Thursday, March23, 2017 L-36.com


Marine Weather and Tides
South Yarmouth, MA

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:35AMSunset 6:58PM Thursday March 23, 2017 6:07 PM EDT (22:07 UTC) Moonrise 3:59AMMoonset 2:15PM Illumination 14% Phase: Waning Crescent; Moon at 26 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- 405 Pm Edt Thu Mar 23 2017
.small craft advisory in effect from Friday morning through late Friday night...
Tonight..NW winds 5 to 10 kt with gusts up to 20 kt...becoming W after midnight. Seas 2 to 3 ft.
Fri..SW winds 10 to 15 kt with gusts up to 30 kt. Seas 2 to 3 ft. A chance of rain.
Fri night..SW winds 10 to 15 kt with gusts up to 30 kt. Seas 2 to 4 ft. A chance of rain.
Sat..W winds 5 to 10 kt with gusts up to 20 kt... Becoming N in the afternoon. Seas 2 to 3 ft. A chance of rain.
Sat night..NE winds 5 to 10 kt...increasing to 10 to 15 kt after midnight. Gusts up to 20 kt. Seas around 2 ft. A chance of rain.
Sun..E winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft. A chance of rain.
Sun night..E winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. A chance of rain.
Mon..SE winds around 15 kt with gusts up to 25 kt. Seas 2 to 3 ft. Rain likely.
Mon night..NE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Rain likely.
Tue..NE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft.
Tue night..E winds around 10 kt with gusts up to 20 kt. Seas 2 to 4 ft. A chance of rain. 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 405 Pm Edt Thu Mar 23 2017
Synopsis for massachusetts and rhode island coastal waters.. High pres will move E of the waters Fri. A cold front will pass across the waters from the N on Sat...stay S of the waters on Sunday...the return as a warm front Mon. Low pres will cross the southern waters on Mon. Another are of low pres will cross the waters late Wed and move east of the waters on Thu. 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 231950
afdbox
area forecast discussion
national weather service taunton ma
350 pm edt Thu mar 23 2017

Synopsis
High pressure along the eastern usa coastline will move offshore
later tonight bring windy and milder conditions Friday.

Unsettled weather this weekend, with potential for a variety of
precipitation types.

Near term /until 6 am Friday morning/
Tonight...

high pressure will move off the mid atlantic coast. Expect
winds to become light and variable for a time as the ridgeline
moves overhead. A light south-southwest flow is possible late at
night as the ridge moves offshore.

Some high thin clouds moving over ontario will reach our area
early tonight. But thicker mid level clouds should hold off
until after midnight, allowing a period of light winds and fair
skies. So we expect radiational cooling the first part of the
night, shutting down later tonight as the clouds thicken. Dew
points start in the single numbers below zero and climb into the
teens by late night. We favored going a couple of degrees below
guidance with a range from the high single numbers in the
interior to near 20 along the coastline. Most areas would be in
the teens.

Short term /6 am Friday morning through Friday night/
Friday...

high pressure offshore will provide a flow of milder air. Winds
above the surface will climb to 30-40 knots by midday. That will
provide a flow of moist air with precipitable water values
reaching near an inch by Friday evening. Weak overrunning
created by this southwest flow will create clouds and light
precipitation starting in the morning. Temperatures will be cold
enough at the start for snow, but quickly moderate to rain by
afternoon if not sooner. The transition period may feature some
sleet.

The best chance for this precipitation will be in northern and
western mass. But frozen amounts will be light, with any
snow/sleet accumulation less than an inch.

Have high confidence in the overall trend, but only moderate
confidence in the precipitation types.

The strong southwest low level jet will also provide the
momentum for gusty winds, especially during the afternoon when
mixing is greatest. It still appears the greatest risk for gusts
over 30 mph to be along the boston-providence corridor and
southeast from there.

Max temperatures should make a 5-10 degree rise from today, but
values in the mixed layer Friday are supportive of highs in the
low to mid 40s so still below march normals.

Friday night...

clouds and a southwest flow of milder air will keep
temperatures from falling too much, and most of that should be
in the evening. Temps may rise a little overnight. We maintained
a chance of showers in far northern mass, but low values for
pops.

Long term /Saturday through Thursday/
Highlights...

* above average temps on Saturday with a few showers
* low confidence next sun-tues with unsettled weather possible at
times with some rain, ice and/or snow possible
* moderating temperatures by mid-next week
pattern overview...

00z models and ensembles are in agreement with the general synoptic
pattern for the long term. Uncertainty increases in the extended do
to mesoscale and thermal issues. Split flow aloft with closed low
over the southern plains and northern stream across southern canada.

The initial closed 500 mb will slowly move into the midwest over the
weekend. This low deamplifies into an open wave as it comes towards
the northeast early next week. Due to the confluent flow aloft, high
pressure persists over northern new england keeping surface
temperatures cool, resulting in mixed precip at times for the
weekend into early next week. The models have slowed again compared
to 22.00z guidance but are similar in timing. Another open wave
moves through the flow during the mid-week with the GFS more
amplified versus the progressive ec. Still a lot of uncertainty with
this timeframe.

Details...

Saturday... Moderate confidence.

850 mb temps Saturday morning will be close to 8c but drop
through the day as cold front begins to slide southward. Surface
temperatures will reach into the mid 50s, cannot rule out a few
60s if the mid- level ridge continues to build and slows the
timing of the front. Along the front, there could be a few rain
showers but not expecting widespread rainfall as heights
continue to build overhead.

Saturday night into Sunday... Moderate confidence.

Cold front will pass through southern new england dropping surface
temps below freezing. The timing of the cold air drainage from the
high pressure over northern new england will determine if precip
type remains all rain, or if snow and/or mixed precip develops. Mid-
level ridging could keep a warm layer around 850 mb which would aid
in the mixed p-type. This is something to watch in the coming days.

For Sunday, cold front will stall somewhere between southern new
england and the mid-atlantic as high pressure begins to move
southeast into the gulf of maine. Depending on how close the high
pressure gets, we could see a dry Sunday or a few showers. One thing
to keep an eye on is the easterly flow, which could keep the low
level moist resulting in drizzle. Still a lot of uncertainty with
this time frame.

Sunday night Monday into Wednesday... Low confidence.

While guidance is in agreement synoptically, still a lot of details
to work out for this portion of the forecast. Biggest uncertainties
will be the placement of the upper level low and how quickly it will
diffuse early next week.

Right now, the stalled front looks to return back north as a warm
front late Sunday into Monday, as surface low pressure moves into
the great lakes. Although warmer air aloft should move easily back
into the region, the low-level cold air may be a little tougher to
dislodge this time due to the nearby surface high pressure. Believe
this is the timeframe where we will see the heaviest precip due to
passage of the open wave. Another open wave right behind this one
will push through the flow developing around shot at precip on
Tuesday.

As mentioned before, still a lot of uncertainty as to the thermal
profiles. Continue to believe that there could be a period where the
region could see a mixed bag of precip with the highest confidence
Sunday night into Monday and another shot Monday night into Tuesday
due to surface temps falling overnight. Still a lot of uncertainty
with this timeframe as thermal profiles will change. Will continue
the mentioning of snow, sleet, ice and/or rain for the forecast
until thermals come better in alignment.

Lastly, weak ridging in between waves may allow for temps to
moderate back to seasonable during the day light hours Monday
and Tuesday.

Aviation /19z Thursday 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/...

tonight...VFR. High confidence
nw winds with gusts 20-25 kt this evening, becoming light and
variable for a time tonight. Winds become light south to
southwest late tonight.

Friday and Friday night...VFR with some MVFR mainly north of
the mass pike. Moderate confidence.

Increasing and lowering clouds during the morning. Areas of MVFR
cigs/vsbys in light snow or sleet, with best chance along or
north of boston and the mass pike. All frozen precip should
change to rain during late morning/early afternoon. Southwest
winds will gust 25-30 knots during the day, highest along the
coast and in higher terrain. Winds diminish Friday night.

Kbos taf... High confidence in taf.

Kbdl taf... High confidence in taf.

Outlook /Saturday through Tuesday/...

Saturday into Sunday... Moderate confidence. A period or two of
showers along with some MVFR CIGS are possible at times as cold
front sags southward over the region. Could see a period of mixed
precip overnight.

Sunday into Monday... Low confidence. Showery weather to start with
possible MVFR cigs. Precip chances increase overnight into Monday
which could result in mixed precip.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Friday night/...

tonight... High confidence.

Diminishing NW winds becoming light SW overnight. Seas near 5
feet on the outer waters east of massachusetts early, but
subsiding during the night. Seas elsewhere less than 5 feet. A
small craft advisory lingers on those eastern outer waters for a
few more hours until seas subside.

Friday... Moderate confidence.

High pressure moves well offshore, bringing southwest winds to
the waters. Potential for wind gusts 25-30 knots. This will
build seas with 5 foot heights on many of the waters by the
afternoon. Patchy light rain may bring brief visibility
restrictions. Small craft advisories are being issued for most
waters. An advisory for the eastern outer waters for Friday will
be issued once we move clear of the existing headline.

Friday night... Moderate confidence.

Southwest winds 25 to 30 knots may become west toward morning.

Seas of 5-7 feet will linger through the night on the outer
waters and all southwest-exposed waters such as ri sound. Small
craft advisory will lower on boston harbor and narragansett bay,
but linger on the remaining waters.

Outlook /Saturday through Tuesday/...

Saturday... High confidence. Increased pressure gradient with
approaching systems may result in gales across the eastern
waters. Cold frontal passage on Saturday may bring some showery
weather for the waters.

Sunday... Moderate confidence. Cold front will be south of the waters
as surface high pressure moves northeast of the region. Conditions
should remain below SCA but if the front gets closer than seas and
winds may be a bit stronger.

Monday... Low confidence. Approaching upper level system and passing
warm front will increase precip as well as wind and seas of the
waters. SCA may be needed.

Box watches/warnings/advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 10 am Friday to 6 am edt Saturday
for anz232>235-237-255-256.

Small craft advisory from noon to 8 pm edt Friday for anz230.

Small craft advisory from 10 am Friday to 3 am edt Saturday
for anz231-251.

Small craft advisory from 10 am to 10 pm edt Friday for anz236.

Small craft advisory until 2 am edt Friday for anz250-254.

Synopsis... Wtb/dunten
near term... Wtb/dunten
short term... Wtb
long term... Dunten
aviation... Wtb/dunten
marine... Wtb/dunten


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44020 - NANTUCKET SOUND 14 mi77 min 39°F2 ft1029.7 hPa (-0.6)
44090 15 mi33 min 36°F3 ft
WAXM3 - Waquoit Bay Reserve, MA 18 mi82 min 38°F -1°F
NTKM3 - 8449130 - Nantucket Island, MA 25 mi49 min WNW 7 G 12 36°F 37°F1030.6 hPa
BZBM3 - 8447930 - Woods Hole, MA 26 mi49 min 37°F 37°F1030.3 hPa
BUZM3 - Buzzards Bay, MA 47 mi67 min NW 18 G 18 36°F 1031.4 hPa (-0.7)

Wind History for Nantucket Island, MA
(wind in knots)    EDIT      (on/off)   Help
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Last
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NW14
G22
NW17
G22
NW17
G34
NW17
G29
NW14
G24
NW15
G27
N20
G26
NW16
G27
NW15
G24
NW14
G22
NW14
G23
NW13
G23
NW14
G22
NW14
G22
NW13
G26
NW16
G22
NW16
G22
NW11
G21
NW10
G16
NW9
G18
NW9
G20
NW13
G22
NW7
G17
NW7
G14
1 day
ago
SW8
G11
SW6
G9
SW5
G10
SW5
G10
SW6
G11
SW6
G10
SW4
G11
W4
G8
NW7
G13
NW5
G10
NW4
SW3
SW5
W5
W6
G12
NW10
G16
NW13
G17
NW9
G22
NW14
G21
NW15
G26
NW14
G24
NW14
G24
NW16
G24
NW15
G24
2 days
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N11
G14
N6
G9
NW4
NW3
NW4
NW4
W6
G9
W5
G8
W5
W4
G7
NW5
NW6
NW4
NW4
NW4
NW6
NW5
G8
N4
N3
N5
SW8
SW4
G12
SW8
G14
SW7
G11

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hyannis, Barnstable Municipal-Boardman Airport, MA5 mi71 minNNW 9 G 1810.00 miFair38°F1°F21%1029.4 hPa
Chatham, Chatham Municipal Airport, MA12 mi75 minNNW 910.00 miFair36°F5°F27%1030.3 hPa
Otis Air National Guard Base, MA17 mi72 minno data10.00 miFair37°F-2°F18%1030.1 hPa

Wind History from HYA (wind in knots)
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Last 24hrNW13
G25
NW16
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G33
N20
G31
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NW12
G29
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G24
NW15
G24
NW15
G23
N12
G25
NW14
G26
NW13
G20
NW13
G24
NW15
G22
NW16
G28
NW12
G22
NW12
G19
NW9
G19
NW12
G18
N9NW9
G18
NW9
G18
NW7
G17
1 day agoSW11SW11SW6SW6W7W6NW8
G16
W7W4CalmW4W10W6W10
G19
NW13
G26
NW17
G21
NW13
G26
NW19
G26
NW19
G28
NW20
G28
NW17
G27
NW15
G36
NW14
G29
NW12
G23
2 days agoN4NW3N4CalmCalmCalmW5CalmNW5N5NW7N5NW3N4N643NE6S8S8S9SW15
G23
W19
G25
SW10

Tide / Current Tables for South Yarmouth, Bass River, Nantucket Sound, Massachusetts
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South Yarmouth
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Thu -- 03:41 AM EDT     0.48 feet Low Tide
Thu -- 03:58 AM EDT     Moonrise
Thu -- 06:38 AM EDT     Sunrise
Thu -- 10:00 AM EDT     2.73 feet High Tide
Thu -- 02:15 PM EDT     Moonset
Thu -- 04:20 PM EDT     0.25 feet Low Tide
Thu -- 06:56 PM EDT     Sunset
Thu -- 10:39 PM EDT     2.55 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.91.410.60.50.81.21.62.12.62.72.62.21.71.10.60.30.30.61.11.62.12.52.5

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Thu -- 12:11 AM EDT     0.00 knots Slack
Thu -- 03:42 AM EDT     1.65 knots Max Flood
Thu -- 03:57 AM EDT     Moonrise
Thu -- 06:37 AM EDT     -0.00 knots Slack
Thu -- 06:37 AM EDT     Sunrise
Thu -- 09:20 AM EDT     -1.54 knots Max Ebb
Thu -- 12:29 PM EDT     0.00 knots Slack
Thu -- 02:15 PM EDT     Moonset
Thu -- 04:09 PM EDT     1.92 knots Max Flood
Thu -- 06:55 PM EDT     Sunset
Thu -- 07:13 PM EDT     -0.00 knots Slack
Thu -- 09:56 PM EDT     -1.55 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.20.61.21.61.61.30.6-0.4-1.2-1.5-1.5-1.1-0.40.41.21.71.91.81.20.2-0.8-1.4-1.6-1.4

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 (18,4,5,8)
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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.