Monday, March25, 2019

Marine Weather and Tides
Siasconset, MA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 6:38AMSunset 7:03PM Monday March 25, 2019 6:05 PM EDT (22:05 UTC) Moonrise 12:00AMMoonset 9:42AM Illumination 76% Phase: Waning Gibbous; Moon at 20 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 245 Pm Edt Mon Mar 25 2019
Synopsis for eastport me to stonington me out 25 nm.. High pres will continue to build in from the W through Tue night then crest over the waters on Wed. High pres will slide E Wed night into Thu. A cold front will move in late Thu night.

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 251927
area forecast discussion
national weather service boston norton ma
327 pm edt Mon mar 25 2019

A coastal storm will track well out to sea tonight. High
pressure builds in from the west Tuesday into Wednesday with
cool and dry weather. A weak cold front may bring a few showers
Thursday night, otherwise moderating temperatures Thursday into
Friday. Mild weather next weekend, but low pressure may bring a
period of rain sometime late Sunday into Monday with much cooler
weather possible by Monday.

Near term through tonight
Mid level shortwave moves to the mid atlc coast tonight with
coastal low pres tracking well south of new eng. This shortwave
will keep mid level cloud shield near the south coast for at
least the first half of tonight and it may even push a bit to
the north, before moving offshore late tonight. However,
northern stream shortwave dropping into northern new eng with
w NW flow aloft will keep deeper moisture to the south. There is
a low risk for a few sprinkles or light showers this evening
from bid to ack, otherwise dry.

Good radiational cooling, especially north of the pike where
clear skies will prevail. Lows will drop into the teens and low
20s here. More clouds along the south coast where expected lows
will be in the upper 20s.

Short term Tuesday through Tuesday night

mid level shortwave moves south across sne, but airmass is bone
dry as high pres builds in from the west. Pwats dropping to less
than 0.1" with dewpoints down into the single numbers. Other
than a few high clouds, a sunny day expected but chilly with
temps 5-10 degrees below normal. High upper 30s to lower 40s.

Tuesday night...

high pres moves into new eng setting the stage for a cold night
with clear skies and light winds. Lows away from the immediate
coast will drop into the teens, with 20s along the coast.

Long term Wednesday through Monday

* dry weather prevails much of this time period
* gradual warming trend Wed & Thu then 60s possible fri-sun
* low risk of showers Thu ngt Fri am then again Sat night sun

pleasant day on Wednesday as a 1034mb surface high moves over the
region. Winds back to the southwest behind the low bringing
moderating temperatures, into the mid-upper 40s (less along the
south coast). Light winds and sunny skies will make it feel spring

Thursday and Friday...

Thursday the high exits to the east and we'll be sandwiched between
it and a passing surface low mid-level shortwave over southeast
canada. This increases the pressure gradient and makes for a breezy
but warm day Thursday as southerly winds continue to advect warmer
air northward. Highs should reach into the 50s save for the south
coast CAPE cod where strong onshore flow over the cold ocean waters
keeps temps in the 40s. As this low moves east it drags a cold front
across northern new england. Given the northward placement of the
parent low and recent model trends, there looks to be less of a
chance that we see the front hold together through much if any
of southern new england. Thus, not expecting widespread rains,
but more scattered shower chances Thursday night, best in nw
mass. Neither will we see much of a temperature drop; lows
remain quite warm in the upper 30s to near 40.

Friday attention turns to a low which forms in the lee of the
rockies early Friday and moves through the ohio valley to the great
lakes region by Saturday morning. We'll stay dry under a brief, weak
high pressure, keeping the warming trend going. Highs on Friday
reach into the upper 50s to near 60, except, again, along the south
coast where onshore flow holds temps in the upper 40s low 50s.

Saturday and Sunday...

strong WAA Friday night through at least Saturday. With 925mb temps
approaching 12c, temps should reach well into the 60s, and even
touch 70, especially in northeast ma. As the low approaches, the
pressure gradient tightens and southwest winds will be breezy
through the day. Good surface heating should make for a well mixed
bl and with a 35-40kt LLJ we could see gusts 25-35 mph mixing down.

Big question will be timing of the cold front rain chances. Trending
the forecast to the slower ec solution which has been more
consistently showing a late Sunday early Monday passage. Overall the
better of the two weekend days right now looks to be Saturday, with
increasing rain chances during the day on Sunday ahead of that cold
front. However, at this time period, still plenty of room for

Aviation 19z Monday through Saturday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday night ...

high confidence inVFR through the period. Just some mid high
clouds through the evening along the south coast and islands
which clear late tonight. Otherwise skc.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf
outlook Wednesday through Saturday ...

Wednesday through Wednesday night:VFR.

Thursday:VFR. Breezy.

Thursday night through Friday:VFR. Breezy. Slight chance ra.

Friday night: mainlyVFR, with local MVFR possible. Slight
chance ra.

Saturday:VFR. Breezy. Slight chance ra.

Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday night ...

a period of N gusts to 25 kt expected on the south coastal
waters late tonight into Tue morning as low pres tracks well to
the south. SCA for south coastal waters. Winds diminish tue
afternoon and evening. Another period of marginal SCA northerly
wind gusts possible late Tue night over eastern waters. A few
showers possible this evening over the southern outer waters,
south of the islands.

Outlook Wednesday through Saturday ...

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

Wednesday night: winds less than 25 kt.

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

Thursday night: low risk for small craft advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain.

Friday: winds less than 25 kt. Seas up to 5 ft.

Friday night: winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain.

Saturday: low risk for small craft advisory winds with gusts up
to 25 kt. Seas up to 5 ft.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 4 am to 2 pm edt Tuesday for anz255-

Small craft advisory from 4 am to 11 am edt Tuesday for anz235-

Synopsis... Kjc bw
near term... Kjc
short term... Kjc
long term... Kjc
aviation... Kjc bw
marine... Kjc bw

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi72 minNE 910.00 miOvercast40°F28°F63%1017.2 hPa

Wind History from ACK (wind in knots)
Last 24hr------------------------------------------------
1 day ago------------------------------------------------
2 days ago------------------------------------------------

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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Wind Forecast for Boston, MA (18,4,5,8)
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Ground Weather Radar Station Upton, NY
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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 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 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.