Lexington Weather

Lexington, Massachusetts, USA

33°F
2/13/2025 11:04pm 
  • Lexington Conditions: Clear
  • Temperature: 32.9°F / 0.5°CColder 2.3°F than last hour.
  • Dew Point: 23.5°FDecreased 4.4°Fsince last hour.
  • Relative Humidity: 68%Decreased 6.0% since last hour.
  • Wind: Wind from NW NW Calm, 10-min avg: 3 mph, gust: 14 mph
  • Barometer: 29.89 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 112315
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
615 PM EST Tue Feb 11 2025

.SYNOPSIS...
Low pressure passes well south of New England tonight and will
bring a coating to an inch or two of light snow to the South
Coast, Cape Cod, and the Islands. Another system moves across 
southern New England Wednesday night through Thursday, with 
light snow to start, transitioning to a wintry mix and then to 
rain Thursday morning. Dry weather returns Friday into early 
Saturday before yet another system brings a round of wintry
precipitation this weekend, probably starting as snow before 
changing to rain near the coast and a wintry mix inland.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
615 PM Update

Key Messages: 

* Light snow near South Coast with minimal impact. Coating for
  most but 1-2" in spots especially along the immediate South
  Coast and Islands.

* Cloudy and cold elsewhere.

Latest high-res model guidance supports going forecast and is in
line with satellite and radar trends. We'll see a sharp northern
edge to the precip shield as low pressure tracks well south of
New England overnight and fights drier air to the north. We may
see some flurries make it close to Hartford (but probably
staying south of the city) and more likely into Providence and
Plymouth, while accumulating snow stays right near South Coast,
Cape Cod, and Islands. Most places should just get a fresh
coating of snow overnight while Islands stand best chance at 1"
or 2" in spots. Everything is done by 5-6 am Wed at latest.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
245 PM update...

Wednesday...

Key Messages: Mainly dry & seasonably cold weather

Frontal wave south of 40N/70W 12z Wed, zips out to sea with weak 
subsidence over SNE. This will support mainly dry weather along with 
a few breaks of sunshine (more clouds than sun). Although, cold NE 
onshore flow streaming across the relatively mild ocean, will yield 
more ocean effect strato-cu over eastern MA, with scattered flurries 
possible from time to time, per hi res simulated reflectivity 
fields. Seasonably cold with highs in the 30s, although it will feel 
colder across eastern MA with blustery NE winds 10-15 mph with gusts 
up to 20 mph at times. 

Wednesday night and Thursday...

Key Messages: wintry mix of snow to sleet to freezing rain Wed night 
into Thu AM, will yield slippery travel, esp NW of I-95

1035 mb high over the maritimes provides low cold air damming (CAD) 
over SNE, while WAA rides up and over the cold surface dome. Precip 
overspreads the region between 06z-12z Thu initially in the form of 
snow as the cold air is deep. However, model soundings indicate warm 
air aloft eventually wins out and changes ptype from snow to sleet 
and then freezing rain. Not expecting freezing rain in the coastal 
plain, just a period of snow and sleet before changing over to all 
rain, as model soundings indicate rapidly warming boundary layer. 
However, farther inland, with secondary surface wave traversing 
somewhere near the I-95 corridor, this locks in shallow cold air 
across the interior during the morning, specifically northern CT 
into western-central MA, possibly as far east as the I-495 corridor. 
Thus, given the duration of mixed precip, including a period of 
freezing rain, decided to issue a winter weather advisory Wed night 
into Thu morning for the area mentioned above, mainly northwest of I-
95. Shallow cold air may linger long enough to impact the Thu AM 
commute in this region.

Then by afternoon, dry slot overspreads the region with precip 
ending from west to east. As the surface low exits into the Gulf of 
Maine, winds turn to the west and become gusty and temps rise into 
the 40s late in the day, perhaps only upper 30s across northwest MA, 
where shallow cold air may be more difficult to scour out. 
Nonetheless, above normal along with some breaks of sunshine 
possible late across western MA/CT.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
245 PM update...

Key Messages: 

* Travel impacts likely this weekend, especially across interior 
  where snow probably changes to a mix or even rain for a time. Less 
  of an impact near coast where change to all rain is more likely.

* Minor snow accumulation possible late Sunday night into Monday 
  morning.

* Dry and cold weather follows early next week.

After a brief respite Fri, active weather pattern continues this 
weekend as southern stream short wave over southern Plains rounds 
broad upper trough in place across Northeast. This setup is fairly 
complex as front stalls somewhere near South Coast and a wave of low 
pressure rides NE along it, so timing is questionable this far out 
but ensemble probabilities favor best chance of precipitation from 
sometime Sat afternoon into Sun. We do know that this system 
will have a lot of moisture available and ensembles show wind 
and moisture fields running 2 to 3 standard deviations above 
normal. Ensemble probabilities reflect that with fairly high 
odds of at least 0.50" of precipitation and even decent odds of 
1" or a little more.

That said, this does not have the look of a significant snowfall for 
SNE as the overall pattern has a "warm" look to it with track of 500 
mb, 700 mb, and 850 mb lows all to the north of our region. It's the 
lowest levels that will ultimately determine precipitation type 
which is highly dependent upon track of surface low. Right now 
model/ensemble consensus favors a track right over SNE but we'll see 
wobbles north and south over next couple of days. 

Cold air in place means snow for much of SNE at start Sat afternoon 
and Sat night, with minor accumulations before coastal areas 
probably see a change to a mix and eventually rain either late Sat 
night or Sun morning. Farther inland, change will be slower to 
occur, if it occurs at all, but best chances of accumulating snow or 
a mix should be in higher elevations of western/central MA and 
perhaps northern CT and northwest RI. However, if we see a low track 
end up farther inland, then even these higher elevation areas would 
see a change to rain as milder air floods in. Based upon ensemble 
snow probabilities (which use 10:1 ratio) this favors an Advisory-
level event for locations near and north of Mass Pike, perhaps for 
other areas should we end up with more in way of mixed precipitation.

Colder air returns behind departing low Sun night into Mon morning, 
which is when we could see a change back to light snow for much of 
SNE and perhaps minor accumulations. 

Dry and cold weather prevails early next week as yet another high 
pressure system coming out of Canada heads to the Ohio Valley and 
East Coast.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Forecast Confidence Levels:

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

00z TAF Update: High confidence.

VFR cigs for most of SNE overnight. Light snow grazes South
Coast with IFR vsbys along immediate coast, Cape Cod, and
Islands mainly 05-09z Wed with less of a chance into KPVD where
we may see some flurries.

MVFR cigs prevail Wed with E/NE winds, gusting to 25kt along
coast. We should also see scattered flurries, mainly near coast,
but not confident enough in timing to include in TAFs. 

Next round of precipitation arrives as we approach end of TAF
period (03-06z) and should bring MVFR cigs/vsbys in light snow 
to CT and western MA with less of a chance farther east.

Looking ahead to Thu, IFR/LIFR with rain likely along the 
coast, wintry mix inland, then all precip ending as rain by
afternoon. Improvement to MVFR/VFR toward 00z Fri. 

KBOS TAF...High confidence. May see flurries (P6SM -SHSN) during
day Wed but not confident enough in timing to include. Looking
ahead to Wed night/Thu, light snow probably starts after
midnight (06z) and quickly changes to rain around 09z with less
than one inch of snow accumulation before the changeover.

KBDL TAF...High confidence. Flurries expected to remain to the
south tonight. Looking ahead to Wed night/Thu, light snow begins
around 04z and changes to a FZRAPL mix 07z-10z, before changing
to rain closer to 13-14z. Snow accumulation around one inch with
less than 0.10" of icing before the change to rain.

Outlook /Thursday Night through Sunday/...

Thursday Night: VFR. Windy with gusts up to 35 kt. Slight
chance FZRA.

Friday: VFR. Windy with gusts up to 30 kt. 

Friday Night: VFR. Breezy. 

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

Saturday Night: MVFR/IFR conditions possible. SN, RA.

Sunday: Breezy. RA, SN.

&&

.MARINE...
Forecaster Confidence Levels:

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

245 PM update...

Key Messages: 

* Light snow may reduce vsby southern waters of MA/RI tonight
* NE winds 15-20G30 kt late Wed night/Thu AM
* Wind shift to WNW late Thu, 20-25 kt

Weak wave of low pressure tracks well south of New England tonight, 
bringing a period of snow to the southern waters of MA/RI. Wave 
tracks south of 40N/70W 12z Wed, then zips east out to sea. Tranquil 
conditions Wed, with NE wind 10-15 kt. Then Wed night, low pres 
approaches from the SW, with NE winds 15-20G30KT across the MA/RI 
waters late Wed night into Thu AM. Low moves up the I95 corridor 
early Thu, then into the Gulf of ME Thu afternoon, with wind shift 
from NE to WNW late. 

Outlook /Thursday Night through Sunday/...

Thursday Night: Strong winds with gusts up to 35 kt. Rough seas
up to 10 ft. 

Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Rough seas up to 10 ft. 

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

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

Saturday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Rain. 

Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 12 ft. Rain. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 10 PM Wednesday to 10 AM EST 
     Thursday for CTZ002>004.
MA...Winter Weather Advisory from 10 PM Wednesday to 10 AM EST 
     Thursday for MAZ002>006-008>012-026.
RI...Winter Weather Advisory from 10 PM Wednesday to 10 AM EST 
     Thursday for RIZ001.
MARINE...Small Craft Advisory from 7 PM Wednesday to 7 PM EST Thursday 
     for ANZ231>235-237-250-251-254>256.

&&

$$

SYNOPSIS...JWD/Nocera
NEAR TERM...JWD
SHORT TERM...Nocera
LONG TERM...JWD
AVIATION...JWD
MARINE...JWD/Nocera
      

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