Lexington Weather

Lexington, Massachusetts, USA

30°F

12/7/2025 6:03am

Lexington Conditions: Few Clouds
Temperature: 29.8°F / -1.2°C
Dew Point: 25.3°F
Relative Humidity: 83%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.97 in Steady
Visibility: 10 miles
Snow Today: 0.0 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 011049
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
549 AM EST Mon Dec 1 2025

.SYNOPSIS...
Monday brings the return to drier, colder and blustery weather. Low 
pressure tracking south of New England brings accumulating snow to 
interior portions of CT and MA Tuesday and Tuesday night, with rain 
most likely in the lower elevations. Beyond that high pressure 
brings dry weather to end the week except for a moisture starved 
front Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message...

* Dry and seasonable with breezy winds. 

High pressure crosses overhead Monday so subsidence beneath the high 
will keep skies clear and dry while gusty NW winds will persist for 
the first half of the day. Winds diminish through the afternoon as 
the center of the high moves directly overhead and the pressure 
gradient drops. This will lead to a decoupled boundary layer and 
calm winds overnight which would lend to some radiational cooling 
early before cloudcover increases as the high moves offshore. Lows 
dip into the low to mid 20s.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Key Messages:

* Coastal system Tuesday morning and night brings plowable snow
  to higher elevations of southern New England. Winter Storm 
  Watch issued for the central and western regions of 
  Massachusetts. 

A mid level shortwave over the Great Plains on Monday then moves 
into the eastern U.S. Tuesday. As it digs into the southeast it 
induces a deepening surface low off the Mid-Atlantic coast that 
lifts up along the New England coast Tuesday into Nova Scotia by 
early Wednesday. Guidance is in fairly good agreement at this point 
that the low tracks along or just inside the 70/40 benchmark. 
However, there are several factors that point to this being a 
largely high elevation snow/low elevation rain storm. First, this is 
a progressive system with no high pressure over Quebec to block its 
exit and keep sub-freezing air locked in at the surface. As such, 
warm advection kicks in quickly on southerly LLJ; so while we start 
off below freezing in the low levels temps will quickly warm above 
freezing outside of the Berkshires and Worcester Hills. This is 
especially true along the south coast as SSTs remain in the 50s. 
Even if precip starts as snow initially, accumulation is unlikely, 
or, worst case would likely be some coatings on grassy surfaces. The 
timing of this system (largely during the day) doesn't bode well for 
snow chances in the low elevations. In these early season cases 
"positive snow depth change" products are often more representative 
in the numerical guidance. This setup featuring an open wave at 750 
mb until downstream of SNE isn't typically a good indicator of a big 
snow storm. Where we do see snow, snow ratios in the guidance have 
trended down over the last 24-48 hours and model soundings indicate 
max omega/lift misses the DGZ so excessively heavy snowfall rates 
aren't expected. The trend with this forecast update was to lower 
the snowfall totals based on the factors discussed above. 

Regardless, there is a lot of moisture available (PWATs over 1.25" 
over the Cape and islands) and strong forcing for ascent; we 
previously mentioned the strong LLJ, and we'll also benefit from a 
coupled upper jet streak (SNE placed between the RRQ of an exiting 
jet and a LFQ of another). This will lead to rainfall totals of over 
an inch in southeast MA by the time precip comes to an end early 
Wednesday morning. While colder temps pulled in on the backside may 
produce a flip to snow briefly on the tail end, QPF will be tapering 
off and not expecting appreciable accumulations.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Key Messages: 

* A few snow showers possible the second half of Thursday with
  the passage of an Arctic cold front, otherwise dry weather 
  Wednesday through Friday. Turning unsettled by next weekend. 

* Temperatures are trending well-below-average Wednesday through
  the upcoming weekend. An Arctic cold front Thursday night to
  bring the coldest air of the season, highs struggling to get 
  above freezing by Friday afternoon.

Wednesday through Sunday is quiet and cold. 500mb pattern
becomes somewhat zonal across much of the CONUS with surface 
high pressure builds in behind the departing coastal low on 
Wednesday. Then an Arctic cold frontal passage late in the day 
Thursday. Moisture is limited, PWATS less than 0.6" should be 
enough for snow showers with the frontal passage. With the 
Arctic cold front, 925mb temperatures fall to -20C to -15C 
Thursday night, temperatures lower into the single digits to low
teens. But, a gusty northwest wind makes it feel much colder, 
wind chills are below 0F across the higher terrain and well into
the single digits for the coastal plain. Towards the end of the
extended, guidance shows a more active pattern, leading to 
unsettled conditions come next weekend.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

12Z update...

Today...High Confidence. 

VFR. NW gusts to 25 kt, diminishing late afternoon.

Tonight...High confidence.

VFR. Light to calm wind.

Tuesday...Moderate Confidence. 

SN for BDL/BAF/ORH and rain for other terminals arrives 12-18z.
VFR lowers to IFR by 18Z. Lower confidence in whether
BOS/BED/PVD may see some SN...more than likely RA or some non-
accumulating SN. 

KBOS Terminal...High confidence in trends.

KBDL Terminal...High confidence in trends.

Outlook /Wednesday through Friday/... 

Wednesday: VFR. Breezy. Patchy BR.

Wednesday Night through Thursday: VFR. Breezy. 

Thursday Night: VFR. Windy with local gusts up to 30 kt. 

Friday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday...High confidence.

W winds become NW through the day today with gusts 25-30 kt 
continuing. SCA for all waters. Winds quickly diminish through Mon 
afternoon as high pres builds in from the west. Light winds Mon 
evening becoming S-SE toward daybreak. Rough seas over southern 
waters will begin to subside during Mon and fall below 5 ft by Mon 
evening. Periods of rain ending tonight from W to E. Dry with good 
vsbys Mon and Mon night. 

Tuesday rain overspreads the waters and SSE winds early increase and 
turn out of the east then northeast late as a low pressure system 
crosses the southern waters. This leads to gusts as strong as 25-30 
kts by late Tuesday. 

Outlook /Wednesday through Friday/...

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 11 ft. Widespread fog. 

Wednesday Night: Winds less than 25 kt. Seas up to 5 ft. 

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. 

Thursday Night: Strong winds with gusts up to 35 kt. Rough seas
up to 13 ft. 

Friday: Winds less than 25 kt. Local rough seas.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Storm Watch from Tuesday morning through late Tuesday 
     night for MAZ002>006-008>012-026.
RI...None.
MARINE...Small Craft Advisory until 3 PM EST this afternoon for ANZ230-
     232>235-237.
     Small Craft Advisory until 5 PM EST this afternoon for ANZ231-
     250-251-254>256.
     Small Craft Advisory until 1 PM EST this afternoon for ANZ236.

&&

$$

SYNOPSIS...BW/Dooley
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...Dooley
AVIATION...Belk/KJC
MARINE...Belk/BW