Vineyard Sound Marine Forecast
|Today...Sw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft.|
|Tonight...W Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming N 5 To 10 Kt After Midnight. Seas 2 To 4 Ft.|
|Sat...N Winds 5 To 10 Kt, Becoming W In The Afternoon. Seas 2 To 3 Ft.|
|Sat Night...Nw Winds Around 10 Kt. Seas Around 2 Ft.|
|Sun...W Winds Around 10 Kt. Seas Around 2 Ft.|
|Sun Night...W Winds Around 10 Kt, Becoming Nw After Midnight. Seas Around 2 Ft. A Chance Of Showers.|
|Mon...Ne Winds Around 10 Kt. Seas Around 2 Ft.|
|Mon Night And Tue...Ne Winds 5 To 10 Kt, Becoming E 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. A Chance Of Showers.|
|Tue Night...Ne Winds Around 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 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
711am EDT Fri Oct 22 2021
Low pressure in Quebec sweeps a cold front across southern New England Friday, bringing a few early showers to northwest CT/MA, followed by another warm and dry afternoon. Much cooler this weekend along with mainly dry weather. Unsettled weather may return for much next week, but confidence in this portion of the forecast period is low. It will be cooler than normal much next week.
Near Term - Until 6pm This Evening
Showers have ended for us this morning leaving a mix of clouds and sun but dry conditions for the day. The cold front is currently sitting to our west in eastern NY and will continue.nue to march east through the day bringing a wind shift to the northwest. No significant changes needed at this time.
Previous Discussion... Today... Short wave trough moving across northern NY state and eventually into northern New England early this morning. Scattered showers with isolated thunder along and ahead of this feature, which will impact northwest CT/MA early this morning. Low level SW jet yielding strong thermal and moisture advection across SNE, with temps and dew pts rising thru the 50s and into the 60s. Already in the mid 60s along the south coast of MA/RI, already warmer than the normal daytime high this time of year! Hence a mild start to the day. These high dew pts are resulting in patchy fog across portions of the CT river valley. Low level jet and strong warming will continue.nue to yield gusty SSW winds along the south coast of MA/RI this morning, possibly lingering into the afternoon.
As the short wave moves east of our longitude, its cold front sweeps across the area later this morning and afternoon, with a wind shift to the west. This will result in drier and less humid (dew pts falling thru the 50s and eventually into the 40s) post frontal airmass to overspread the region. However, across the Cape and Islands, this is delayed as mid level flow remains SW there, with front lingering just offshore. This may result in showers clipping Nantucket this afternoon, as a frontal wave tries to develop along the boundary.
Otherwise, a mix of sun and clouds expected elsewhere and another warmer than normal day with 925 mb temps around +13C and 850 mb +6C to +8C at 18z, supporting highs around 70! Normal high this time of year is in the lower 60s, upper 50s hilly terrain.
Short Term - 6pm This Evening Through 6pm Saturday
Tonight... Height falls will drive cold front farther offshore, with post frontal airmass finally overspreading Nantucket and the outer Cape. Hence, cooler and dry weather prevails. Lows will be seasonably cool, with mins in the 40s, upper 30s possible northwest MA and 50- 55 across Cape Cod and Islands, given delay of post frontal airmass.
Saturday... Trailing short wave energy rotates through the long wave trough and across SNE. Hence, lots of clouds with cyclonic flow aloft. Although, column struggles to saturate with model soundings indicating lots of low level dry air in response to post frontal airmass. Thus, any precipitation may be limited to a few brief spot showers or sprinkles. Much of the day should be dry along with some breaks of sunshine from time to time. Seasonably cool with temps aloft about 0C at 850 mb, but downslope west winds will support highs 60- 65 across RI and eastern MA, upper 50s elsewhere. Modest west winds 10-20 mph.
Long Term - Saturday Night Through Thursday
Highlights... * Seasonable temperatures with highs in the 50s & 60s
* Dry for the weekend then a series of storm systems brings unsettled weather for the first half of the week, then again late week
Details... After a comfortable and dry weekend a series of shortwave troughs lined up from coast to coast will move through the northeast bringing wet weather to the region, first around Monday/Tuesday then again Thursday/Friday.
Sunday the persistent mid level low over southeast Canada finally begins its gradual exit to the east placing southern New England under a dry airmass and zonal flow. Cross sections show moisture at 850 mb but very dry air above it, so we should see a good deal of sun with a few clouds mixed in. Temperatures won't change much from Saturday, topping out in the upper 50s and low 60s. By late in the day the atmosphere begins to saturate from the top down bringing steadily thickening clouds ahead of incoming wet weather.
Sunday night flow becomes more meridional as the first in a series of shortwaves approaches from the Great Lakes. Winds back to the southwest pulling in more warmth and moisture (PWATs (Precipitable Waters) back over 1 inch). As the surface low approaches the warm front lifts north Sunday night bringing widespread rain showers. Confidence in this portion of the forecast is lower owing to track and timing discrepancies amongst the guidance, though the ECMWF (European Centre for Medium-Range Weather Forecasts) has come more in line with the GFS's wetter solution in the last 24 hours; this brings the low closer to southern New England, so POPs have been increased for the Monday and Tuesday period. EPS ensemble % chance of rainfall during this period has also increased significantly giving confidence to the wetter solution. Temperatures during this time remain steady; highs in the upper 50s and low 60s. Lows will be seasonable, if a bit mild, especially along the south coast thanks to the higher dewpoints.
We get a break as mid level ridging builds in briefly around mid week (exact timing is less certain), but another strong system is loading up. A surface low generated in the lee of the Rockies Mon/Tuesday moves toward the Great Lakes by Thursday with a deep 500 mb trough aloft. This will bring the chance for rain and gusty winds for the second half of the week.
Forecaster Confidence Levels.
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Today...SSW winds 15-20 kt with few gusts to 25 kt especially RI and southern MA waters. Mainly dry weather, but showers south of Nantucket this afternoon.
Tonight...winds shift to the west 5-15 kt. Mainly dry weather and good vsby.
Saturday...west winds 10-20 kt, mainly dry weather and good vsby.
Outlook /Saturday Night through Tuesday/... Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.
Monday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.
Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers.
Tuesday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory until 11am EDT this morning for ANZ232>235-237. Small Craft Advisory until 8am EDT this morning for ANZ236. Small Craft Advisory until 2pm EDT this afternoon for ANZ250. Small Craft Advisory until 8pm EDT this evening for ANZ254>256.