Sunday, April22, 2018 L-36.com


Marine Weather and Tides
Siasconset, MA

Version 3.4
What's New / NOTES
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
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.

Sunrise 5:51AMSunset 7:35PM Sunday April 22, 2018 5:53 PM EDT (21:53 UTC) Moonrise 11:36AMMoonset 1:24AM Illumination 51% Phase: First Quarter Moon; Moon at 7 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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ANZ005 325 Pm Edt Sun Apr 22 2018
Synopsis for eastport me to stonington me out 25 nm.. High pres will build toward the waters from the W today. The high will settle across the area Mon and begin to move E Tue. Low pres will approach from the sw Wed then cross the region Thu.

7 Day Forecast for Marine Location Near Siasconset, MA
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location: 38.84, -69.85     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 221949
afdbox
area forecast discussion
national weather service boston norton ma
349 pm edt Sun apr 22 2018

Synopsis
High pressure remains in control through Tuesday bringing dry
weather with moderating temperatures. Wet weather returns
Wednesday into Thursday as low pressure moves through our
region. Unsettled weather continues into the weekend, but not a
washout.

Near term until 6 am Monday morning
Just about as quiet as it gets around here weatherwise with high
pressure in control. Satellite imagery shows clear skies around
region with nearest (high) clouds in pa and southern nj.

Deep mixing to nearly 850 mb has prevented sea breezes from
developing so far this afternoon. However, model guidance
suggests winds aloft will weaken just enough to allow a weak sea
breeze to develop along E ma coast and a slightly stronger sw
sea breeze along south coast from mid to late afternoon.

Mixing has also brought drier air to surface, as dewpoints have
fallen into teens and lower 20s, resulting in relative humidity
values dropping to less than 20 percent. Dewpoints will
gradually recover through this evening as mixing subsides.

Otherwise, clear skies and light winds tonight with patchy
valley fog. Leaned closer to MOS for lows which tend to perform
well in these situations. Lows drop back into 30s to around 40
with some patchy frost inland.

Short term 6 am Monday morning through Monday night
High pressure becomes centered over sne Monday. Once again
plenty of sunshine with light winds, and coastal sea breezes
will get underway by their usual late morning time frame. This
will give way to S SW flow Monday night as the high shifts
offshore, with some increase in high clouds late.

Stayed close to MOS with highs in the 50s 60s Monday, perhaps
approaching 70 in ct valley, and lows falling back into 30s to
near 40 Monday night.

Long term Tuesday through Sunday
* highlights...

- wet and breezy midweek
- perhaps a reprieve Friday
- more showers possible Saturday
overview and model preferences...

22 12z guidance remains in decent overall agreement through
this portion of the forecast, although more detail differences
arise after Wednesday.

Generally expecting two mid level waves to phase over the ohio
valley central appalachians towards Wednesday. This amplify the
resulting trough, and steer a low pressure closer to southern
new england Wednesday into Thursday. Near normal temperatures
much of this period, except for Wednesday.

Continue to favor an ensemble approach for this portion of the
forecast, especially after Wednesday.

Details...

dry weather through Tuesday, with a large high pressure over the
maritimes. Some question as to how quickly this high pressure
will move offshore. Latest guidance has sped up the arrival of
rainfall into late Tuesday night. Some surface ridging noted
over southern new england Wednesday morning, so this might be
too fast. Preferred a slower arrival to rainfall than the
latest guidance for this reason.

Good setup for a soaking rain Wednesday into Wednesday night.

This looks to be our most likely period of wet weather during
the next 7 days. Southern new england should be in the dry slot
of this system Thursday, although there could be some lingering
showers north of the mass pike Thursday morning.

A brief dry period possible Thursday night into early Friday,
before another low pressure moves into the great lakes. This
system should be close enough where there would at least be a
chance for some showers. Not looking like a washout, though.

High pressure may start to arrive Sunday, leading to drier
weather.

Aviation 20z Sunday through Friday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Monday night ... High confidence.

Sea breeze potential still questionable along E ma coast this
afternoon as winds aloft have been just strong enough to
maintain W NW flow. However, there should be some weakening in
winds later this afternoon to allow sea breeze to develop
between 20z-23z. Confidence is higher for south coastal sea
breeze which should get underway around 20z as well.

Vfr. Light W NW winds prevail tonight with local MVFR ifr
visibility in patchy valley fog. Higher confidence in sea
breezes along both coasts mon.

Kbos terminal... Moderate confidence in taf. E sea breeze
expected 20z-23z but if it does not occur, winds will veer to n.

Kbdl terminal... High confidence in taf.

Outlook Tuesday through Friday ... High confidence.

Tuesday:VFR.

Tuesday night: mainlyVFR, with local ifr possible. Chance ra.

Wednesday: MVFR ifr conditions possible. Breezy. Ra.

Wednesday night: mainlyVFR, with local ifr possible. Breezy.

Chance shra, chance ra.

Thursday:VFR. Breezy. Slight chance shra.

Thursday night:VFR. Breezy.

Friday:VFR. Breezy. Chance shra.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Monday night ... High confidence.

High pressure builds over waters with light winds, flat seas,
and good visibility.

Only concern for recreational boaters is for sea breezes along
south coast this afternoon with 15-20kt gusts and choppy seas
near shore, especially when opposing outgoing tide. Similar
conditions Monday.

Outlook Tuesday through Friday ... High confidence.

Tuesday: winds less than 25 kt.

Tuesday night: winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain.

Wednesday: low risk for small craft advisory winds with gusts
up to 25 kt. Areas of rough seas. Rain.

Wednesday night: winds less than 25 kt. Rough seas up to 12 ft.

Chance of rain, slight chance of rain showers.

Thursday: winds less than 25 kt. Rough seas up to 9 ft.

Thursday night: winds less than 25 kt. Areas of rough seas.

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

Equipment
Noaa weather radio transmitters serving providence and hyannis
are out of service due to phone line problems. The phone
company has prioritized the issues and is working to get the
weather broadcast back on the air as soon as possible.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... None.

Synopsis... Belk jwd
near term... Jwd
short term... Jwd
long term... Belk
aviation... Belk jwd
marine... Belk jwd
equipment... Staff


Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi60 minSW 910.00 miFair50°F30°F46%1027.5 hPa

Wind History from ACK (wind in knots)
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Last 24hrSW8SW7S6SW5SW7SW5W8NW6NW6N9N8N7NW6NW6NW6NW9NW10NW7NW84SW14SW10SW10SW9
1 day agoNW7NW5W5N13NW8N13NW11NW8NW14
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2 days agoN9NW4W5W6W11W8W9NW13
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Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of Northeast    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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Boston, MA (17,4,5,8)
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Ground Weather Radar Station Upton, NY
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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.