Vineyard Sound Marine Forecast
| Today...S Winds Around 5 Kt, Increasing To 5 To 10 Kt This Afternoon. Seas 1 Foot Or Less. Wave Detail: S 1 Foot At 2 Seconds And Se 1 Foot At 9 Seconds. |
| Tonight...S Winds 5 To 10 Kt. Seas 1 Foot Or Less. Wave Detail: Se 1 Foot At 3 Seconds And Se 1 Foot At 9 Seconds. Patchy Fog. |
| Fri...Sw Winds 5 To 10 Kt. Seas 1 Foot Or Less. Wave Detail: Sw 1 Foot At 3 Seconds And Se 1 Foot At 3 Seconds. |
| Fri Night...Sw Winds 5 To 10 Kt. Seas 1 Foot Or Less. Wave Detail: Sw 1 Foot At 4 Seconds And Se 1 Foot At 8 Seconds. |
| Sat And Sat Night...Ne Winds 5 To 10 Kt. Seas 1 Foot Or Less. Wave Detail: E 1 Foot At 2 Seconds And Sw 1 Foot At 4 Seconds. |
| Sun Through Mon Night...Se Winds 5 To 10 Kt. Seas 1 Foot Or Less. Wave Detail: Ne 1 Foot At 2 Seconds And S 1 Foot At 7 Seconds. 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 243am EDT Thu September 12 2024 Synopsis High pressure will continue to dominate our weather through at least the middle of next week. Although there is a low chance at a shower or thundershower in northeast Massachusetts on Friday, largely dry weather and above average temperatures will prevail across Southern New England for the foreseeable future. Near Term - Through Today 230am Update: High pressure remains established in the waters just east of Provincetown early this morning bringing another night of strong overnight radiational cooling. Currently MVY is the coldest spot in the mid 40s, as is typical on strong radiational cooling nights. Temps were generally coolest (upper 40s to low 50s) in southeast New England, with lower to mid 50s more common elsewhere. Although fog has again developed in the CT River Valley, there's been some fog at times at Nantucket and at New Bedford but it's been more intermittent at these latter locations. We could see additional development thru sunrise but should be pretty temporary. So for today, high pressure over the waters will lurch southeastward but still be nearby Southern New England and will maintain dry weather again today. There could be a little more cloud cover than the past couple days, (and by "a little more", more of a partly to mostly sunny look vs the bluebird skies the last few days) especially to the north as a low-amplitude mid- level shortwave trough seen on water vapor satellite imagery near southwest Quebec moves across northern New England. A surface trough developing in association with this mid-level wave looks to develop in the lee of the White Mtns, and that should support a hybrid synoptic onshore flow/seabreeze over eastern and northeast MA today. While it should be pretty mild today in many areas, ended up incorporating some of the Canadian-GEM Regional guidance to show the relatively cooler onshore flow over the North Shore/Essex County area. Highs today should reach well into the 70s to the lower 80s for most, with cooler mid 70s along the south coast and the North Shore area from the seabreeze/onshore flow. .SHORT TERM /TONIGHT THROUGH 6pm FRIDAY/... 230am Update: Tonight: Another night of strong radiational cooling again anticipated for tonight, with surface ridge of high pressure still in control. Dewpoint temps are about 3 to 5 degrees higher than last night, and radiation fog across a wider portion of CT-RI- Southeast MA seems more likely tonight than the last few nights. NAM-based guidance hits this potential the hardest but most available visby guidance sources show visbys in the half to 5 SM range south of the Mass Pike. Ended up showing fog developing after midnight for these areas, but as this moisture is really shallow and becomes trapped under a strengthening temperature inversion, it is less certain if fog develops when it might dissipate. Lows mainly in the 50s, given milder daytime highs and milder 925-850 mb temps. Friday: Although the general theme of warming temps and generally dry weather for most of Southern New England will continue into Friday, there are a couple things that we'll need to monitor with subsequent guidance. The first is when any nighttime fog/stratus over the southern roughly half of the forecast area dissipates. As mentioned above, fog becomes trapped underneath warming temps aloft; although I opted for dissipating fog by sunrise with how dry it has been, BUFKIT profiles indicate if fog develops it may not fully dissipate until mid to late morning. Thereafter, full sun should bring highs to above normal levels, in the upper 70s to the mid 80s, with mid 70s for the Cape and Islands. The other aspect of the forecast that will need to be monitored is if we can Probability of Precipitation a shower or thunderstorm or two over the Merrimack Valley/North Shore area (or, move off the White Mtns in NH and move SE to these areas) after 3pm til sundown. Most guidance shows a digging shortwave trough over northeast Quebec into the Gulf of Maine, rotating around an anomalously strong (590 dm) upper level ridge over the U.P of MI. Associated with this feature is a plume of pretty steep lapse rates between 850-500 mb which are around 7-7.5 C/km, but also is pretty capped, midlevels are dry and there isn't much of a lifting source other the mesoscale wind effects such as seabreezes. Despite this, high res guidance sources (NSSL WRF, Canadian GEM Regional, WRF FV3, NAM-3km) as well as the global GFS (Global Forecast System) show some pop-up convection in northeast MA. Thinking drier weather prevails, but opted for a 15% Probability of Precipitation for thunderstorms in northeast MA Friday afternoon; its possible if anything develops it could make it near the Boston area and possibly bring the first measurable (non-trace) rain since August 20th. Long Term - Friday Night Through Wednesday Highlights: * Moderate confidence in areas of low stratus forming late Friday night into Saturday morning across coastal areas, which may lead to patchy drizzle. * Otherwise, very quiet weather continues this weekend into next week with no appreciable rainfall during the forecast period. * Temperatures are comfortable with slightly above normal highs and seasonably cool overnight lows. Very quiet weather continues across the northeast for this weekend through potentially Wednesday or Thursday of next week. Why? The northeast is under the influence of a mid-level ridge and surface high-pressure. While no rain is in the forecast, low-level moisture may become trapped below the subsidence inversion overnight Friday into Saturday morning and possibly lead to low stratus and drizzle for areas along the coast in eastern Massachusetts and Rhode Island. Will say, have moderate confidence in this occurring, the tough part are the exact areas where this may develop. Perhaps there will be greater confidence as the near term/high resolution begin to reach this portion of the forecast. If the low stratus develops, it may take as late as noon time to fully lift due to the declining sun angle. Otherwise, dry weather prevails, with the best chance for any rain late Wednesday to Thursday. That said, 00z guidance does hint the surface high to the north builds back south and suppresses any tropical moisture to the south - which is supported by the global ensembles. Probs of 0.01" in 24 hours are less than 10% right through Thursday. Only time will tell. Nevertheless, quiet stretch of weather continues with mild afternoon temperatures and cooler at night. As mentioned before, the NBM does not do well in regards to minimum temperatures on nigheights when there is effective radiational cooling and blended in cooler guidance to lower these temperatures. Normal afternoon highs for mid-September are middle to upper 70s, as for normal night time lows, those are mid-50s to 60F. Expect highs in the low to mid-80s and overnight lows in the upper 40s to mid-50s. Tropics continue to 'heat up' which comes as no surprise since this is climatologically the peak for tropical systems in the Atlantic basin. Tropical Depression Seven located west of Cape Verde is forecast to a Tropical Storm some point today. Closer to home, NHC monitors an area of development off of the southeast coast of the United States and has a 30% chance of development over the next 7 days. Fortunately for our region, strong high pressure and the mid- level steering should keep any tropical impacts away from southern New England. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Friday: High confidence. High pressure will continue remains over the waters for the next several days. Light winds with daily sea breezes are expected, and seas 2 ft or less expected. Fog may develop tonight over the southern waters and near Cape Cod Bay, which could reduce visbys to under 1 mile. There is also a low (<15%) chance at a thunderstorm over the northeast waters late Friday afternoon, although dry weather should prevail. Outlook /Friday Night through Monday/... Friday Night: Winds less than 25 kt. Saturday: Winds less than 25 kt. Local visibility 1 to 3 nm. Saturday Night through Monday: Winds less than 25 kt. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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