


Coastal Waters Forecast
Issued by NWS Boston, MA
Issued by NWS Boston, MA
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482 FZUS51 KBOX 292006 CWFBOX Coastal Waters Forecast for Massachusetts and Rhode Island National Weather Service Boston/Norton MA 406 PM EDT Fri Aug 29 2025 Coastal waters from the Merrimack River MA to Watch Hill RI out to 25 NM ANZ200-300900- 406 PM EDT Fri Aug 29 2025 .Synopsis for Massachusetts and Rhode Island coastal waters... A cold front will move offshore tonight. High pressure will build into the Northeast behind the front and remain anchored over the region into the middle of next week. $$ ANZ250-300900- Coastal waters east of Ipswich Bay and the Stellwagen Bank National Marine Sanctuary- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt with gusts up to 20 kt, becoming W after midnight. Seas 2 to 3 ft. Wave Detail: S 2 ft at 4 seconds and E 1 foot at 8 seconds. Showers likely with isolated tstms this evening, then a chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 5 seconds. .SAT NIGHT...SW winds around 10 kt, becoming NW after midnight. Seas 2 to 3 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 7 seconds. .SUN...NW winds 5 to 10 kt, becoming NE in the afternoon. Seas 2 to 3 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 8 seconds. .SUN NIGHT...S winds around 5 kt, becoming W after midnight. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and N 1 foot at 3 seconds. .MON AND MON NIGHT...N winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 2 seconds. .TUE AND TUE NIGHT...NE winds 5 to 10 kt, becoming S. Seas around 2 ft. .WED AND WED NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft. Winds and seas higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ251-300900- Massachusetts Bay and Ipswich Bay- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt with gusts up to 20 kt, becoming W after midnight. Seas around 2 ft. Wave Detail: SE 2 ft at 4 seconds and E 1 foot at 8 seconds. Showers with a slight chance of tstms this evening, then a slight chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening with vsby 1 to 3 NM. .SAT...NW winds around 10 kt, becoming SW in the afternoon. Seas around 2 ft. Wave Detail: N 1 foot at 3 seconds and SE 1 foot at 5 seconds. .SAT NIGHT...SW winds 5 to 10 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: E 2 ft at 8 seconds and W 1 foot at 2 seconds. .SUN...NW winds 5 to 10 kt, becoming E in the afternoon. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 3 seconds. .SUN NIGHT...S winds 5 to 10 kt, becoming W after midnight. Seas around 2 ft. Wave Detail: E 2 ft at 8 seconds and NW 1 foot at 3 seconds. .MON AND MON NIGHT...NW winds 5 to 10 kt. Seas around 2 ft. Wave Detail: N 1 foot at 3 seconds and E 1 foot at 7 seconds. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Winds and seas higher in and near tstms. 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. $$ ANZ231-300900- Cape Cod Bay- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt with gusts up to 20 kt, becoming W 5 to 10 kt after midnight. Seas around 2 ft this evening, then 1 foot or less. Wave Detail: SW 1 foot at 3 seconds and E 1 foot at 3 seconds. Showers likely with isolated tstms this evening, then a chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming N in the afternoon. Seas around 2 ft in the morning, then 1 foot or less. Wave Detail: NW 1 foot at 3 seconds and SE 1 foot at 5 seconds, becoming NW 1 foot at 3 seconds and N 1 foot at 3 seconds. .SAT NIGHT...SW winds 5 to 10 kt, becoming NW after midnight. Seas 1 foot or less. Wave Detail: NW 1 foot at 3 seconds and NE 1 foot at 3 seconds. .SUN...NW winds 5 to 10 kt, becoming NE in the afternoon. Seas 1 foot or less. Wave Detail: NW 1 foot at 3 seconds and N 1 foot at 3 seconds. .SUN NIGHT...SE winds around 5 kt, becoming W after midnight. Seas 1 foot or less. Wave Detail: N 1 foot at 3 seconds and SE 1 foot at 7 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas 1 foot or less. Wave Detail: N 1 foot at 3 seconds and SE 1 foot at 7 seconds. .TUE THROUGH WED NIGHT...S winds 5 to 10 kt. Seas around 2 ft. Winds and seas higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ254-300900- Coastal waters from Provincetown MA to Chatham MA to Nantucket MA out 20 nm- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds around 10 kt with gusts up to 20 kt, becoming SW after midnight. Seas 2 to 3 ft. Wave Detail: S 2 ft at 5 seconds and E 1 foot at 8 seconds. A slight chance of showers this evening, then a chance of showers after midnight with vsby 1 to 3 NM. .SAT...W winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: SE 2 ft at 7 seconds and W 1 foot at 3 seconds. .SAT NIGHT...SW winds 5 to 10 kt, becoming NW after midnight. Seas 2 to 3 ft. Wave Detail: S 2 ft at 7 seconds and SE 2 ft at 8 seconds. .SUN...N winds 5 to 10 kt. Seas 2 to 3 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 3 seconds. .SUN NIGHT...N winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 4 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: E 2 ft at 8 seconds and N 1 foot at 4 seconds. .TUE THROUGH WED NIGHT...S winds 5 to 10 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. $$ ANZ255-300900- Coastal Waters extending out to 25 nm South of Marthas Vineyard and Nantucket- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds around 10 kt, becoming SW after midnight. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and SW 1 foot at 5 seconds. A chance of showers. .SAT...W winds around 10 kt. Seas 2 to 3 ft. Wave Detail: W 2 ft at 4 seconds and SE 2 ft at 7 seconds. .SAT NIGHT...W winds around 10 kt, becoming NW after midnight. Seas 2 to 3 ft. Wave Detail: W 2 ft at 4 seconds and S 2 ft at 7 seconds. .SUN...N winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NW 2 ft at 4 seconds and SE 2 ft at 7 seconds. .SUN NIGHT THROUGH MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NE 2 ft at 3 seconds and SE 2 ft at 7 seconds. .TUE THROUGH WED NIGHT...S winds around 10 kt. Seas 2 to 4 ft. Wave Detail: E 4 ft at 9 seconds and NE 2 ft at 6 seconds. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ256-300900- Coastal Waters from Montauk NY to Marthas Vineyard extending out to 20 nm South of Block Island- 406 PM EDT Fri Aug 29 2025 .TONIGHT...SW winds around 10 kt, becoming NW after midnight. Seas 2 to 3 ft. Wave Detail: W 2 ft at 4 seconds and S 2 ft at 5 seconds. A chance of showers. Isolated tstms this evening. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas 2 to 3 ft. Wave Detail: NW 2 ft at 4 seconds and SE 2 ft at 8 seconds. .SAT NIGHT...W winds 10 to 15 kt, becoming NW after midnight. Seas 2 to 3 ft. Wave Detail: W 2 ft at 4 seconds and S 2 ft at 7 seconds. .SUN...N winds 5 to 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 7 seconds. .SUN NIGHT...SE winds around 5 kt, becoming N after midnight. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NE 1 foot at 2 seconds. .MON AND MON NIGHT...NE winds around 10 kt. Seas around 2 ft. Wave Detail: NE 2 ft at 3 seconds and SE 2 ft at 8 seconds. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt. Seas 2 to 4 ft. Winds and seas higher in and near tstms. 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. $$ ANZ232-300900- Nantucket Sound- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt, becoming W after midnight. Seas around 2 ft. Wave Detail: SW 2 ft at 5 seconds and E 1 foot at 3 seconds. Showers likely, mainly this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: NW 1 foot at 3 seconds and SE 1 foot at 7 seconds. .SAT NIGHT...W winds 10 to 15 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: W 1 foot at 3 seconds and SE 1 foot at 7 seconds. .SUN...N winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NW 1 foot at 3 seconds and N 1 foot at 3 seconds. .SUN NIGHT...E winds 5 to 10 kt, becoming N after midnight. Seas 1 foot or less. Wave Detail: NE 1 foot at 2 seconds and NW 1 foot at 3 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NE 1 foot at 2 seconds and NW 1 foot at 3 seconds. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt. Seas 2 to 3 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ233-300900- Vineyard Sound- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: SW 2 ft at 5 seconds and SE 1 foot at 8 seconds. Showers likely with isolated tstms this evening, then a chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: NW 1 foot at 3 seconds and SE 1 foot at 7 seconds. .SAT NIGHT...W winds 10 to 15 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: SW 2 ft at 4 seconds and SE 1 foot at 7 seconds. .SUN...N winds 5 to 10 kt. Seas around 2 ft in the morning, then 1 foot or less. Wave Detail: NW 1 foot at 3 seconds and N 1 foot at 3 seconds, becoming N 1 foot at 2 seconds and W 1 foot at 4 seconds. .SUN NIGHT...S winds 5 to 10 kt, becoming NW after midnight. Seas 1 foot or less. Wave Detail: NE 1 foot at 2 seconds and SW 1 foot at 5 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NW 1 foot at 2 seconds and NE 1 foot at 2 seconds. .TUE THROUGH WED NIGHT...S winds 5 to 10 kt. Seas around 2 ft. Winds and seas higher in and near tstms. 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. $$ ANZ234-300900- Buzzards Bay- 406 PM EDT Fri Aug 29 2025 .TONIGHT...S winds 10 to 15 kt with gusts up to 20 kt, becoming NW after midnight. Seas around 2 ft this evening, then 1 foot or less. Wave Detail: SW 2 ft at 4 seconds and E 1 foot at 3 seconds, becoming SW 1 foot at 4 seconds and SE 1 foot at 8 seconds. Showers likely with isolated tstms this evening, then a chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming SW in the afternoon. Seas 1 foot or less, then around 2 ft in the afternoon. Wave Detail: NW 1 foot at 3 seconds and SE 1 foot at 7 seconds, becoming SW 1 foot at 3 seconds and SE 1 foot at 7 seconds. .SAT NIGHT...NW winds around 10 kt. Seas around 2 ft. Wave Detail: SW 1 foot at 4 seconds and SE 1 foot at 7 seconds. .SUN...N winds 5 to 10 kt, becoming E in the afternoon. Seas 1 foot or less. Wave Detail: N 1 foot at 2 seconds and NW 1 foot at 3 seconds. .SUN NIGHT...S winds 5 to 10 kt, becoming NW after midnight. Seas 1 foot or less. Wave Detail: NE 1 foot at 2 seconds and SW 1 foot at 5 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: NW 1 foot at 2 seconds and NE 1 foot at 2 seconds. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft. Winds and seas higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ235-300900- Rhode Island Sound- 406 PM EDT Fri Aug 29 2025 .TONIGHT...SW winds 10 to 15 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: SW 2 ft at 4 seconds and SE 1 foot at 8 seconds. Showers with isolated tstms this evening, then a chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 7 seconds. .SAT NIGHT...NW winds 10 to 15 kt. Seas around 2 ft. Wave Detail: W 2 ft at 4 seconds and SE 2 ft at 7 seconds. .SUN...N winds 5 to 10 kt, becoming SW in the afternoon. Seas around 2 ft. Wave Detail: NW 2 ft at 3 seconds and SE 2 ft at 7 seconds. .SUN NIGHT...S winds 5 to 10 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: S 2 ft at 5 seconds and NE 1 foot at 2 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 2 seconds. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt. Seas 2 to 3 ft. Winds and seas higher in and near tstms. 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. $$ ANZ237-300900- Block Island Sound- 406 PM EDT Fri Aug 29 2025 .TONIGHT...SW winds around 10 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: SW 2 ft at 4 seconds and SE 1 foot at 8 seconds. Showers likely with a slight chance of tstms this evening, then a slight chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 3 seconds. .SAT NIGHT...NW winds around 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and W 1 foot at 3 seconds. .SUN...N winds 5 to 10 kt, becoming SW in the afternoon. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NW 1 foot at 3 seconds. .SUN NIGHT...S winds 5 to 10 kt, becoming NW after midnight. Seas around 2 ft. Wave Detail: SE 2 ft at 6 seconds and SW 1 foot at 2 seconds. .MON AND MON NIGHT...NE winds 5 to 10 kt. Seas around 2 ft. Wave Detail: SE 2 ft at 7 seconds and NE 1 foot at 2 seconds. .TUE THROUGH WED NIGHT...S winds 5 to 10 kt. Seas 2 to 3 ft. Winds and seas higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ ANZ230-300900- Boston Harbor- 406 PM EDT Fri Aug 29 2025 .TONIGHT...SW winds 5 to 10 kt, becoming W after midnight. Waves around 2 ft this evening, then 1 foot or less. Showers with a chance of tstms this evening, then a slight chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds around 10 kt, becoming W in the afternoon. Waves 1 foot or less. .SAT NIGHT...W winds 5 to 10 kt. Waves 1 foot or less. .SUN...NW winds 5 to 10 kt, becoming E in the afternoon. Waves 1 foot or less. .SUN NIGHT...S winds 5 to 10 kt, becoming W after midnight. Waves 1 foot or less. .MON AND MON NIGHT...NW winds 5 to 10 kt. Waves around 2 ft. .TUE THROUGH WED NIGHT...S winds 10 to 15 kt. Waves around 2 ft. Winds and waves higher in and near tstms. 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. $$ ANZ236-300900- Narragansett Bay- 406 PM EDT Fri Aug 29 2025 .TONIGHT...SW winds 5 to 10 kt, becoming NW after midnight. Waves around 2 ft this evening, then 1 foot or less. Showers with a slight chance of tstms this evening, then a slight chance of showers after midnight. Some tstms may produce gusty winds, small hail, and heavy rainfall this evening. .SAT...NW winds 5 to 10 kt, becoming W in the afternoon. Waves around 2 ft. .SAT NIGHT...NW winds 5 to 10 kt. Waves around 2 ft. .SUN...N winds 5 to 10 kt, becoming SE in the afternoon. Waves around 2 ft in the morning, then 1 foot or less. .SUN NIGHT...S winds 5 to 10 kt, becoming NW after midnight. Waves 1 foot or less. .MON AND MON NIGHT...N winds 5 to 10 kt. Waves 1 foot or less. .TUE THROUGH WED NIGHT...S winds 5 to 10 kt. Waves around 2 ft. Winds and waves higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height. $$ 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