Saturday, February24, 2018

Marine Weather and Tides
Siasconset, 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 6:24AMSunset 5:31PM Saturday February 24, 2018 10:52 AM EST (15:52 UTC) Moonrise 12:51PMMoonset 2:33AM Illumination 69% Phase: Waxing Gibbous; Moon at 9 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 1030 Am Est Sat Feb 24 2018
Synopsis for eastport me to stonington me out 25 nm.. High pres will build toward the waters through tonight. Low pres will cross S of the waters Sun night. High pres will then build toward the waters through mid week.

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 241500
area forecast discussion
national weather service taunton ma
1000 am est Sat feb 24 2018

Unseasonably mild today with a period of showers possible south
of the mass pike late today and early this evening. A frontal
system will bring more precipitation late tonight and Sunday
with rain mixed with sleet at times in the coastal plain and
snow sleet and freezing changing to rain in the interior. Near-
seasonable, quiet and dry for the first half of next week,
attention turns towards late week and an anticipated stormy

Near term through tonight
10 am update...

very pleasant feb conditions this morning. Temps already running
in the upper 40s and low 50s with plenty of sunshine out of
terrain-waves near the berkshires and lingering stratus across
mvy ack, which should be clearing in the next hour or so.

Increased highs a bit as a result as timing of the clouds
associated with a weak leading wave moves in this afternoon
being slower than previously forecast. Many locations make the
50s, or even upper 50s.

Otherwise, narrow corridor of shra later this afternoon and
evening, mainly S of the mass pike. Not too much with this
initial round as the moisture in the column remains somewhat
low until tonight.

Short term Sunday
*** mixed precipitation event for interior late tonight and
Sunday with some snow and ice accumulations ***
a few showers likely impacting south coast early evening,
otherwise dry weather through midnight before main area of
overrunning precip ahead of the warm front begins to overspread
the region from the SW to NE late tonight into Sunday.

Ptype will be biggest challenge with this event. Initially, the
column is warm but all the guidance is indicating a good cold
air damming signature developing overnight into Sunday as high
pres builds over the maritimes. In fact, notable cooling in the
925-950 mb layer 06-15z with temps dropping to -2 to -4c before
warmer air moves in from the south. Warming temps above this
layer will set up a sleet and freezing rain scenario in the
interior where low level cold air will be difficult to dislodge
given warm front remaining to the south and a sfc wave tracking
along the boundary to lock in the cold air near the surface.

Some snow is also likely late tonight and early Sunday, north
of the pike and especially near nh border where cold air just
deep enough as precip moves in. In the coastal plain, mainly
rain is expected, but given cold air below 850 mb, some sleet
will likely mix in with the rain late tonight and Sunday morning
even along the south coast.

Expect 1-3 inches snow sleet accum in the interior north of the
mass pike with highest amounts near nh border. If warmer air
aloft is delayed a few hours it is possible a few locations
could approach 4-5 inches but this is a low probability. We are
concerned with several hours of freezing rain and icy
conditions across portions of the interior during Sunday,
especially over the berkshires, worcester hills and portions of
the ct valley. Ice accretion up to one tenth of an inch is
possible with up to 0.25" over the berkshires. Expect temps to
gradually rise above freezing Sun afternoon in the interior as
precip intensity diminishes.

Winter weather advisories will be issued for all of central and
western ma and northern ct. Some freezing rain is possible in
nw ri and interior NE ma but confidence not yet high enough for
an advisory in this area. Across NE ma may be dealing with more
of a snow sleet to rain scenario.

Long term Sunday night through Friday
* highlights...

- quiet, dry, near-seasonable early week period
- stormy pattern emerging late week for the beginning of march
* overview...

blocky N atlantic pattern, associated +3 standard deviation h5 high
retrograding W into SE canada, parent 1040+ surface high, pressing
the thermal wind axis S through which N S stream impulses merge, dug
through a prevailing W CONUS h5 trof before ejecting and stretching
e. Energy piling up, cutting off for a time given the block, an area
of favorable storm development emerges off the SE canadian coast,
evolving S W towards the NE CONUS per retrograding high, E ejecting
energy. Airmass juxtaposition key as to outcomes towards the end of
the week after a quiet start. Only confidence is persistence of ne
winds of significant duration during high astro-tides, concern with
respect to coastal flooding. Lower confidence otherwise, consensus
forecast guidance heavily weighted with ensemble means. Hit targets
of opportunity below.

* discussion...

Thursday into the weekend...

while considerable ensemble member deterministic guidance spread
there's cohesive signal of a great lakes warm occlusion transferring
energy offshore beneath a more favorable region of storm development
evolving towards the NE conus. Occluded front transitioning to an
inverted trof, energy pinwheeling round a closed, stacking low well
offshore. Questions surround frontal boundary magnitude buffeting
the pressing N high, how far N E outcomes slide into new england.

Ncep noting poor run-to-run continuity with ejecting waves, ec, even
the 24.0z, worse than GFS which appears to be locking in. Warm core
low, absent arctic air, anticipate precip-type issues, rain snow,
lean to occluded front inverted trof hanging up into the NE conus
as energy transfers, low rolls up offshore. Only confidence is the
persistence of NE winds during high astro-tides, concern of coastal
flooding. Only chance pops given spread.

Aviation 15z Saturday through Wednesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday ... Moderate confidence.

Today... MVFR ifr eroding over S SE coastal terminals, while bkn
MVFR decks filter into W new england. With increasing sunshine
should see decks erode, optimistically. However, towards later
in the day, increasing low-mid level decks and -ra, especially
for ct, ri, southeast ma. Light winds overall turning NW late.

Tonight...VFR in the evening, lowering to MVFR from west to east
late. Rain, sleet and freezing rain developing from SW to ne
well after midnight with snow sleet across northern ma. Mainly
rain mixed with sleet coastal plain.

Sunday... Widespread ifr lifr developing. Rain, mixed with sleet
at times in the morning in the coastal plain. Snow, sleet and
freezing rain changing to rain interior.

Kbos terminal... High confidence in trends. Conditions improving
toVFR early this morning, but exact timing may be off a few

Kbdl terminal... High confidence in trends. Conditions improving
toVFR early this morning, but exact timing may be off a few

Outlook Sunday night through Wednesday ... Moderate confidence.

Sunday: mainly ifr, with local MVFR possible. Windy with gusts
to 30 kt. Ra, pl, fzra.

Sunday night: mainlyVFR, with local ifr possible. Slight
chance ra.

Monday through Wednesday:VFR.

Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday ... Moderate confidence.

Today... Diminishing winds becoming northerly late today. Seas
below sca.

Tonight and Sunday... Increasing easterly winds late tonight and
especially Sunday as low level jet moves across the waters.

Given cold air above the boundary layer, mixing will likely be
sufficient for a period of gale force gusts, especially over
the south coastal waters during sun. Otherwise, expect sca
conditions with gusts to 25-30 kt. Gale watches issued where
highest confidence of gales.

Outlook Sunday night through Wednesday ...

Sunday: low risk for gale force winds with gusts up to 35 kt.

Rough seas up to 10 ft. Rain. Visibility 1 nm or less.

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

Slight chance of rain.

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

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

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

Tuesday night: winds less than 25 kt.

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

Box watches warnings advisories
Ct... Winter weather advisory from 1 am to 1 pm est Sunday for

Ma... Winter weather advisory from 1 am to 1 pm est Sunday for

Ri... None.

Marine... Small craft advisory from 3 am to 4 pm est Sunday for

Small craft advisory from 6 am to 5 pm est Sunday for anz230.

Small craft advisory from 3 am to 7 pm est Sunday for anz231.

Small craft advisory from 6 am to 1 pm est Sunday for anz236.

Gale watch from Sunday morning through Sunday afternoon for

Small craft advisory from 6 am to 7 pm est Sunday for anz250-

Gale watch from Sunday morning through Sunday afternoon for

Synopsis... Kjc sipprell
near term... Doody
short term... Kjc
long term... Sipprell
aviation... Kjc sipprell
marine... Kjc sipprell

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi59 minW 101.25 miFog/Mist42°F42°F100%1019.8 hPa

Wind History from ACK (wind in knots)
Last 24hrE14E14SE13SE14SE10E11E11E14SE13SE12SE8S11SW9SW13W16
1 day agoNE15NE15N16NE16NE15
2 days agoSW12SW13SW12SW12SW15SW16SW15SW14SW13SW14SW14W13W12N4N7N13NE11N13NE14N16NE15N14NE11NE14

Tide / Current Tables for
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Weather Map and Satellite Images
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IR Satellite Image from GEOS

GOES Local Image of Northeast    EDIT

Wind Forecast for Boston, MA (10,2,3,4)
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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.