Lexington Weather

Lexington, Massachusetts, USA

32°F
2/13/2025 11:56pm 
  • Lexington Conditions: Clear
  • Temperature: 31.6°F / -0.2°CColder 1.5°F than last hour.
  • Dew Point: 21.9°FDecreased 1.8°Fsince last hour.
  • Feels Like: 22.3°F
  • Relative Humidity: 67%Decreased 1.0% since last hour.
  • Wind: Wind from NW NW 12 mph, 10-min avg: 2 mph, gust: 12 mph
  • Barometer: 29.92 inRising 0.04  inHg/hr Rising Slowly
  • Visibility: 10 miles
  • Snow Today: 1.3 in
  •   
Southeast Middlesex County, MA - Wind Advisory
 - SEE ALL NEARBY ALERTS -

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 111112
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
612 AM EST Tue Feb 11 2025

.SYNOPSIS...
Dry and cold conditions today with below normal temperatures. Low 
pressure will track well south of New England tonight and may bring 
some light snow to the immediate south coast and Islands followed by 
drying conditions Wednesday. Another system moves across southern 
New England Wednesday night through Thursday, with light snow 
to start, transitioning to wintry mix and then rain Thursday 
morning. There is potential for light snow accumulations. Drier 
weather returns for Friday into early on Saturday before another
strong frontal system brings another period of mixed 
precipitation over the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
* Dry today with increasing clouds. 

Quiet weather today with high pressure in control. Skies will 
quickly become more overcast with high clouds moving in as moisture 
increases above 700 mb. SW winds will increase as the pressure 
gradient tightens just a bit thanks to a shortwave trough passing to 
our north. This may lead to some gusts of 20 to 25 mph but not 
expecting them to be widespread.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Key Messages...

* System passing to our south may bring a dusting of snow to the 
  immediate south coast with an inch or two possible on the islands. 

* Dry on Wednesday with a few stray flurries possible. 

Tonight a low pressure system passes well south of the 70/40 
benchmark brushing SNE with the northern extent of its precipitation 
shield. Most guidance has remained on track for less than an inch of 
snow on the south coast including the newest 00z and 06z HRRR 
guidance which was leaned on heavily for this update. Best shot at 
seeing 1+ inches of snow is the islands where around 0.01" of QPF is 
possible. GEFS guidance indicates a 50-60% chance of an inch of
snow while the EPS odds are nil. Regardless, any snow that 
falls isn't expected to be impactful with light snow in around 
midnight and out by 6 am. Lows dip into the teens (interior) and
low to mid 20s. 

Wednesday high pressure centered to our north keeps the weather 
quiet ahead of an incoming shortwave/surface low Wednesday night. 
Winds will be generally light with onshore easterly flow. Can't rule 
out a few widely scattered showers/flurries with increasing low 
level moisture on those easterly winds later in the day but the 
appreciable precipitation doesn't move in until Wednesday night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Key Messages: 

* Wed night into Thurs, system brings a wintry mix of snow, icing 
  and eventually rain. 

* Uncertainty in snow amounts with Weds night system, but more 
  likely minor accumulations. 

* A low-pressure system approaches Saturday, likely bringing another 
  round of wintry precip to southern New England.


Details: 

A mid-level shortwave trough moves across the Great Lakes region and 
across the northeast Wednesday night into Thursday. Coupled with an 
upper level jet and a plume of above normal moisture (PWATs 250-280% 
of normal), this will support another round of precipitation across 
southern New England. 

Models are in good agreement with a sufficiently cold antecedent 
airmass in place Wednesday night when the precipitation arrives.
For most areas, this will support the precipitation type as 
snow at the onset Wednesday night. There is also good model 
agreement with a warm front pushing northward after midnight. As
the warm air aloft works in from south to north, snow 
transitions to sleet/freezing rain and eventually to all rain. 
There may be a period at the onset of the warm front where the 
forcing may support mesoscale banding with moderate snow rates 
in spots. Areas on or hugging the east coast may transition 
sooner than surrounding locations with a little nudge from the 
easterly onshore flow. Models diverge when it comes to how the 
system develops as it tracks northward with some solutions 
showing development of a secondary low. The GFS/GEFS members 
have been a fan of this solution. In that case, shallow cool air
may stick around in northern MA for a bit longer leading to a 
longer period of wintry precip before switching to all rain. 
Conditions dry out in the afternoon as the bulk of the system 
exits northeast. As far as amounts go, GEFS probabilities for > 
3" of snow range from 30 to as 60% in far north MA and the 
Berkshires and less than 3" elsewhere. Compared to previous 
runs, the 00z run has trended downward. The ECMWF ens trends 
warmer quicker resulting in considerably lower probabilities, 
favoring a trace to 3". Light accumulations, if any, are looking
more likely overall still. Can't rule out some minor impact to 
the AM commute mainly for northern MA. 


Strong cold air advection follows the system as a cold front pushes 
across Thursday night with high pressure moving in. Friday will be 
cooler and dry with highs below normal in the low 30s. After brief 
ridging aloft, another mid-level trough approaches southern New 
England for the weekend. This will support another system bringing 
precipitation in the Saturday-early Sunday timeframe. There is a 
notable amount of spread in models when it comes to the details 
still (track, timing). The track in particular has varied among 
guidance which will have implications on precipitation type. Details 
will be ironed out as we get closer.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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

Today...High confidence.

VFR conditions. SW winds at 8-12 kts develop by the afternoon
with a occasional gusts up to 18 kts. Winds decrease after 21z 
becoming light SW less than 8 kts. 

Tonight...Moderate confidence.

Light snow approaches south coast tonight, around or after 06z. Uncertainty
with northern extent of snow area. Best chance for a period of
light snow with IFR vsbys and minor accumulations will be over 
the Islands with lower probability along the south coast. VFR
northward of south coast and Cape/Islands. 

Wednesday...High confidence. 

VFR. NE winds 10-15 kts. 

KBOS TAF...High Confidence in TAF.

KBDL TAF...High Confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly IFR, with areas MVFR possible. Breezy.
PL, chance SN, FZRA.

Thursday: Mainly IFR, with local MVFR possible. Breezy. Chance
RA, FZRA, PL.

Thursday Night through Friday: VFR. Windy with gusts up to
35 kt. 

Friday Night: VFR. Breezy. 

Saturday: Mainly VFR, with local IFR possible. Chance SN.

&&

.MARINE...
Forecaster Confidence Levels:

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

W/NW winds to 10-15 kt shift to SW 10-20 kt today. Winds will 
then become N-NE 10- 20 kt late tonight as front slides south of
the region. A low to our south will bring snow to the southern
waters tonight with light winds. Winds turn out of the NE on
Wednesday increasing to 10-15 kts with gusts to 20 kts. 

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Areas of rough seas. Rain, chance of
snow. Areas of visibility 1 to 3 nm.

Thursday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Rough seas up to 10 ft. Rain. 

Thursday Night: Strong winds with gusts up to 30 kt. Rough seas
up to 9 ft. Slight chance of rain. 

Friday: Strong winds with gusts up to 30 kt. Areas of rough
seas. 

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. 

Saturday: Winds less than 25 kt. Chance of rain, chance of
snow.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 7 PM Wednesday to 7 PM EST Thursday 
     for ANZ231>235-237-250-251-254>256.

&&

$$

SYNOPSIS...BW/Mensch
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...Mensch
AVIATION...BW/Mensch
MARINE...BW/Mensch
      

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