Tuesday, December1, 2020
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Marine Weather and Tides
South Yarmouth, MA

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 6:47AMSunset 4:12PM Tuesday December 1, 2020 4:13 AM EST (09:13 UTC) Moonrise 6:11PMMoonset 8:55AM Illumination 98% Phase: Waning Gibbous; Moon at 16 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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ANZ232 Nantucket Sound- 116 Am Est Tue Dec 1 2020
.gale warning in effect until 7 am est this morning...
Rest of tonight..S winds 25 to 30 kt with gusts up to 40 kt. Seas 4 to 7 ft. Patchy fog. Showers likely with a slight chance of tstms. Vsby 1 to 3 nm.
Tue..S winds 10 to 15 kt, becoming sw 15 to 20 kt in the afternoon. Gusts up to 30 kt. Seas 3 to 5 ft. Patchy fog. A chance of showers. Vsby 1 to 3 nm.
Tue night..SW winds 15 to 20 kt with gusts up to 30 kt. Seas 3 to 5 ft. A chance of showers.
Wed..SW winds 15 to 20 kt with gusts up to 25 kt. Seas 3 to 5 ft.
Wed night..W winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 6 ft.
Thu and Thu night..W winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft.
Fri..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft.
Fri night..W winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. A chance of showers.
Sat..NW winds around 10 kt. Seas 2 to 3 ft.
Sat night..NW winds around 10 kt. Seas 2 to 3 ft. A chance of showers. Winds and seas higher in and near tstms. 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.
ANZ200 116 Am Est Tue Dec 1 2020
Synopsis for massachusetts and rhode island coastal waters.. A strong area of low pressure moves north through new york state tonight, bringing southerly gales and high seas. The low moves north through canada Tuesday and Wednesday. High pressure then builds into the mid atlantic Thursday. A coastal weather system may bring showers Friday night and Saturday. For additional information on possible hazardous weather for the week ahead, please visit www.weather.gov/boston/ehwo.


7 Day Forecast for Marine Location Near South Yarmouth, MA
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location: 41.64, -70.2     debug


Area Discussion for - Boston, MA
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FXUS61 KBOX 010634 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 134 AM EST Tue Dec 1 2020

SYNOPSIS. A strong low pressure will pass well to our west this evening and tonight, bringing a period of strong to damaging wind gusts along with heavy rain and localized street flooding. It remains mild on Tuesday with a few left over showers possible, but not a washout. More seasonable temperatures will return by Wednesday with mainly dry weather persisting through Thursday. There is the potential for a coastal storm by this weekend or early next week but whether that comes to fruition remains uncertain.

NEAR TERM /UNTIL 6 AM THIS MORNING/.

120 AM Update .

A narrow band of rain oriented N-S tapped into an area of 50 J/kg of 0-3km MLCAPE and gave a corridor roughly along West Kingston RI-Providence RI-Norwood MA around an inch of rain in an hour. Nothing severe except for possible localized minor street flooding. This band of rain has weakened as it lifts north into the Boston area as it exits the area of marginal instability. That is pretty much the last major slug of rain associated with this system that has brought a bout of strong to damaging winds as well as drought-alleviating rainfall to our area. There is an area of convection well south of Block Island that may impact the Cape and Islands, especially Nantucket towards daybreak. That is associated with a secondary jet max that will surge north in the early to mid morning hours. Most areas west of the Cape Cod canal will be mostly dry, but a narrow corridor along the Cape and Islands could receive up to half an inch of rain in the morning hours.

PREVIOUS DISCUSSION .

1015 PM Update .

As the 994 mb sfc low continues to lift north from the NY Tug Hill Plateau into S Quebec, the heavier rain has also lifted north into New Hampshire. The nose of the 70-80 kt 850 mb LLJ is currently over Eastern MA and the Cape and Islands. We are watching an area of convection just south of Eastern Long Island and Block Island, and that could give Eastern MA another round of heavier showers and even a rumble or two of thunder. This could lead to localized poor drainage flooding, given that up to 2 inches of rain have already fallen but no significant issues expected. Headlines wise, have taken down Wind Advisories over Central MA/Northern CT and converted High Wind Warnings to Wind Advisories over Eastern MA and RI. The rest of the night will be very mild though with temperatures staying around 60F with the cold front still well to the west.

SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/. Tuesday into Tuesday night oddly enough our shot of cold air aloft comes from the southwest, as the low lifts north into Canada and wraps sub 0C 850 mb air around it into Southern New England. Expect one more day of warmer than average temps on Tuesday, however, thanks to continued low level warm southerly flow. Given the warm advection at the sfc and cold advection aloft, could see scattered instability showers during the day on Tuesday. This also means winds remain gusty as the jet overhead is much weaker, but more apt to mix down. Winds will gust 25 to 30 mph. Temperatures finally make a return to closer to normal by Tuesday night with lows falling into the 30s.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/. Highlights .

* Dry with near seasonable temps for the rest of the week.

* "Potential" for a coastal low late next weekend.

Overview .

Closed low slowly lifts north into Canada through end of week, keeping temperatures near more seasonable levels for early December. We may see some rain/snow showers across interior Tue/Wed as series of short waves rotate through region, but overall dry weather is expected.

Large scale pattern should feature rising heights over Greenland and trough centered over Great Lakes. As ridge builds downstream, models try to close off another upper low somewhere over Northeast or off coast. While this favors some sort of coastal low development, there us obviously a lot of uncertainty in a Day 6-7 forecast, since a lot of moving parts need to come together. Something we'll monitor over next few days and expect to see usual wobbles in deterministic solutions. A peek at ensemble member low positions shows not only a lot of spread in track but in timing. Airmass in place ahead of system doesn't seem to be unusually cold so this may very well favor rain as opposed to snow, but all options are on table depending on where upper low closes off (if it ends up doing that at all). Keep in mind it's just as possible that low could end up passing far offshore or not even develop at all!

AVIATION /07Z TUESDAY THROUGH SATURDAY/. Forecaster Confidence Levels .

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

00z Update .

Tonight . Moderate confidence.

MVFR to IFR conditions for all sites with showers, locally heavy and embedded t-storms. Strong SSE wind gusts 40-50 kt is expected to continue in the coastal plain along and SE of I-95 corridor for the next several hours, lingering over Cape/Islands through about midnight. 25-40 kt gusts across western MA and northern CT. LLWS expected too. Bulk of heavy rain should exit by midnight, but locally heavy showers and embedded t-storms may linger over Cape/Islands overnight.

Tuesday . Moderate confidence.

Mainly MVFR to localized IFR to start, trending MVFR to low VFR by the afternoon. South winds turning SSW by the afternoon with gusts up to 25 kt possible.

Tuesday Night: Mainly VFR, with localized MVFR possible. Breezy. Slight chance SHRA.

KBOS TAF . Moderate confidence in the TAF.

KBDL TAF . Moderate confidence in the TAF.

Outlook /Wednesday Night through Saturday/ .

Wednesday: Mainly VFR, with local MVFR possible. Breezy.

Wednesday Night through Friday: VFR. Breezy.

Friday Night: VFR. Breezy. Slight chance SHRA.

Saturday: VFR. Slight chance SHRA.

MARINE. * Existing Storm Warnings have been downgraded to Gale Warnings.

Gale Warnings for all waters as strong low level jet slowly moves north from our waters. Southerly gusts up to 45 kt possible with building seas to 12-16 ft over outer waters. Heavy downpours and embedded thunderstorms will also reduce vsbys at times. Winds comes down 25 to 30 kts on Tuesday with seas 10 to 13 ft. By Tuesday night winds and seas come down slowly.

Outlook /Wednesday Night through Saturday/ .

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 11 ft.

Wednesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 10 ft.

Thursday: Low risk for Small Craft Advisory winds with gusts up to 20 kt. Areas of rough seas.

Thursday Night: Winds less than 25 kt. Seas up to 5 ft.

Friday: Low risk for Small Craft Advisory winds with gusts up to 20 kt. Seas up to 5 ft. Slight chance of rain showers.

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers.

Saturday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

TIDES/COASTAL FLOODING. Strong southerly winds late this afternoon and evening along the south coast of MA/RI. Astronomical tides are fortunately low, and it will likely take a 3+ ft surge to produce minor coastal flooding along the south coast. Surge forecast around 2 ft but could get up to 3 ft in Narragansett Bay in a worst case scenario due to channeling effect. This would result in very minor flooding along portions of Narragansett Bay. However, timing of highest surge may lag the high tide by a few hours. We will continue to monitor this potential for the this evening high tide cycle, but do not expect significant impacts.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . Wind Advisory until 7 AM EST this morning for MAZ007-016>024. RI . Wind Advisory until 7 AM EST this morning for RIZ002>008. MARINE . Gale Warning until 7 AM EST this morning for ANZ230>237-251. Gale Warning until 1 PM EST this afternoon for ANZ250-254>256.

SYNOPSIS . Frank/BW NEAR TERM . BW/Chai SHORT TERM . BW LONG TERM . JWD AVIATION . BW/JWD MARINE . BW/JWD TIDES/COASTAL FLOODING .


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44020 - NANTUCKET SOUND 11 mi44 min SSE 25 G 35 51°F
CHTM3 14 mi56 min S 25 G 33 59°F 51°F1003.2 hPa
44090 15 mi47 min 51°F4 ft
WAXM3 - Waquoit Bay Reserve, MA 18 mi89 min ESE 6 60°F 1002 hPa60°F
NTKM3 - 8449130 - Nantucket Island, MA 25 mi56 min SSE 9.9 G 21 60°F 50°F1002.7 hPa
BZBM3 - 8447930 - Woods Hole, MA 26 mi56 min 62°F 52°F1001.4 hPa
44018 - SE Cape Cod 30NM East of Nantucket, MA 39 mi44 min SSE 21 G 37 58°F 51°F1002.1 hPa56°F
BUZM3 - Buzzards Bay, MA 47 mi74 min SSE 25 G 28 1000.6 hPa (+0.5)

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hyannis, Barnstable Municipal-Boardman Airport, MA5 mi18 minSSE 14 G 234.00 miLight Rain Fog/Mist59°F59°F100%1001.6 hPa
Chatham, Chatham Municipal Airport, MA12 mi22 minSSE 14 G 322.50 miLight Rain Fog/Mist59°F57°F93%1002.8 hPa
Otis Air National Guard Base, MA17 mi19 minSSE 16 G 253.00 miFog/Mist61°F60°F100%1002.4 hPa

Link to 5 minute data for KHYA

Wind History from HYA (wind in knots)
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1 day agoW3W4W6W4W6W8CalmS6SW10SW10SW10SW10SW8CalmCalmCalmCalmCalmCalmCalmCalmNE3CalmCalm
2 days agoCalmCalmCalmCalmN5N3Calm554W9W5W4CalmNW7NW5NW5NW5NW5W6W4W3W5W4

Tide / Current Tables for South Yarmouth, Bass River, Nantucket Sound, Massachusetts (2)
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South Yarmouth
Click for Map
Tue -- 01:20 AM EST     2.64 feet High Tide
Tue -- 06:48 AM EST     Sunrise
Tue -- 07:10 AM EST     0.33 feet Low Tide
Tue -- 07:55 AM EST     Moonset
Tue -- 01:22 PM EST     2.97 feet High Tide
Tue -- 04:11 PM EST     Sunset
Tue -- 05:10 PM EST     Moonrise
Tue -- 07:43 PM EST     0.02 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.32.62.62.21.71.20.60.30.50.91.52.12.62.92.92.521.30.60.100.30.81.4

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Tue -- 12:27 AM EST     -1.64 knots Max Ebb
Tue -- 03:32 AM EST     0.00 knots Slack
Tue -- 06:47 AM EST     Sunrise
Tue -- 06:50 AM EST     1.79 knots Max Flood
Tue -- 07:53 AM EST     Moonset
Tue -- 09:53 AM EST     -0.00 knots Slack
Tue -- 12:35 PM EST     -1.77 knots Max Ebb
Tue -- 03:43 PM EST     0.00 knots Slack
Tue -- 04:10 PM EST     Sunset
Tue -- 05:10 PM EST     Moonrise
Tue -- 07:10 PM EST     2.07 knots Max Flood
Tue -- 10:28 PM EST     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-1.6-1.6-1.2-0.50.41.21.71.81.50.9-0.1-1.1-1.7-1.7-1.4-0.70.31.21.82.11.91.40.5-0.6

Weather Map
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GEOS Local Image of    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Ground Weather Radar Station Boston, MA
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.