Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Mist, Overcast
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: 2 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 212305
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
705 PM EDT Fri Aug 21 2026

.WHAT HAS CHANGED...
A Rip Current Statement has been issued for Plymouth and 
Barnstable Counties for Saturday.

&&

.KEY MESSAGES...

- Below normal temperatures and overcast conditions continue 
  through the weekend. Drizzle/misty weather through Saturday 
  then a period of heavier rain possible overnight into Sunday.

- Drier and warmer next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Below normal temperatures and overcast 
conditions continue through the weekend. Drizzle/misty weather 
through Saturday then a period of heavier rain possible 
overnight into Sunday.

The low pressure system that's brought the misty and overcast 
weather today has dipped a little further south of Long Island 
than previously expected. The latest guidance suite is 
projecting the low slowly moves east through today then swings 
northeast around Nantucket tonight into Saturday. The interior 
is more likely to remain dry with a few pockets of mist through 
the rest of today, but eastern and Southeast MA and RI should 
see the mist linger with periodic light showers into Saturday. 
Most of southern New England should see a dry Saturday morning, 
except the Cape/Islands could see a few lingering showers. As 
the low weakens and wraps around the Cape Saturday, another 
round of heavier showers is expected to push into southern New 
England later Saturday evening into the overnight period. This 
round has the potential to develop a few heavier, convective 
bands of rain given the higher PWATs near 2.0" and favorable 
IVT. Guidance is split a few different ways on QPF totals: 
Global ensembles show generally a 30 to 40 percent chance of
1.0" in 24 hours over the Cape/Islands by sunrise Sunday, except
the GFS ensemble which indicates much less rainfall and also
located further offshore. CAM and higher resolution guidance has
the same bullseye on the Cape, but also identifies and secondary
precip max approaching 1.0" in 24 hours across interior CT and
western MA. Given how the guidance is struggling to resolve the
exact track of the low due to the unexpected southern drop
today, confidence is on the lower end specifically regarding
rainfall across the interior, as a little wobbling east or west
in the northeastward progression of the low will have a larger
impact on precip totals.

More of the same on Sunday as a cold front slowly approaches, 
sending moisture from the south out ahead of it. NE/E flow 
early becomes southerly advecting 70+ dewpoints into the region 
with PWATs 2+ inches. This while the surface low lifts north and
east with the best convergence/forcing in the early morning 
with a lull possible in the late morning/afternoon then 
potential for some showers and thunderstorms in the afternoon. 
Given those dewpoints, CAPE values jump to 500-1000 J/kg and 
depending on how quickly the cold front arrives it could 
overcome marginal lapse rates to produce a strong to severe 
storm, especially in western SNE, given 0-6 km bulk shear values
of 50+ kts.

Otherwise, temperatures through the first half of the weekend 
will remain below seasonable under prolonged 
onshore/northeasterly flow... highs likely remain in the upper 
60s to low 70s through Saturday.

KEY MESSAGE 2...Drier and warmer next week. 

By Monday the cold front has pushed through and ushers in a 
much drier and warmer start to the week. Dewpoints fall from 
near 65-70F Sun to 45-50F Mon. Rising heights and building 
surface high pressure will help to keep the forecast drier with 
perhaps some diurnal showers Tue under a weak shortwave. 
Otherwise, generally zonal flow takes hold through at least 
Thursday with no significant disturbances on the horizon, and no
intrusions of anomalous heat or cold. Temperatures remain 
comfortable ranging from the mid 70s to low 80s.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

00z TAF Update: 

Tonight into Saturday: Moderate confidence. 

IFR for southeast MA but ceilings should deteriorate down to 
MVFR-IFR levels tonight and overnight northward to BOS, BED and 
ORH. Intervals of mist and drizzle at 4-6 SM. BDL should stay 
BKN VFR most of the night. Conditions should then generally hold
steady into Sat daytime hrs. N to NE winds 5-10 kt.

Saturday Night: Moderate confidence. 

Conditions to turn to widespread MVFR-IFR with a round of 
steadier light to moderate rain after approximately 06z Sunday; 
timing is uncertain and subject to further adjustment. NE to N 
winds 5-10 kt. 

KBOS Terminal...Moderate confidence in TAF. Mainly OVC VFR 
ceilings today with NE winds around 10 kt, with off-and-on mist 
and drizzle. Categories more likely to deteriorate to sub-VFR 
ceilings with 4-6 SM BR/DZ tonight.

KBDL Terminal...High confidence in TAF. Stronger confidence in 
prevailing VFR and relatively drier weather.

Outlook /Sunday through Wednesday/...

Sunday: Mainly VFR, with local IFR possible. Chance SHRA,
slight chance TSRA.

Sunday Night: VFR. 

Monday: VFR. Breezy. 

Monday Night: VFR. 

Tuesday through Wednesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Saturday Night...High confidence.

Gusty NE winds near 25kts and waves near 5 ft across the 
southern waters gradually diminish through this evening and into
tonight as the low weakens and moves further offshore. 
Otherwise, winds generally 18-20 kts and seas 3-4 ft through 
most of Saturday become more variable as the low breaks down 
Saturday night into Sunday morning.

Despite the lower wave heights, the prolonged northeasterly 
flow will cause higher swells and longer swell periods Saturday
which has prompted a Rip Current Statement for Plymouth and 
Barnstable Counties. Eastern, ocean-facing beaches will be 
primarily affected, especially across the northern portion of 
Cape Cod; however, bay- facing beaches may also experience rip 
currents.

Outlook /Sunday through Wednesday/...

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers, slight chance of thunderstorms. 

Sunday Night: Winds less than 25 kt. Local rough seas. Chance
of rain showers, slight chance of thunderstorms. 

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

Tuesday through Wednesday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents from 6 AM EDT Saturday through Saturday 
     afternoon for MAZ019-022.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...BW/McMinn
AVIATION...Loconto/BW
MARINE...McMinn