Nantucket Sound Marine Forecast
| This Afternoon...Sw Winds 10 To 15 Kt. Seas Around 2 Ft. Wave Detail: Sw 1 Foot At 3 Seconds And Se 1 Foot At 9 Seconds. |
| Tonight...Sw Winds 10 To 15 Kt, Becoming Nw After Midnight. Seas Around 2 Ft. Wave Detail: Sw 2 Ft At 3 Seconds And Se 1 Foot At 10 Seconds. |
| Mon...Ne Winds 5 To 10 Kt, Becoming Se In The Afternoon. Seas Around 2 Ft. Wave Detail: Ne 1 Foot At 5 Seconds And Sw 1 Foot At 6 Seconds. |
| Mon Night...Sw Winds Around 5 Kt. Seas 2 To 3 Ft. Wave Detail: Se 2 Ft At 14 Seconds And S 1 Foot At 5 Seconds. |
| Tue...Nw Winds 5 To 10 Kt, Becoming Ne 10 To 15 Kt In The Afternoon. Seas 2 To 4 Ft. Wave Detail: E 3 Ft At 12 Seconds And W 1 Foot At 4 Seconds. |
| Tue Night...Ne Winds 10 To 15 Kt With Gusts Up To 20 Kt, Increasing To 20 To 25 Kt With Gusts Up To 30 Kt After Midnight. Seas 3 To 5 Ft. Wave Detail: Ne 4 Ft At 7 Seconds. |
| Wed Through Thu...Ne Winds 20 To 25 Kt With Gusts Up To 30 Kt. Seas 4 To 6 Ft. |
| Thu Night...Ne Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 3 To 5 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 222pm EDT Sunday September 28 2025 Synopsis Skies will continue to clear through the rest of today, giving way to clear skies tonight. Warm and dry weather continues tomorrow with reduced humidity. Quiet conditions Tuesday through next weekend as mid-level ridging and surface high pressure is in control across the northeast. Trending cooler this week and potential for morning frost in the high terrain by late week. A brief period of gusty northeast winds midweek due to a strengthening pressure gradient between high pressure and distant Hurricane Humberto. Additionally, large swell will lead to dangerous rip currents midweek as Hurricane Humberto moves out to sea. Near Term - Through Tonight Key Messages: * Cooler tonight with clear skies Skies continue to clear across southern New England today with clouds associated with the weak low passing to our south moving offshore. Skies should be clear across the region tonight with light winds as high pressure begins to creep in, allowing for good radiational cooling. Dew points fall as well as drier air begins to move in; lows may fall into the 40s over the interior with low to mid 50s elsewhere. Coastal areas may remain slightly warmer overnight with lows in the low 60s possible. Short Term - Monday Through Monday Night Key Messages: * Less humid Monday, though still warm High pressure continues to build over the region Monday, keeping skies clear and winds remaining light. Local sea breezes will develop in the late morning/early afternoon hours. 925 mb temperatures range between 16-19C, supporting high temperatures in the mid to upper 70s again with some spots reaching 80F. However, it will feel less humid as dew points fall into the 40s and 50s. Some high clouds may begin to move in during the afternoon hours associated with Tropical Storm Imelda, which will remain well to our south. A front moves through going into Tuesday which will shift winds more NE. Lows Monday night won't be as cool as tonight with continued high clouds limiting radiational cooling; temperatures are expected to fall into the mid 50s for most, with lows again in the low 60s possible in coastal areas. A few spots in the upper CT Valley may see a few temperatures in the upper 40s, but it won't be as widespread as tonight. Long Term - Tuesday Through Saturday Key Messages: * Prolonged dry period this week through the upcoming weekend. * Mild Tuesday, below normal temperatures Wednesday through Friday, with the potential for frost in higher terrain overnight Wednesday and Thursday. Return of seasonable temperatures next weekend. * Large swell from distant Hurricane Humberto to bring rough surf and dangerous rip currents to south facing beaches midweek. Very little has changed in the extended section of the forecast. A prolong period of quiet weather across much of the northeast due to an amplified mid-level ridge and surface high pressure. With very low PWATs, continue to anticipate mainly clear days and nigheights into the end of the coming week. No notable rainfall either. Temperature wise, Tuesday is the warmer of the days, as 925mb are +15C to +18C, supportive of temperatures in the middle to upper 70s, while the coast is a tad cooler due to the onshore wind. Wednesday through Friday, those values drop into the single digits and lower teens, with below normal temperatures in the upper 50s to middle 60s. Additionally, overnight temperatures of Wednesday and Thursday are expected to be quite cold in the 30s because of radiational cooling. Cannot rule out frost developing in the high elevations at or above 1,000 feet in the Berkshires and northern hills of Worcester County. The fall frost/freeze program for those areas ends on October 1st, thus no headlines would be issued, plan accordingly. Heading towards next weekend, temperatures aloft warm, will return to seasonable daytime and overnight temperatures. Midweek there are gusty northeast winds as result of a strengthening pressure gradient between the surface high pressure over New England and Hurricane Humberto. Minimal impacts to those on land, though it could result in marginal gale force gusts for our mariners. Additionally, swells for Hurricane Humberto will build off shore by Wednesday to 10 to 12 feet. While it's outside of peak beach season it's anticipated to bring strong/dangerous rip currents to south facing beaches. Marine Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Relatively tranquil boating conditions through Monday with weak high pressure over the waters bringing light winds and seas. Seas do begin to build late Monday night/early Tuesday morning with some areas in the outer waters reaching 5 ft. Outlook /Tuesday through Thursday/... Tuesday: Winds less than 25 kt. Areas of rough seas. Tuesday Night: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 10 ft. Wednesday through Wednesday Night: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft. Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 9 ft. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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