...High Confidence.

A period of NW gusts to 25 kt should develop this evening, 
especially over the eastern waters. SCA was issued for eastern MA 
waters and outer southern waters. Winds diminish late tonight 
through Tue while shifting to SW late Tue and Tue night. Lowering 
vsbys late Mon into Mon night in snow, changing to rain over 
southern waters.

Outlook /Tuesday through Friday/...

Tuesday: Winds less than 25 kt. Slight chance of rain, slight
chance of freezing rain. 

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 from 7 PM this evening to 5 AM EST Monday 
     for ANZ231-232-251-255-256.
     Small Craft Advisory until 5 AM EST Monday for ANZ250-254.

&&

$$

DISCUSSION...KJC/McMinn
AVIATION...KJC
MARINE...KJC/McMinn