Marine Weather Net

Coastal Waters out 25 NM South of Marthas Vineyard and Nantucket Marine Forecast


THIS AFTERNOON

W
WINDS
15 - 20
KNOTS

TONIGHT

NW
WINDS
10 - 15
KNOTS

THU

NW
WINDS
5 - 10
KNOTS

THU NIGHT

SW
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ255 Forecast Issued: 1016 AM EDT Wed Sep 23 2020

SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE TONIGHT
This Afternoon...W Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 5 To 8 Ft.
Tonight...Nw Winds 10 To 15 Kt. Gusts Up To 25 Kt In The Evening. Seas 3 To 5 Ft.
Thu...Nw Winds 5 To 10 Kt, Becoming W In The Afternoon. Seas 2 To 3 Ft.
Thu Night...Sw Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Fri And Fri Night...Sw Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Sat...S Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Sat Night And Sun...S Winds 10 To 15 Kt. Gusts Up To 20 Kt. Seas 2 To 4 Ft. A Chance Of Showers.
Sun Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 5 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
956am EDT Wednesday September 23 2020

Synopsis
Post-tropical Cyclone Teddy will quickly move past the Canadian Maritimes today. A high pressure over the Mid Atlantic and central Appalachians today will slowly move offshore this week. Gusty winds will diminish later today. Warmer but continued dry weather will likely last into Saturday. A pattern change toward showery weather arrives later Sunday into next week, with much needed rainfall arriving. Although there will also be many hours of dry weather during this time.

Near Term - Until 6pm This Evening
10 AM

No significant changes were made with this update. Morning temperatures are quickly warming up after dropping to the 40s and low 50s. Now, temperatures are quickly rising and are expected to reach the middle and upper 70s under mostly sunny skies.

Previous Discussion... With the departure of Teddy through the Canadian Maritimes, a high pressure across the Mid Atlantic states will maintain a modest pressure gradient across southern New England. Plenty f sunshine today will result in decent mixing, with gusty winds continuing, although not nearly as strong as yesterday.

With less cloud cover and more of an offshore wind today, temperatures will recover more quickly than yesterday, especially with some downsloping. above normal temperatures expected today

See sections further down for items about the Fire Weather and Coastal Flooding concerns.

Short Term - 6pm This Evening Through 6pm Thursday
Mainly high pressure in control through Thursday. Dry weather continues with less wind. Winds turn west tonight, then southwest Thursday. Above normal temperatures continue.

Long Term - Thursday Night Through Tuesday
Highlights... * Warmer than average through the weekend

* Dry pattern continues into Saturday. A pattern chance comes late weekend into next week bringing periodic rain chances.

Details... Thursday night through Saturday... The quiet and dry weather pattern holds steady through at least the end of the week and likely into the first half of the weekend. At the mid levels flow remains generally zonal with a moisture starved shortwave or two moving through the flow, lacking enough moisture to bring with it any real chance of rain. Maritime high pressure building north and west will direct mild SW flow into southern New England along with marginally warmer dewpoints. This with the westerly flow aloft will keep temperatures above average through the weekend, in the upper 70s. Low temperatures will be mild, especially Saturday night into Sunday owing to the increasing dewpoints (into the low 60s). The ECMWF (European Centre for Medium-Range Weather Forecasts) continues to depict a quicker return of rain chances (as early as Saturday morning) as shortwave energy passes close enough to impact us, while the GFS shunts it farther to the south. For now, sticking with a dry forecast in line with the GFS ensemble guidance.

Sunday through Tuesday... A decidedly different (read: wetter) pattern is on tap for much of next week as a large upper level trough settles over the eastern U.S. EPS and GEFS 500 mb height anomalies are in good agreement that we'll see a robust ridge set up over the west coast with troughing further east. The first, shallower trough digs in around late Monday/Tuesday pulling moisture/rainfall up the east coast into our area, followed by a deeper trough toward mid week which would again mean wet weather. Plenty of uncertainty remains on details but overall next week is looking unsettled with potential for our next shot of colder air not until late in the week.

Marine
Post-tropical cyclone Teddy will move through the Maritimes today. Winds will continue to diminish today. Based on latest observations, downgraded the remaining Gale Warnings to Small Craft Advisories early this morning.

Otherwise, Small Craft Advisories continue for a while longer. Thinking seas will take longer to subside, so extended into this evening across most waters. Winds and seas subside tonight into Thursday.

Outlook /Thursday Night through Sunday/... Thursday Night through Saturday: Winds less than 25 kt.

Saturday Night: Winds less than 25 kt. Slight chance of rain showers.
Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.
Fire Weather
Relative humidity values and winds will not quite reach the thresholds for another Red Flag Warning. After coordinating with state fire agency partners, will issue a Special Weather Statement to highlight the elevated fire danger due to low relative humidity and gusty winds.

Tides / Coastal Flooding
Lingering swell and wave energy from Post-tropical Cyclone Teddy will continue to impact the southern New England coast with rough surf today. High Surf Advisory continues for the southern New England coast, with the greatest concern along the east coast of MA.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...High Surf Advisory until 8pm EDT this evening for MAZ007-019- 020-022>024. RI...High Surf Advisory until 8pm EDT this evening for RIZ006>008.
MARINE...
Small Craft Advisory until noon EDT today for ANZ231-232-235- 237. Small Craft Advisory until 11pm EDT this evening for ANZ250. Small Craft Advisory until 8pm EDT this evening for ANZ251- 256. Small Craft Advisory until 2am EDT Thursday for ANZ254-255.