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 201852
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
152 PM EST Tue Jan 20 2026

.WHAT HAS CHANGED...
There have been no significant changes since the last forecast 
update.

&&

.KEY MESSAGES...

-Near-normal to warmer than normal temperatures Wed/Thu as a 
 weak clipper the system brings some higher terrain light snow 
 and light rain for the coastal plain tomorrow night

-Above normal temps Thursday with gusty winds at 30 to 40mph

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

-We continue to monitor a potential coastal storm for late in
 the weekend, but confidence remains very low.

&&

.DISCUSSION...

Key message 1...Near-normal to warmer than normal temperatures 
Wed/Thu as a weak clipper the system brings some higher terrain 
light snow and light rain for the coastal plain tomorrow night

A mid-level ridge builds overhead tonight with an area of surface 
high pressure positioned to our south. This will support a wind 
shift to the southwest overnight which will allow warmer air to 
advect into the region during the day tomorrow. After a chilly start 
to Wednesday with single digit low temperatures, warm advection and 
southwest flow will allow afternoon temperatures to approach near to 
slightly above normal temperatures ranging from the upper 20s across 
the interior northwest to the upper 30s over southeast MA and The 
Cape/Islands. 

Models continue to resolve a subtle short-wave aloft embedded in 
larger upper-level trough moving overhead tomorrow night.
Positive vorticity advection in conjunction with low-level warm air 
advection will support a period of light snow showers for much of 
the interior/high terrain. Moisture will be very limited with PWATs 
only between 0.25-04". Not expecting any significant accumulations 
with only a dusting to an inch tomorrow night.
Areas further south and east more likely to see some spotty rain 
showers.

Key Message 2...Above normal temps Thursday with gusty winds at
30 to 40mph

Thursday will likely be our last mild day for the foreseeable 
future, before an arctic airmass moves in this weekend.  Mid-level 
ridge and light WAA allow 850 mb temps to warm to -5C, which will 
translate into highs in the low to mid 40s.  Thursday will be very 
breezy as strong westerlies develop due to a tight pressure gradient 
between high pressure over the Atlantic and low pressure over the 
Great Lakes.  Bufkit soundings show a fairly deep mixed layer up to 
800 mb, where winds are around 35-45mph.  Gusts of 30-40mph should 
be able to mix down to the surface during the peak heating hours in 
the afternoon. 

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

Arctic front arrives on Friday with highs likely peaking in the 
upper 20s to low 30s early in the day before plunging to near zero 
by Friday night.  The Arctic front will bring continued gusty winds, 
with NW gusts of 30-40mph once again in the afternoon, and remaining 
gusty overnight.  This will bring the windchill index/feels-like 
temperature into the single digits for Friday afternoon and into the 
negative teens to twenties for Friday night.  High temperatures on 
Saturday will likely be the coldest of the season thus far, with 
highs only topping out in the single digits to low teens. It will be 
less windy on Saturday with NW winds gusting 15-20mph; however, this 
will keep the wind chill index in the -10 to -20 range.  Winds 
finally look to diminish on Saturday night as the center of the 
arctic high moves overhead; however, this will set the stage for 
good radiational cooling conditions, allowing low temperatures to 
drop near or below zero by Sunday morning.  Not much relief from the 
Cold on Sunday as highs remain well below normal in the low teens 
and wind chills still near or below zero. Wind chills below -15 can 
cause frostbite in as little as 30 minutes on exposed skin, so use 
caution if spending time outdoors this weekend, especially at night. 
 Cold weather looks to continue into next week, as CPC continues to 
highlight much of the Northeast in a moderate risk for well below-
normal temperatures. 


Key Message 4...We continue to monitor a potential coastal 
storm for late in the weekend, but confidence remains very low.

Guidance continues to indicate a potential coastal low sometime 
between Sunday and Monday.  There is still significant uncertainty 
with this system, as both deterministic and ensemble guidance are 
very spread out along its path, as it could travel up the coast or 
out to sea as it exits the mid-Atlantic.  With a track out to sea, 
snow impacts would be little to none; however, if this system 
approaches the 40/70 benchmark and travels up the coast, there would 
be more significant snow impacts, especially with cold air already 
in place. The probabilistic Winter Storm Severity Index shows a 20-
30% chance for major winter storm impacts Sunday into Monday.


&&

.AVIATION /18Z TUESDAY 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. West winds gusting 20-25 knots, becoming light after 00z.

Tonight: High Confidence.

VFR. West winds 5-10 knots.

Wednesday: High Confidence.

VFR. Southwest winds 5-10 knots.

Wednesday Night: Moderate Confidence.

Increasing mid-level cloudiness. Low-end MVFR cloud bases around
3000 feet possible. Scattered -SN.
 
KBOS Terminal...

VFR. Gusty W winds 23-27 knots through this evening.

KBDL Terminal...

VFR. Increasing W winds through this evening with gusts of 
20-25 knots.

Outlook /Thursday through Sunday/...

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

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

Friday through Saturday: VFR. Breezy. 

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.

Tonight through Wednesday night

SCY criteria persists through about midnight before winds diminish 
and seas subside below SCY levels. This will be in response to high 
pressure building south of the coastal waters. A brief period of 
calmer conditions tomorrow morning and afternoon before before 
southwest winds kick back up to SCY criteria Wednesday night into 
Thursday. Increasing winds on Thursday as well, possibly reach gale 
force for the outer waters by Thursday evening.

Outlook /Thursday through Sunday/...

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

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. Chance of freezing spray, slight chance of snow. 

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

Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of snow, chance of freezing spray. 

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Chance of snow, chance of freezing
spray. Visibility 1 nm or less.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ230-
     231-236-251.
     Small Craft Advisory until 1 AM EST Wednesday for ANZ232>235-
     237.
     Small Craft Advisory until 7 AM EST Thursday for ANZ250-
     254>256.

&&

$$

DISCUSSION...KP/RM
AVIATION...RM
MARINE...RM