Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Mist, Overcast
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: 2 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 221915
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
315 PM EDT Sat Aug 22 2026

.WHAT HAS CHANGED...

No significant changes to the forecast.

&&

.KEY MESSAGES...

- Spotty light showers/drizzle tonight but much of the time it
  will be dry. More humid Sun with a few showers & t-storms
  possible especially near & west of the CT River Valley where
  an isolated strong-severe t-storm or two is possible.

- Drier with a return to seasonable temperatures next week. Rain
  chances return Thursday/Friday.

 &&

.DISCUSSION...

KEY MESSAGE 1...Spotty light showers/drizzle tonight but much 
of the time it will be dry. More humid Sun with a few showers & 
t-storms possible especially near & west of the CT River Valley 
where an isolated strong-severe t-storm or two is possible.

Weak offshore low pressure will continue to result in moist/light NE 
low level flow into tonight. The result will be rather cloudy skies 
tonight with just some spotty light showers/drizzle at times...but 
this activity will be quite light with much of the time featuring 
dry weather. Some shortwave energy may allow for a few elevated 
heavier showers and perhaps a couple t-storms to develop near the 
southeast New England coast toward daybreak...mainly near the Cape 
and Islands. Some of the earlier model guidance has this activity 
further west...but latest indicating that the main risk for this 
will be towards the Cape and Islands closer to the shortwave energy.

Overnight low temps will only drop into the lower to middle 60s 
given clouds and an abundance of low level moisture. Areas of fog 
will be possible too...especially near the coast and in the 
Worcester Hills.

Again...we will need to watch for a few showers and isolated t-
storms near the Cape and Islands early Sun morning. Otherwise...the 
main concern for a few showers and thunderstorms will be Sun 
afternoon/early evening given diurnal instability and shortwave 
energy to our west. The bulk of the height falls/forcing  will be to 
our west. Therefore...greatest risk for a few showers and 
thunderstorms will be near and west of the CT River Valley Sun 
afternoon/early evening. Instability will be limited by a lot of 
cloud cover...but effective shear of 40+ knots will result in the 
low risk for an isolated strong to severe severe thunderstorm or 
two. Main severe weather risk would be a very localized damaging 
wind gusts and brief torrential rainfall. Greatest risk for this 
would near and west of the CT River Valley. That being said...much 
of the day will feature dry weather...but with a bit more humidity 
compared to this afternoon. Highs will be in the 70s to near 80.

KEY MESSAGE 2...Drier with a return to seasonable temperatures 
next week. Rain chances return Thursday/Friday.

A post-frontal air mass will usher in drier conditions and warmer 
temperatures with westerly winds Monday. As skies gradually clear 
from the dreary weekend, dewpoints will begin to drop slightly... 
into the upper 50s as opposed to the low to mid 60s we've been 
seeing. High pressure begins to slowly build Tuesday into Wednesday, 
prolonging the clear skies, drier weather, and warmer temperatures 
through the middle of the week. Chances for rain showers return 
Thursday and Friday as a low pressure system develops over the Great 
Lakes and meanders east through southern Ontario. Some uncertainty 
regarding the onset of the showers as there's little consistency in 
the global ensembles on the actual placement of the low as it tracks 
through Canada.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...

Forecaster Confidence Levels...

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

18z TAF Update...

This afternoon through tonight...Moderate confidence.

Mainly MVFR conditions at mid-aftternoon will deteriorate to 
generally IFR with localized IFR cigs/vsbys tonight. A few 
spotty showers/light drizzle and fog patches are possible at 
times too. Perhaps a few heavier showers and isolated t-storms 
graze areas towards the Cape and Islands toward daybreak Sun. 
Calm/light NE winds.

Sunday and Sunday night...Moderate confidence.

Mainly IFR with localized LIFR conditions Sun morning should
improve to mainly MVFR-VFR levels by Sun afternoon/night. A few
showers and t-storms are possible too with the greatest risk 
near and west of the CT River Valley during the afternoon/early 
evening. Light ENE gradually becoming light S by Sun night. 

KBOS Terminal...Moderate confidence in TAF. 

KBDL Terminal...Moderate confidence in TAF.

Outlook /Monday through Thursday/...

Monday: VFR. Breezy. 

Monday Night: VFR. 

Tuesday through Wednesday: VFR. Breezy. 

Wednesday Night: VFR. 

Thursday: Mainly VFR, with local IFR possible. Slight chance
SHRA.

&&

.MARINE...

Forecaster Confidence Levels...

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

Tonight through Sunday night...High confidence.

A wave of low pressure across the waters will be lifting into the 
Canadian Maritimes tonight. The pressure gradient though will remain 
weak enough to keep winds/seas below small craft advisory thresholds 
through Sunday night. Areas of fog will reduce visibilities for 
mariners at times especially later tonight into Sun morning. 

Outlook /Monday through Thursday/...

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

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

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

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

Wednesday Night through Thursday: Winds less than 25 kt. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 6 PM EDT this evening for MAZ019-
     022.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Frank/McMinn
AVIATION...Frank/McMinn
MARINE...Frank/McMinn