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 251737
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
137 PM EDT Sat Apr 25 2026

.WHAT HAS CHANGED...
Increases to rain chances and northeast wind speeds and gusts 
for Sunday into Monday for southeast New England. While these 
changes were minor, more significant increases could be needed 
pending the track of coastal low pressure to Southern New 
England.

&&

.KEY MESSAGES...

- Increasing cloudiness today and generally dry with cooling 
  onshore breezes, although light rain showers develop late 
  today and tonight in western MA into portions of CT and 
  southern RI. 

- Coastal low pressure just to our south brings cloudy and cool
  weather, northeast breezes and periods of rain showers to 
  southeast New England Sunday, possibly into Monday.

- Dry weather with onshore breezes resume early to middle of
  next week with a warming trend to temps, before weather turns
  more unsettled late in the week.

&&

.DISCUSSION...
KEY MESSAGE 1...Increasing cloudiness today with cooling onshore 
breezes, although light rain showers develop late today and 
especially tonight for western MA and portions of CT and 
southern RI. 

Sfc ridge in place across most of Southern New England will
supply another round of modest onshore flow/seabreezes today, 
with cool temperatures in part from a upper-level low parked 
over the Canadian Maritimes. To our west is a stream of mid to 
high level moisture across western NY, which will be advancing 
across our area through today. Expect increasing cloudiness 
toward an overcast look by this afternoon, although for the vast
majority of Southern New England, that "overcast" is really a 
pretty extensive canopy of mid to high cloud cover. With mid to 
high clouds and onshore flow, I kept highs on the cooler end of 
guidance in the mid/upper 40s for eastern MA and the South 
Coast, and lower to mid 50s further into the interior.

Although much of the area is dry today/tonight, the exception is
in far western MA and adjacent Hartford County in CT, and 
eventually into Tolland County RI and southern RI late tonight. 
Showers associated with an initially weak mid-level shortwave 
trough over MI end up shifting ESE today, and some of those 
showers should be able to make it into western MA/Hartford 
County area late in the day (shortly before sundown), then 
expand ESE toward southern RI tonight. The eastern and northern 
extent of these showers should be stunted by northwesterly 
confluent mid-level flow and the drier air in place; most BUFKIT
profiles show a pretty robust plume of dry air below 850 mb in 
central/eastern MA and northern RI. The NAM still remains a more
bullish outlier on QPF, and even though the GFS did tick upward
some, some of that QPF will be lost to saturate the profile. 
Offering periods of light rain from about Westfield to 
Willimantic south and west thru midnight, then expanding 
southeast towards southern RI/Newport area overnight. Possible 
that some of that could mix with wet snowflakes in the terrain 
in Tolland County but really not of much impact. High res 
guidance also shows a rather sharp precip cutoff, far more so 
than the coarser-res global models show and that probably is 
what transpires. This then sets us up for a lower-confidence 
forecast as we head into Sunday and Monday, to be addressed in 
the next Key Message. 

KEY MESSAGE 2...Coastal low pressure just to our south brings
cloudy and cool weather, northeast breezes and periods of rain
showers to southeast New England Sunday, possibly into Monday.

Low pressure south of Long Island Sunday morning, on the
southern periphery of the high pressure in place over New 
England, should still favor at least overcast with best chance 
for rain along the South Coast, Cape and Islands, to go along 
with enhanced NE winds. Devil's in the details and the main 
issue is how far north and how quickly will this low pressure 
get to at least southeast New England for Sunday and possibly 
into Monday. Seemingly key in that evolution is how quickly will
the trough over MI today become entrained with the circulation 
over Atlantic Canada and close off. The NAM, SREF and to a more 
limited extent the 12z ECMWF show the trough closing off 
soonest, producing a slow-moving gale low south of Nantucket, 
which then slowly meanders NNE into Monday. Were this to verify,
much of southeast New England would see a chilly, raw and wet 
Sunday and Monday with periods of rain and NE gusts to near gale
force (e.g. NAM shows 950 mb NE winds 55-60 kt). The risk for 
rain in that outcome would also extend as far north as the Mass 
Pike, and especially eastern MA. Though I think it's too early 
to outright dismiss this, it doesn't have much support from the 
GFS/Canadian/more recent 00z ECMWF camp, which closes off the 
mid- level shortwave too late to a more offshore solution, 
keeping lighter rain showers to the coastal waters, Martha's 
Vineyard, Nantucket and Cape Cod with NE breezes, with mostly 
cloudy but generally dry conditions elsewhere for Sunday into 
Monday. Cluster analyses also suggest the NAM solution is more 
of an outlier. Will weight the forecast closer to the 
GFS/Canadian more offshore idea, but still shows chance to 
borderline likely PoP and NE winds increasing Sunday night into 
Monday for southeast New England. If other guidance were to come
on board with the NAM in subsequent guidance, then the 
potential for more substantial forecast changes would be in the 
cards. Astro tides are decreasing so really no risk for coastal 
flooding. Highs in the 40s to lower-mid 50s Sunday, coolest 
southeast New England, and in the 50s to lower 60s for Monday, 
though in the lower 50s for eastern MA with NE breezes.

KEY MESSAGE 3...Dry weather with onshore breezes resume early to 
middle of next week with a warming trend to temps, before 
weather turns more unsettled late in the week. 

High pressure then reasserts itself once the coastal low pulls
away either Monday or Tuesday - viewed as more likely Monday. 
This brings what should be nice weather with onshore breezes and
temperatures gradually modifying, although still slightly 
cooler than normal. Our weather pattern then turns more 
unsettled for mid to late in the week, with a possible risk for 
coastal cloudiness/rain showers Wednesday, and then troughing 
and a cold front around Thursday/Friday.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

Rest of Today and Tonight: High confidence. 

VFR. Satellite showing increasing mid to high level clouds this
afternoon which should continue. Ceilings start to lower to 
lower-end VFR/MVFR levels near BDL around 20-23z with rain 
showers. VFR visibility for most. Rain showers and MVFR ceilings
then expand southeast to near PVD overnight. SE winds this
afternoon will persist into the evening, remaining below 10 kt.
They then will shift SSW for some before going light and
variable in some areas to calm. Rain showers are a possibility
towards the Cape and Islands heading into Sunday morning.

Sunday and Sunday Night: High confidence. 

BKN/OVC VFR for most, with NE winds 5-10 kt. Lowest 
ceilings (MVFR) and stronger NE winds around 10-15 kt for the 
Cape and Islands, to go along with periods of showers as low 
pressure passes to our south. Chances for showers may linger
through Sunday night towards ACK.

KBOS Terminal...High confidence in TAF. Winds overnight may
periodically go calm.

KBDL Terminal...High confidence in TAF.


Outlook /Sunday through Thursday/...

Sunday: Mainly VFR, with local MVFR possible. Slight chance RA.

Sunday Night through Monday: VFR. Breezy. Slight chance SHRA.

Monday Night through Tuesday: VFR. Breezy. 

Tuesday Night through Wednesday: Mainly VFR, with local MVFR
possible. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today and Tonight: High confidence. 

Winds and seas are below SCA criteria through tonight, with E/SE 
winds around 10-15 kt and seas 3 ft or less, building to around 
4 ft on southern waters. Dry weather today, although a risk for 
showers on the southern waters tonight. 

Sunday and Sunday Night: Moderate confidence. 

Coastal low pressure passes over the southern waters Sunday into
Sunday night. Expect increasing northeast winds to around
20-25 kt and building seas, which could warrant SCAs on the 
southern waters if the low pressure passes closer to Southern 
New England's waters. NE winds around 10-20 kt northeast waters.
Though it is unlikely, a period of stronger northeast winds 
possibly into the 30 kt range could develop Sunday night 
southeast of Cape Cod. Rain showers southern waters, but mainly 
dry eastern waters.

Outlook /Sunday through Thursday/...

Sunday: Winds less than 25 kt. Chance of rain. 

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers. 

Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Chance of rain
showers. 

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

Tuesday: Winds less than 25 kt. Local rough seas. Slight chance
of rain showers. 

Tuesday Night: Winds less than 25 kt. Areas of rough seas.
Slight chance of rain showers. 

Wednesday: Winds less than 25 kt. Rough seas up to 8 ft. Chance
of rain showers.

&&

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

&&

$$

DISCUSSION...Loconto
AVIATION...Belk/Loconto/Hrencecin
MARINE...Loconto