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 061736
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1236 PM EST Tue Jan 6 2026

.WHAT HAS CHANGED...
A Winter Weather Advisory has been issued for the threat of freezing 
rain across portions of southern New England. Most locations along 
the I-95 corridor experience a light glace of ice, though locations 
across interior southern New England may see ice accumulation 
between 0.1" and 0.2". Plan on slick travel Tuesday evening 
through Wednesday morning.

&&

.KEY MESSAGES...

- Mixed precipitation expected Tuesday night into Wednesday
  morning. 

- Milder with rain later in the week but no flooding expected.

&&

.DISCUSSION...
KEY MESSAGE 1...Mixed precipitation expected Tuesday night into 
Wednesday morning. 

Starting off early this morning, a few slick spots from a few snow 
showers overnight. Today is dry and cloudy with high temperatures in 
the middle 30s. The more impactful weather arrives this evening as a 
low-pressure system/mid-level shortwave tracks across the region. 
This is a fast moving system, pushing east of the Gulf of Maine by 
Wednesday. As the low-pressure system tracks just north of our 
region, the best lift and moisture is displaced over central New 
England. That said, still feel confident in icing across interior 
southern New England. While surface temperatures remain below 
freezing, you may think, why isn't this snow? Well, ~1,500 feet 
above the ground temperatures are roughly +3C, this warm nose 
extends from 900mb to 800mb. As the snow falls through this layer it 
melts, becoming a rain drop, and then falls into a shallow freezing 
layer at the surface. It's here were the refreezing on untreated 
surfaces occurs. This is well visualized on forecast BUFKIT 
soundings, with the WAA from southwesterly winds. Where we expect 
the greatest ice accumulation, Berkshires and the Worcester Hills, 
with 0.1" and 0.2" of ice accumulation is possible. The lower 
elevations will experience less, 0.01" to 0.1", enough to make 
untreated sidewalks, driveways, roadways slick! This lead to a 
Winter Weather Advisory across much of Massachusetts, the exception 
being Southeast Massachusetts, Cape Cod, and the Islands. And 
northern/central Rhode Island and all of northern Connecticut. 
Timing wise, arriving to western areas between 6PM and 8PM, eastern 
areas between 9PM and 11PM. Expect road conditions will deteriorate 
soon after, especially untreated surfaces. Throughout the night, 
temperatures will gradually rise, with the threat of freezing rain 
retreating from south to north, mainly between 3AM and 7AM. The flow 
becomes west/northwest by late Wednesday morning, a few CAA 
rain/snow showers are possible through midafternoon with highs in 
the middle to upper 30s. With CAA, expecting breezy winds and gusts 
20 to 30 MPH.

KEY MESSAGE 2...Milder with rain later in the week. No flooding 
expected. 

There is good agreement among ensemble guidance for a pattern change 
later in the week favoring milder temperatures, especially for 
Fri/Sat. A subtropical ridge builds in from the south into Friday 
with a fairly potent northern stream shortwave trough moving across 
the Great Lakes/Quebec over the weekend. A jet of strong SW flow 
will help advect in above normal moisture into the region, around 
200-250 percent of normal. Given the mild airmass in place, this 
will support a round or two of rain in the Friday to Saturday 
timeframe. Comparing against climatology the moisture isn't 
considerably anomalous and with the fairly progressive nature of the 
pattern doesn't raise flags for excessive rainfall. This aligns with 
ensembles showing a range of 0.25" to 0.60" of rain in the more 
likely range. Additional snowmelt will need to be considered as 
well, but currently ensemble river forecasts have no indication of 
flooding concerns. 

Relatively cooler air moves behind the system bringing seasonable 
temperatures Sunday into early next week. Gusty SW winds are 
possible on Sunday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

18z TAF update...

Through 00z...

IFR-MVFR cigs across E coastal MA will expand across rest of
eastern MA/RI through late afternoon/evening. Light N-NE wind.

Tonight... Moderate Confidence. 

Lowering cigs/vsbys becoming widespread IFR-LIFR as RA and FZRA
overspreads the region. Mostly FZRA interior with brief snow
possible at onset north of Route 2. Brief FZRA may impact BOS-
PVD corridor at the onset of precipitation 02-05z. Otherwise, 
rain near the coast. Light N-NE wind becoming E near the coast.

Wednesday... Moderate Confidence. 

IFR-LIFR conditions persist in the morning with gradual
improvement to MVFR-VFR through the afternoon away from the 
coast. Areas of FZRA or FZDZ in the interior may expand toward 
the E-NE MA coast during the morning. Winds shifting to N-NW 
during the morning increasing mid-late afternoon

Wednesday night... High confidence.

Mainly VFR, although MVFR may linger into the evening for
Cape/Islands. NW wind 5-15 kt.

KBOS Terminal... Moderate Confidence. 

IFR cigs with LIFR cigs/vsbys developing late tonight into Wed
morning. Rain develops after 02z but could begin as a brief
period of FZRA before temps climb above freezing. Winds shift
back to N-NW Wed morning and that may lead to some -FZRA/-FZDZ
as colder air is drawn southward. 

KBDL Terminal... Moderate Confidence.

Conditions lowering to IFR tonight with pockets of LIFR. Areas
of FZRA develop after 00z transitioning to -RA/-DZ late tonight
as temps climb above freezing.

Outlook /Thursday through Saturday/...

Thursday through Thursday Night: VFR. 

Friday: Mainly VFR, with local IFR possible. Breezy. RA likely.

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

Saturday: Mainly MVFR, with areas IFR possible. Breezy. RA
likely.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Wednesday... High Confidence. 

An area of high pressure remains anchored off shore today with light 
winds and relatively dry conditions. A warm front overspreads the 
region early this evening with periods of rain overnight. Seas are 
1' to 3' today, increasing 2' to 4' overnight. Light E/NE wind 
today, then E/SE tonight. 

Wednesday, low-pressure system exits the Gulf of Maine, increasing 
wind from the W, gusting between 20 to 30 knots. Occasional rain 
showers tapper off from southwest to northeast during the late 
morning into the early afternoon. Increasing seas across the 
southern waters, between 4' and 8', eastern waters 2' to 5'. These 
conditions will lead to a Small Craft Advisory.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Winds less than 25 kt. Local rough seas. 

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

Thursday Night: Winds less than 25 kt. 

Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Seas locally approaching 5 ft. Chance of rain. 

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. Rain likely. 

Saturday: Winds less than 25 kt. Areas of rough seas. Rain
likely.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 7 PM this evening to 10 AM EST 
     Wednesday for CTZ002>004.
MA...Winter Weather Advisory from 7 PM this evening to 10 AM EST 
     Wednesday for MAZ002>017-026.
RI...Winter Weather Advisory from 7 PM this evening to 10 AM EST 
     Wednesday for RIZ001>004.
MARINE...Small Craft Advisory from 1 PM Wednesday to 1 AM EST Thursday 
     for ANZ235-237-250-254.
     Small Craft Advisory from 7 AM Wednesday to 1 AM EST Thursday 
     for ANZ255-256.

&&

$$

DISCUSSION...Dooley/Mensch
AVIATION...KJC
MARINE...Dooley/Mensch