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 221238
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
838 AM EDT Sat Aug 22 2026

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

&&

.KEY MESSAGES...

- Misty with drizzle today ahead of heavier rain tonight into 
  Sunday.

- Drier and warmer next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Misty with drizzle today ahead of heavier rain 
tonight into Sunday.

Low pressure has continued to bring scattered light showers and 
drizzle/mist across parts of the Cape and south coast tonight as it 
has continued trekking northeast, while more interior parts of the 
region have remained mostly dry. This trend should continue to start 
the day. Based on latest observations, the low is centered just 
south of Nantucket as of the time of writing this discussion. 
Guidance remains in agreement with the general track of this low 
after it remained further south of Long Island than initially 
forecast; it will curve up and around the Cape and Islands through 
the day today, moving up into the NH/ME coast into Sunday morning. 
Misty conditions with periods of drizzle remain the main story for 
today as a result of prevailing cyclonic flow. Some CAMs hinted at a 
brief period of showers in the late morning to afternoon hours, with 
some even showing them passing through the interior. Highs today 
will likely not get out of the low 70s for southern New England.

Heavier rainfall moves through tonight, generally after midnight, as 
the low continues on. PWATs remain elevated, approaching 2.0" 
towards SE MA and the Cape and Islands. IVT remains favorable for 
heavier showers, though the more anomalous values should remain 
further offshore. With regards to rainfall totals, ensembles top out 
at around a 20% chance of totals meeting or exceeding 1" in 24 hours 
ending Sunday over the Cape and Islands. The exception remains the 
GEFS, which continues to be drier than the other ensembles. 
Ensembles have somewhat trended higher totals slightly more offshore 
over the last few runs while deterministic guidance has somewhat 
varied more from run to run. The HREF PMM has 24 hour totals getting 
to around 0.75"-1" over the same area, including into parts of RI 
and SE MA; 48 hour totals could reach 1.5". High-res guidance 
indicates streaks of higher totals stretching northeast across the 
coastal plain, but this could change depending on just how close to 
land the low tracks while it cuts around Cape Cod.

Overcast and misty conditions with periods of drizzle remain the 
story for Sunday as well as the low continues north and a front 
starts to approach from the west. Ahead of this front, the flow 
turns more southerly to southwesterly. This will advect in more 
moisture from the south and increase dewpoints into the 70s. PWATs 
approaching 2.0" and higher will filer in as well. Notably, CAMs 
have MUCAPE values approaching 1500-1700 J/kg with limited CIN over 
the interior for Sunday afternoon. 0-6 km shear approaches 50 kt 
with effective bulk shear around 35 kt. All of these parameters 
combined with any possible forcing from the front could set the 
stage for some scattered thunderstorms, some of which could turn 
strong to severe over the interior. With more southerly flow as 
well, highs Sunday increase back into the upper 70s and low 80s.

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

Sunday's cold front shifts offshore for Monday. Post-frontal 
passage, much drier air and warmer temperatures take hold with more 
westerly winds, clearing out clouds and dropping dewpoints through 
Wednesday. The base of the trough tracks directly overhead into 
Tuesday and heights rise behind it as it continues eastward, though 
a weak shortwave may track through and bring a low chance of diurnal 
showers. High pressure continues building into the region into the 
middle of next week and flow aloft becomes more zonal. Low pressure 
developing over the Great Lakes towards the second half of the week 
may play more of a role later in the week, but for the time being, 
no major disturbances are expected through Thursday.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

12z TAF Update: 

Today...Moderate confidence. 

Primarily MVFR or low end VFR ceilings. Patchy IFR ceilings 
remain a possible towards SE MA/Cape and Islands. Periods of 
mist and drizzle for immediate east coast and Cape/Island
terminals. Few -SHRA possible over the Cape/Islands. Winds 
generally NE to N at 5-12 kt.

Tonight...Moderate confidence. 

Widespread IFR should overspread the region heading into 
tonight with areas of LIFR possible, especially for 
Cape/Islands. -SHRA and -DZ possible overnight. Exact timing is
lower confidence. Winds NE/E at 5-10 kts.

Sunday...Moderate confidence.

MVFR-IFR ceilings with periods of showers during the day.
Scattered TSRA possible in the afternoon hours. Winds shift 
more S to SW after 21Z ahead of an approaching cold front.

KBOS Terminal...Moderate confidence in TAF. Conditions should
deteriorate to MVFR, then remain there through the day. Periods
of mist and drizzle possible throughout the day as well. Few
-SHRA possible overnight with a rounds of showers Sunday
 morning. Low chance for an embedded thunderstorm in the late
 afternoon/evening. 

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR. Slight chance SHRA.

Monday: VFR. Breezy. 

Monday Night: VFR. 

Tuesday: VFR. Breezy. 

Tuesday Night: VFR. 

Wednesday: VFR. Breezy. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Sunday...High confidence.

NE to N winds generally 15-20 kts and seas 3-4 ft through most 
of today become more light variable today into tonight as the 
low breaks down into Sunday morning. Winds then shift more S for
Sunday at around 5-10 kt, gusting to just under 20 kt
occasionally during the afternoon.

Despite the lower wave heights, the prolonged northeasterly 
flow will cause higher swells and longer swell periods today 
which is why a Rip Current Statement for Plymouth and 
Barnstable Counties will be in effect. 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. Swells diminish for Sunday, and
the risk for rip currents decreases with them.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers. 

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

Monday Night through Tuesday Night: Winds less than 25 kt. Seas
locally approaching 5 ft. 

Wednesday: Winds less than 25 kt. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 6 PM EDT this evening for MAZ019-
     022.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Hrencecin
AVIATION...Hrencecin/Mensch
MARINE...Hrencecin