Lexington Weather

Lexington, Massachusetts, USA

63°F

4/26/2025 7:43pm

Lexington Conditions: Overcast
Temperature: 63.0°F / 17.2°C
Dew Point: 61.5°F
Relative Humidity: 95%
Wind: WSW Calm, 10-min avg: 1 mph, gust: 5 mph
Barometer: 29.61 in Steady
Visibility: 10 miles
Rain Today: 0.64 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 211938
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
338 PM EDT Mon Apr 21 2025

.SYNOPSIS...
A warm front will spread increased cloudiness into Southern New 
England through tonight, with passing showers around and after 
midnight. Rain showers then taper off early on Tuesday with 
decreasing cloudiness in most areas toward mild temperatures in 
the 60s to low 70s, but cloud cover may linger into the 
afternoon for the southern coast with cooler temperatures. Mild 
and dry weather for the rest of the workweek, before our weather
pattern turns more unsettled again around the weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
330 PM Update:

Key Messages: 

* Turning overcast tonight, with periods of rain showers around
  and after midnight. 

* Rain showers taper off overnight in western New England, but may 
  linger into the pre-dawn hours in eastern New England. 

* Lows mid 40s to around 50.

Details:

Although we started the day with full sunshine with coastal 
seabreezes, we're starting to see increased cloud cover in most 
areas west of I-495 in MA. This is associated with increased 
moisture from a warm front which trails from northern VT through 
western RI; warm sector regime currently confined to much of the 
eastern Gt Lakes, central/southern NY and western MA/CT precedes a 
cold front now working its way through the Ohio Valley. 

Cloud cover will only continue to gradually increase through tonight 
and overnight, although many areas to remain dry thru midnight. Rain 
showers then move into western New England around midnight, then 
slowly progressing eastward into eastern MA and RI toward the pre-
dawn hours. Precipitable water values increase to around 1.2" with 
the increased SW flow aloft; wouldn't rule out some very brief 
downpours in a few showers but they're expected to pass through with 
little overall fanfare. Through early Tuesday morning we should see 
areal-average rain amts of up to a quarter-inch. Rain showers should 
be coming to an end west of Worcester close to daybreak while 
continuing into eastern MA, RI and the Cape and Islands. With the 
warm advection (925 mb temps warm to around +12C) and increased 
cloud cover, sided low temps toward milder side of guidance into the 
mid to upper 40s.  

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
330 PM Update:

Key Messages: 

* Overcast to start Tue; improvement away from the coastlines by mid 
  morning, but it may take until the afternoon before peeks of sun 
  break out for the South Coast, Cape and Islands. Temps range from 
  mid 60s to low 70s away from the southern coast, but only in the 
  50s to low 60s south coast, Cape/Islands.

* Dry cold frontal passage Tue night, with modest NW breezes. 
  Seasonable lows in the mid 40s.

Tuesday and Tuesday Night: 

Rain showers from the overnight will be progressing off to the east 
and offshore thru the early to mid morning hours. So while we start 
off the day with overcast conditions, expect decreasing cloud cover 
and warming temperatures away from the coasts into the 60s to low 
70s. Forecast challenge for Tuesday resides along the south coast, 
Cape and Islands; very limited mixing is progged given the cooler 
marine boundary layer with moisture trapped beneath the warm airmass 
aloft. This is visualized in forecast soundings at New Bedford, 
Westerly, Falmouth/Hyannis and Nantucket. It could be quite a while, 
potentially into the afternoon, before low clouds begin to erode 
given those profiles. and that would cut into how warm temperatures 
may get for the southern coast, with cooler SWly onshore flow for 
these locations as well. Thus opted for highs only in the 50s, 
perhaps near 60. If cloud cover does scatter out earlier, then temps 
would be too cool and could reach up into low to mid 60s.

We then get a dry cold frontal passage for Tuesday evening, with 
increased NWly breezes and falling dewpoint temps. However dry 
weather is expected to accompany the front and in the intervening 
hours behind its passage. Lows mainly in the 40s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Key Messages:

* Warmer and drier Wednesday and Thursday with  mostly clear skies. 

* Pattern becomes more unsettled Friday through the weekend with 
  periodic chances for precipitation. 

Wednesday through Weekend: 

A cold front moves through Tuesday night into early Wednesday 
morning, bringing a slightly cooler and drier airmass to southern 
New England. Wednesday trends slightly cooler than Tuesday, although 
still warmer than normal overall. Highs range in the 50s for the 
Cape/Island and high 60s for the interior. Light NW winds expected 
under broad high pressure with localized sea breezes in the 
afternoon for the coastal areas. 

A similar pattern stays in place through the end of the week with 
zonal flow and 850mb temperature anomalies signaling at slightly 
above normal temperatures. Ensemble guidance shows a transition to a 
more unsettled pattern Friday into the weekend.

Heights fall across the region ahead of an upper level trough moving 
over the Great Lakes. A weaker leading shortwave moves through 
Friday evening with the main trough moving through by the end of the 
weekend. This will bring a few rounds of spotty showers to the area; 
however, still need to iron out the details with the timing/chances 
of the first wave of showers on Friday. A more consistent round of 
rain moves in overnight through Saturday. Slightly cooler for the 
weekend as temperatures range around normal. Conditions gradually 
drying out for Sunday.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

18z TAF Update:

Through 00z Tuesday: High confidence. 

VFR. S winds around 7-12 kt, with seabreezes continuing at BOS 
until about 22-23z.

Tonight: High confidence. 

VFR thru at least 04z Tue. Categories then start to deteriorate
to MVFR from 04-08z from W to E, in 4-6 SM -SHRA and ceilings 
010-020. Outside chance at IFR ceilings but think chances for
IFR are decreasing. -SHRA should be ongoing from ORH east by end
of this period, while trending dry for BAF/BDL. S winds around
10 kt, with areas of low level shear as SW jet of 40 kt moves
overhead.

Tuesday: High confidence in trends but moderate on timing. 

Sub-VFR ceilings (mainly MVFR/IFR range) early to scatter out 
to VFR 13-15z. It may take longer for south-coastal/Cape 
airports to scatter out to VFR and showed MVFR-IFR ceilings thru
at least 18z before trending to VFR. SW winds around 5-10 kt
then shift to WSW/W around 10 kt, with occasional gusts to 20 kt
for the interior.

Tuesday Night: High confidence.

VFR. WNW winds around 5-10 kt.
 
KBOS TAF...High confidence in TAF. Winds to shift to a 150-160
direction by 22z before turning southerly by 00z. VFR thru 07z,
then categories trend to MVFR with light showers. Improvement to
VFR anticipated by 13z. 

KBDL TAF...High confidence in TAF. VFR thru 04z, then 
categories trend to MVFR with light showers. Improvement to VFR 
anticipated by 11z. 

Outlook /Tuesday Night through Saturday/...

Tuesday Night: VFR. Breezy. 

Wednesday through Thursday Night: VFR. 

Friday: VFR. Breezy. 

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

Saturday: Mainly MVFR, with local VFR possible. Breezy. SHRA
likely.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tonight through Tuesday Night: High confidence. 

Generally tranquil boating conditions through early tonight with
SE to S winds around 10-15 kt and seas 2-3 ft. Winds then 
become S/SW around 15-20 kt tonight into Tuesday with passing
rain showers. SW gusts could reach near 25 kt over the far 
southeast offshore waters, before becoming west late Tuesday 
night.

Seas also begin to build to around 4 ft overnight tonight, 
perhaps near 5 ft over the southern offshore waters. Seas
continue around that range through Tuesday night. 

With the potential for limited mixing over the waters as a mild
airmass moves overhead, it will be close but felt conditions 
were borderline for SCAs and refrained from hoisting at this 
time. Later shifts could consider one to cover the Tuesday
timeframe if winds or seas increase further, but this does not 
seem likely.

Outlook /Tuesday Night through Saturday/...

Tuesday Night: Winds less than 25 kt. Seas locally approaching
5 ft. 

Wednesday through Friday: Winds less than 25 kt. 

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

Saturday: Low risk for Small Craft Advisory winds with gusts up
to 20 kt. Seas up to 5 ft. Rain showers likely. 

&&

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

&&

$$

SYNOPSIS...Loconto/McMinn
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...McMinn
AVIATION...Loconto/McMinn
MARINE...Loconto/McMinn