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 Boston / Norton, MA

        
000
FXUS61 KBOX 290532
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
132 AM EDT Wed Apr 29 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...

- Coastal low clouds move inland tonight.

- Beneficial rainfall Wednesday night into Thursday.

- Cooler pattern prevails Friday through weekend but mostly dry.

&&

.DISCUSSION...
KEY MESSAGE 1...Coastal low clouds move inland tonight.

High pressure will remain in control through Wednesday with ridging 
aloft and dry weather expected. However, an inverted trough from low 
pressure that is well offshore was producing some low clouds that 
can be seen on satellite south and east of Cape Cod. These low 
clouds were being held offshore by daytime heating but will 
eventually expand inland tonight as boundary layer cools, most 
likely across much of eastern MA and RI, perhaps as far west as 
Worcester per model cross sections. Moist E/NE flow will also 
produce areas of fog, and perhaps some spotty drizzle, mainly
near Cape Cod and the Islands.


KEY MESSAGE 2...Beneficial rainfall Wednesday night into Thursday.

We may see some showers sneak into eastern MA Wednesday evening 
associated with inverted trough, otherwise showers will become more 
widespread Wednesday night into Thursday with passage of upper 
trough from Ohio Valley and secondary surface low that tracks from 
mid Atlantic to Cape Cod. Timing has sped up a bit and now it looks 
like most of the rain will come to an end early Thursday afternoon 
as dry slot comes through quickly.

Speed of system, combined with modest dynamics and moisture, will 
limit rainfall totals from being excessive, but most areas should 
still pick up 0.25 to 1.00" of much needed rainfall, perhaps a 
little more in northern MA. 

Astro tides are fairly low so coastal flooding is not much of a 
concern along E MA coast. Persistent onshore flow may bring a surge 
of up to 1 foot later in week, but by then winds turn offshore as 
surface low lifts farther to the north.


KEY MESSAGE 3...Cooler pattern prevails Friday through weekend but 
mostly dry.

Blocky pattern takes hold later this week and over weekend as upper 
low takes up residence over southern Ontario. Southern New England 
should be far enough removed from coldest air aloft to keep us 
mostly dry, especially given W/NW flow, but pattern certainly favors 
diurnal clouds and perhaps a few afternoon sprinkles Friday, 
Saturday, and Sunday. 

It does look like upper low may lift farther north early next week, 
allowing for more of a zonal flow across northern tier of states 
which would lead to drier and milder weather Monday and Tuesday. 
However, models are notorious for breaking down these blocky 
patterns too quickly, such that it may take a little longer to see 
improving conditions. For now, forecast reflects model blend to iron 
out the uncertainty.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

06z TAF Update:

For today, slow improvement at best. Ceilings may briefly lift 
to MVFR near the coast late morning to early afternoon, but IFR 
likely redevelops by mid to late afternoon with a chance of 
-SHRA/-DZ. VFR continues across the western terminals. 

By tonight, MVFR/IFR conditions become more widespread as 
showers overspread the region, continuing into Thursday. 

KBOS Terminal...Moderate confidence in TAF timing. Very slow
improvement to MVFR late in the afternoon. There is the
potential for IFR ceilings to persist all day.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday: MVFR/IFR conditions possible. Breezy. Chance SHRA.

Thursday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA.

Friday: VFR. Breezy. 

Friday Night through Saturday Night: VFR. 

Sunday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence through the end of the week.

Persistent E/NE winds continue as high pressure remains over the 
Maritimes and low pressure meanders well offshore SE of 40/70 
benchmark for next few days. 

NE winds may approach SCA around Cape Cod with 20kt gusts but main
issue will be rough seas of 5 to 8 feet on outer waters through
Thu where SCA remains posted. May have to extend it into Rhode 
Island and Block Island Sounds should confidence increase in 
later forecasts.

Otherwise, areas of fog and drizzle should develop tonight, 
especially on south coastal waters, with little improvement Wed. 
Showers expected Wed night and Thu as low pressure tracks from the 
mid Atlantic to Cape Cod and Gulf of Maine.

Outlook /Thursday through Sunday/...

Thursday: Winds less than 25 kt. Rough seas up to 10 ft. Rain
showers. 

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers. 

Friday through Friday Night: Winds less than 25 kt. Seas up to
5 ft. 

Saturday through Saturday Night: Winds less than 25 kt. Areas
of seas approaching 5 ft. Slight chance of rain showers. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ250-
     254>256.

&&

$$

DISCUSSION...JWD
AVIATION...Dooley/FT
MARINE...JWD