172 FZUS51 KBOX 170803 CWFBOX Coastal Waters Forecast for Massachusetts and Rhode Island National Weather Service Boston/Norton MA 403 AM EDT Wed Sep 17 2025 Coastal waters from the Merrimack River MA to Watch Hill RI out to 25 NM ANZ200-172100- 403 AM EDT Wed Sep 17 2025 .Synopsis for Massachusetts and Rhode Island coastal waters... A high pres to our N slowly moves E of the region through mid-week as a low pres passes well to our S. Showers expected over the srn coastal waters tonight. A cold front will cross the region Fri, followed by a large high pres building in from the N for this weekend. $$ ANZ250-172100- Coastal waters east of Ipswich Bay and the Stellwagen Bank National Marine Sanctuary- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 8 seconds. .TONIGHT...SE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 8 seconds. A chance of showers after midnight. .THU...NE winds 5 to 10 kt, becoming E in the afternoon. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 7 seconds. A chance of showers in the morning. .THU NIGHT...SW winds 5 to 10 kt, becoming W after midnight. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 8 seconds and SW 2 ft at 3 seconds. .FRI AND FRI NIGHT...N winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: NE 4 ft at 7 seconds and W 2 ft at 3 seconds. .SAT THROUGH SUN NIGHT...S winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: N 4 ft at 6 seconds and S 3 ft at 4 seconds. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ251-172100- Massachusetts Bay and Ipswich Bay- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 5 to 10 kt. Seas around 2 ft. Wave Detail: E 2 ft at 7 seconds. .TONIGHT...SE winds 5 to 10 kt, becoming E after midnight. Seas around 2 ft. Wave Detail: E 2 ft at 8 seconds. A chance of showers. .THU...N winds 5 to 10 kt, becoming SE in the afternoon. Seas around 2 ft. Wave Detail: E 2 ft at 7 seconds. A chance of showers in the morning. .THU NIGHT...S winds 5 to 10 kt, becoming W after midnight. Seas around 2 ft. Wave Detail: E 2 ft at 8 seconds and SW 1 foot at 3 seconds. .FRI AND FRI NIGHT...N winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 5 seconds and W 2 ft at 3 seconds. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 4 seconds and NE 3 ft at 6 seconds. 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. $$ ANZ231-172100- Cape Cod Bay- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds around 10 kt. Seas around 2 ft. Wave Detail: E 1 foot at 3 seconds. A slight chance of showers this afternoon. .TONIGHT...E winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 3 seconds. A chance of showers. .THU...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: E 2 ft at 2 seconds and S 1 foot at 4 seconds. A chance of showers. .THU NIGHT...SW winds 5 to 10 kt. Seas around 2 ft. Wave Detail: E 2 ft at 5 seconds and S 1 foot at 3 seconds. .FRI...NW winds around 10 kt, becoming N in the afternoon. Gusts up to 20 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and W 1 foot at 3 seconds. .FRI NIGHT...N winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: N 3 ft at 5 seconds. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ254-172100- Coastal waters from Provincetown MA to Chatham MA to Nantucket MA out 20 nm- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 10 to 15 kt. Seas 2 to 4 ft. Wave Detail: SE 3 ft at 7 seconds. A slight chance of showers this afternoon. .TONIGHT...E winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers. .THU...NE winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: S 3 ft at 7 seconds. A chance of showers. .THU NIGHT...W winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: S 3 ft at 7 seconds. .FRI AND FRI NIGHT...N winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: N 4 ft at 6 seconds and W 2 ft at 3 seconds. .SAT THROUGH SUN NIGHT...S winds 15 to 20 kt. Seas 2 to 4 ft. Wave Detail: N 4 ft at 6 seconds and SE 2 ft at 3 seconds. 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. $$ ANZ255-172100- Coastal Waters extending out to 25 nm South of Marthas Vineyard and Nantucket- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds around 15 kt with gusts up to 20 kt. Seas 3 to 4 ft. Wave Detail: E 4 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Seas 3 to 4 ft. Wave Detail: E 4 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers. .THU...E winds around 10 kt, becoming N in the afternoon. Seas 2 to 3 ft. Wave Detail: S 3 ft at 7 seconds. Patchy fog. A chance of showers. Vsby 1 to 3 NM. .THU NIGHT...W winds 5 to 10 kt, increasing to 10 to 15 kt after midnight. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 7 seconds and SW 2 ft at 5 seconds. .FRI AND FRI NIGHT...NE winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: NE 4 ft at 5 seconds and W 2 ft at 4 seconds. .SAT THROUGH SUN NIGHT...SE winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Wave Detail: NE 4 ft at 5 seconds and SE 2 ft at 4 seconds. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ256-172100- Coastal Waters from Montauk NY to Marthas Vineyard extending out to 20 nm South of Block Island- 403 AM EDT Wed Sep 17 2025 ...SMALL CRAFT ADVISORY IN EFFECT THROUGH THIS EVENING... .TODAY...E winds 15 to 20 kt. Seas 4 to 5 ft. Wave Detail: E 5 ft at 8 seconds and S 1 foot at 7 seconds. A slight chance of showers this morning, then a chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Gusts up to 20 kt in the evening. Seas 3 to 5 ft. Wave Detail: E 5 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers. Patchy fog after midnight. .THU...NE winds around 10 kt, becoming N in the afternoon. Seas 3 to 4 ft. Wave Detail: S 4 ft at 7 seconds. Patchy fog in the morning. A chance of showers in the morning. .THU NIGHT...W winds 5 to 10 kt, increasing to 10 to 15 kt after midnight. Seas around 3 ft. Wave Detail: SE 3 ft at 7 seconds and SW 2 ft at 5 seconds. .FRI...W winds 10 to 15 kt. Seas around 3 ft. Wave Detail: SE 3 ft at 8 seconds and W 2 ft at 4 seconds. .FRI NIGHT...N winds 10 to 15 kt, becoming NE 15 to 20 kt after midnight. Gusts up to 25 kt. Seas 3 to 4 ft. Wave Detail: NE 4 ft at 5 seconds and W 2 ft at 5 seconds. .SAT THROUGH SUN NIGHT...SE winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. 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. $$ ANZ232-172100- Nantucket Sound- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 10 to 15 kt. Gusts up to 20 kt this afternoon. Seas 2 to 3 ft. Wave Detail: E 2 ft at 4 seconds and S 1 foot at 7 seconds. A slight chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds. A chance of showers. .THU...E winds 5 to 10 kt. Seas around 2 ft. Wave Detail: E 2 ft at 6 seconds and S 1 foot at 7 seconds. A chance of showers. .THU NIGHT...SW winds 5 to 10 kt, becoming W 10 to 15 kt after midnight. Seas around 2 ft. Wave Detail: W 2 ft at 3 seconds and E 2 ft at 7 seconds. .FRI AND FRI NIGHT...N winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 4 seconds and W 2 ft at 3 seconds. .SAT THROUGH SUN NIGHT...S winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 4 seconds and W 1 foot at 5 seconds. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ233-172100- Vineyard Sound- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 10 to 15 kt. Gusts up to 20 kt this afternoon. Seas 2 to 3 ft. Wave Detail: E 2 ft at 4 seconds and S 1 foot at 7 seconds. A chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Seas around 2 ft. Wave Detail: E 2 ft at 4 seconds and S 1 foot at 7 seconds. A chance of showers. .THU...NE winds around 10 kt, becoming N in the afternoon. Seas around 2 ft. Wave Detail: E 1 foot at 4 seconds and S 1 foot at 6 seconds. A chance of showers. Patchy fog in the morning. .THU NIGHT...W winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SW 1 foot at 5 seconds and SE 1 foot at 6 seconds. .FRI AND FRI NIGHT...N winds 15 to 20 kt. Seas 2 to 3 ft. Wave Detail: NE 2 ft at 3 seconds and W 1 foot at 4 seconds. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Wave Detail: NE 2 ft at 4 seconds and W 1 foot at 5 seconds. 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. $$ ANZ234-172100- Buzzards Bay- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 10 to 15 kt. Gusts up to 20 kt this afternoon. Seas around 2 ft. Wave Detail: E 1 foot at 3 seconds and S 1 foot at 7 seconds. A slight chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Seas around 2 ft. Wave Detail: E 1 foot at 3 seconds and S 1 foot at 7 seconds. A chance of showers. .THU...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NE 1 foot at 2 seconds and S 1 foot at 7 seconds. A chance of showers. Patchy fog in the morning. .THU NIGHT...SW winds 5 to 10 kt. Seas around 2 ft. Wave Detail: S 1 foot at 5 seconds. .FRI AND FRI NIGHT...N winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Wave Detail: NE 2 ft at 3 seconds and W 1 foot at 3 seconds. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft. Wave Detail: NE 2 ft at 3 seconds and W 1 foot at 5 seconds. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ235-172100- Rhode Island Sound- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds around 15 kt with gusts up to 20 kt. Seas 2 to 4 ft. Wave Detail: E 4 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Gusts up to 20 kt in the evening. Seas 2 to 4 ft. Wave Detail: E 4 ft at 8 seconds and S 1 foot at 7 seconds. A chance of showers. Patchy fog after midnight. .THU...NE winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: E 3 ft at 7 seconds and S 1 foot at 6 seconds. Patchy fog in the morning. A chance of showers in the morning. .THU NIGHT...W winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: SE 3 ft at 7 seconds and SW 2 ft at 5 seconds. .FRI...NW winds around 10 kt. Seas 2 to 3 ft. Wave Detail: W 2 ft at 3 seconds and SE 2 ft at 7 seconds. .FRI NIGHT...N winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 8 seconds and SW 2 ft at 6 seconds. .SAT THROUGH SUN NIGHT...S winds 15 to 20 kt. Seas 2 to 3 ft. 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. $$ ANZ237-172100- Block Island Sound- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds around 15 kt with gusts up to 20 kt. Seas 3 to 4 ft. Wave Detail: SE 4 ft at 7 seconds. A slight chance of showers this morning, then a chance of showers this afternoon. .TONIGHT...E winds 10 to 15 kt. Gusts up to 20 kt in the evening. Seas 3 to 4 ft. Wave Detail: SE 4 ft at 7 seconds. A chance of showers. Patchy fog after midnight. .THU...NE winds around 10 kt, becoming E in the afternoon. Seas 2 to 3 ft. Wave Detail: E 3 ft at 7 seconds and S 1 foot at 6 seconds. Patchy fog in the morning. A chance of showers in the morning. .THU NIGHT...W winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: S 3 ft at 6 seconds. .FRI...NW winds around 10 kt. Seas 2 to 3 ft. Wave Detail: W 2 ft at 4 seconds and SE 2 ft at 7 seconds. .FRI NIGHT...N winds 10 to 15 kt, becoming NE 15 to 20 kt after midnight. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 5 seconds and W 2 ft at 5 seconds. .SAT THROUGH SUN NIGHT...S winds 15 to 20 kt. Seas 2 to 3 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ230-172100- Boston Harbor- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 5 to 10 kt. Waves 1 foot or less. .TONIGHT...SE winds 5 to 10 kt, becoming NE after midnight. Waves 1 foot or less. A chance of showers. Patchy fog after midnight. .THU...N winds around 5 kt, becoming E in the afternoon. Waves 1 foot or less. A chance of showers in the morning. .THU NIGHT...S winds 5 to 10 kt, becoming W after midnight. Waves 1 foot or less. .FRI AND FRI NIGHT...N winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. 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. $$ ANZ236-172100- Narragansett Bay- 403 AM EDT Wed Sep 17 2025 .TODAY...E winds 10 to 15 kt. Waves around 2 ft. A slight chance of showers this afternoon. .TONIGHT...NE winds 5 to 10 kt. Waves around 2 ft. A chance of showers. Patchy fog after midnight. .THU...NE winds 5 to 10 kt. Waves around 2 ft. Patchy fog in the morning. A chance of showers in the morning. .THU NIGHT...SW winds 5 to 10 kt. Waves around 2 ft. .FRI AND FRI NIGHT...N winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. .SAT THROUGH SUN NIGHT...S winds 10 to 15 kt. Waves around 2 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ For the latest updates...please visit our webpage at www.weather.gov/boston You can follow us on Facebook at www.facebook.com/NWSBoston You can follow us on Twitter at @NWSBoston