Lexington Weather

Lexington, Massachusetts, USA

49°F

10/6/2024 4:12am

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 031750
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
150 PM 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/...
10 AM Update: 

A weak front can be seen in satellite imagery as it progresses
eastward this morning. A few batches of mid-level clouds around
this morning with some hints of it scattering out bringing in
breaks of sunshine. No changes needed to the current forecast.
Expect a mild day with a mix of clouds and sun. 


640 AM Update...

* Mix of clouds & sun today...highs in the lower to middle 70s

A deck of mid level cloudiness northwest of I-95 generally has
kept early morning temps in the 50 to 55 degree range.
Meanwhile...mainly clear skies across eastern MA/RI which has
allowed early morning temps to drop mainly into the 40s. 

We do think that the broken deck of clouds across the interior 
scour out to some degree by afternoon...so expect a mixture of 
clouds and sunshine. 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.

&&

.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 /18Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

12z TAF Update...

This Afternoon...High Confidence. 

VFR. Localized sea breezes this afternoon along the very 
immediate eastern MA coast. Scattered cloud decks between 
3000-5000 ft.

Tonight...Moderate confidence.

Mainly VFR with pockets of IFR to LIFR possible due to 
radiation fog across the CT River Valley (BAF/BDL/ORD) as well 
the typical low-lying spots across eastern MA.

Friday... High Confidence

Any fog formation overnight will dissipate by mid morning
leading to VFR across the region. Clouds push in from the west
by early afternoon, with cigs around 5000 ft developing by late
afternoon. Light winds from the S/SW, though SSE/SE at 
Nantucket and other immediate coast terminals.


BOS TAF...High confidence in TAF.

VFR. Sea breeze with SE winds 8-12 kts this afternoon. Winds
transition light south 23-00z then light SSW overnight. Sea
breeze develops likely in the 15-16z time frame with SSE/SE
winds. 

BDL TAF...High confidence in TAF. 

VFR conditions today and tonight, although localized patches of
ground fog may flirt with terminal overnight. Light SW/SSW winds
Friday. 

Outlook /Friday Night through Monday/...

Friday Night: VFR. 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. 

We have allowed the small craft advisory to expire. 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: 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: 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...None.

&&

$$

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