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 222333
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
733 PM EDT Mon Jun 22 2026

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

&&

.KEY MESSAGES...

- Widespread rain tonight into early Tuesday with periods of
  heavy rain. Showers likely continue Tuesday. A few embedded 
  storms or downpours possible.

- Dry and warm temperatures Wednesday and Thursday. Shower and 
  storm chances increase for the end of the work week.

&&

.DISCUSSION...
KEY MESSAGE 1...Widespread rain tonight into early Tuesday with
periods of heavy rain. Showers likely continue Tuesday. A few 
embedded storms or downpours possible.

Widespread rain has overspread southern New England this 
afternoon. Expect this activity to continue for the remainder of
today into tonight as the first wave of low pressure moves 
across the region. There will likely be just enough instability 
to support embedded downpours and even a few embedded 
thunderstorms. The highest risk for this will be tonight and 
overnight into very early Tuesday morning as an axis of 
instability shifts across the region. Precipitable water values 
range 1.2-2.0" and model soundings show sufficient warm cloud 
depths to support efficient rain processes, so pockets of 
heavier rain rates are supported. The HREF 3-hour PMM QPF shows 
3-hour amounts 0.5 to near 1.2" in 3 hours overnight into early 
Tuesday morning. Given the instability and moisture amount, 
1"/hr rates are possible, but would be fairly isolated and 
within any embedded storms. 

Confidence decreases with regards to the details Tuesday. A second 
wave will track nearby Tuesday into Wednesday; however, the track is 
still uncertain. How north or south this tracks will dictate the how 
widespread the rain/showers will be as well as chances for any 
embedded storms. It is likely showers continue Tuesday morning into 
the afternoon slowly clearing from west to east in the late 
afternoon and evening. HREF means track the main portion of the 
system south of the region with the north shield of the 
showers/embedded storms brushing across mainly the south coast of 
southern New England and southeast MA through the evening. Some 
hints of instability support a few embedded weak storms or 
downpours and given the more likely track should keep the 
highest risk south and east. In terms of totals, 1-2" continues 
to be most likely for amounts. Given we have had an extended dry
period, flash flood guidance is fairly high is 2-3 inches/hour 
in most areas. Therefore, widespread flash flooding is not a 
concern. Urban and low drainage flooding is possible, especially
in areas that are impacted by the embedded heavier rain rates. 
We will have to keep a watch on our more flashy areas 
(Providence). 
 

KEY MESSAGE 2...Dry and warm temperatures Wednesday and Thursday. 
Shower and storm chances increase for the end of the work week.

Surface high pressure will keep the weather dry through the middle 
of the week, after the rain comes to an end on Tuesday. High 
temperatures will be in the low to mid 80s across the area, which is 
near to a few degrees above seasonal normals, and overnight lows in 
the 50s and 60s. High temperatures could be tempered a bit under 
cloud cover and rain for Friday, but rebound over the weekend as the 
front moves away from the region. 

A low pressure system will move into the Great Lakes region 
Thursday, then into southeastern Canada by the end of the week, 
while a shortwave trough passes across the northeast. This system 
will bring the next chances for rain to New England, beginning as 
early as Thursday night, and continuing into Friday morning. 
Coverage becomes more scattered by Friday afternoon, with isolated 
to scattered thunderstorms are possible during those afternoon hours.

Ensemble and some machine learning guidance has low probability for 
severe storms Friday, but how high that probability is and how much 
of the region is covered varies fairly significantly among models. 
Given this spread, and how far out in the forecast it is, confidence 
on overall severe potential is low, but a couple strong 
thunderstorms cannot be totally ruled out at this time. 

High pressure and dry weather return for the weekend.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

00Z Update

Today: High confidence. 

Mostly VFR conditions, with MVFR or lower within heavier
embedded rain showers. -SHRA starting to erode from west to 
east, becoming more scattered in coverage, rather than 
widespread rain. Ceilings decrease to MVFR from west to east 
later this evening. SE to E winds at 6-12 kts. 

Tonight: Moderate confidence (ceilings/thunder probs)

Ceilings deteriorate to IFR/LIFR overnight. Scattered rain
showers that could be heavy at times, with isolated embedded
thunder. Location of heavier rain and any thunderstorms
uncertain. Patchy fog possible for Cape and Island terminals, 
potentially down to 1/2 or 1/4SM at ACK early Tuesday morning. 
Easterly winds 8-12 kts. 

Tuesday...Moderate Confidence.

IFR/LIFR at least for the morning. Scattered showers through the
day with a few embedded downpours possible. Embedded storms
possible for SE MA terminals through mid-morning. Scattered showers
continue through much of the day. There is another risk for an 
isolated storm by the afternoon into early evening; however, 
confidence is lower on this potential. Wind NW 5-10 kts, 
shifting NE at BOS in the afternoon. Precipitation ends from
west to east gradually by around 18Z, with improving ceilings 
after 20Z. Sub VFR conditions will linger the longest for Cape 
and Island terminals. 

KBOS Terminal...Moderate Confidence.

Rain. Moderate to heavy at times. Ceilings fall to MVFR after 
00Z and to IFR after 03Z. LIFR ceilings are possible. Winds may
become steadier east tonight. Potential for embedded thunder 
overnight mainly between 04 through 12Z. Scattered showers 
continue Tuesday with NW winds shifting NE in the afternoon 8-12
kts. 
 
KBDL Terminal...High confidence in TAF trends. Moderate
confidence in timing.

Outlook /Tuesday Night through Saturday/...

Wednesday through Thursday: VFR. 

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

Friday: VFR. Breezy. Chance SHRA, slight chance TSRA.

Friday Night: VFR. Slight chance SHRA.

Saturday: VFR. Chance SHRA, 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. Gusts 22-25 kt possible for brief periods
across the Cape and islands, as well as the eastern outer 
coastal waters. 

Rain and a few embedded storms tonight before finally moving 
off to the east Tuesday evening. Moderate to heavy rainfall at 
times expected, resulting in poor visibility less than 1 mile at
times.

Outlook /Tuesday Night through Saturday/...

Wednesday: Winds less than 25 kt. Seas up to 5 ft. 

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

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. 

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

Saturday: 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 until 8 AM EDT Tuesday for ANZ255-256.

&&

$$

DISCUSSION...Mensch/Sava
AVIATION...Mensch/Sava
MARINE...Mensch/Sava