Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Light rain, Mostly cloudy
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 220656
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
256 AM EDT Mon Jun 22 2026

.WHAT HAS CHANGED...
No changes to the forecast at this time.

&&

.KEY MESSAGES...

- Periods of heavy rain possible later today into early 
  Tuesday.

- Drier air with seasonable temperatures expected midweek.
  Chances for rain return for the end of this week.

&&

.DISCUSSION...
KEY MESSAGE 1...Periods of heavy rain possible later today into
early Tuesday.

Have high confidence in a widespread, soaking rain across our
region later today into Tuesday morning. Even at this time
range, there remain different ideas on where the bands of
heaviest rainfall will be. Currently have the greatest
confidence across northern CT and western and central MA, where
terrain will assist the dynamic lifting processes.

Thinking total rainfall of 1.0-1.5 inches is the most likely
outcome. The probability for 2+ inches of rainfall remains 
about 30 to 40 percent. Not expecting flooding, as our region
remains abnormally dry. Flash flood guidance is 2-3 inches in 
an hour, which we should not achieve. Overall, this is looking 
like a beneficial rainfall for southern New England. 

We should dry out from west to east as a low pressure along the
south coast of New England moves offshore Tuesday.

KEY MESSAGE 2...Drier air with seasonable temperatures expected
midweek. Chances for rain return for the end of this week.

Surface high pressure will keep the weather dry through the 
middle of this week, after the rain comes to an end on Tuesday.

A low pressure system is expected to move into the Great Lakes 
by Thursday, then track into southeastern Canada by the end of 
this week. In addition, a weak shortwave trough should pass 
across the northeast. This combination will bring the next 
rainfall chances, beginning some time Thursday night into  
Friday morning. Isolated to scattered thunderstorms are possible
during this time as well, especially Friday afternoon, with the
highest chances across western MA.

The GEFS has low, but non-zero, probability for severe storms 
Friday, as well as some of the other ensemble and machine 
learning guidance. However, this probability varies significantly
amongst the guidance still. Given this spread, and how far out 
in the forecast it is, confidence on overall severe potential
remains low. 

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

Today: High confidence overall, though trending moderate for 
this afternoon due to timing of rainfall.

VFR most of the day, though clouds thicken up and lower through
the day. Sub-VFR ceilings and arrival of light -SHRA unlikely to
be sooner than 20z across western New England, and not until 
22-00z at earliest for central/eastern TAFs. Any -SHRA during 
this period should be light. W winds under 10 kt, then shift to 
S/SE then E late under 10 kt. 

Tonight: Moderate confidence. 

Conditions deteriorate to widespread MVFR-IFR. Steadier rainfall
arrives. But the timing and location of the eventual moderate 
to heavy rainfall remains unclear. The earliest reasonable start 
time is 01-03z across western New England, and after 03-05z for
the eastern TAFs. TSRA also possible.

Tuesday...High confidence in trends. Moderate confidence in
timing.

IFR early, improving to VFR from W to E during the afternoon as
rainfall ends. MVFR may linger across the Cape and islands
through late afternoon.


KBOS Terminal...High confidence in TAF trends. Moderate
confidence in timing.
 
KBDL Terminal...High confidence in TAF trends. Moderate
confidence in timing.

Outlook /Tuesday Night through Friday/...

Tuesday Night through Thursday: VFR. 

Thursday Night: VFR. Chance SHRA, slight chance TSRA.

Friday: Mainly VFR, with local MVFR possible. Breezy. SHRA
likely, slight chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday...High confidence.

A Small Craft Advisory continues for the outer coastal waters 
south of Block Island and east to Nantucket for this afternoon 
into Tuesday morning. Potential for gusts to 25 kt across some
of the waters across the Cape and islands, as well as the
eastern outer coastal waters. However, confidence is not high
enough yet that it will persist long enough to warrant expanding
the Advisory. This will need to be monitored with later
forecasts.

Rain arrives across the waters tonight, before finally moving
off to the east some time Tuesday afternoon into Tuesday
evening. Moderate to heavy rainfall at times expected, 
resulting in poor visibility less than 1 mile at times.

Outlook /Tuesday Night through Friday/...

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

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

Wednesday Night through Thursday: Winds less than 25 kt. 

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

Friday: Winds less than 25 kt. Chance of rain showers, slight
chance of thunderstorms. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 4 PM this afternoon to 8 AM EDT 
     Tuesday for ANZ255-256.

&&

$$

DISCUSSION...Belk
AVIATION...Belk
MARINE...Belk