Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Overcast
Temperature: 35.1°F / 1.7°C
Dew Point: 32.4°F
Relative Humidity: 90%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.00 in Falling Slowly
Visibility: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Lexington, MA

        
000
FXUS61 KBOX 142107
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
407 PM EST Sun Dec 14 2025

.SYNOPSIS...
A brief shot of arctic air follows a departing low pressure
tonight into Monday, with wind chill values dropping to between 
0 to 10 below. Cold weather continues Monday night into Tuesday
but with much lighter winds. A warming trend in temperatures is
expected Wednesday and especially by Thursday with high 
temperatures of 50+ possible. A round of rainfall is looking 
likely later Thursday into Friday accompanied by a period of 
strong southerly winds. A brief shot of much colder weather with
another period of strong winds possible Friday into early 
Saturday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Key Messages...

* Accumulating snow ends into this evening, confined mostly to
  southeast MA this afternoon.

* Turning colder tonight. Lows in the single digits and teens.
  Minimum wind chill values between 0 to 10 below. A few
  locations towards NW MA could see wind chill values as low as
  20 below.

Accumulating snow had largely ended across most of RI and
portions of southeast MA. As such, canceled a portion of the 
Winter Weather Advisory already. Will monitor the progress of
the snowfall this afternoon, and perhaps cancel more of the
remaining Advisory towards 4 PM. Otherwise, it will still expire
at 7 PM this evening.

As of this writing, the heaviest snow band extended from between
the Vineyard and Nantucket northeast across the outer Cape. The
outer Cape is where additional accumulating snow is possible. 

Still expecting snowfall to diminish from NW to SE this
afternoon. Will continue the Winter Weather Advisories as they
are for now. Will likely be able to cancel some of these
advisories prior to the 7 PM expiration time.

Once the snowfall ends, just turning colder with clearing skies
and gusts WNW winds overnight. Considered a Cold Weather 
Advisory towards the Berkshires, but thinking the colder 
conditions will not be widespread enough to warrant a headline.
This will need to be monitored this evening.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Key Messages...

* Gusty WNW winds through Monday

* Dry weather with below normal temperatures

A sprawling high pressure over the central USA will maintain dry
and cold conditions across southern New England into Monday
night. Some sunshine to start the day, with increasing clouds
during the afternoon. Mostly cloudy skies expected Monday night,
but not much in the way of precipitation. There is a low chance
for a stray snow shower from the Great Lakes to make it into the
Berkshires Monday Night.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Key Messages...

* Rain, potentially heavy at times, likely later Thursday into 
  Friday.

* Period of strong winds possible Friday into early Saturday. 

Details...

Tuesday: 

Extended period will start off with continued below normal 
temperatures on Tuesday. 850mb temperatures aloft warm slightly as 
the mid-level pattern moderates a bit from Monday, this will likely 
bring highs in the upper 20s to mid 30s. Surface high pressure 
positioned to the south will support mainly dry conditions and light 
southwesterly winds.

Wednesday through Friday: 

Wednesday into Thursday, there is a good consensus among ensemble 
guidance for a change in the pattern aloft. A more zonal pattern is 
favored for Wednesday and by Thursday higher heights advect into the 
region ahead of our next system. This will start a trend in warming 
temperatures as warmer temperatures aloft move in  also accompanied 
by breezier southwest winds. High temperatures Thursday rise into 
the 40s for most areas. Thursday, a mid-level shortwave trough 
approaches with strong WAA ahead of it. A strong 850mb temperature 
anomaly overhead should support a mild day with high temperatures in 
the 40s to near 50 in spots. Models keep things dry despite the warm 
and moist advection through the day Thursday ahead of the 
approaching system. Can't rule out a stray shower later in the day 
Thursday. 

Ensemble guidance favors the bulk of the system to move through 
sometime Thursday evening into Friday, although there are some 
timing differences among individual members. There will be a good 
amount of synoptic support for soaking rain event with a strong 
southerly LLJ transporting in a plume of above normal moisture (170-
220% of normal) combined with broad ascent & frontal forcing. This 
may also support a period of moderate to heavy rainfall. With plenty 
of WAA ahead of the system, this system will be simply rain for 
everyone. Ensembles generally show a range of 0.25 to 0.80" for rain 
amounts. Rain should decrease from west to east Friday AM to Friday 
afternoon with a cold front pushing in behind it. If the front moves 
through during the day, it may end up being a non-diurnal type day 
with the high temperatures occurring at in the morning (40s/50s), 
especially further west. 

Another concern with this system will be the potential for strong 
winds. The suite of deterministic and ensemble guidance has shown 
good agreement with a strong LLJ over the region. NAEFS and ECMWF 
EFI highlights this jet and potential gusts to be anomalously
high. The LLJ orients generally SW to NE eventually shifting 
over southeast MA Friday night with 925mb winds 50-70 kts. The 
challenge will be the degree of mixing we will get under the 
inversion and what locations will have the higher potential. 
There is also second period favored gusty winds behind the cold 
front on Friday. We are still pretty far out, so details are 
still fuzzy. Models are still struggling with the timing of the 
system and cold front which will influence timing/magnitude of 
gusts. So for now, there is a signal worth monitoring for a 
period of stronger winds in the Thursday night to Friday 
timeframe.

Trending colder behind the cold front Friday night and Saturday with 
temperatures returning to below normal. 

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

Tonight...High Confidence 

MVFR-IFR and even brief LIFR conditions are expected in areas
towards the Cape and Islands in ocean effect snow showers. This
activity should dissipate just after midnight. Otherwise, WNW 
wind gusts of 20 to 25 knots with a few gusts near 30 knots 
across the high terrain and near the coast develop.

Monday...High Confidence 

Mainly VFR with NW gusts up to 30 knots. A few fair-weather
clouds early, but should be VFR. VFR CIGS developing during the
afternoon.

Monday Night...High Confidence.

VFR CIGS. Lighter W winds.

KBOS Terminal...High confidence in trends. Moderate confidence
in timing. Little additional accumulation, although some very
light snow possible before 21Z.

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday through Friday/... 

Tuesday: VFR. 

Tuesday Night through Thursday: VFR. Breezy. 

Thursday Night: Mainly MVFR, with local IFR possible. Strong
winds with local gusts up to 40 kt. RA likely.

Friday: Mainly VFR, with local MVFR possible. Strong winds with
local gusts up to 40 kt. RA likely.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Monday Night...High confidence.

Winds quickly increase to gales this evening as colder air
arrives and continues into Monday. Expecting wind gusts between
35-40 kt later this evening into Monday afternoon. Areas of 
very light freezing spray possible tonight and Monday. 
Elsewhere, Small Craft Advisory conditions expected in 
Narragansett Bay and Boston Harbor.

Outlook /Tuesday through Friday/...

Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. 

Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas locally approaching 5 ft. 

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

Wednesday Night: Winds less than 25 kt. Areas of rough seas. 

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

Thursday Night: Moderate risk for gale force winds with gusts
up to 45 kt. Areas of rough seas. Rain likely. 

Friday: gale force winds with areas of gusts up to 45 kt. Rough
seas up to 12 ft. Chance of rain. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Weather Advisory until 7 PM EST this evening for 
     MAZ022>024.
RI...None.
MARINE...Small Craft Advisory until 3 PM EST Monday for ANZ230-236.
     Gale Warning until 1 PM EST Monday for ANZ231>235-237-250-251-
     254>256.
     Freezing Spray Advisory from 1 AM to 10 AM EST Monday for 
     ANZ232>234.

&&

$$

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