Lexington Weather

Lexington, Massachusetts, USA

51°F

10/6/2024 2:17am

Lexington Conditions: Clear
Temperature: 51.1°F / 10.6°C
Dew Point: 44.4°F
Relative Humidity: 78%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.12 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 030736
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
336 AM EDT Thu Oct 3 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 
few brief showers late Friday night into early 
Saturday...followed by plenty of sunshine and very pleasant high
temperatures Saturday and Sunday afternoons. An approaching 
cold front will likely bring a round of showers sometime late 
Sunday night into Monday...followed by mainly dry but cool/fall-
like weather for Tuesday and Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

Decaying shortwave continues move eastward this morning before 
retracting into Canada as mid level ridging develops by this 
afternoon. Most significant impact of this shortwave/associated cold 
front is the wind shift to the southwest that will allow moisture to 
build through the day, and the increased cloud cover that was 
observed over western MA/CT overnight that capped radiational 
cooling. Away from the clouds, in eastern MA and parts of RI, 
temperatures fell into the 40s; which is a sigh for sore eyes for 
Fall lovers who have not seen many cool mornings yet this season. 

From Worcester, east, patchy radiation that developed overnight will 
dissipate by mid morning. Building ridge and SW flow will allow 
temperatures to rebound handsomely by this afternoon, into the low 
and mid 70s away from the immediate coastline. Lingering scattered 
cloud cover will be tough to shake across the interior thanks to 
lingering moisture atop the boundary layer.  

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...

Sprawling high remains in place overnight tonight into early Friday, 
though southerly/southwesterly flow will support low to mid level 
clouds along the south coast overnight tonight. Additionally, with 
dewpoints climbing into the low and mid 50s, river valley fog is 
likely across the CT River Valley as clearing skies and light winds 
support healthy radiational cooling overnight. 

Friday looks to be another mild day as 850mb temperatures peak 
around 12C around 15Z before falling as approaching shortwave breaks 
down mid level ridging by late afternoon. Do expect more sun than 
clouds, but residual patchy cloud cover. Will note that guidance is 
having trouble resolving exactly how widespread clouds will be, 
which will likely impact just how warm temps are able to climb, but 
anticipating another day with most localities in the 70s to round 
out the week. Any precip associated with the aforementioned 
shortwave look to hold off until after 00Z. &&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...

Key Points...

* A few brief showers possible late Fri night into early Sat 
* Plenty of sunshine & very pleasant the rest of Sat into Sun
* Round of showers are on tap for late Sun night into Mon
* Mainly dry but cool/fall-like weather Tue-Wed with frost possible

Details...

Fri night and Sat...

A shortwave/weak cold front crosses the region late Fri night into 
mid-morning Sat...which may be accompanied by a few brief showers. 
Otherwise...drier air working in from the north should allow plenty 
of sunshine to develop by Sat afternoon. 850T near +8C should allow 
high temps to reach the lower to middle 70s in many locations.

Sat night and Sun...

Weak mid level ridge axis approaches from the west Sat night and 
crosses the region Sun. This will result in dry/tranquil weather. 
Good radiational cooling should allow Sat night low temps to bottom 
out mainly in the 40s Sat night. Plenty of sunshine on Sun...so 
highs will recover into the upper 60s to the lower 70s.

Late Sun night into Mon...

The next shortwave/cold front will be approaching from the west. A 
modest southwest LLJ/Pwat plume ahead of this cold front should 
result in a period of showers sometime late Sun night into Mon. So 
it does appear that the upcoming work week will get off to a wet 
start.

Tue and Wed...

A closed amplifying closed low over Quebec will carve out a deep 
trough across the northeast. So while Tue and Wed will mainly be 
dry...it will bring our first taste of fall-like weather to the 
region. High temps will probably be held in the upper 50s across the 
high terrain...to the lower to middle 60s elsewhere. Overnight low 
temps Tue night will likely drop into the 30s across much of the 
region and some frost will be possible. Even the Urban Heat Islands 
of Boston and Providence should see overnight lows bottom out in the 
lower to middle 40s.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

06z TAF Update...

Through this evening... High confidence

Patchy IFR possible due to radiation fog at interior terminals
across eastern MA, mainly BED. Some scattered MVFR cigs possible
through daybreak across the Cape and Islands, otherwise, VFR
expected through the day. Winds shift to the SW today behind
cold frontal passage, but will be light, less than 10kt. 

Thursday Night...Moderate confidence.

VFR, but MVFR along the south coast. Pockets of IFR to LIFR
possible due to radiation fog across the CT River Valley
(BAF/BDL/ORE) Light SW winds.


Friday... High Confidence

Any fog formation overnight will dissipate by mid morning
leading to VFR across the region. Afternoon cloud development
with cigs around 5000ft likely. Light winds from the S/SW,
though SE at Nantucket. 

BOS TAF...Moderate confidence.

VFR. Light S/SSW winds through the period. 

BDL TAF...High Confidence in TAF. 

VFR conditions, though IFR/LIFR possible early Friday morning
due to patchy radiational fog. Light and variable winds 
overnight and light SSW winds through the period.


Outlook /Friday Night through Monday/...

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

Saturday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.

Saturday Night through Sunday: VFR. 

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

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

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Thursday night...High confidence. 

As of 3 am, waves have diminished below 5 ft but remain
borderline SCA, so elected to keep current headline in place
through the 12Z expiration. Waves are expected to continue to
slacken through the day to 2-4ft. SSW winds of less than 15kt
expected through Friday. Marine stratus and patchy fog possible
tonight across the southern waters.

Outlook /Friday Night through Monday/...

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

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

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

&&

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

&&

$$

SYNOPSIS...Frank/KS
NEAR TERM...KJC/KS
SHORT TERM...KS
LONG TERM...Frank
AVIATION...KS
MARINE...Frank/KS