Lexington Weather

Lexington, Massachusetts, USA

63°F

4/26/2025 7:59pm

Lexington Conditions: Overcast
Temperature: 63.0°F / 17.2°C
Dew Point: 61.5°F
Relative Humidity: 95%
Wind: SW 4 mph, 10-min avg: 2 mph, gust: 7 mph
Barometer: 29.62 in Steady
Visibility: 10 miles
Rain Today: 0.64 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 242319
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
719 PM EDT Thu Apr 24 2025

.SYNOPSIS...
Other than a hit or miss shower in northern Massachusetts early
tonight, mild and dry weather continues into tonight.
Unseasonably warm temperatures are expected away from the coast
Friday, with a few areas reaching to around 80 degrees. Cloud 
cover increases Friday night. Cooler with widespread rain 
showers Saturday ahead of our next system, drying out for 
Sunday. Cooler and breezy on Sunday, followed by continued dry 
weather through Wednesday and mild temperatures. A front arrives
Wednesday with next chance of showers.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
415 PM Update:

Key Messages: 

* Passing, hit-or-miss showers northern MA early tonight, but many 
  will remain dry tonight. 

* Mild with lows in the 40s to near 50. 

Details:

Sunny and rather mild day for many away from the coasts cooler by 
seabreezes, with current temps inland reaching into the lower to mid 
70s. To our north and west in northern NY is a sfc warm front and a 
weak 500 mb impulse in WNW flow aloft associated with it located 
back in the northern Gt Lakes region. Current radar shows a cluster 
of showers in regime of weak elevated instability associated with 
this warm front, trailing from near Watertown NY on ESE towards the 
northwest suburbs of Albany NY. Recent radar trends as well as 
trends in GOES-16 Day Cloud Phase RGB imagery indicate this activity 
is not generating lightning. With similar lapse rates but drier 
conditions east of the ongoing activity, not expecting lightning to 
pop in any of these, with this shower activity expected to progress 
towards the east or east-southeast through 10 PM. Best chance for 
rain showers in northern MA given W to WNWly 850-500 mb winds but we 
don't expect any downpours or washouts to result from these passing 
showers, with dry weather in all areas by midnight. 

Most of the evening should feature mostly clear to partly cloudy 
skies, higher cloud cover to the north, but will be of the mid to 
high level type of clouds. Although we should have some radiational 
cooling, warm/moist advection and continued southerly winds are 
expected to keep temperatures from falling too far. Tonight's lows 
should be rather mild in the mid 40s to lower 50s. 

One other aspect that I'll make mention is the potential for a 
smoky/hazy look to skies overnight from the sizable wildfire burning 
in SE NJ. It's been difficult to track the smoke plume given canopy 
of high clouds on satellite images nearby the site, although today's 
HRRR-Smoke model offers the potential for some of the smoke from it 
to move into southern and central portions of Southern New England 
overnight tonight, although its surface visibility output suggests 
no restrictions to visbys are forecast. The warm temps aloft coming 
in should allow for a pretty good temperature inversion to develop. 
Confidence is low but given the thermal profile/inversion, it 
wouldn't entirely be surprising if people may at least smell some 
smoke as we move into the overnight to early morning hours.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
415 PM Update:

Key Messages: 

* Very warm and still rather dry Friday, with cooler seabreezes near 
  the coasts. Highs inland well into the 70s/around 80! 

* Increasing clouds early Friday night, with rains developing 
  overnight. Mild with lows in the 50s, maybe a few areas staying 
  above 60 degrees.

Friday: 

Partly to mostly sunny conditions for Friday - a little more than 
expected today but with still quite a bit of sun. Coastal areas will 
again see seabreezes develop and likely to be pretty early in the 
day, with temperatures along the immediate coast reaching into the 
60s. Have to watch for additional spotty rain showers over northern 
MA into the North Shore during the afternoon associated with a warm 
front, but many areas will be dry. However the main story for Friday 
is the very warm temperatures expected inland, with enough sunshine 
and 925 mb temps around +18. Highs should soar to well into the 70s 
to a few low-80s in western portions of Southern New England. Note 
again carrying over from the overnight that there may be some wafts 
of smoke around from the wildfire in southern NJ, but we don't 
expect visbys to be restricted or rise to the level of causing 
health problems. 

Friday Night: 

Cloud cover then increases significantly towards full overcast early 
Friday evening, ahead of a frontal system that moves into the 
Northeast into Saturday. Most areas however should be dry for the 
first part of the evening. PoPs then increase into the Likely to 
Categorical range as we move into the overnight to early Saturday 
morning timeframe, but the bulk of the rains arrive on Saturday. 
Total rain amts thru 12z Saturday should be less than a quarter-
inch, even as PW values start to rise to around 1.2". Stands to be 
even milder Friday evening, and while I showed lows dropping into 
the 50s, some areas in western MA and CT could stay just above 60 
degrees, making it one of the mildest nights yet seen so far in 2025.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Key Messages: 

* Widespread rainfall expected Saturday. 

* Drier and cooler Sunday with breezy NW winds. Isolated showers 
  possible in the afternoon. 

* First half of next week trends dry with above normal temperatures 

Saturday - Sunday: 

A northern stream trough moves across the region this weekend with 
an associated upper level low tracking across the Great Lakes and 
New England. Synoptic ascent increases ahead of the trough with a 
plume of amomalous moisture (200-240% of normal) advecting into 
southern New England. This will support widespread rainfall 
Saturday. It will also be breezy with with the presence of a 
southern LLJ shifting across the region. Can't rule some rumbles of 
thunder in the afternoon/early evening with marginal instability in 
the mid-levels. A cold front pushes through in the afternoon 
bringing a switch from southerly winds to windy NW winds. Front 
could bring a quick onset of gusts with it as well. Can't rule out a 
few strong gusts with the onset of the front with gusts up to 30-40 
mph. The bulk of the rain exits to the east late Saturday night into 
early Sunday morning. In terms of totals, ensemble means for QPF sit 
in the 0.50-0.75" range with a lower probability (30-50%) of > 1" 
being highlighted for parts of of western MA. 

Sunday trends overall drier and cooler (seasonable). As the upper 
low tracks east, the backside of the system swings across the region 
in the afternoon with some marginal wrap around moisture. This may 
be enough to support some isolated showers, mainly in northern MA. A 
NW-SE oriented LLJ positions across the region Sunday which will 
support another windy day with NW winds with gusts 25-35 mph, 
perhaps a few isolated gusts to 40 mph. 

Monday - Wednesday: 

Early next week trends dry with ensembles showing high temperatures 
leaning above normal as mid-level ridging builds in. Next chance for 
precipitation arrives mid-week.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

00Z TAF Update:

Tonight: High confidence. 

VFR. Light showers have formed across northern MA moving SE
towards ORH, BED, and BOS. With dry air near the surface, not
expecting much more then some sprinkles to reach the surface.
Light thundershowers have formed across western NY into western
MA. Not expecting these showers to produce lightning much longer
but could bring a brief wetting rain to terminals around the CT
river valley. Areas of haze/smoke around tonight from the SE NJ
wildfire, but it doesnt look as though visbys will be reduced 
at this time. SW winds around 5-10 kt. Possible LLWS after 03z 
from SWly 40 kt jet.

Friday: High confidence.  

VFR. Winds become S around 10 kt again Fri, with seabreezes at
BOS developing early (12-14z). There may still be some
smoke/haze around Southern New England in the morning hours on
Friday. 

Friday Night: Moderate confidence. 

Generally VFR through late evening, though categories
deteriorate to MVFR-LIFR with steady rain developing towards
daybreak. 
 
KBOS TAF...High confidence in TAF. VFR. 

Seabreezes likely to develop early on Fri. Possible haze/smoke 
tonight into early Fri, but we don't expect visbys to be 
reduced.

KBDL TAF...High confidence in TAF. 

VFR with south winds around 10 kt. Possible haze/smoke tonight 
into early Fri, but we don't expect visbys to be reduced.

Outlook /Saturday through Tuesday/...

Saturday: Mainly MVFR, with areas IFR possible. Windy with
local gusts up to 30 kt. SHRA, isolated TSRA.

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

Sunday through Sunday Night: VFR. Breezy. Slight chance SHRA.

Monday through Monday Night: VFR. 

Tuesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tranquil boating conditions for mariners through Friday, with
southerly winds around 10-15 kt and seas 2-3 ft. Dry weather
prevails. 

SW winds then increase Friday evening to around 20 kt, with seas
rising to around 4 ft. Conditions are borderline for SCA but
will be increasing further into Saturday. Rain develops Friday
night, with visbys reduced to around 4 miles.

Outlook /Saturday through Tuesday/...

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Rain showers, isolated
thunderstorms. 

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain showers. 

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

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers. 

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

Monday Night: Winds less than 25 kt. 

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

&&

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

&&

$$

SYNOPSIS...Loconto/Mensch
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...Mensch
AVIATION...KP
MARINE...Loconto/Mensch