Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Light snow, 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: 1½ miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 211704
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1204 PM EST Wed Jan 21 2026

.WHAT HAS CHANGED...
Biggest question of the forecast period is how much impact the late 
weekend/early next week winter storm brings to SNE. Snow is looking 
increasingly likely but details remain uncertain 4+ days out from 
this system.

&&

.KEY MESSAGES...

- A weak clipper system brings some light snow to the higher terrain 
areas and light rain for the coastal plain tonight.

-Temperatures surge above normal Thursday with gusty winds 25-35
 mph.

- Arctic front arrives Friday night, with dangerous cold and wind 
chills expected this weekend and into next week.

- A late- weekend coastal storm could bring impactful snow to 
Southern New England Sunday into Monday but confidence in details is 
low.

&&

.DISCUSSION...
KEY MESSAGE 1...A weak clipper system brings some light snow to
the higher terrain areas and light rain for the coastal plain 
tonight.

High pressure to our south moves offshore today and an upper-level 
trough moves through New England this afternoon. Winds shifting to 
the southwest on the backside of the high will bring a surge of 
slightly warmer, more moist air. This new airmass combining with the 
upper-level trough will initiate a few hours in the evening of light 
snow showers across the interior. Snowfall will be light in nature 
with snow totals of a coating to an inch in the higher terrain 
areas. Areas further south and east will have slightly elevated 
temperatures compared to the interior, and will most likely see rain 
showers instead of snow.

KEY MESSAGE 2...Temperatures surge above normal Thursday with 
gusty winds 25-35 mph.

Continued southwesterly flow and warm air advection helps warm 850 
mb temperatures to -2C to -5C and 925 mb temperatures to near 0C 
Thursday and allows surface temperatures to surge above normal... 
afternoon highs in the upper 30s in the higher terrain to low 40s in 
the coastal plain. The pressure gradient begins to tighten as 
another low pressure system move through the Great Lakes and high 
pressure stalls over the Atlantic Ocean. Winds will pick up during 
the afternoon hours as the land rapidly warms... expecting gusts to 
increase to 25-35mph through the afternoon.

Key Message 3...Arctic front arrives Friday night, with dangerous 
cold and wind chills expected this weekend and into next week.  

After a warm Thursday, Friday will be quite the transition into the 
coldest weekend of the winter. This comes thanks to a dry arctic 
front which sweeps through SNE on Friday. Temperatures should make 
it into the upper 20s and low 30s for a time on Friday before 
plummeting into the single digits on either side of 0. This airmass 
is unusually cold, with 850 mb temps as cold as -25 to -30 C and the 
aforementioned low temps 3 SDs below average for late January. This 
is dangerous cold, especially when combined with the strong LLJ 
overhead which model soundings suggest will mix down very 
efficiently in the strong CAA. At the moment gusts 30-40 mph are 
most likely, which would make temperatures Saturday morning feel 
like -10 to -20 F in the high terrain, -5 to -15 everywhere else. 
This will likely necessitate some Cold Weather Advisories, with 
Extreme Cold Warnings more than likely contained to the highest 
terrain of the Berkshires. Though Saturday morning will be the 
coldest period of this stretch of below normal temperatures, the 
unusual cold is sticking around into the beginning of next week. 
Highs on Saturday will be in the single digits to mid teens, warming 
to the teens/mid 20s Sunday and Monday. 

Additionally, the combination of strong winds and extremely cold
temperatures are likely to generate moderate to heavy freezing
spray on our waters Friday night through Sunday morning. 

Key Message 4...A late- weekend coastal storm could bring impactful 
snow to Southern New England Sunday into Monday but confidence in 
details is low. 

After the dangerous cold attention turns to a late weekend storm 
that has most of the eastern half of the country's attention at this 
point. This exceptional outbreak of cold coinciding with a large 
high pressure anchored over the northern tier of the country 
together with a frontal zone and plume of subtropical moisture will 
bring snow and ice from the southeast U.S. into the Mid Atlantic 
Sat/Sun and then has the potential to bring impactful snowfall to 
New England Sunday into Monday. This, as a surface low forms along 
the frontal boundary deepening as it passes off the eastern 
seaboard. Given this storm is over 4 days from its anticipated 
arrival in SNE it's not unusual for there to be significant question 
as to the details, which is indeed the case here. It will be 
partially dependent on the eventual track of the surface low. A pass 
near the 70/40 benchmark would be most impactful for the I-95 
corridor with lesser impact if it passes further south. A look at 
ensemble member low locations in the EPS and GEFS shows an extremely 
wide spread in the envelope of possible tracks with individual 
members depicting snow totals from a few inches to 10+. Latest model 
runs indicate at 40-60% chance of AOA 6" of snow. For now, suffice 
to say the better chance of major impacts remains to our southwest, 
but we are in play for that potential as well. Stay tuned.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

18Z update...

Through 00Z: High Confidence.

VFR. Southwest winds 5-10 knots.

Tonight: High Confidence.

Increasing mid-level cloudiness. Low-end MVFR cloud bases 
around 3000 feet possible with scattered -SN arriving as early 
at 00-03z, from west to east, and -RA for the Cape/Islands.
-RA/SN clears out bewteen 06-09Z from west to east.

Thursday: High Confidence.

Conditions improve to VFR with SW winds gusting up to 25 kts.

Thursday Night: High Confidence.

VFR. Light west winds, 5-10 knots.
 
KBOS Terminal...High Confidence in trends. Moderate Confidence 
in timing.

Expect -SN to move over the terminal around 03Z. -SN persists
for a couple of hours and may changeover to -RA/-RASN by 06-07Z
before tapering off west to east.

KBDL Terminal...High Confidence in trends. Moderate Confidence 
in timing.

Outlook /Friday through Sunday/...

Thursday Night: VFR. Breezy. 

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

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

Saturday: VFR. Windy with local gusts up to 30 kt. 

Saturday Night: VFR. Breezy. Slight chance SN.

Sunday: Mainly VFR, with local IFR possible. Breezy. Chance SN.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Thursday...

High pressure moves to the south of the coastal waters today, and 
conditions calm briefly today. Southwesterly winds increase tonight 
to above 25 knots across the outer waters and persist through 
Thursday. Seas subside to below 5 feet today, but begin to build 
once again tonight. Seas further build Thursday to 5-8 feet across 
the outer waters.

Outlook /Friday through Sunday/...

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

Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Seas up to 5 ft. 

Friday Night: Strong winds with gusts up to 35 kt. Areas of
rough seas. Freezing spray, slight chance of snow. 

Saturday: Moderate risk for Small Craft Advisory winds with
areas of gusts up to 30 kt. Areas of rough seas. Freezing
spray, slight chance of snow. 

Saturday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Freezing spray, chance of snow. 

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Freezing spray, chance of snow. Visibility 1 nm or less.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 7 PM this evening to 7 PM EST 
     Thursday for ANZ232-233-235-237.
     Small Craft Advisory until 7 PM EST Thursday for ANZ250-
     254>256.

&&

$$

DISCUSSION...BW/McMinn
AVIATION...BW/McMinn
MARINE...BW/McMinn