Tuesday, June27, 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 5:07AMSunset 8:21PM Tuesday June 27, 2017 1:23 PM EDT (17:23 UTC) Moonrise 9:11AMMoonset 11:11PM Illumination 14% Phase: Waxing Crescent; Moon at 4 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 Pm Edt Tue Jun 27 2017
.small craft advisory in effect until 8 pm edt this evening...
This afternoon..S winds around 10 kt with gusts up to 20 kt. Seas around 2 ft. A slight chance of showers.
Tonight..S winds 5 to 10 kt with gusts up to 20 kt, becoming W after midnight. Seas around 2 ft. A chance of showers.
Wed..W winds 5 to 10 kt. Gusts up to 25 kt in the afternoon. Seas 2 to 3 ft.
Wed night..W winds 5 to 10 kt. Gusts up to 20 kt in the evening. Seas 2 to 3 ft.
Thu..SW winds 5 to 10 kt, increasing to 15 to 20 kt with gusts up to 25 kt in the afternoon. Seas 2 to 3 ft.
Thu night..SW winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. A chance of showers.
Fri..SW winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft.
Fri night..SW winds around 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Sat..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft.
Sat night..SW winds around 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. A chance of showers and tstms. 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 Pm Edt Tue Jun 27 2017
Synopsis for massachusetts and rhode island coastal waters.. A cold front will result in scattered showers and tstms this afternoon and this evening. High pres builds south of the waters Wed. A warm front will lift north through new eng Thu with gusty sw winds developing late Thu into Fri and lasting through Sat. 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 271411
afdbox
area forecast discussion
national weather service taunton ma
1011 am edt Tue jun 27 2017

Synopsis
A strong jet stream will result in widespread afternoon showers
and thunderstorms across massachusetts, rhode island and
connecticut. A few of the storms may contain gusty winds and
small hail. A warming trend begins for the latter half of the
week with a return to summer heat and humidity Friday and
Saturday. A warm front may bring some showers and some
thunderstorms Thursday night, with more showers and
thunderstorms possible Friday through the weekend.

Near term until 6 pm this evening
A band of showers is moving northeast across ri and into se
mass, associated with a weak shortwave that is mostly visible in
the low level fields. Lightning detectors have shown a few
flashes and pulses with this line. These should be clear of
eastern mass around midday. A second zone of clouds may sweep
across our region midday early afternoon but should then move
off.

Expect periods of Sun much of the afternoon that will allow for
some solar heating. Temps at the top of the mixed layer will be
8-10c or its equivalent, so we expect MAX sfc temps 75-80.

We continue to watch the potential for strong thunderstorms this
afternoon evening. Morning soundings show an elevated dry
adiabatic lapse rate reaching 700 to 750 mb, 850 mb winds around
25 knots, and 500 mb winds 50-60 knots. Cold temperatures aloft
are giving us stability parameters favorable for convection.

Synoptically, a sharp upper trough is moving through the eastern
great lakes with a 120-knot upper jet moving around the base of
the trough and across new england. Our area will mainly be on
the left entrance region of the jet rather than one of the more
favored areas for upper venting. Wet bulb zero values this
morning ranged from 6700 feet at albany to 8800 feet at
brookhaven ny... Gray me and chatham were 7300-7400 feet. We
note SPC has areas west of i-95 in a marginal risk for severe
weather. Considering all of this, we will maintain some enhanced
wording for strong winds and small hail in the forecast.

Observed winds aloft in the projected mixed layer this morning
were 20-25 knots. Model guidance forecasts a range of 20-30
knots during the afternoon. Expect afternoon wind gusts of 20-25
knots, with some potential for gusts of 25-30 knots.

Short term 6 pm this evening through 6 pm Wednesday
Tonight...

cyclonic flow continues along with cold temps aloft and 40-45 kt of
deep layer shear. This will support leftover showers and isolated t-
storms to persist into the evening (especially over ri and eastern
ma) before taping off after midnight. Patchy fog possible given
leftover low level moisture from earlier storms
Wednesday...

mid level flow is still cyclonic however flow becomes more wnw which
results in column drying out along with surface dew pts falling into
the 40s. Cyclonic flow aloft combined with cold temps will yield
plenty of diurnal clouds and the risk of an isolated shower t-storm.

However given lack of moisture areal coverage should be limited to
isolated. Otherwise a fairly nice day by late june standards with a
mix of Sun and clouds, highs 75-80 along with comfortable humidity
with dew pts in the upper 40s and low 50s!

Long term Wednesday night through Monday
Highlights...

* thunderstorm chances increase Thursday night through Sunday
* heat and humidity return Friday, lasting into the weekend
pattern details...

00z guidance is in general agreement synoptically with some
difference in strength and timing for each wave late in the week.

Upper level trough axis will begin to push offshore on Wednesday
resulting in a quasi-zonal flow for the region beginning on
Thursday. The upper level pattern will become more amplified by the
weekend resulting in a broad trough over the great lakes with sub-
tropical ridge building over the weekend. Because of the ridging
over the east coast and the midwest trough, a cold front will be
come nearly stationary with very little eastward progress this
weekend. Ridging out west by Sunday will push towards the great
lakes by early next week, pushing the broad upper level trough over
the northeast.

Details...

Wednesday night into Thursday...

surface high pressure over the region Wednesday night will help keep
winds light and skies clear. Overnight lows will drop into the mid
to upper 50s with metro regions in the 60s.

Dry day to start on Thursday as high pressure will slide offshore.

The flow will turn more active with zonal flow aloft and a few weak
waves passing through. Impressive warming aloft as surface warm
front pushes through the region. This will push southern new england
in the warm sector resulting in increasingly warm and humid
temperatures.

A weak shortwave will move through the flow Thursday evening night.

With zonal pattern and both 850mb isotherms and winds becoming
parallel, appears that anything the fires across upstate ny will
ride through the flow moving into the area. In fact, guidance is
indicating a lingering MCS will move through the flow late in the
afternoon evening which could result in a few strong storms, esp
north of the pike. However, new convection could refire along its
southern edge given the strong low level jet and moisture over the
area. Trends will have to be watched.

Depending on the outcome of convection and cloud cover,
temperatures will remain in the low 80s. But it will feel warmer as
humidity will be on the rise. Showers and thunderstorms will
continue during the overnight hours keeping temps in the upper 60s.

Friday into Sunday...

unsettled weather pattern for this time period as southern new
england remains in the warm sector with heat and humidity. 850 mb
temps warming to 17-18c as well as southwesterly flow, will allow
for the summer heat to returns to the region. Appears that the
potential for 90 degrees is possible on Friday and Saturday as the
back door cold front continues to remain well north of the region.

Heat headlines may be needed as 70f dewpoints beginning to pool into
the area.

There remains a chance for showers and thunderstorms each day, but
difficult to place the exact timing and location of any strong
storms due to lack of surface boundary. Daytime heating will allow
for scattered showers and thunderstorms to develop on Friday.

Another shot for scattered showers and thunderstorms will develop on
Saturday, but western locations have the better shot thanks to
approaching pre-frontal trough. Lower confidence for eastern
locations as subtropical ridge will build in pushing a dry slot into
the area on Saturday. Cold front will approach on Sunday triggering
another round of showers and thunderstorms for southern new england.

Through this period, the potential for strong to severe weather
appears possible as the region remains in the warm sector. Plenty of
instability and moisture will continue to pool into the area with 0-
6 km shear values around 30 kts. Main risk will be strong gusty
winds as well as heavy downpours as pwats will be above 1.5 inches.

Still uncertainty with this portion of the forecast so stay tuned
for updates.

Monday...

cold front will slowly pass through the region on Monday, however is
appears that it may get hung up. Cyclonic flow aloft with southwest
flow in the mid-levels may trigger another round of showers for the
area. Low confidence on this portion of the forecast as there is
still a spread in the guidance.

Aviation 14z Tuesday through Saturday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

7 am update...

short term through Wednesday ... High confidence.

This afternoon...

vfr. Periods of MVFR CIGS vsbys possible in heavier showers and
embedded t-storms this afternoon evening. A few of the stronger
storms may contain gusty winds and small hail. Increasing
pressure gradient will result in gusty ssw winds even in the
absence of t-storms.

Tonight...

marginalVFR-MVFR in scattered showers and t-storms during the
evening, especially across eastern ma and ri. Activity should
diminish after midnight.

Wednesday...

vfr and drier weather. Although can t rule out an isolated
shower t-storm during the afternoon. Modest wnw winds.

Kbos terminal... High confidence in taf. Showers and t-storms
likely this afternoon. A few of the stronger storms may contain
small hail and gusty winds.

Kbdl terminal... High confidence in taf. Showers and t-storms
likely this afternoon. A few of the stronger storms may contain
small hail and gusty winds.

Outlook Wednesday night through Saturday ...

Thursday... High confidence. MainlyVFR. Afternoon evening showers
possible in the interior with showers t-storms possible all sne thu
night. Gusty SW winds to 25-30 kt developing, especially coastal
plain.

Friday into Saturday... Moderate confidence. Patchy early morning fog
each day. Otherwise mainlyVFR, except local ifr in possible strong
thunderstorms, mainly during the afternoon and evening hours
through the period.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Wednesday ... High confidence.

This afternoon...

ssw winds increase up to 25 kt along the ri and ma coastline.

Strongest winds near shore and occurring from noon to 6 pm. Sca
posted for all the near shore waters. Showers and t-storms develop
this afternoon. A few strong storms possible especially north shore
of boston.

Tonight...

showers and thunderstorms most numerous during the evening hours. A
few strong storms possible with gusty winds and small hail. Ssw
winds may yield patchy fog especially during the evening. Improving
after midnight.

Wednesday...

winds become wnw at modest speeds. This results in good vsby and
mainly dry weather, other than an isolated shower or t-storm.

Outlook Wednesday night through Saturday ...

Thursday... Moderate confidence. Small craft advisories will likely
be needed. Increasing SW winds with gusts to 25+ kt likely,
especially over nearshore waters. Building seas may reach 6 to 8 ft
over southern waters Thu night.

Friday into Saturday... Moderate confidence. SW winds continue,
mainly 20-25 kt with building seas. Scattered thunderstorms, some
with reduced visibilities and strong gusty winds for each day.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory until 8 pm edt this evening for
anz230>237-251.

Synopsis... Nocera dunten
near term... Wtb nocera dunten
short term... Nocera
long term... Dunten
aviation... Nocera dunten
marine... Nocera dunten


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44020 - NANTUCKET SOUND 14 mi94 min 67°F1 ft1016.7 hPa (+0.0)
44090 15 mi50 min 64°F1 ft
WAXM3 - Waquoit Bay Reserve, MA 18 mi99 min 2.9 73°F 1017 hPa64°F
NTKM3 - 8449130 - Nantucket Island, MA 25 mi66 min S 6 G 15 72°F 70°F1016.7 hPa
BZBM3 - 8447930 - Woods Hole, MA 26 mi66 min 68°F 68°F1016 hPa
BUZM3 - Buzzards Bay, MA 47 mi84 min SSE 8.9 G 8.9 65°F 1016.1 hPa (-0.9)

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 mi88 minSSW 1210.00 miMostly Cloudy73°F62°F69%1016.2 hPa
Chatham, Chatham Municipal Airport, MA12 mi32 minSSW 7 G 1610.00 miFair75°F64°F69%1016.7 hPa
Otis Air National Guard Base, MA17 mi29 minS 910.00 miMostly Cloudy72°F62°F73%1016.9 hPa

Wind History from HYA (wind in knots)
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Last 24hrSW14
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SW14SW12SW17S14SW14SW11SW10SW8SW7SW5SW7W4CalmCalmCalmS3SW7SW6S8S10S8SW12SW11
1 day agoS9S10SW15
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SW9SW9W8NW3CalmCalmCalmNW3CalmNW6NW86N75N7SW11
2 days agoSW9S7SW9W9
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W7W5W7W5W4W5W5W5W4CalmCalmCalmCalmW3NW7NW83N6S7SW9
G15

Tide / Current Tables for South Yarmouth, Bass River, Nantucket Sound, Massachusetts
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South Yarmouth
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Tue -- 03:52 AM EDT     3.61 feet High Tide
Tue -- 05:08 AM EDT     Sunrise
Tue -- 09:10 AM EDT     Moonrise
Tue -- 10:13 AM EDT     -0.58 feet Low Tide
Tue -- 04:33 PM EDT     3.19 feet High Tide
Tue -- 08:19 PM EDT     Sunset
Tue -- 10:30 PM EDT     -0.17 feet Low Tide
Tue -- 11:10 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
11.92.83.43.63.32.61.70.8-0.1-0.6-0.40.20.91.82.63.13.22.82.11.30.5-0.1-0.1

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Tue -- 12:09 AM EDT     -0.00 knots Slack
Tue -- 02:55 AM EDT     -2.02 knots Max Ebb
Tue -- 05:08 AM EDT     Sunrise
Tue -- 06:05 AM EDT     0.00 knots Slack
Tue -- 09:10 AM EDT     Moonrise
Tue -- 09:37 AM EDT     2.35 knots Max Flood
Tue -- 12:52 PM EDT     -0.00 knots Slack
Tue -- 03:34 PM EDT     -1.87 knots Max Ebb
Tue -- 06:44 PM EDT     0.00 knots Slack
Tue -- 08:18 PM EDT     Sunset
Tue -- 10:03 PM EDT     1.94 knots Max Flood
Tue -- 11:09 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.2-1-1.8-2-1.7-1.1-0.111.82.32.31.91-0.2-1.2-1.8-1.8-1.4-0.70.31.21.71.91.8

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

GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (13,3,4,5)
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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.