Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Partly cloudy
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: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 091840
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
240 PM EDT Wed Sep 9 2026

.WHAT HAS CHANGED...
No significant changes to the forecast.

&&

.KEY MESSAGES...

- Frontal passage tonight into tomorrow morning brings scattered
  showers and gusty southwest winds, especially over far
  southeastern Massachusetts, Cape Cod, and the Islands.

- Dry weather, comfortable humidities and light onshore winds  
  Friday through Saturday night. Cool nighttime low temperatures
  Friday night. 

- Frontal boundary Sunday brings increased humidity and chances
  for rain Sunday afternoon and evening. 

- High pressure returns for early next week, bringing a return
  to seasonable temperatures and low humidities. 

&&

.DISCUSSION...
KEY MESSAGE 1...Frontal passage tonight into tomorrow morning brings 
scattered showers and gusty southwest winds, especially over far 
southeastern Massachusetts, Cape Cod, and the Islands.

The rest of today is largely dry outside of a sct'd warm advection 
shower, as yesterday's cold front lifts back to the northeast, this 
time as a warm front. A robust LLJ advects higher moisture into 
southern New England as well, with PWATs climbing to near 2.0 inches 
after 00z. Thus, there remains a low chance for showers throughout 
this evening. Given the added cloud cover and winds overnight, 
expecting a mild night with lows ranging from the upper 60s to lower 
70s.

As the cold front approaches overnight, additional showers move into 
the region during the predawn hours of Thursday, mainly 4-7 AM. 
However, dynamics are lacking as the front reaches southern New 
England. While there is a moisture-rich environment, the lack of 
ideal forcing means rainfall isn't expected to be widespread or 
necessarily heavy.

The wind will be more noticeable. As we've mentioned over the past 
day or so, there is a robust LLJ with winds aloft ranging between 45 
and 55 kt. While mixing will be limited inland due to the nocturnal 
inversion, there should be enough mixing to allow gusts across the 
interior to range between 20 and 30 MPH. Along and east of I-95, 
gusts of 30-40 MPH remain possible, with a small area mainly near 
the Cape and far southeastern Massachusetts where 40+ MPH isn't out 
of the question prior to sunrise. Throughout the day Thursday, wind 
direction shifts more to the west, with gusts ranging from 20 to 30 
MPH.

Currently, we feel the greatest impacts will be for the marine 
community. Gale Warnings are in effect around the Cape and Islands 
for those stronger winds. By Thursday afternoon, the surface cold 
front is offshore. However, temperatures aloft are slower to lower, 
so it will still be fairly seasonable Thursday afternoon. Then comes 
a reinforcement of colder air Thursday night, with 925 mb 
temperatures falling from around +20C Thursday to +10C Friday.

KEY MESSAGE 2...Dry weather, comfortable humidities and light 
onshore winds Friday through Saturday night. Cool nighttime low 
temperatures Friday night. 

Forecast for Friday into Saturday remains consistent in showing a 
large high pressure area coming in from the eastern Great Lakes and 
southeast Ontario Friday, then settling over the Northeast Friday 
evening before moving offshore Saturday. This will bring dry and 
pleasant weather conditions to Southern New England, with seasonably 
mild days with full sun during the daytime hours Friday and Saturday 
but a cool Friday night due to strong radiational cooling. Some of 
the more typical sites which radiate well under clear skies and 
light winds could see low temperatures drop into the mid 40s, 
including areas around I-495, NW MA and Martha's Vineyard. High 
temperatures in the mid 70s, with lower 70s near the Cape and 
Islands. Conditions look favorable for outdoor plans Friday and 
Saturday. 

KEY MESSAGE 3...Frontal boundary Sunday brings increased 
humidity and chances for rain Sunday afternoon and evening. 

The high pressure moving eastward allows for an increasingly moist 
airmass ahead of a cold frontal boundary which arrives Sunday 
afternoon into Sunday evening. Most models show increasing rain 
chances centered around Sunday afternoon or into the evening. While 
there are good chances for rain in this Sunday afternoon to Sunday 
evening timeframe, there is more uncertainty in terms of how much 
rain falls. It looks as though the placement of the greatest 
rainfall seems confined to the South Coast, Cape Cod and the 
Islands. While it looks as though Sunday evening looks wet for these 
areas, we're not expecting rainfall to become especially heavy as 
the frontal boundary looks progressive. 

KEY MESSAGE 4...High pressure returns for early next week, 
bringing a return to seasonable temperatures and low humidities.

Behind the frontal boundary Sunday night, high pressure from Canada 
builds back in, bringing seasonable temperatures, dry weather and 
low levels of humidity for the early part of next week. The 
potential exists for a couple of cooler nights Monday night and 
Tuesday night with high pressure in the vicinity.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

18z TAF Update: No significant changes.

This Afternoon and Tonight...High confidence in trends, lower in 
timing.

Clouds filtering in from the north, mainly VFR with ceilings 050-
080. There remains a low chance of a shower late this afternoon into 
early evening as a warm front lifts north, mainly between 22z-04z. 
Otherwise, dry overnight with low-end VFR ceilings 035-050. Winds 
shift to the S to SSW this afternoon and become gusty, with gusts of 
20-25 kt this afternoon, then 25-30 kt overnight. Cannot rule out 
wind gusts between 35-40 kt overnight into early Thursday morning, 
mainly across far southeastern Massachusetts, Cape Cod, and the 
Islands.

Thursday...High confidence.

Mainly VFR with drying conditions. Winds shift from SSW to SW, while 
gusts ease slightly to 20-30 kt, with the strongest gusts near the 
coast and higher elevations.

Thursday Night...High confidence.

VFR. NW winds 5-10 kt.

KBOS Terminal...High confidence in TAF. 

Sea breeze should kick out by 20z, then turning south. SHRA
chances 23z-03z. 

KBDL Terminal...High confidence in TAF.

Outlook /Friday through Monday/...

Friday through Saturday: VFR. 

Saturday Night through Sunday: VFR. Chance SHRA.

Sunday Night through Monday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Thursday Night...High confidence.

An approaching cold front will result in a developing southwest low-
level jet later today. The southwest low-level jet peaks later 
tonight into early Thursday morning, when 925 mb winds reach 45-55 
kt. While not all of this will mix down...we expect widespread 
southwest wind gusts of 25-35 kt. Strong Small Craft headlines 
continue for most waters, but brief gale-force gusts are certainly 
possible. Gale Warnings continue for Buzzards Bay and Cape Cod Bay, 
as well as Nantucket Sound. Based on pattern recognition...a brief 
period of SW wind gusts of 35-40 kt appears reasonable and is 
supported by BUFKIT soundings.

Winds ease and become more westerly into Thursday though seas remain 
elevated. Any Gale Warnings likely will need to be converted to a 
Small Craft Advisory through Thursday afternoon.

Outlook /Friday through Monday/...

Friday through Saturday: Winds less than 25 kt. 

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

Sunday: Winds less than 25 kt. Chance of rain showers. 

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

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 8 PM this evening to 8 PM EDT 
     Thursday for ANZ230-235>237-250-251-254>256.
     Gale Warning from 10 PM this evening to noon EDT Thursday for 
     ANZ231>234.

&&

$$

DISCUSSION...Loconto/Dooley
AVIATION...Loconto/Dooley
MARINE...Loconto/Dooley