Lexington Weather

Lexington, Massachusetts, USA

49°F

10/6/2024 4:02am

Lexington Conditions: Clear
Temperature: 49.3°F / 9.6°C
Dew Point: 44.1°F
Relative Humidity: 82%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.10 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 030216
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1016 PM EDT Wed Oct 2 2024

.SYNOPSIS...
Dry weather will continue through the rest of the week with warming 
temperatures into the 70s. An approaching cold front may bring a 
brief period of scattered showers Saturday morning, which will be 
followed by lots of sunshine. A ridge of high pressure will bring 
dry and pleasant weather Sunday, but an approaching cold front may 
bring a period of showers by Monday. Dry but cooler fall-like 
weather will be ushered into the region Tuesday and Wednesday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...


10 PM Update...

Radiational cooling is out in full force across eastern MA and
RI where temperatures have fallen into the upper 40s in some of
our typically prone spots like Boston and Norwood. Clouds moving
in ahead of the approaching cold front/shortwave have capped
cooling in the CT River Valley, so temperatures remain in the
mid to upper 50s there. It's likely that more localities along
the I-495 and 128 corridors fall into the 40s over the next few
hours before the cloud deck moves east. 

Some patchy fog has already developed in Norwood. As mentioned
by the previous forecaster, there remains the risk for a very
isolated shower tonight across the high terrain of western MA. 

Previous update...


Weakening shortwave moves across SNE this evening. Scattered 
showers accompanying this shortwave are already showing signs of
dissipating as they approach eastern NY. There is a low risk 
for a few sprinkles in the high terrain of western MA this 
evening within the deeper moisture axis. Otherwise mainly dry 
weather will prevail as weakening shortwave outruns the deeper 
moisture axis followed by rising heights overnight. Partly to 
mostly cloudy skies expected with lows upper 40s to lower 50s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Thursday...

Upper level ridge builds northward into New Eng as surface high pres 
remains across the region. Large scale subsidence will promote dry 
conditions, but enough lingering moisture for sct-bkn strato-cu 
developing. So a mix of sun and clouds with warming temps as low 
levels moderate. Highs will reach the low-mid 70s, but a bit cooler 
along the coast where sea-breezes develop. 

Thursday night...

High pres remains in control as it gradually shifts east of New Eng. 
Another dry night with light winds but patchy stratus and fog may 
develop. Lows will range from the upper 40s to lower 50s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights:

* Increased cloud cover on Friday, followed by showers late evening 
  into early Saturday morning. 

* Turning dry and seasonable for Saturday afternoon and again 
  Sunday. 

* Rain chances return Monday, followed by noticeably cooler weather.

Friday through Sunday...

The mid-level ridge shifts east on Friday with a broad trough coming 
in from the west. Winds aloft are from the southwest and will bring 
up the humidity and increase clouds for Friday. Although it is a dry 
day, do think there will be more clouds than sun. Did trend the 
highs a little cooler than the previous forecast as a result, but 
still seasonable in the upper 60s to mid 70s. 

There is still some uncertainty with the amplitude of the trough and 
this will likely dictate the areal coverage of showers for Friday 
night through early Saturday. The GFS and GEM are far more robust 
than the ECMWF. NMB had little to no PROBs of precipitation south of 
the Mass Pike on Saturday, so did deviate, added 'Slight Chance' 
POPs. Nothing that will washout, generally a few hundredths of an 
inch to a tenth of an inch. Rest of the weekend features mid-level 
ridging and surface high pressure building in for the rest of the 
weekend. Highs will trend slightly above normal, upper 60s and mid 
70s Saturday, then normal Sunday in the mid 60s to 70F.

Monday and Tuesday...

A robust shortwave and surface cold front moves across the northeast 
with a better chance for wetting rains on Monday. That said, it's 
not a high probability that everyone will receive a healthy drink of 
water. Global ensembles show a 10 to 20 percent chance of totals to 
surpass 0.5", with the highest likelihood in northern Massachusetts. 
Probabilities do increase when we set the threshold to 0.1" the GEFS 
more conservative at 50 to 70 percent, while the ECMWF ENS at 70 to 
90 percent. Drying out into Tuesday, though a mid-level low does 
linger to the north and weak shortwaves pivot through and that could 
lead to a spot shower on Tuesday. 

Trending cooler, normal highs for early October are typically 
between 65F and 70F, think Monday will fall just shy of that, but 
cooler on Tuesday in the upper 50s to mid 60s. Where we will really 
notice the air mass change is during our overnight lows. Monday 
night into Tuesday lows flirt with the upper 30s across northwestern 
Massachusetts while the coast remains in the upper 40s. Then Tuesday 
night into Wednesday morning lows are mid 30s to mid 40s. Coolest 
areas in northern Massachusetts; northern Worcester Hills and the 
east slope of the Berkshires, these locations could see its first 
frost of the season. But, would not receive 'Frost Advisory' as the 
Frost/Freeze Program ended as of October 1st for those locations. 

Tropical Weather...

The National Hurricane Center continues to forecast Hurricane Kirk 
to become a major hurricane over the next 48 hours, potentially to a 
category four hurricane by early Friday. While there are no direct 
impacts to land, we could see larger waves radiate towards the coast 
of southern New England, as the track of Kirk will follow the great 
circle line. As we are outside of beach season, we would not issue a 
high surf advisory or rip current statement, rather message the risk 
of large waves in the AFD.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

00z TAF Update...

Tonight...Moderate confidence.

Mainly VFR, with areas of MVFR across portions of interior
southern New England. Winds generally light and variable.

Thursday...High confidence.

VFR. Light SW winds for the interior terminals and SE to ESE 
winds for the east/immediate coast terminals. 

Thursday Night...Moderate confidence.

VFR, but MVFR along the south coast. Light SW winds. 

BOS TAF...Moderate confidence.

VFR. Watching MVFR CIGs moving in with a decaying cold front to
the west. May see low-end VFR, BKN040, develop between 03z and
08z. If clearing occurs, may see briefly lower CIGs develop and
hinted at this with a SCT006. VFR for Thursday with a sea-breeze
after 15z/16z.

BDL TAF...High Confidence in TAF. 

VFR conditions. Light and variable winds overnight and light SSW
winds Thursday. 

Outlook /Friday through Monday/...

Friday: VFR. 

Friday Night through Saturday: VFR. Slight chance SHRA.

Saturday Night through Sunday: VFR. 

Sunday Night: VFR. Slight chance SHRA.

Monday: VFR. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Thursday night...High confidence. 

Extended the SCA through tonight for the outer SE waters for 
persistent 5 ft easterly swell. Otherwise, expect 3-4 ft over outer 
waters through Thu night with winds less than 15 kt. 

Outlook /Friday through Monday/...

Friday: Winds less than 25 kt. 

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

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers. 

Saturday Night through Sunday Night: Winds less than 25 kt.
Seas up to 5 ft. 

Monday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for ANZ254-255.

&&

$$

SYNOPSIS...KJC/Dooley
NEAR TERM...KJC/KS
SHORT TERM...KJC
LONG TERM...Dooley
AVIATION...Dooley/Mensch
MARINE...KJC/Dooley