Sunday, August25, 2019

Marine Weather and Tides
Siasconset, MA

Version 3.4
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
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Sunrise 6:02AMSunset 7:31PM Sunday August 25, 2019 12:29 AM EDT (04:29 UTC) Moonrise 12:36AMMoonset 3:36PM Illumination 29% Phase: Waning Crescent; Moon at 24 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 1210 Am Edt Sun Aug 25 2019
Synopsis for eastport me to stonington me out 25 nm.. High pressure will remain overhead through Tuesday, then slides offshore through Wednesday night. A cold front crosses the area on Thursday.

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 250204
area forecast discussion
national weather service boston norton ma
1004 pm edt Sat aug 24 2019

High pressure in canada will contribute to developing low
clouds and light showers later tonight into Sunday, especially
across southeast new england. High pressure lingers into
midweek, with seasonable and dry conditions to continue. Still
have an eye on the tropics at this time, with potential high
surf and dangerous rip currents for the atlantic-exposed
shoreline of new england.

Near term until 6 am Sunday morning
No significant changes planned for the forecast.

High pressure centered over eastern canada continues on its
path to the maritimes. An east-northeast flow around that high
is crossing the gulf of maine and moving into southern new
england. Expect this to bring increasing low-level moisture in
the form of low clouds light showers drizzle late tonight. Most
likely to be affected would be eastern mass.

Observed temperatures were in the 60s at 9 pm, with dew points
in the 50s. Expect min temps in the 50s inland and around 60 in
areas in eastern ma that get the low clouds.

Short term 6 am Sunday morning through Sunday night
2 pm update...


low clouds, showers linger S e. Looking pleasant N w. As noted in
the tonight discussion, following low-level h925-85 thetae dry air
advection. Continued h8-7 dry-subsidence inversion beneath which the
profile remains cool, destabilized, daytime heating plus convergent
elements of h925-85 winds, broken to overcast low clouds and light
shower chances are likely to continue over SE new england whereas
more scattered to broken cloud decks and dry prevail NW ma and ct.

Showers mainly during the morning, thinking daytime heating and
boundary layer mixing should limit the deep-layer moisture profile
with some dry-air contamination. Continued preference to consensus
of near-term high-res guidance. Another tricky high-temperature
forecast dependent on cloud shield edge. Should see blustery ne
winds for all locations, strongest of course along the coast.

Sunday night...

low clouds linger, however shower chances diminish. Mid to upper
level high nudging S round which h925-85 dry air advection should
finally sweep through all new england, the accompanying subsidence
inversion deepening down to the surface through the atmospheric
column. Moisture continuing to pool beneath through which NE long-
fetch flow prevails, low clouds seem likely over SE new england
whereas over mostly clear NW ma and ct it's another night of
radiational cooling and patchy dense fog within the valleys. Once
again a tricky low-temperature forecast given the uncertainty as to
the cloud-shield edge. Mild se, cooler nw.

Long term Monday through Saturday

* below normal temperatures early next week, especially across
eastern massachusetts into rhode island
* onshore winds will bring spotty light rain or showers at
times into mid week
* temperatures return to near normal levels around mid week,
becoming warmer than normal by Friday
* another chance for showers late Wednesday through Thursday

Monday through Tuesday...

a large high pressure will continue to be the primary influence on
our weather. Strong subsidence inversion present in the model
soundings from pretty much all of the guidance. The question remains
if there will be enough of a near surface layer beneath this
inversion where the onshore flow could push enough moisture into
southern new england for some spotty drizzle. The moisture is very,
very shallow, so trended the forecast in a drier direction.

Below normal temperatures expected during this time, especially
towards ri and eastern ma.

The easterly winds may become gusty as the pressure gradient
increases around the southern section of the high from Monday
into Tuesday. May see gusts up to 20 to as high as 30 mph,
highest across CAPE cod and the islands.

Wednesday through Friday...

this is the most likely period for our next round of wet weather.

Mid level flow is rather amplified, and not translating east very
quickly. Thus, expecting a low pressure over central canada to take
a long time to push a series of fronts our way. The first cold front
is currently thought to arrive sometime Thursday into Friday. A
second front, may arrive sometime Friday night into Saturday. Given
this time range, and the mid level flow pattern, am expecting this
timing to change a bit over the coming days.

Still monitoring the tropics. Latest forecasts still take a
disturbance off the SE usa coast out to sea. The most likely impact
from this system may be a period of rough surf along ocean-exposed
beaches, particularly those which are also south-facing.

Temperatures should be a bit higher with increased southerly flow
ahead of the approaching cold front. Near normal towards mid week,
and perhaps slightly above normal late next week.

Aviation 02z Sunday through Thursday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday night ... Moderate confidence.


e SE ma and ri,VFR through 3 am with ceilings lowering to MVFR
after that. Light showers drizzle forecast with the clouds.

Persistent 10 to 15 kt E NE winds.

Vfr for most of the rest of SRN new england. Will be watching
the potential for developing fog in the ct rvr valley and the
usual fog spots. Ifr in any fog late tonight.


conditions lift and improve toVFR across NW new england with sct
low-endVFR cigs. E NE winds around 10 kts. Sct-bkn MVFR continues
along with morning -shra across SE new england with E NE 10 to
15 kts with gusts around 20 kts.

Sunday night...

few-sct across the interior with light winds, the threat of ifr
fg once again. Sct-bkn MVFR continues across SE new england with
breezy E NE winds 10 to 15 kts.

Kbos terminal...

high confidence in trends. Moderate confidence in timing for
lower cigs.

Kbdl terminal...

high confidence in taf.

Outlook Monday through Thursday ... Moderate confidence.

Monday:VFR. Breezy.

Monday night through Tuesday:VFR.

Tuesday night:VFR. Slight chance shra.

Wednesday through Wednesday night: mainlyVFR, with local MVFR
possible. Chance shra.

Thursday:VFR. Slight chance shra.

Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday night ... High confidence.

Long-fetch E NE winds the height of which will occur on Sunday
with gusts up to 30 kts and seas building up around 5 feet. This
as high pressure builds over the maritimes while low pressure
lingering well offshore to the south. A downward trend Sunday
night into Monday as high pressure wins out and builds across
the region. Small craft advisories in effect for a majority of
the waters, especially S se, beginning early Sunday morning.

Scattered light showers at times, developing late tonight and
continuing into early Sunday.

Outlook Monday through Thursday ... Moderate confidence.

Monday through Tuesday: winds less than 25 kt. Seas up to 5 ft.

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

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

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 8 am to 8 pm edt Sunday for

Small craft advisory from 10 am to 6 pm edt Sunday for anz231-

Small craft advisory from 10 am to 8 pm edt Sunday for anz235-

Small craft advisory from 6 am Sunday to 6 am edt Monday for

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

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi37 minNE 1010.00 miFair63°F57°F84%1024.2 hPa

Link to 5 minute data for KACK

Wind History from ACK (wind in knots)
Last 24hrN10N12N16N14N13N13N13
1 day agoSW9W9NW10SW5W7W4N4NE3N8N12N13N8N9NW5NW6N7N9N7NE3CalmNE3CalmN3N5
2 days agoSW11SW11SW7SW6S4CalmS3CalmSW4SW5SW10SW8SW11SW10SW11SW8SW13SW10SW13SW8SW7SW9SW11W9

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 (0,6,7,8)
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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.