Lexington Weather

Lexington, Massachusetts, USA

63°F

4/26/2025 8:41pm

Lexington Conditions: Overcast
Temperature: 62.8°F / 17.1°C
Dew Point: 61.3°F
Relative Humidity: 95%
Wind: SE Calm, 10-min avg: 2 mph, gust: 8 mph
Barometer: 29.62 in Steady
Visibility: 10 miles
Rain Today: 0.64 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 231048
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
648 AM EDT Wed Apr 23 2025

.SYNOPSIS...
Warm and dry today followed by a chilly night driven by radiational 
cooling. Rather mild and dry conditions continue with high pressure 
over New England to round out the end of the work week, though there 
is a low chance of a passing shower late Thursday evening/night for 
northern Massachusetts, majority of the region is dry. A system for 
Saturday brings the next chance for widespread rainfall, though 
exact details remain uncertainty. Drier conditions return late this 
weekend into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages...

* Seasonable day with lots of sun and light winds. 

* Chillier night tonight outside of the urban centers. 

Quiet, zonal flow in the mid levels today with high pressure 
building at the surface will allow for a seasonable and quiet 
weather day. Relatively light NW winds continue through the daytime 
hours, 5-10 mph. These will become calm overnight as good 
radiational cooling conditions allow the boundary layer to decouple. 
So, light winds and clear skies will allow locations outside of the 
typical urban corridors to cool into the upper 30s and low 40s.

&&

.SHORT TERM /THURSDAY/...
Short Term

Key Messages...

* Warmer on Thursday with quiet and dry weather, save for the chance 
  of a spot shower in NW MA in the evening. 

A broad mid level ridge overhead together with surface high pressure 
just offshore will prolong the quiet and dry weather through 
Thursday. The only exception is for western and central MA which may 
be in close enough proximity to a weak shortwave and moisture plume 
to our north to support widely scattered showers Thursday evening. 
Temperature-wise, we will warm a few degrees on Thursday as warm 
advection in the low levels pushes 925 mb temps up a few degrees 
closer to 12C which would result in highs in the upper 60s and mid 
70s, cooler along the south coast.

&&

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

* Warm and mostly dry Friday, outside of a stray shower in northern 
  Massachusetts Thursday evening/night. 

* The next chance for widespread rain comes in Saturday, but there 
  are uncertainties with the exact timing. 

* Drier conditions Sunday into early next week. 

The Big Picture: Nearly zonal flow at 500mb across the CONUS into 
Friday, a 850mb shortwave may produce a couple of spotty showers 
late Thursday evening into predawn Friday for those in far northern 
Massachusetts. Otherwise, dry on Friday with surface high pressure 
across New England. This feature moves northeast towards Nova Scotia 
ahead of the only soaking chance of rain for this part of the 
forecast, arriving Saturday. Behind the system, mid-level ridging, 
surface high pressure builds in from the northwest with drier 
conditions Sunday into Tuesday of next week. 

Thursday Night to Friday Night: Weak shortwave rides the northern 
edge of the 850mb high, with the greatest forcing displaced to the 
north in northern New England. Cannot rule out a rouge shower for 
areas in northern Massachusetts, mainly along and north of Route 2. 
Will have mild overnight lows in the 50s. Otherwise, dry conditions 
and increased cloud cover for Friday. Will be another warm day, as 
850mb temperatures remain above normal +10C to +12C a quick look at 
BUFKIT and GFS and NAM show mixing Friday afternoon to 850mb. Highs 
Friday reach the mid-70s and for those in the CT River Valley may 
reach near 80F. At the coast it will be cooler do to the onshore 
wind/seabreeze given the time of year, and there the highs cooler in 
the low-60s, perhaps upper 50s for the Islands and outer Cape Cod. 
Increasing clouds, becoming cloudy overnight ahead of the incoming 
system, will lead to a mild night in the 50s.

Saturday and Saturday Night: Broad northern stream mid-level trough 
moves across the northeast and development of a low-pressure system 
with a southerly LLJ. Will have anomolous PWATs advect into southern 
New England, 1.3" to 1.5", which is ~3 standard deviation above 
normal. There remains a uncertainty with respect to the exact timing 
of the onset and end time the rain, as mentioned previously, 
GFS is biased towards a more progressive outcome, continued to 
lean towards the slower solution which would bring rain in from 
west to east overnight with the steadiest through the day on 
Saturday, even rumbles of thunder cannot be ruled out with 
limited MUCAPE of a few hundred J/kg. A widespread soaking rain,
modest probabilities for rainfall amounts greater than 0.5" 
across the region at 60 to 70 percent. Increase the potential 
rainfall to 1.0" or greater will have probabilites between 30 
and 40 percent. WPC does have a low chance of excessive 
rainfall, placing all of southern New England under a marginal 
outlook. Will want to check back with us if you have outdoor 
plans for Saturday. 

Sunday through Tuesday: Quiet weather to follow on Sunday, though it 
will be cooler, but features drying conditions as mid-level ridging 
and surface high pressure arrives. North-northeast flow Sunday lends 
to a cooler afternoon, highs in the upper-50s to low-60s. The flow 
becomes southwest Monday and Tuesday, bringing warmer temperatures 
in the upper-60s to low-70s on Monday, then low and middle 70s on 
Tuesday.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

12Z TAF Update:

Today: High Confidence

VFR. West/northwest winds around 10 knots. About a 50/50 chance
for a sea-breeze at BOS, but likely would be after 18Z if it
develops.

Tonight: High Confidence

VFR. Light and variable winds.

Thursday: High Confidence. 

VFR. Winds light and variable, becoming southerly 5-10 kts in
the afternoon. 
 
KBOS TAF...High confidence in TAF. 

KBDL TAF...High confidence in TAF. 

Outlook /Thursday Night through Sunday/...

Thursday Night through Friday: VFR. 

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

Saturday: Mainly MVFR, with local IFR possible. Breezy. SHRA
likely, isolated TSRA.

Saturday Night: VFR. Breezy. Chance SHRA.

Sunday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today through Thursday...

A cold front crosses the waters early this morning resulting in a 
wind shift to the northwest. This will also  help usher out any 
remaining fog/low stratus over the south coastal waters. High 
pressure builds in from the west today and will support calm 
conditions over the coastal waters through at least Thursday. 

Outlook /Thursday Night through Sunday/...

Thursday Night through Friday: Winds less than 25 kt. 

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

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Rain showers likely,
isolated thunderstorms. 

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

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

&&

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

&&

$$

SYNOPSIS...BW/Dooley
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...Dooley
AVIATION...BW/Dooley
MARINE...BW/Dooley