Lexington Weather

Lexington, Massachusetts, USA

51°F

5/23/2025 11:00pm

Lexington Conditions: Overcast
Temperature: 50.5°F / 10.3°C
Dew Point: 48.6°F
Relative Humidity: 93%
Wind: SSE 2 mph, 10-min avg: 2 mph, gust: 5 mph
Barometer: 29.75 in Steady
Visibility: 10 miles
Rain Today: 0.35 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 240222
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1022 PM EDT Fri May 23 2025

.SYNOPSIS...
Low pressure moving to the Maritimes will bring a few showers 
at times and cool temperatures into Saturday. Mainly dry 
conditions Sunday into Memorial Day with a slow warming trend
but still below normal temperatures, Temperatures return to 
more seasonable levels Tuesday through the end of the week. Our 
next chance for rain looks to be sometime late next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Key Messages:

* Showers developing through this evening with improving conditions 
  overnight

Mainly minor tweaks this evening. Tweaked rainfall timing and
and chances overnight as brunt of the showers move offshore 
late this evening. Not expecting much change to temperatures 
the rest of tonight.

Previous discussion...

Showers to the west will be overspreading SNE from west to east 
during the afternoon and evening as shortwave moves into the region. 
Expect scattered to numerous showers developing making for a 
somewhat wet evening, especially north of the south coast. Showers 
should lift mostly to the north by midnight as some drying moves up 
from the south. It should be mainly dry overnight with just a low 
risk of a few showers across northern MA.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Key Messages:

* Continued cool Sat with a few showers at times

Saturday...

Little change in the overall pattern with upper low to the 
north and another shortwave rotating in from the NW. With deep 
moisture remaining in place, expect another round of scattered 
showers developing especially in the afternoon, although 
certainly not a washout and plenty of dry periods. Temps will 
continue to moderate but still well below normal. Highs will 
reach the upper 50s to lower 60s. 

Saturday night...

The upper low slides slowly moves east from Maine with drier NW flow 
developing overnight. Other than a few lingering evening showers, we 
are looking at a mostly dry night with partial clearing developing. 
Lows will be in the 40s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Key Messages: 

* Mostly cloudy on Sunday, but more optimism for partly to mostly 
  sunny conditions for the Memorial Day holiday. Temps still cooler 
  than normal. Other than a spot shower on Sunday, dry weather 
  prevails.

* Warming trend begins Tue and likely into Wed as well with high 
  pressure in control. 

* Next chance of rain around Thurs-Fri but currently not looking 
  like a significant rain event. 

Details: 

Sunday and Monday: 

The stubborn upper level low over the Northeast will slowly start to 
pull away later on Memorial Day, although lower-than-normal 500 mb 
heights and cooler-than-normal 925-850 mb temps will still govern 
conditions in Southern New England. Sunday looks to feature the most 
diurnally-driven cloudiness toward partly to mostly cloudy look to 
sky cover, and can't rule out a stray shower in northwest MA but the 
majority of the day is dry. Looks to be a little less RH in the 
column as we move into the Memorial Day holiday so more optimism on 
partly to mostly sunny conditions.

Temps will still run about 5-10 degrees cooler than normal. Highs on 
Sunday in the lower to mid 60s. With a bit more sun on Monday, 
better chance that highs near the coast reach into the low 70s but 
still only in the mid 60s along the coasts. 

Tuesday:

Warming, modifying trend back to more seasonable temperatures then 
looks to be in the offing as we move into Tue. High pressure at 
surface and shortwave ridging aloft then reasserts itself into 
Southern New England with dry weather and mostly sunny conditions. 
Highs 75-80 degrees inland and cooler lower 70s along the coasts.

Wednesday into Friday:   

Looks like most of the 12z ensemble guidance has slowed down the 
arrival of our next period of more unsettled weather into Wed night 
and Thurs, as another upper level low moves into the Gt Lakes from 
the northern Plains. Wednesday could end up being generally dry but 
with increased cloud cover. Monitoring late next week (Thurs - Fri) 
for better chances at rain showers, but this is still not set in 
stone as 500 mb confluent flow aloft may still hold dry weather 
around; recent guidance has shifted the greatest QPF into the mid-
Atlc region vs the Northeast. Maintained NBM with little edits to it 
for the time being, which feature increasing chances for rain for 
the Thurs-Fri timeframe but at Chance levels. Temps overall are 
seasonable to slightly above normal.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Tonight: Moderate confidence. 

Rain showers lift northward into NH/VT between 03-05z. Some 
improvement in cloud bases to BKN VFR levels roughly along the 
Mass Pike south, with MVFR bases more likely to continue thru 
overnight. W/SW winds 5-10 kt.

Saturday and Saturday Night...High confidence.

Areas of MVFR cigs during the morning improving to VFR in the
afternoon with VFR persisting Sat night. A few showers possible
during the day. WNW wind gusts to 20 kt, up to 25 kt over the 
Islands.
 
BOS TAF...Moderate confidence. Couldn't rule out an MVFR base
thru 03z as rain showers move across, but should be largely VFR
otherwise overnight. Possible hit/miss -SHRA again Sat after 17z
but left as PROB30s with better chc in interior SNE. 

BDL TAF...Moderate confidence. BKN VFR thru tonight; ceilings
then trend MVFR after 15z Sat, with hit/miss rain showers which
were indicated with VCSH. 

Outlook /Sunday through Wednesday/...

Sunday through Tuesday Night: VFR. 

Wednesday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Saturday Night: High confidence. 

Rough seas over eastern MA waters will slowly subside through
tonight dropping below 5 ft toward daybreak, but seas on the
southern waters will build to 5 ft overnight in response to
10-20 kt westerly winds. A period of 25 kt W wind gusts possible 
over southern waters Sat, with WNW winds 10-20 kt Sat night.

Outlook /Sunday through Wednesday/...

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

Sunday Night through Tuesday Night: Winds less than 25 kt. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ250-251.
     Small Craft Advisory until 2 AM EDT Sunday for ANZ254>256.

&&

$$

SYNOPSIS...KJC/Loconto
NEAR TERM...Belk/KJC
SHORT TERM...KJC
LONG TERM...Loconto
AVIATION...Belk/KJC/Loconto
MARINE...KJC/Loconto