Thursday, November23, 2017 L-36.com


Marine Weather and Tides
South Yarmouth, MA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 6:39AMSunset 4:15PM Thursday November 23, 2017 10:56 PM EST (03:56 UTC) Moonrise 11:39AMMoonset 9:38PM Illumination 29% Phase: Waxing Crescent; Moon at 5 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- 929 Pm Est Thu Nov 23 2017
Overnight..W winds 5 to 10 kt. Seas 2 to 3 ft.
Fri..W winds 5 to 10 kt. Seas around 2 ft.
Fri night..SW winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft.
Sat..SW winds 5 to 10 kt with gusts up to 20 kt. Seas around 2 ft.
Sat night..W winds 5 to 10 kt, increasing to 10 to 15 kt with gusts up to 20 kt after midnight. Seas 2 to 3 ft. A chance of showers.
Sun..NW winds 10 to 15 kt, increasing to 15 to 20 kt in the afternoon. Gusts up to 25 kt. Seas 2 to 4 ft.
Sun night..NW winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft.
Mon..W winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft.
Mon night..NW winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft.
Tue..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Tue night..SW winds around 15 kt with gusts up to 25 kt. Seas 2 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.
ANZ200 929 Pm Est Thu Nov 23 2017
Synopsis for massachusetts and rhode island coastal waters.. High pres will build over the waters tonight and tomorrow. Unsettled weather returns on Sat as low pres moves E across srn quebec. Gusty nw winds follow on Sun ahead of high pres building towards the E coast. High pres to follow into early next week. For information on possible hazardous weather beyond the 24-36 hour forecast period, please visit www.weather.gov/boston and follow the current hazards link above the map on the left.

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 240241
afdbox
area forecast discussion
national weather service taunton ma
941 pm est Thu nov 23 2017

Synopsis
Quiet weather through Friday with dry and cool conditions.

Milder air returns Saturday ahead of a cold front. That cold
front swings through southern new england late Saturday and
early Saturday night. Blustery and cooler weather follows
Sunday. Conditions trend toward dry and milder again Tuesday
and Wednesday, and then cool again Thursday behind another cold
front.

Near term until 6 am Friday morning
940 pm update...

satellite data continues to indicate some high clouds moving
across new england. Thus far, these clouds have not prevented
temperatures from falling quickly this evening, especially
under an area of clouds across ri and eastern ma. Clouds just
moving into western ma appears to be slightly lower in height
and thicker. These clouds should impact temperatures as they
pass overhead.

No precipitation upstream. So the main adjustment was to tweak
temperatures based on observed and expected trends. 24 01z lamp
guidance looked to have the best handle, so used that as the
basis for this forecast update.

Previous discussion...

scattered to broken mid to high cloud decks filtering across
the region could put a blanket on thanksgiving festivities
keeping temperatures slightly warmer. Positively- tilted open
wave and attendant weak vortmax sweeps through the region early
across the n-stream, a flattening feature, as energy sweeps up
from the se. Mid to high clouds sweeping through however into a
region of drier air and subsidence, can already see some erosion
in the latest goes-16 satellite. Perhaps some blanket
insolation impacts so did not go with coldest of MOS guidance.

Towards the lower end with forecast light winds, looking at lows
down into the 20s, warmer along the shore.

Short term 6 am Friday morning through Friday night
Nice day on tap. With daytime mixing under mostly clear conditions,
the mid to high clouds eroding out, winds turn S sw. Warm air
advection proceeding aloft, mixing is limited to around h95.

Looking at highs in the upper 40s to low 50s, edging towards the
warmer end of guidance.

With both N and S stream energy still neighboring our region,
dry subsidence inversion prevails. As we go towards evening, the
cap well in place, mixing up to just beneath, and the boundary
layer cools, likely to see the moisture pooling condense and
subsequently could see the development of low-level stratus
evening and overnight especially over SE new england. Lows down
into the 30s most places, but warmer SE around the low 40s. With
daytime mixing, dewpoints should be low enough that 5 to 10
degree dewpoint depressions prevail. So despite the overnight
n W looking favorable for radiational cooling, do not expect fog
to be an issue.

Long term Saturday through Thursday
Big picture...

longwave scale shows a broad trough along the usa east coast and
west atlantic, a second trough over the eastern pacific, and a ridge
over the the plains. The eastern trough lingers much of the week
while the overall flow trends zonal.

Model consensus shows northern stream shortwaves crossing new
england Saturday night Sunday and again Wednesday. The models also
show a southern stream low crossing the southeast usa Thursday
trailing the Wednesday northern shortwave.

The mass and thermal fields are similar through Mon night Tuesday,
but then diverge by showing different timing of the northern and
southern stream features. The feature that becomes the northern and
southern shortwaves next week is currently over the aleutians and
diving south over the pacific ocean... And it reaches the usa west
coast by Monday. Expect changeable solutions regarding this feature
until that time.

Contour heights and thermal fields are a little above normal
Saturday, trend colder than normal Sunday-Monday, then trend above
normal midweek next.

Details...

Saturday...

low pressure passes well offshore. General agreement that the
southern shortwave remains unphased with the northern trough.

Meanwhile, the northern trough doesn't dig much until the offshore
low is moving past us. So expect the precipitation to remain over
the ocean.

Cold front approaches during the afternoon and passes through
southern new england during the evening early night. Moisture is
limited below 700 mb much of the time, but runs deep briefly during
the evening. Precipitable water values climb to about 0.85 inches
during the evening, which is above normal for late november. We will
show low-end chance pops during the late afternoon evening.

Temps in the mixed layer are forecast at 850-mb equiv of -1c to -4c,
so expect MAX sfc temps in the 50s. Behind the front, the airmass
cools and dries slowly, so min temps at night should only fall to
the 30s and low 40s.

Sunday-Monday...

upper trough digs over new england Sunday. Cold pool will be in
place with 500-mb temps at -28c working to destabilize the airmass.

Moisture lingers below 800 mb during this time. Expect quite a few
clouds to pop during the day, but moisture is too limited for
showers. Mixed layer temps will support MAX sfc temps in the upper
30s and 40s.

The trough moves off on Monday and high pressure builds surface and
aloft. Expect a fair day with MAX sfc temps in the 40s.

Tuesday through Thursday...

another cold front crosses us midweek, driven by the northern stream
shortwave. As noted above, there are timing uncertainties among the
models, so we used a blend. This favors a Wednesday passage at this
time, but the uncertainties noted above may change that exact
timing. This will need to be monitored. The blend of model data
supports slight chance pops Wednesday with the cold FROPA and mainly
dry Thursday.

Aviation 03z Friday through Tuesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday night ... High confidence.

Vfr. W NW winds diminish overnight, turning S SW into Friday.

Bkn-ovc MVFR CIGS possible for SE new england into Friday night.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf.

Outlook Saturday through Tuesday ...

Saturday through Saturday night: mainlyVFR, with local MVFR
possible. Breezy. Slight chance shra.

Sunday:VFR. Windy with local gusts to 30 kt.

Sunday night through Tuesday:VFR. Breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday night ...

small craft advisories adjusted to account for seas. Should
conclude toward daybreak Friday morning. High pressure mainly
in control. Good boating weather as swells diminish.

Outlook Saturday through Tuesday ...

Saturday: winds less than 25 kt. Areas of seas approaching
5 ft.

Saturday night: winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.

Sunday: moderate risk for small craft advisory winds with gusts
up to 25 kt. Areas of seas approaching 5 ft.

Sunday night: winds less than 25 kt. Local rough seas.

Monday: low risk for small craft advisory winds with gusts up
to 25 kt. Local rough seas.

Monday night: winds less than 25 kt. Seas locally approaching
5 ft.

Tuesday: winds less than 25 kt. Areas of seas approaching 5 ft.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory for hazardous seas until 7 am est Friday
for anz254>256.

Synopsis... Wtb sipprell
near term... Wtb belk sipprell
short term... Sipprell
long term... Wtb
aviation... Wtb sipprell
marine... Wtb belk sipprell


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44020 - NANTUCKET SOUND 14 mi66 min WNW 9.7 G 12 42°F 48°F1 ft1015.3 hPa (+0.0)30°F
44090 15 mi26 min 50°F1 ft
WAXM3 - Waquoit Bay Reserve, MA 18 mi71 min 1 31°F 1015 hPa26°F
NTKM3 - 8449130 - Nantucket Island, MA 25 mi38 min W 2.9 G 6 40°F 47°F1015.8 hPa
BZBM3 - 8447930 - Woods Hole, MA 26 mi38 min 41°F 50°F1015.7 hPa
BUZM3 - Buzzards Bay, MA 47 mi56 min WNW 9.9 G 12 41°F 1016.3 hPa (+0.7)

Wind History for Nantucket Island, MA
(wind in knots)    EDIT      (on/off)   Help
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NW15
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hyannis, Barnstable Municipal-Boardman Airport, MA5 mi60 minN 010.00 miFair28°F24°F85%1015 hPa
Chatham, Chatham Municipal Airport, MA12 mi64 minW 310.00 miFair32°F24°F73%1015.5 hPa
Otis Air National Guard Base, MA17 mi61 minN 010.00 miFair28°F24°F86%1015.6 hPa

Wind History from HYA (wind in knots)
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Last 24hrNW13
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NW4W5W6NW7NW7NW6N8
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NW6NW6SW4SW7W8W5W4CalmCalmCalmCalmCalmCalm
1 day agoSW13
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S6S3S3SE4CalmS3S4S4S10
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W7N3NE4NE7NE6N6N3NW15
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2 days agoW8W14
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W9W5CalmCalmCalmSW10SW13SW9SW13
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S12SW12SW13SW16
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Tide / Current Tables for South Yarmouth, Bass River, Nantucket Sound, Massachusetts
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South Yarmouth
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Thu -- 03:53 AM EST     2.65 feet High Tide
Thu -- 06:39 AM EST     Sunrise
Thu -- 09:47 AM EST     0.39 feet Low Tide
Thu -- 10:38 AM EST     Moonrise
Thu -- 03:58 PM EST     2.89 feet High Tide
Thu -- 04:14 PM EST     Sunset
Thu -- 08:37 PM EST     Moonset
Thu -- 10:20 PM EST     0.12 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.91.52.12.52.72.521.510.50.40.71.21.82.32.72.92.72.21.710.50.10.2

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Thu -- 12:26 AM EST     -0.00 knots Slack
Thu -- 03:01 AM EST     -1.61 knots Max Ebb
Thu -- 06:12 AM EST     0.00 knots Slack
Thu -- 06:38 AM EST     Sunrise
Thu -- 09:26 AM EST     1.66 knots Max Flood
Thu -- 10:37 AM EST     Moonrise
Thu -- 12:34 PM EST     -0.00 knots Slack
Thu -- 03:12 PM EST     -1.67 knots Max Ebb
Thu -- 04:14 PM EST     Sunset
Thu -- 06:21 PM EST     0.00 knots Slack
Thu -- 08:37 PM EST     Moonset
Thu -- 09:49 PM EST     1.97 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.5-0.6-1.4-1.6-1.4-0.9-0.20.71.31.61.61.30.6-0.4-1.3-1.7-1.5-1.1-0.30.61.41.921.7

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (22,6,7,8)
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Ground Weather Radar Station Boston, MA
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Disclaimer:
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 numerious 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.