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 272021
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
421 PM EDT Mon Apr 27 2026

.WHAT HAS CHANGED...
No significant changes made to the forecast.

&&

.KEY MESSAGES...

- Quiet weather continues through Tue night with highs mainly in
  the 60s to 70+ in the CT Valley...But only 50s along the
  immediate coast. Lows in the 30s to the lower 40s.

- Unsettled weather returns late Wednesday and Thursday with a soaking
  rain likely. 

- Remains unsettled Friday into the weekend with cooler than 
  normal temperatures. Isolated showers possible.

&&

.DISCUSSION...
KEY MESSAGE 1...Quiet weather continues through Tue night with 
highs mainly in the 60s to 70+ in the CT Valley...But only 50s 
along the immediate coast. Lows in the 30s to the lower 40s.

A ridge of high pressure will remain in control of our weather 
through Tue night. This high pressure system will result in mainly 
clear skies tonight with another excellent night of radiational 
cooling. Low temps will drop well down into the 30s across the 
many of our locations...to the lower 40s in some of the 
urban centers. Airmass is still quite dry...But can not rule out 
some patches of fog/low clouds developing overnight near the coast. 
Low confidence on whether or not this happens...but greatest risk 
towards the Cape and Islands. 

Plenty of sunshine is expected on Tue...Although do expect some mid-
high level cloudiness to overspread the region during the day. 
Onshore flow a bit stronger than today...so high temps probably a 
few degrees lower than today on the coastal plain. 
Nonetheless...still expect highs to reach into the 60s in most 
locations away from the immediate coast. The mild spots will again 
be the CT Valley where high temps of 70+ seem likely. 
Meanwhile...onshore flow will hold high temps mainly in the lower to 
middle 50s along the immediate coast, Cape and Islands. 

Mainly dry and cool again Tue night with another good night of 
radiational cooling. Lows will be in the 30s in many locations with 
lower 40s in most urban centers. We will need to watch for some 
stratus and perhaps some fog patches working in off the ocean into 
eastern MA/Cape overnight. Perhaps even a touch of spotty 
drizzle/very light showers working in off the ocean too. 

KEY MESSAGE 2...Unsettled weather returns late Wednesday and 
Thursday with a soaking rain likely. 

Wednesday will be a "transition" day as the weather pattern becomes 
unsettled by Thursday morning. Most places remain dry for Wednesday 
with high pressure in place. As a trough approaches from the west, 
moisture begins to advect into the region mainly from the west. 
Expect cloudy skies for the day with continued NE flow. Only areas 
that may see an isolated shower or two are the eastern coastal 
areas.

The shortwave trough and frontal system arrive overnight Wednesday 
into Thursday. Precipitable water values rise to around 1.0", 
supportive of widespread showers/rain. Model guidance is still a 
little split in the details, especially with the development of a 
secondary low pressure that tracks around/just offshore of the Cape 
Thursday. This may have some influence on rain amounts as well as 
the wind direction/speed. We are still continuing to monitor coastal 
flooding, but even minor coastal appears very low probability at 
this point for the eastern coastal areas. The bulk of the rain exits 
Thursday night. Most places should get at at least a half an inch. 
There are some low probabilities for around 1" of rain for 
northeast MA.  

KEY MESSAGE 3...Remains unsettled Friday into the weekend with 
cooler than normal temperatures. Isolated showers possible.

Weather pattern remains unsettled Friday through the weekend with 
troughing aloft. This will bring cooler than normal temperatures and 
partly to mostly cloudy skies overall. Can't rule out pop-up showers 
on Friday into the weekend underneath the trough/cyclonic flow 
aloft. There is some marginal instability present, so can't rule out 
a graupel within any showers. There is a small percent of 
model/ensemble guidance that indicates the potential for a coastal 
system to give a glancing blow to southern new england over the 
weekend. In this scenario this could bring rain/gusty winds later 
Saturday into Sunday to portions of southern new england. Again, 
this is still low probability scenario right now being 
displayed by a small percentage of model solutions. This will 
continue to be monitor as confidence in the upper pattern and 
details increases as we get closer. 

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

18z TAF Update...High confidence. 

Mainly VFR conditions continue through Tue night. We will need to 
watch for some spotty low clouds/fog patches towards the 
Cape/Islands overnight...But not completely sold on it given the 
airmass is quite dry. We are more concerned about stratus and 
perhaps some fog patches approaching the eastern MA coast, Cape and 
Islands very late Tue night. An easterly component to the winds 
continue on the order of 5 to 15 knots during the daylight hours 
with the strongest near the coast. NE winds gust to between 20
and 25 knots across the Cape and especially Nantucket during the
daylight hours. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday: VFR. Slight chance SHRA.

Wednesday Night: Mainly VFR, with local IFR possible. SHRA.

Thursday: MVFR/IFR conditions possible. Breezy. SHRA, slight
chance TSRA.

Thursday Night: Mainly VFR, with areas MVFR possible. Windy
with local gusts up to 30 kt. Chance SHRA.

Friday: Mainly VFR, with local MVFR possible. Windy with local
gusts up to 30 kt. Slight chance SHRA.

Friday Night: Mainly VFR, with local MVFR possible. Breezy. 

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 Tuesday night...High confidence.

High pressure centered over the Canadian Maritimes with distant low 
pressure well southeast of the Benchmark will result in persistent 
NE winds tonight through Tue night. This long fetch will generate 3 
to 6 foot seas across the outer-waters...so current small craft 
headlines will persist. Some marginal NE 20-25 knot wind gusts 
possible for Nantucket sound again on Tue...so another small craft 
headline may need to be posted for Tue once the current once expires 
this evening for that region.

Outlook /Wednesday through Saturday/...

Wednesday: Winds less than 25 kt. Areas of rough seas. Chance
of rain showers. 

Wednesday Night: Winds less than 25 kt. Local rough seas.
Chance of rain showers. 

Thursday: Winds less than 25 kt. Areas of rough seas. Rain
showers, slight chance of thunderstorms. 

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers. 

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Slight chance of rain showers. 

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

Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ232.
     Small Craft Advisory from 2 AM Tuesday to 8 AM EDT Thursday 
     for ANZ250.
     Small Craft Advisory until 8 AM EDT Thursday for ANZ254>256.

&&

$$

DISCUSSION...Frank/Mensch
AVIATION...Frank
MARINE...Frank/Mensch