Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Clear
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 182350
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
750 PM EDT Sun Oct 18 2026

.WHAT HAS CHANGED...
Global and ensemble guidance as trended a bit farther NW with
the track of an offshore storm later this week. While there will 
need to be more multi-run consistency to call this a true trend,
this adjustment shows that the eventual path of this system is 
still far from set in stone at this time. Otherwise, a Gale 
Watch has been upgraded to a Gale Warning for the outer waters 
Tuesday into Thursday. Closer to shore, a Gale Watch has been 
issued for the same timeframe.

&&

.KEY MESSAGES...

- Not as cold tonight with clear skies and light to calm winds.
  Dry for most through Monday Night.

- Increasing chances for rainfall across coastal areas for this
  upcoming work week as a offshore Storm gradually approaches
  from the south. The system likely brings significant marine  
  impacts in the form of strong winds, rough seas, and beach 
  erosion through much of the upcoming week.

&&

.DISCUSSION...
KEY MESSAGE 1...Not as cold tonight with clear skies and light
to calm winds. Dry for most through Monday Night.

Center of a high pressure reaches the Maritimes this evening,
but is still strong enough to dominate our weather through
Monday. Then southern new England is stuck between a high
pressure over the North Atlantic and another over Ohio. This
slight weakness in the pressure pattern opens the door for a low
pressure off the Mid Atlantic coast to nudge slightly farther 
north late Monday into Monday night.

For most of our region, dry weather will continue through Monday 
night with a slight warming trends. The exception will be 
towards the outer Cape and Nantucket, where some showers are
possible Monday evening and night. Still, there will be plenty
of dry hours there as well.

KEY MESSAGE 2...Increasing chances for rainfall across coastal
areas for this upcoming work week as a offshore Storm gradually 
approaches from the south. The system likely brings significant 
marine impacts in the form of strong winds, rough seas, and
beach erosion through much of the upcoming week.

Confidence is somewhat lower than normal for the eventual track
and intensity of this week's nor'easter. While the majority of
guidance tracks the low center well to the S of the 40/70
benchmark, there has been a trend NW amongst AI, high res, and
an increasing number of global guidance. This subtle NW jog is
likely driven by the interaction between the cutoff low driving 
the nor'easter and an additional shortwave trough moving S from 
Canada by later Wednesday. The main change has been to amplify
the shortwave from a flat/positive tilt to more of a neutral
tilt. This positioning allows for a stronger more amplified
system and thus a track further N. In terms of QPF, the
northward trend has brought a notable uptick in the probability 
of >0.5" of rainfall along and S of the I-95 corridor. As of the 
12z suite, most models show a 40-60% chance of rain totals in
this range. There are still some models, namely the NAM and AI
guidance that show a track even further north and the chance for 
a soaking rain event for much of the region. This is certainly a
low probability event but nonetheless a possibility at this 
time.

The higher confidence aspect of the forecast continues to be
significant marine impacts driven by increasing NE winds. Low
pressure to the S will move against high pressure over southern 
Quebec later Monday. The resulting pressure gradient will bring 
an increasing likelihood of Gale force winds well to the north 
of the actual surface low. Winds build up towards Monday night 
as the low pressure deepens and drifts to the north. Ensembles 
have shown near 80-90 percent probabilities of sustained winds 
reaching gale-force over the southern waters despite a low track
to the S of the benchmark. Thus, we opted to upgrade Gale
Watches to Gale Warnings for the outer waters and have
introduced Gale Watches for the near coastal Waters. Finally, we 
will have to monitor the chance for significant beach erosion as
well with a prolonged easterly fetch of winds and waves through
the week.

Later this week, the aforementioned trough likely pushes the
coastal low farther offshore putting an end to any lingering
impacts. Significant ridging aloft over much of the CONUS looks 
to persist and even intensify, then becomes more tilted towards 
the Great Lakes region towards the weekend. This would be
associated with a strong Canadian high pressure that looks to
strengthen over the northeast after originating from the
Canadian Prairies, which would lean towards drier conditions for 
the whole region once again.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

Through Tonight...High confidence.

VFR. Calm/light winds continuing. Stronger E winds towards 
Nantucket, with G20kt possible by daybreak.

Monday and Monday Night...High confidence.

VFR, with the exception of the Cape and Islands towards the 
late afternoon and evening hours, when MVFR ceilings may 
develop. Chances for -SHRA increase there as well and should 
remain generally over the Cape and Islands, along with an 
increased chance for gusts to 25 kt. Winds from the NE and light
to calm further inland, 5-10 kt sustained closer to the coasts.
N to NE winds increase Monday night, with gusts 15-30 kt towards
daybreak Tuesday. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday through Friday/...

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

Tuesday Night: VFR. Windy with gusts up to 35 kt. 

Wednesday: Mainly VFR, with local MVFR possible. Windy with
gusts up to 35 kt. 

Wednesday Night: VFR. Windy with local gusts up to 30 kt.
Slight chance SHRA.

Thursday: VFR. Windy with local gusts up to 30 kt. 

Thursday Night through Friday: VFR. Windy with areas of gusts
up to 30 kt.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Monday Night...High confidence.

Relatively light winds and seas expected through most of
tonight. A low pressure well south of the waters will begin to
generate stronger winds and rougher seas late tonight into 
Monday across the outer coastal waters. Small Craft Advisory 
conditions are expected across the southern coastal waters, but
will keep the focus on the period of stronger winds mid week. 

Outlook /Tuesday through Friday/...

Tuesday: Strong winds with gusts up to 40 kt. Rough seas up to
14 ft. Slight chance of rain showers. 

Tuesday Night: Moderate risk for gale force winds with gusts up
to 40 kt. Rough seas up to 14 ft. 

Wednesday: Moderate risk for gale force winds with gusts up to
40 kt. Rough seas up to 15 ft. Chance of rain showers. 

Wednesday Night: Strong winds with gusts up to 40 kt. Rough
seas up to 14 ft. Chance of rain showers. 

Thursday: Low risk for gale force winds with gusts up to 35 kt.
Rough seas up to 13 ft. Chance of rain showers. 

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

Friday: Strong winds with gusts up to 35 kt. Rough seas up to
13 ft. Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Watch from Monday evening through Wednesday evening for 
     ANZ231>235-237.
     Gale Warning from 8 PM Monday to 8 PM EDT Wednesday for 
     ANZ254>256-281>283.

&&

$$

DISCUSSION...Belk/FT
AVIATION...Belk/FT
MARINE...Belk/FT