Lexington Weather

Lexington, Massachusetts, USA

50°F

10/6/2024 2:55am

Lexington Conditions: Clear
Temperature: 50.4°F / 10.2°C
Dew Point: 44.1°F
Relative Humidity: 79%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.11 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 020208
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1008 PM EDT Tue Oct 1 2024

.SYNOPSIS...
Elongated high pressure over the Canadian Maritimes yields
mainly dry weather through this work week. Temperatures moderate 
to above normal levels by Thursday, and especially Friday. An
approaching cold front may bring a period of isolated showers
Saturday, but a washout is not expected. Dry and pleasant
weather should return by Sunday, then a stronger storm may
result in more significant rainfall by Monday.

&&

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

10 PM Update...

Light returns on radar continue to move onshore across eastern
MA but are failing to materialize into accumulating QPF with no
sites reporting rain over the last hour or two, likely because
cloud bases are a bit too high for much to reach the surface
(between 3000-4000ft). 

Elsewhere, conditions appear favorable for patchy radiation fog
formation in the CT River Vally, but time will tell if it is
able to materialize as guidance has overestimated the geographic
extent of fog the last few evenings.

Previous Update...

Latest KBOX radar data appeared to be just clipping the tops of
some ocean-effect bands of light rain or drizzle. Not expecting
much accumulation, but did add a mention of some patchy drizzle
for the overnight. Should not be going away as the low level
humidity increases overnight along with the persistent easterly
wind.

Minor tweaks to temperatures to reflect observed trends as 
well.

Previous Discussion...

High pres over Maritimes with ridging extending southward into
SNE will continue to result in low level easterly flow and
persistent low level moisture. At the same time we will have
some mid-high clouds to contend with. More stratus and fog is
likely to redevelop, but HREF and NBM probs are highlighting the 
interior as the more favorable areas for low cigs and vsbys. 
Still can't rule out some stratus and fog near the coast, but
greater risk appears to be further in the interior. In addition, 
can't rule out an isolated shower this evening. Lows will range 
from the upper 40s to lower 50s for most locations.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Wednesday...

Weakening upper level trough and shortwave approaches from west 
while surface ridging remains in place. Expect a similar day
with any morning stratus and fog gradually lifting to strato-cu 
layer. Clouds will become mixed with some sunshine although more
clouds than sun. Leading edge of deeper moisture assocd with the 
shortwave moves into western New Eng during the afternoon, but 
forcing is weakening and guidance is consistent with precip
shield across New York dissipating as moves into surface ridging 
across New Eng. Other than a low risk for an afternoon spot
shower in western MA, mainly dry conditions expected. Highs will 
range from mid-upper 60s. 

Wednesday night...

Weak shortwave and enhanced moisture in the 850-700 mb layer moves 
across New Eng during the night. Low risk for a spot shower as
the shortwave moves through, otherwise mainly dry conditions
with partly to mostly cloudy skies. Patchy late night stratus
and fog will likely redevelop. Lows will be mainly upper 40s to 
lower 50s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Points...

* Dry with above normal temperatures Thursday into Friday
* Period of isolated showers possible Sat across northern MA, 
  but not a washout
* Dry Sunday, but unsettled/wet weather may arrive by Monday

Details...

Latest guidance suite is in rather good overall agreement with
the synoptic pattern into Thursday, then the timing differences
become more significant, leading to low confidence in the 
timing details for next weekend into early next week.

At this time, looking like a high pressure near Nova Scotia
holds strong enough across our region to maintain dry weather
into Friday. A moisture-starved cold front may pass by Saturday
with a limited chance for showers, before another high pressure
takes over. Right now, looking like dry weather for most until
next Monday. But again, that timing may change due to the low
confidence in the overall pattern.

Above normal temperatures late this week, expected to trend to 
near to slightly below normal this weekend.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Forecast Confidence Levels:

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

Tonight...Moderate confidence. 

MVFR widespread, with IFR possible towards the CT Valley and 
ORH with fog redeveloping. LIFR is possible, but confidence is 
low; not included in any TAFs for now. Winds calming down to be 
less than 10 knots at ENE/NE for much of the area, aside from 
ACK..

Wednesday...Moderate Confidence.

Similar pattern to today's expected. Morning IFR/MVFR expected 
to improve to VFR after the sun comes up. Light E/NE winds 
continue.

Wednesday Night...Moderate Confidence.

Mainly VFR, with areas MVFR across the higher terrain of central
and western southern New England.

BOS TAF...Moderate Confidence in TAF. MVFR/VFR conditions
expected to continue. Patchy drizzle at times could lead to wet
runways.

BDL TAF...Moderate Confidence in TAF. VFR dropping to MVFR, and
possibly IFR briefly, tonight. Lower confidence in IFR, so did 
not include in TAF for now, but do believe it to be possible. 

Outlook /Thursday through Sunday/...

Friday through Sunday: VFR. 

Sunday Night: VFR. Slight chance SHRA.

Monday: Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Wednesday night...High confidence. 

Persistent E-NE winds below 20 kt through the period. 3-4 ft  
easterly swell over outer waters, with some 5 ft seas possible
south of the Islands tonight into Wed, so decided to issue a 
Small Craft Advisory. Marine stratus and patchy fog possible 
tonight and Wed morning. 

Outlook /Thursday through Sunday/... 

Friday through Saturday: Winds less than 25 kt. Seas locally
approaching 5 ft. 

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

Sunday 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 PM EDT Wednesday for ANZ254-255.
     Small Craft Advisory until 2 PM EDT Wednesday for ANZ256.

&&

$$

SYNOPSIS...Belk/KJC
NEAR TERM...KJC/KS
SHORT TERM...Belk/KJC
LONG TERM...Belk
AVIATION...Belk/Hrencecin
MARINE...Belk/KJC