Coastal Waters out 25 NM South of Marthas Vineyard and Nantucket Marine Forecast
| This Afternoon...E Winds Around 5 Kt. Seas 2 To 3 Ft. Wave Detail: S 3 Ft At 7 Seconds And E 1 Foot At 8 Seconds. |
| Tonight...Se Winds Around 5 Kt. Seas Around 2 Ft. Wave Detail: S 2 Ft At 7 Seconds And E 1 Foot At 7 Seconds. Patchy Fog After Midnight. Showers Likely After Midnight With Vsby 1 To 3 Nm. |
| Sun...S Winds Around 5 Kt, Becoming W In The Afternoon. Seas Around 2 Ft. Wave Detail: S 2 Ft At 7 Seconds And Sw 1 Foot At 2 Seconds. Patchy Fog In The Morning. A Chance Of Showers In The Morning With Vsby 1 To 3 Nm. |
| Sun Night...W Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: S 2 Ft At 7 Seconds And Se 2 Ft At 10 Seconds. |
| Mon...Ne Winds Around 10 Kt, Becoming E In The Afternoon. Seas 2 To 3 Ft. Wave Detail: S 2 Ft At 6 Seconds And Se 2 Ft At 12 Seconds. |
| Mon Night...S Winds Around 5 Kt, Becoming W After Midnight. Seas 2 To 4 Ft. Wave Detail: S 4 Ft At 16 Seconds And S 2 Ft At 6 Seconds. |
| Tue...N Winds 5 To 10 Kt. Seas 4 To 6 Ft. |
| Tue Night...Ne Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 5 To 8 Ft. |
| Wed...Ne Winds 25 To 30 Kt. Seas 7 To 10 Ft. |
| Wed Night...Ne Winds 25 To 30 Kt. Seas 8 To 11 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. |
| Area Forecast Discussion National Weather Service Boston/Norton MA 230pm EDT Sat September 27 2025 Synopsis Some showers are possible late tonight into early Sunday, mainly along the south coast, otherwise rather warm conditions will continue into early next week. A dry cold front will push south of New England Tuesday followed by much cooler temperatures Wednesday and Thursday as strong high pressure builds to the north. Temperatures moderate Friday as the high pressure moves over New England. Near Term - Through Tonight Key Messages: * Some showers possible late tonight, particularly along the south coast Dry and warm conditions continue through the rest of today with partly cloudy skies. A weak low pressure off the Mid Atlantic coast moves just south of New England tonight, bringing with it the chance for some scattered showers along the south coast. Guidance continues to vary a bit with regards to the northern extent of these showers; the latest HREF keeps any appreciable Quantitative Precipitation Forecast well to the south of New England while the GFS (Global Forecast System) and ECMWF (European Centre for Medium-Range Weather Forecasts) bring just under 0.1" up to parts of central MA and the Boston metro area. The latest CMC has trended more towards NAM guidance, keeping precipitation over the south coast and Islands. Some of the high-res guidance has some showers making their way further north and inland, but no appreciable Quantitative Precipitation Forecast is associated with them. In general, the highest chances for some showers continue to be over the south coast and especially the Islands after midnight tonight. Lows tonight expected to be in the upper 50s and low 60s. Short Term - Sunday Through Sunday Night Key Messages: * Skies clear out Sunday morning with more humidity and warmer than normal high temperatures * Cooler Sunday night Showers from the passing low Saturday night will clear out heading into Monday morning. High pressure that's moved over the Great Lakes will continue to spread eastward into southern New England. Clouds will clear over the region from NW to SE as drier air begins to move in. 925 mb temperatures aloft will be around 20C Sunday afternoon, and with SW winds, highs in the upper 70s and low 80s are very likely especially across the interior. Surface moisture will remain elevated as dew points remain in the 60s Sunday afternoon, so it may feel a bit humid. This moisture diminishes going into Sunday night, which will be more noticeable over the interior where dew points fall in the low 50s and upper 40s. PWAT (Precipitable Water) values go from around 1" during the day to at or below 0.5" by Monday morning. Lows Sunday night will be in the upper 40s to mid 50s over the interior with slightly higher temps into the low 60s possible over the coastal areas. Long Term - Monday Through Friday Key Messages: * Warm and dry to start the work week Monday and Tuesday * Trending much cooler Wednesday - Friday and then warming again into next weekend * Hurricane Humberto stays well offshore southern New England, but will likely bring high surf and dangerous rip currents to coastal areas during the middle of next week Monday and Tuesday High pressure builds over southern New England from west to east on Monday and Tuesday. Air mass will be warmer than normal to start the work week with 925 hPa temps near 16C. This will support afternoon high temperatures in the 70s both Monday and Tuesday. Expect sunny conditions with high pressure suppressing any significant cloud cover. Wednesday through Saturday Hurricane Humberto is expected to stay well offshore from southern New England during the middle of next week. However, we're likely to experience high surf and dangerous rip currents along the coastlines. A very large area of high pressure builds south from Canada on Wednesday with a much cooler air mass. 925 hPa temps plummet to near 5C on Wednesday. This will support cooler temperatures with afternoon highs in the 50s/60s and overnight lows in the upper 30s/low 40s (upper 40s/low 50s near the coast). Chilliest temperatures expected Thursday night. Generally a quiet weather weak with high pressure firmly in control through next weekend. Marine Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Some showers and lower visibilities possible tonight over the southern waters associated with a weak low pres. Otherwise, tranquil boating conditions through Sunday night with light winds and seas as weak high pressure will be over the waters. Outlook /Monday through Wednesday/... Monday: Winds less than 25 kt. Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Tuesday: Winds less than 25 kt. Local rough seas. Tuesday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Wednesday: Strong winds with gusts up to 35 kt. Rough seas up to 12 ft. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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