Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: 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: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 131904
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
304 PM EDT Fri Mar 13 2026

.WHAT HAS CHANGED...
Wind Advisory posted for the higher terrain of the Worcester
Hills and East Slopes of the Berkshires. Gale Warnings for the 
southern coastal waters of MA and RI.

&&

.KEY MESSAGES...

- Strong westerly wind gusts of 35-50 mph Saturday.

- A period of heavy rainfall, strong winds, and unseasonably 
  mild temps Mon into Mon night. Some river and small stream 
  flooding expected.

- Trending colder with mainly dry weather Tue through Thu.

&&

.DISCUSSION...
KEY MESSAGE 1...Strong westerly wind gusts of 35-50 mph
Saturday.

After a brief period of light rain and snow showers late this
evening into the early morning hours, attention turns to the
more significant impact of gusty winds. Little to no snow
accumulation expected, except perhaps across the highest
elevations towards NW MA, where 1-2 inches is possible.

Increasing south to southwest winds late tonight into Saturday.
Based on model sounding, thinking much of southern New England
will have wind gusts of 30-40 mph. Some locations across the
higher terrain, namely the Worcester Hills and the east slopes
of the Berkshires, are expected more in the 45-50 mph range.
This was more in line with the NBM 90th percentile gusts, which
were used for this forecast. Stronger wind gusts are possible, 
but would require near perfect mixing and momentum transfer. 
Posted a Wind Advisory for the higher terrain areas, but it is 
marginal. 

Otherwise, dry weather expected for Saturday as winds become
west by mid morning.


KEY MESSAGE 2...A period of heavy rainfall, strong winds and 
unseasonably mild temps Mon into Mon night. Some river and small 
stream flooding expected.

Monday and Monday night are looking like the most impactful
weather period of the forecast bringing heavy rain and gusty 
winds. This, as a deep mid level trough digs into the Ohio 
Valley Monday into Tuesday dragging a surface frontal system 
through Southern New England Monday into Monday night. A warm 
front lifts north during the day on Monday as a deep plume of 
moisture begins to move overhead. This will lead to widespread 
warm advection showers as well as temperatures 10 to 15 degrees 
warmer than Sunday, in the upper 50s and low 60s. This is an 
anomolous system both in the magnitude of moisture and
wind/dynamics. Dewpoints surge into the mid to upper 50s in the 
warm sector on Monday while PWATs reach nearly 1.5 inches which 
is outside of the climatology for mid March. There's a very
strong LLJ present as well, 60-70kt at 925 mb. Additionally,
given the anomalous warmth and and moisture in the warm sector, 
we can't rule out some convective elements with elevated
instability, even potential for a fine line along the cold
front. This could serve to contribute to localized downpours and 
to help bring those strong winds to the surface. Added together,
there is a signal for a potentially significant event if things
come together. An addition of 1 to 2 inches of rain (locally 
even higher) together with the rapid snow melt will lead to 
flooding concerns on local rivers and streams. MMEFS ensemble 
guidance continues to highlight a 60-80% chance of minor
flooding and 20-30% chance for moderate flooding. The greatest
risk looks to be the Pawtuxet, Pawcatuck, and wood Rivers in RI
with lesser concerns on the Assabet River, Deerfield River, and
the lower reaches of the CT River. 

The southerly wind trajectory will make it difficult to mix down
the LLJ, limiting wind damage potential much of the time thanks 
to a decent inversion. If there was a window for the best chance
of some of these strong winds mixing down it would be overnight
Monday as the cold front passes through. Precip comes to an end
by sunrise, potentially as late as mid morning for far eastern 
MA. 


KEY MESSAGE 3...Trending colder with mainly dry weather Tue 
through Thu.

Cooler and drier weather Tuesday behind a front. Cyclonic flow 
remains overhead, but things remain dry through at least
Thursday. The peak of the cold airmass overhead is Wednesday, so 
that will be the coolest day of the week with highs in the 30s
to near 40. 40s return late week.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

Tonight...High confidence. 

VFR dominates, but brief MVFR conditions possible for a few
hours around midnight EDT in brief passing rain/snow showers. 
Greatest risk for this will be across northern MA. Southerly 
wind gusts increasing to between 20 and 30 knot for a time 
overnight.

Saturday...High confidence. 

Mainly VFR conditions expected outside a few brief passing
rain/snow showers possible mainly in northwest MA. Westerly wind
gusts of 30-40 knots with a few gusts up to 45 knots possible
across the higher terrain. 

Saturday Night...High Confidence.

VFR with a diminishing west wind.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday: VFR. Breezy. 

Sunday Night: Mainly VFR, with local IFR possible. Windy with
local gusts up to 30 kt. Chance RA, chance FZRA.

Monday: Mainly IFR, with areas MVFR possible. Strong winds with
local gusts up to 40 kt. RA, isolated TSRA.

Monday Night: Mainly MVFR, with areas IFR possible. Strong
winds with gusts up to 45 kt. RA, slight chance TSRA.

Tuesday: VFR. Windy with gusts up to 30 kt. Chance RA, slight
chance SN.

Tuesday Night: VFR. Windy with local gusts up to 30 kt. 

Wednesday: VFR. Breezy. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Rough seas linger across the outer coastal waters into Saturday
night. Winds expected to increase from the south to southwest 
tonight, then become west by mid morning Saturday. Frequent
gale-force gusts, mainly across the southern coastal waters.
There is a risk for gale-force gusts across the Stellwagen Bank
NMS during Saturday afternoon into the evening. However, do not
yet have enough confidence in this outcome, so opted for a Gale
Watch instead. Diminishing winds and seas Saturday night.

Outlook /Sunday through Wednesday/...

Sunday: Winds less than 25 kt. 

Sunday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. Slight chance of rain. 

Monday: Moderate risk for gale force winds with gusts up to
45 kt. Rough seas up to 15 ft. Rain, isolated thunderstorms. 

Monday Night: gale force winds with gusts up to 45 kt. Rough
seas up to 15 ft. Rain, slight chance of thunderstorms. 

Tuesday: Strong winds with gusts up to 35 kt. Rough seas up to
13 ft. Chance of rain, slight chance of snow. 

Tuesday Night: Strong winds with gusts up to 35 kt. Rough seas
up to 12 ft. 

Wednesday: Winds less than 25 kt. Local rough seas. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Wind Advisory from 10 AM to 7 PM EDT Saturday for MAZ002-004-
     008-009.
RI...None.
MARINE...Small Craft Advisory from 10 AM Saturday to 1 AM EDT Sunday 
     for ANZ230.
     Small Craft Advisory from 1 AM Saturday to 1 AM EDT Sunday for 
     ANZ231.
     Gale Warning from 2 AM to 5 PM EDT Saturday for ANZ232>235-237.
     Small Craft Advisory from 1 AM to 7 PM EDT Saturday for ANZ236.
     Gale Watch from Saturday afternoon through Saturday evening 
     for ANZ250.
     Small Craft Advisory from 10 PM this evening to 1 AM EDT 
     Sunday for ANZ251.
     Gale Warning from 5 AM to 7 PM EDT Saturday for ANZ254.
     Gale Warning from midnight tonight to 7 PM EDT Saturday for 
     ANZ255-256.

&&

$$

DISCUSSION...Belk/BW
AVIATION...Belk/BW
MARINE...Belk/BW