Coastal Waters out 25 NM South of Marthas Vineyard and Nantucket Marine Forecast
| Overnight...E Winds Around 10 Kt. Seas Around 2 Ft. Wave Detail: E 2 Ft At 9 Seconds And Ne 1 Foot At 2 Seconds. Patchy Fog. Vsby 1 Nm Or Less. |
| Sun...E Winds Around 10 Kt. Seas Around 2 Ft. Wave Detail: Ne 2 Ft At 3 Seconds And S 1 Foot At 6 Seconds. Patchy Fog In The Morning With Vsby 1 To 3 Nm. |
| Sun Night...E Winds 5 To 10 Kt. Seas 2 To 3 Ft. Wave Detail: Se 2 Ft At 7 Seconds And Se 2 Ft At 8 Seconds. |
| Mon...E Winds 5 To 10 Kt. Seas 2 To 3 Ft. Wave Detail: Se 2 Ft At 8 Seconds And E 2 Ft At 8 Seconds. |
| Mon Night Through Tue Night...Se Winds 5 To 10 Kt. Seas 2 To 3 Ft. Wave Detail: S 3 Ft At 8 Seconds And Se 3 Ft At 8 Seconds. |
| Wed Through Thu Night...Ne Winds 10 To 15 Kt. Seas 3 To 5 Ft. Wave Detail: Se 5 Ft At 8 Seconds And Se 2 Ft At 11 Seconds. 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. |
| Area Forecast Discussion National Weather Service Boston/Norton MA 1038pm EDT Sat September 14 2024 Synopsis Dry weather with above normal temperatures will continue for the weekend and into next week. Chances for rain comes mid to late next week, but uncertainty remains high. Near Term - Until 6am Sunday Morning Update: 10:30PM In general our forecast remains on track, did modify the sky cover as the marine stratus that moved on shore earlier this evening did dissipate in many locations, leaving behind a few to scattered group of lower clouds. Heading into the overnight hours this will remain our biggest challenge, which will have the more significant impacts for aviation; cloud base forecast. Temperature continue to slowly fall, following the trend from earlier this evening, at this time did not deviate from original forecast. Will be interesting as cloud cover isn't as expansive although if you look at the nighttime microphysics can see some stratus trying to develop along the Sea Coast of NH which has started to move south into NE MA. 745 PM Ocean stratus already working its way inland across eastern MA. Have significantly increased sky cover in latest update as latest NAMNest handling current situation quite well. Should see the stratus/fog overspread much of central/eastern MA and RI. Only unsure in how widespread the fog will be as haven't yet seen visibilities falling as of this update. Temps looked to be on track, but may need to increase them in future updates especially where stratus is quite widespread. Previous discussion... High pressure remains in control tonight as it builds south from northern New Eng. This will provide dry weather, but will have to monitor potential stratus and fog moving westward from the ocean. There are mixed signals in the guidance regarding the extent of stratus and fog so confidence is not high. Soundings do show very shallow moisture near the ground below the inversion so we are continuing increased cloud cover for areas of stratus overnight. Lows will range through the 50s with light winds. Short Term - 6am Sunday Morning Through Sunday Night Sunday... Any stratus and fog should burn off by mid morning as shallow moisture mixes out, leading to another day with lots of sunshine and warm temps as deep later ridge builds across New Eng. However, low level temps are a bit cooler across eastern New England as the surface high pressure builds to the east with persistent E flow. Highs will range through the 70s (coolest eastern MA coast) with lower 80s in the CT valley. It will also be a bit drier with dewpoints in the 50s. Sunday night... High pressure will bring mostly clear skies and light to calm winds leading to good radiational cooling. Lows will bottom out in the lower 50s for much of the region, with some upper 40s in the colder spots in eastern MA. Long Term - Monday Through Saturday Highlights * Dry and quiet weather to start the week with a few more mild days along with cool nights.am fog possible. * Turning unsettled mid to perhaps late in the week. Considerable uncertainty to the exact track of a system off the coast of the Carolinas. This brings the next shot for showers and more seasonable temperatures. Monday through Tuesday... A highly amplified ridge axis will initially (Monday AM) be in place from the Great Lakes region through New England into the central Atlantic, while there is a disturbance just off the Carolinas coastline. The ridge gradually builds offshore beginning late on Mon, but especially on Tue. The disturbance off the Carolinas coast will rotate inland into the Mid Atlantic/OH Valley into Tue. High pressure builds overhead on Monday before shifting offshore Monday night into Tue, but still nudges into the region. Dry and quiet weather anticipated through this timeframe with high pressure continuing to dominate the weather. Big question for both AMs will be the stratus/fog development. Given the E to SE/S increase in moisture this should really amplify the risk, especially on Tue. Think on Monday would most likely be radiation fog. High temps both days ranging from the 70s to mid 80s. Wednesday through Friday... Ridge axis continues to shift further offshore, with a broad trough/upper low overhead from the disturbance previously mentioned. Overall not certain how things will evolve with this feature with how north it traverses and if/when it dives further south. At this point have fairly heavily leaned toward the latest NBM guidance given the uncertainty. This is likely the next opportunity for more widespread rain showers. The big question is how far north/northeast does the upper low lift and the moisture plume associated with it. There are considerable differences amongst deterministic guidance at this point with the GFS/GEM bringing the 1.5 to 2+ inch PWATs overhead Wednesday into Thu, whereas the ECWMF keeps this moisture locked more to the south of our region. Warm cloud layer depths would be between 3-4.5 km, which would bring more warm rain processes, though there appears to be little instability to work with at this point. Both the NAEFS/EPS guidance showing a tight PWAT (Precipitable Water) gradient as well per the Situational Awareness Table, but the elevated 1.5-2 STD anomalies generally remain to our south. Can also see differences between ensemble systems where the GEFS generally keeps any heavier precipitation to the south as opposed to the GEPS/EPS. There are nil probs of 24 hr Quantitative Precipitation Forecast at or above 1" for the GEFS guidance through this timeframe for southern New England, whereas the GEPS/EPS have low (10-30 percent) probs. Something to keep an eye on in the coming days. Given the prolonged easterly flow during this timeframe will see our temps generally near to cooler than seasonable. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Sunday night: High Confidence. Tranquil boating conditions with winds, mostly E-SE, and seas below SCA (Small Craft Advisory) levels. Vsbys may be reduced in developing fog overnight. Outlook /Monday through Thursday/... Monday through Tuesday: Winds less than 25 kt. Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Wednesday Night through Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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