Marine Weather Net

Boston Harbor Marine Forecast


TODAY

NW
WINDS
5 - 10
KNOTS

TONIGHT

NW
WINDS
5 - 10
KNOTS

SUN

NW
WINDS
5 - 10
KNOTS

SUN NIGHT

N
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ230 Forecast Issued: 703 AM EDT Sat Oct 25 2025

Today...Nw Winds 5 To 10 Kt. Gusts Up To 20 Kt This Morning. Waves Around 2 Ft This Morning, Then 1 Foot Or Less.
Tonight...Nw Winds 5 To 10 Kt. Waves Around 2 Ft In The Evening, Then 1 Foot Or Less.
Sun...Nw Winds 5 To 10 Kt. Waves 1 Foot Or Less.
Sun Night...N Winds 5 To 10 Kt. Waves 1 Foot Or Less, Then Around 2 Ft After Midnight.
Mon And Mon Night...N Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves Around 2 Ft.
Tue Through Wed Night...N Winds 20 To 25 Kt With Gusts Up To 30 Kt. Waves 2 To 3 Ft. A Chance Of Showers. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height.
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Area Forecast Discussion
National Weather Service Boston/Norton MA
842am EDT Sat Oct 25 2025

Synopsis
High pressure across eastern Canada will result in dry and cool weather this weekend. A few showers are possible mainly near the coast early next week. A more significant storm system with a period of gusty winds and widespread rain are possible by late in the week.

Near Term - Until 6pm This Evening
Key Messages... * Partly sunny & cool today with highs in the 50s

Details... High pressure building across eastern Canada will bring dry but cool weather to the region today. High temperatures today will be in the 50s...slightly below normal for this time of year. Northwest winds of 5 to 15 mph are on tap for the region. Overall, not a bad day for this time of year.

Short Term - 6pm This Evening Through 6pm Sunday
Key Messages... * Dry and seasonably cool tonight with lows in the 30s * Partly sunny/cool Sun...Highs mainly in the 50s

Details... High pressure across eastern Canada will continue to result in dry and cool weather tonight and Sunday. Light NNW flow may allow for a brief spot shower or two across the Cape/Islands later on Sunday...but for all intensive purposes it will be dry with partly sunny skies.

Low temperatures tonight will be mainly in the 30s. Highs on Sunday will generally be in the 50s...but portions of the high terrain will only see highs in the upper 40s.

Long Term - Sunday Night Through Friday
Key Messages... * A few showers possible early next week mainly near the coast with a more significant storm system possible by late in the week

* Cool daytime temperatures next week but it may turn milder by late in the week if low pressure takes an inland track

Details... The forecast next week still remains quite uncertain. Vigorous northern stream energy initially in the Maritimes will retrograde southwestward during the week and eventually interact with additional energy dropping southward towards the southeast. Specific timing and amplification of this energy will determine the track/intensity of a few waves of low pressure. Making the forecast even more complex will be the Tropical Storm Melissa. This is supposed to become a Major Hurricane in the Caribbean by Sunday and move very slowly northeastward through the middle of next week.

What we do know is that high pressure across Quebec will shift east into the Maritimes next week. As this happens, northeast low level flow will increase early in the week given the magnitude of the high pressure system and an initial wave of low pressure off the southeast/mid-Atlantic coast. Appears this initial wave of low pressure will be relatively weak and track well southeast of the Benchmark. So while northeast low level flow may result in a few showers mainly near the coast early next week, thinking that the initial surface low will pass too far east of the region for any significant rainfall. However, as the second piece of shortwave energy amplifies over the southeast the followup low pressure system will likely track further northwest. Appears that our best chance for a widespread rain event will be late Wednesday into early Friday. Still a lot of uncertainty though and fortunately astronomical tides are rather low...so it will be hard to get much more than splashover/minor coastal flooding. And while there maybe some wind as well...the pressure gradient and easterly LLJ likely will not support anything too significant. Again though nothing is set it stone and will need a few more days to sort things out.

High temperatures much of next week will be cool with the onshore flow, but clouds and the threat of precipitation will limit nighttime cooling. In fact, there are some indications that the late week low pressure system may take an inland track. If that happens we may see a surge of milder air work into the region for a time late next week.

Marine
Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.

Today through Sunday...High confidence.

High pressure across eastern Canada will result in NNW less than 15 knots. So winds and seas will remain below Small Craft Advisory thresholds this weekend.

Outlook /Sunday Night through Wednesday/... Sunday Night: Winds less than 25 kt. Slight chance of rain showers.
Monday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.
Monday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Chance of rain showers.

Tuesday: Strong winds with gusts up to 40 kt. Rough seas up to 10 ft. Chance of rain showers.

Tuesday Night: Strong winds with gusts up to 40 kt. Rough seas up to 11 ft. Chance of rain showers.

Wednesday: Strong winds with gusts up to 35 kt. Rough seas up to 10 ft. Chance of rain showers.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.

Marine
None.