
Nantucket Sound Marine Forecast
Today...W Winds 25 To 30 Kt With Gusts Up To 45 Kt. Seas 4 To 6 Ft. Wave Detail: W 5 Ft At 5 Seconds And S 1 Foot At 10 Seconds. Freezing Spray. |
Tonight...W Winds 20 To 25 Kt With Gusts Up To 40 Kt. Seas 3 To 5 Ft. Wave Detail: W 4 Ft At 5 Seconds. Freezing Spray. |
Wed...W Winds 15 To 20 Kt With Gusts Up To 30 Kt, Diminishing To 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 3 To 5 Ft, Subsiding To 2 To 3 Ft In The Afternoon. Wave Detail: W 4 Ft At 5 Seconds And Ne 1 Foot At 5 Seconds, Becoming W 3 Ft At 4 Seconds And Ne 1 Foot At 7 Seconds. Freezing Spray. |
Wed Night...W Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming Nw 5 To 10 Kt After Midnight. Seas Around 2 Ft In The Evening, Then 1 Foot Or Less. Wave Detail: W 2 Ft At 4 Seconds, Becoming Nw 1 Foot At 4 Seconds. |
Thu...N Winds 5 To 10 Kt, Increasing To 10 To 15 Kt In The Afternoon. Seas 1 Foot Or Less. Wave Detail: Nw 1 Foot At 4 Seconds And Ne 1 Foot At 8 Seconds. A Chance Of Snow. |
Thu Night...Nw Winds 10 To 15 Kt, Increasing To 15 To 20 Kt After Midnight. Seas 2 To 3 Ft. Wave Detail: Nw 3 Ft At 4 Seconds And E 1 Foot At 7 Seconds. A Chance Of Snow. A Chance Of Light Freezing Spray After Midnight. Vsby 1 Nm Or Less In The Evening. |
Fri...Nw Winds 15 To 20 Kt. Seas 2 To 3 Ft. A Chance Of Light Freezing Spray. |
Fri Night Through Sat Night...W 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. |
Area Forecast Discussion National Weather Service Boston/Norton MA 338am EST Tuesday Feb 18 2025 Synopsis Very cold temperatures along with strong winds continue today. It still will be cold on Wednesday but with much less wind. A coastal storm may brush the far southeast New England coast with some accumulating snow Thursday into Thursday night. Trending milder and drier Friday into the upcoming weekend. Near Term - Until 6pm This Evening Key Messages... * Bitter Cold Wind Chills of 0 to 15 below into mid-morning * Windy & very cold today...High Mainly lower-middle 20s * A brief spot snow shower possible in western MA/CT Details... Strong sub 970 mb low pressure system across the Canadian Maritimes will continue to result in unseasonably cold and windy weather across southern New England today. The windy conditions will result in Wind Chills of 0 to 15 below zero into mid morning with the coldest readings in the highest terrain. A Cold Weather Advisory remains in effect for the high terrain of the Berks and Worcester Hills. Despite partly sunny skies...850T near -20C will result in high temps close to 15 degrees below normal for this time of year. Highs should mainly be in the lower to middle 20s today with some upper teens across the highest terrain. Wind Chills this afternoon will only be in the single digits and lower teens. The strong low pressure system in the Maritimes will bring a WNW low level jet on the order of 45-55 knots. The very cold temps aloft will result in steep low level lapse rates and excellent mixing of the low level jet. While winds will not be quite as strong as yesterday...it will still be quite windy. Diurnal heating will allow westerly wind gusts of 40 to 55 mph across much of the region with perhaps a few brief gusts near 60 mph in the high terrain. We will continue the Wind Advisory for most locations with the High Wind Warning for the high terrain of the Berks and Worcester Hills. Lastly...strong/very cold westerly flow may allow a long lake effect streamer to survive for a time into portions of western MA/CT today. If this occurs...will be very localized but is a possibility. Short Term - 6pm This Evening Through 6pm Wednesday Key Messages... * Blustery and very cold tonight with lows between 5 and 15 above * Wind Chills Dropping to between 0 to 10 below overnight * Plenty of sunshine Wed...but with much less wind & highs 25-30 Details... Tonight... Low pressure will lift well north of the Canadian Maritimes tonight. This weakens the pressure gradient enough to allow winds to diminish a bit...but it still will remain breezy overnight. The atmosphere will still not be able to decouple though which should keep temps from completely bottoming out. Nonetheless...lows to drop to between 5 and 10 above across the high terrain to between 10 and 15 elsewhere. Enough wind will result in Wind chills dropping to between 0 and 10 below zero overnight...but should remain above the thresholds for any additional Cold Weather Advisories. Wednesday... A shortwave dropping southeast into the northern plains will result in heigheights rising a bit across southern New England Wed. While temps will still be unseasonably cold...we do expect afternoon highs to recover a bit into the 25 to 30 degree range along with plenty of sunshine and a lot less wind. Still a bit of a breeze...but much less than what we will see today. Long Term - Wednesday Night Through Monday Key Messages: * Very cold Wednesday night, followed by below normal temperatures through the end of the workweek, then temperatures moderate into this coming weekend. * Snow is possible for the south coast, Cape Cod, and the islands from Thursday into Friday, with the passage of a coastal system. * Less active period of weather Friday night into this upcoming weekend, lesser confidence into early next week. Wednesday Night: Expecting a fairly cold night with temperatures dipping into the single digits across the region with "warm" areas along the immediate coast, Cape Cod, and the islands, it is here the lows dip into the teens and low 20s. Not much wind to knock down temperatures any further, though there may be enough wind in the Berkshire and northern Worcester Hills to make it feel between 0F and -10F, shy of the criteria for cold weather advisories. Thursday and Thursday Night: We continue to monitor the potential for a coastal low pressure system to develop off the southeast coast of the CONUS and then travel NNE, passing off shore during the day through Thursday night. Should have enough cold air locked in place to limit PType to snow, thanks to strong high pressure to our north/west. Highs range from the upper 20s to low 30s. At current, the 00z set of guidance continues to indicate a close brush, with the greatest chance for accumulation of snow along the immediate south coast of Rhode Island and Massachusetts, which includes, the islands and Cape Cod. The outlier is the NAM12km, this would bring the system closer to shore and more Quantitative Precipitation Forecast. Worth a mention, but not a likely outcome at this point. FWIW, across Cape Cod and the islands the DESI probability of 3" or more of snow during a 24 hour period are between 40 to 50 percent. Further inland, areas along the I-95 corridor between Boston and Providence, there are low probabilities, less than 30 percent for 1" or greater of snow during a 24 hour period. As the low lifts away from the region, draws in colder air and temperatures fall back into the teens, along with gusty northwest winds. Friday through Sunday: Surface low pressure system exits early Friday morning, outside of a lingering snow showers across eastern Massachusetts, there is a drying trend through the weekend. Mid- level ridging develops along with surface high pressure, this helps to moderate temperatures into the upper 30s. Will watch a trailing trough and shortwave late on Sunday, while there is little moisture associated, can not rule out a passing rain/snow showers. Early next week there are signs of continued moderation in temperatures with highs reaching the low 40s. As for the next impactful weather, there remains too much spread in the guidance at this time, leaned on the NBM for POPs, which has chance rain/snow showers possibly late Monday into Tuesday. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. High Confidence... * Gale Warnings continue through tonight * Freezing Spray Advisories continue into mid morning Wed Today into Wednesday...High Confidence. Strong low pressure lifting north of the Canadian Maritimes will continue to result in strong cold advection with W wind gusts of 35 to 45 knots into tonight. While the stronger of these winds will be today...still expect Gale force gusts to persist into tonight. The pressure gradient should drop enough on Wed...so that small craft headlines will be able to replace the current Gale Warnings. In addition...given the very cold airmass moving across the waters expect areas of moderate freezing spray into mid morning Wed. Freezing Spray Advisories remain in effect. Outlook /Wednesday Night through Saturday/... Wednesday Night: Winds less than 25 kt. Thursday: Winds less than 25 kt. Chance of snow. Thursday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of snow, chance of freezing spray. Local visibility 1 nm or less. Friday through Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of freezing spray. Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. NOAA Boston MA Office: Watches - Warnings - Advisories CT...Wind Advisory until 5pm EST this afternoon for CTZ002>004. MA...Wind Advisory until 5pm EST this afternoon for MAZ003-005>007- 010>024. High Wind Warning until 5pm EST this afternoon for MAZ002-004- 008-009-026. Cold Weather Advisory until 10am EST this morning for MAZ002- 004-008-009-026. RI...Wind Advisory until 5pm EST this afternoon for RIZ001>008. Marine Gale Warning until 10pm EST this evening for ANZ230-236. Freezing Spray Advisory until 10am EST Wednesday for ANZ230>237-250-251-254>256. Gale Warning until 5am EST Wednesday for ANZ231-250-251-254. Gale Warning until 1am EST Wednesday for ANZ232>235-237. Gale Warning until 4am EST Wednesday for ANZ255-256. |