Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Clear
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 Boston / Norton, MA

        
000
FXUS61 KBOX 210543
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
143 AM EDT Tue Apr 21 2026

.WHAT HAS CHANGED...
There is potential for elevated fire risk on Thursday, otherwise
the general forecast trends remain unchanged.

&&

.KEY MESSAGES...

- Chilly temperatures tonight will be followed by a period of dry/quiet
  weather ahead of our next chance for showers Tuesday night 
  into Wednesday

- Shower chances for Wednesday, followed by more seasonable
  temperatures Thursday through the upcoming weekend. Risk for
  elevated fire weather concerns Thursday due to low relative  
  humidly and gusty northwest winds.

&&

.DISCUSSION...
KEY MESSAGE 1...Chilly temperatures tonight will be followed by a 
period of dry/quiet weather ahead of our next chance for showers 
Tuesday night into Wednesday.

Short-wave energy moving over southern New England this afternoon 
ejects southeast overnight bringing an end to any afternoon showers. 
Northwest flow follows with moderate low-level CAA that will bring 
925 hPa temps down to -5C. Additionally, with light winds and clear 
skies, we can expect a chilly night with well below normal 
temperatures in the upper 20s to low 30s for much of southern New 
England. Locations across the interior Northwest may even observe 
temperatures in the high teens. 

A mid-level ridge builds in from the west tomorrow afternoon which 
will bring 925 hPa temps up closer to 0C. This will support a second 
consecutive afternoon with high temperatures peaking in the low 50s. 
Overall a dry and sunny Tuesday dominated by surface high 
pressure.

As surface high pressure shifts east tomorrow night into Wednesday, 
return flow and warm advection from the south may support a few 
isolated to scattered showers across southern New England. 

KEY MESSAGE 2...Shower chances for Wednesday, followed by more 
seasonable temperatures Thursday through the upcoming weekend. Risk 
for elevated fire weather concerns Thursday due to low relative 
humidly and gusty northwest winds. 

There are no significant weather events on the horizon for Wednesday 
through this upcoming weekend, a few nuisance hiccups at best. There 
is a weak system passing through early Wednesday, this is associated 
with an 850mb shortwave, leading to showery activity. Given marginal 
temperatures aloft, 925-850mb, between -2C to +2C, cannot rule out a 
few of the showers containing wet snow. No impacts expected due to 
the recent warmth. However, a coating isn't out of the question for 
northern Berkshires and northern Worcester Hills. Otherwise, mostly 
dry period of weather for the rest of the work week and increasing 
temperatures. As mentioned by the previous forecaster, 925mb temps 
rebound to +5C to +8C for Thursday and Friday, returning afternoon 
highs to the lower 50s and upper 50s. Nightly lows are seasonable in 
the lower 40s and upper 30s. 

Thursday shows potential for elevated risk for fires to spread. The 
key factors include a mixed boundary layer, leading to low 
dewpoints/humidity, and gusty NW wind around 20-30 mph. Will need to 
monitor and collaborate with state officials on whether or not a 
Special Weather Statement would be needed. 

Looking ahead to the weekend, SNE is placed on the western side of a 
mid-level trough, under NW flow. Shortwave energy does pass through 
the flow, this may lead to instances of showers, though a washout is 
not expected at this time. There isn't much of a deviation in 925mb 
temperatures for the weekend, but added cloud cover, highs could be 
a few degrees cooler Saturday and Sunday in the upper 50s to 60F.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

06z TAF Update:

Through 12z Tuesday: High confidence. 

Mainly VFR, though BKN low-end VFR/periods MVFR for the Cape
airports and periods of unrestricted-visby -SHRA continue thru
about 10z. N winds 5-10 kt, light to calm interior airports. 

Today: High confidence. 

VFR. Light NE winds to shift to southerly 5-10 kt, with
SE seabreezes along the eastern MA and RI coasts starting 
around 15-17z. 

Tonight and Wednesday: High confidence overall, though moderate
on timing.

VFR with initial high clouds lowering and thickening thru first
half of the night. Warm-frontal precip breaks out around 
~07-10z Wed in western New England, and while mainly rain 
predominates, it could mix with wet snowflakes for higher 
terrain locations especially if timing is on the earlier end of 
that window. Precip then spreads further east thru 10-15z as
rain showers. Arrival of precip brings ceilings dropping to 
mainly MVFR (with intervals IFR). Sub-VFR ceilings beginning to
slowly improve for western terminals after 22z but probably
takes until Wed night before more significant improvement
develops.

SE to S winds 5-10 kt, though speeds could trend lighter on Wed
once precip arrives.

KBOS Terminal...High Confidence in TAF. SE seabreezes could 
develop as soon as 14z but is more likely around 15-16z.

KBDL Terminal... High Confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday: Mainly VFR, with local IFR possible. Slight chance
SHRA.

Wednesday Night: Mainly VFR, with local MVFR possible. 

Thursday: VFR. Breezy. 

Thursday Night through Friday: VFR. 

Friday Night through Saturday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Tonight through Tomorrow Night

High pressure moves over the coastal waters tonight through tomorrow 
bringing relatively calm conditions to the coastal waters. Generally 
expect seas with significant wave heights 3 feet or less and modest 
wind speeds around 10 knots with some gusts to 15 knots possible. 
Winds will be out of the north tonight and tomorrow before a shift 
to southerly flow tomorrow night. 

Outlook /Wednesday through Saturday/...

Wednesday through Wednesday Night: Winds less than 25 kt. Seas
locally approaching 5 ft. Slight chance of rain showers. 

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

Thursday Night through Friday Night: Winds less than 25 kt. 

Saturday: Winds less than 25 kt. Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Dooley/RM
AVIATION...Loconto
MARINE...RM