Montauk NY to Marthas Vineyard out 20 NM South of Block Island Marine Forecast
| This Afternoon...Se Winds 5 To 10 Kt, Becoming S 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. Wave Detail: S 2 Ft At 4 Seconds And Se 2 Ft At 8 Seconds. |
| Tonight...Sw Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Evening. Seas 2 To 3 Ft. Wave Detail: S 3 Ft At 4 Seconds And Se 2 Ft At 8 Seconds. |
| Tue...Sw Winds 5 To 10 Kt, Becoming Se In The Afternoon. Seas Around 2 Ft. Wave Detail: Sw 2 Ft At 4 Seconds And Se 2 Ft At 8 Seconds. |
| Tue Night...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 4 Seconds And Se 2 Ft At 8 Seconds. |
| Wed...Se Winds Around 10 Kt. Seas 2 To 4 Ft. Wave Detail: S 4 Ft At 8 Seconds And Se 2 Ft At 4 Seconds. |
| Wed Night...Se Winds 10 To 15 Kt. Seas 4 To 6 Ft. Wave Detail: S 5 Ft At 8 Seconds And E 1 Foot At 4 Seconds. A Chance Of Showers In The Evening. Showers Likely After Midnight. |
| Thu...Se Winds 5 To 10 Kt. Seas 4 To 6 Ft. Showers Likely. |
| Thu Night And Fri...S Winds 5 To 10 Kt. Seas 3 To 5 Ft. |
| Fri Night...Sw Winds 5 To 10 Kt. Seas 3 To 4 Ft. A Chance Of Showers. 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. |
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Area Forecast Discussion National Weather Service Boston/Norton MA 659am EDT Monday May 12 2025 Synopsis High pressure remains in control through Tuesday. The threat for scattered showers will increase for the second half of the week...but not expecting a washout with plenty of dry weather mixed in too. It will also turn a bit humid by late in the week. Near Term - Through Tonight Key Point: * Frost Advisory for interior Massachusetts this morning * Sunny dry conditions to start the week High pressure remains in control today with a mid-level ridge aloft limiting any substantial cloud cover for a second straight afternoon. Expecting a very pleasant spring day with high temps in the upper 60s to low 70s. The pressure gradient strengthens this afternoon in response short-wave energy traversing over northern Maine. This will support steady southwest winds this afternoon from 10-15 mph with some gusts from 20-25 mph expected. Overall a quiet start to the week. Short Term - Tuesday Tonight and Tomorrow Key Messages * Continued dry conditions tonight and tomorrow * Warm and sunny across the interior on Tuesday. Cooler along the east coast Tonight Little change in the overall synoptic pattern tonight. An upper-level ridge aloft continues to support quiet weather. Low-level west/southwest flow allows some moisture to trickle into southern New England which should support increasing cloudiness overnight. Nonetheless, only expecting FEW to SCT coverage at most. Should have fairly efficient cooling overnight which will allow most locations in southern New England to experience low temps in the upper 40s/low 50s by Tuesday morning. This is close to the climatological normal for mid-May. Tomorrow A surface Anti-cyclone builds east over The Gulf of Maine tomorrow. This will support east/southeasterly winds in southern New England for much of the day. While high pressure will continue to support more sun than clouds Tuesday afternoon, cooler onshore flow will have the east coastal areas feeling significantly cooler than the interior. High temps near the coast in the low to mid 60s. Inland, expect high temperatures to gradually increase from the upper 60s/low 70s along I-95 to the mid to upper 70s in the CT River Valley. Clouds increase from southwest to northeast tomorrow as well as a blocked cut-off low over The Mid-Atlantic States slowly traverses Northeast. Long Term - Tuesday Night Through Sunday Key Messages... * Scattered showers at times along with increasing humidity, but plenty of dry periods as well * Greatest risk for a few t-storms appears to be Fri and Sat * Seasonable temps Wed-Thu, then above normal Fri thru Sun Details... Tuesday night into Thursday... Upper level ridge axis is forecast to break down as Ohio Valley trough deamplifies and slowly approaches New England through Thu sending multiple shortwaves into the region. This combined with plume of PWATs (Precipitable Waters) around 1.5 inches will result in scattered showers at times, although given weak forcing and lack of instability not expecting a washout with dry periods. Initially, any showers Tuesday night into Wednesday should be mostly confined to central/western MA and northern CT with drier air likely holding on across eastern MA. Then shower risk expected to expand across rest of SNE Wednesday night and Thu. Near seasonable temps Wednesday and Thu, upper 60s and low 70s, with increasing humidity as dewpoints climb into the 60s Thu. Friday through Sunday Weak upper trough axis slides east of New England by Fri, then pattern will be governed by an upper low from western Lakes to SE Canada with multiple shortwaves moving into the region within the SW flow aloft. Pattern will remain unsettled but rather low confidence on timing of any shortwaves. There will a continued risk of showers and perhaps some convection/thunder threat Fri and Sat as instability is forecast to increase, but this will all depend on favorable timing of shortwaves with diurnal heating. Above normal temps expected with moderate humidity levels. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Tuesday...High Confidence. High pressure will support relatively calm conditions over the coastal waters between today and Tuesday. Southwest winds may flirt with SCY criteria over the east coastal waters this afternoon with 20-25 knot gusts possible, though generally expect sub-SCY criteria gusts. Seas should remain 4 feet or less over the outer marine zones today followed by 0-2 foot seas tonight into Tuesday. Outlook /Tuesday Night through Friday/... Tuesday Night: Winds less than 25 kt. Wednesday: Winds less than 25 kt. Slight chance of rain showers. Wednesday Night through Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Friday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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