Wednesday, March29, 2017 L-36.com


Marine Weather and Tides
Popponesset Island, 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 6:25AMSunset 7:05PM Wednesday March 29, 2017 10:33 PM EDT (02:33 UTC) Moonrise 7:39AMMoonset 9:03PM Illumination 7% Phase: Waxing Crescent; Moon at 3 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- 717 Pm Edt Wed Mar 29 2017
.small craft advisory in effect through Thursday afternoon...
Tonight..N winds 10 to 15 kt with gusts up to 30 kt. Seas 2 to 3 ft.
Thu..N winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft.
Thu night..N winds 5 to 10 kt. Seas around 2 ft.
Fri..E winds 5 to 10 kt. Seas around 2 ft. A chance of rain and sleet.
Fri night..E winds 10 to 15 kt with gusts up to 25 kt... Increasing to 15 to 20 kt with gusts up to 35 kt after midnight. Seas 2 to 3 ft. Rain. Vsby 1 to 3 nm.
Sat..E winds 15 to 20 kt...becoming ne 20 to 25 kt in the afternoon. Gusts up to 35 kt. Seas 3 to 5 ft. Rain. Vsby 1 to 3 nm.
Sat night..N winds 20 to 25 kt with gusts up to 35 kt... Diminishing to 15 to 20 kt with gusts up to 25 kt after midnight. Seas 2 to 4 ft. A chance of rain.
Sun..NW winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft.
Sun night..NW winds 5 to 10 kt with gusts up to 20 kt. Seas around 2 ft.
Mon..N winds 5 to 10 kt. Seas 1 foot or less.
Mon night..SE winds 5 to 10 kt. Seas 1 foot or less. 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 717 Pm Edt Wed Mar 29 2017
Synopsis for massachusetts and rhode island coastal waters.. High pressure builds south into new england through Thursday. More unsettled weather is in the forecast for late Friday into Saturday as low pressure likely tracks just southeast of the waters followed by high pressure Sunday into early next week. 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 Popponesset Island, MA
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location: 41.59, -70.46     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 292300
afdbox
area forecast discussion
national weather service taunton ma
700 pm edt Wed mar 29 2017

Synopsis
Expect a clearing trend with dry weather continuing through Thursday.

Low pressure from the ohio valley passes S of new england Saturday.

This brings snow and mixed precipitation Friday into Saturday with
several inches of snow possible over higher elevations north of the
mass pike. High pressure brings dry weather Sunday and Monday,
followed by another approaching storm on Tuesday.

Near term /until 6 am Thursday morning/
7 pm update...

lingering cloud cover rotating south across sne this evening
but clouds will clear out by late evening. Diminishing coastal
winds. Adjusted sky grids for current trends, otherwise
forecast on track.

Previous discussion...

overall quiet weather and turning chilly. High pressure
building into the area will result in initial breezy NW flow
with gusts up to 30 mph along the E coast of ma, especially for
the outer cape's to gradually relax. Drying out through the
atmospheric column with increasing subsidence. Should become
mostly clear with colder air still in place aloft. Lows down
into the 20s for most areas, with the colder conditions n/w over
the high terrain, perhaps even the adjacent low lying valleys
with lighter flow.

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

high pressure in control. Overall light winds with enhanced ridging
across the region. However initial moisture and mid-level energy
begins to eject atop the ridge into the NE CONUS towards late. With
a slight moderation in the airmass with increasing clouds towards
evening, expect it to turn out to be a nice day warming into the
upper 40s to low 50s. Some scattered clouds. Could be underdoing
the temperatures a degree or two, however the airmass aloft
will be slightly cooler than that which was observed today.

Thursday night...

potential snow / sleet especially n/w portions of S new england for
the Friday morning commute. Increasing h7 diffluence collocated with
building mid-level h5-7 moisture. Convergent isentropic upslope rear-
ward with the nose of the h85-7 low, however models diverge on the
strength of such flow with the high-res solutions a bit more robust
than global models. Nevertheless, pops increasing to likely in n/w
ma and ct especially. With increasing moistening and lift within
the snow growth region, should see precipitation start out as snow.

Yet with a warm nose punctuating around h7-8, considering the depth
and magnitude of the cold layer below, could see snow change over
to sleet. A coating up to an inch of snow is possible, with higher
amounts for the n/w high terrain. Temperatures marginal, slightly
below freezing, and overnight. The intensity light, perhaps some
challenges with accumulation, so mainly concerned given this time
of year for exposed elevated surfaces to becoming snow covered. Lows
down around the low to mid 30s. N/e winds.

Long term /Friday through Wednesday/
Highlights
* snow sleet and freezing rain north of the pike Fri into sat
* rain snow and sleet changing to rain south of the pike
* several inches of snow/sleet accumulation and light ice
accumulation possible north of the pike with greatest risk over
higher elevations
Friday through Saturday...

models agree on overall pattern with potent mid level low over ohio
valley tracking south of new eng with intensifying secondary low
tracking neat 40n Fri night into sat. There are differences with the
interaction of this mid level low with northern stream trof in
canada which impacts QPF and thermal profile. GFS is weaker with
northern stream trof and less interaction which translates to a
weaker low level jet and a bit less QPF but much colder thermal
profile. GFS would suggest mostly snow north of the pike with
potential for up to a foot, especially higher elevations. However,
nam and ECMWF to a lesser extent are stronger with the northern
stream trof with stronger low level jet, heavier QPF but much more
aggressive with warm nose above 850 mb. This would imply less snow
but a prolonged period of sleet and freezing rain.

A very uncertain ptype and snowfall forecast as minor changes in
thermal profile will result in much different outcomes. We are still
48-72h out in the model world so really can't lock into any one
solution as changes are likely. Due to uncertainty we used a blend
of model temp profiles to derive snow and ice accum.

Timing and precip types/accumulation...

initial shot of warm advection precip will overspread sne fri
morning assocd with the mid level warm front. The column is
starting out rather cold but warmer air in the 850-700 mb layer will
be approaching from the sw. Expect snow or mixed snow/rain/sleet
south of the pike and especially near the coast as warmer air aloft
moves up from the sw. North of the pike expect mainly snow on
Friday. Precipitation will be heavy at times late Fri and especially
fri night into early Sat as the secondary low tracks to the
south and comma head moves across the region.

The biggest uncertainty is how far north the warm nose aloft gets.

We will mention a mix of snow sleet and freezing rain north of the
pike Fri night.

Precip should begin to taper off Sat afternoon as the low moves east
of new eng and may transition back to snow before ending as
deeper cold air move back southward.

Potential for 6+ inches of snow north of the pike with greatest risk
over higher elevations, so we issued a winter storm watch for this
area. Some ice accumulation is possible as well if the warm layer
advances northward. South of the pike across ct/ri and SE ma expect
amounts mainly under 2 inches and confined to the grass and trees
due to temps remaining above freezing. However, this is not a high
confidence forecast due to uncertainty in precip type.

Gusty NE winds developing along the coast during Sat and may need
wind advisories for gusts over 40 mph.

Sunday onward...

a low confidence forecast concerning a very active weather pattern.

Evaluating upstream, persistence of a low over the gulf of alaska
promotes downstream ridging promoting equatorward flow along its e
periphery. Pacific-origin energy sheared s, cyclogenesis occurs over
the 4-corners region of the SW conus. Pushing E it undergoes further
amplification and negative tilt to the lee of higher terrain before
shooting off downstream through the progressive flow. It then comes
down to the environment ahead, on the strength and location of any
preceding high pressure noting isallobaric / ageostrophic flow and
any subsequent cold air damming above which initial overrunning in
advance of c CONUS storm systems is likely to occur.

Despite uncertainty with low level thermal fields coupled with the
magnitude and track of synoptic features, considering the late-march
into early-april timeframe, increasing length of daytime heating, as
well as lack of arctic air and near-neutral teleconnections, am left
to believe that any wintry weather outcomes, will be marginal with a
low to moderate impact potential. Much of the focus in n/w ma, along
the high terrain as we've seen recently with recent weather. Initial
focus on the Monday night into Tuesday timeframe.

Consensus blend of forecast data preferred. Ensemble members still
exhibiting a large amount of spread.

Aviation /00z Thursday through Monday/
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Thursday night/...

tonight...

vfr with clearing skies. NW gusts to 25 kt near the coast will
diminish.

Thursday...

vfr with light winds. Mid to high level CIGS increasing late.

Thursday night...

cigs lower and thickening towards morning, especially n/w. With
developing sn, MVFR-lifr conditions developing, more so for the n/w
high terrain terminals of n/w ma and ct. Light n/e winds.

Kbos taf... CIGS continuing to lift, erode. Gusty winds initially
which could get up to 30 kts. Will hold at a general 25 kts
through the evening and overnight, tapering into morning.

Kbdl taf...VFR. Quiet.

Outlook /Friday through Monday/...

Friday through Saturday... Moderate confidence.

Widespread ifr/lifr expected with some improvement from west to east
sat afternoon. Snow/sleet/freezing rain north of the pike and
rain/snow/sleet to the south transitioning to all rain by Fri night.

Gusty easterly winds near the coast Fri night becoming NE sat.

Sunday into Monday...

vfr. NW winds becoming E with time. Increasing clouds late in the
period.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Thursday night/...

initially breezy overnight with near-gale force gusts. Believe there
to be a low risk of NW gales. Winds taper into the morning period as
high pressure builds into the region. Allowing winds to become light,
will see seas dampen with time resulting in the end of small craft
advisories towards Thursday evening. Increasing clouds towards Friday
morning as winds become n/e ahead of the next storm system.

Outlook /Friday through Monday/...

Friday-Saturday... Moderate confidence.

Easterly winds below SCA Fri but increasing Fri night with risk for
gale force gusts to 35 kt. Winds becoming NE Sat with gales
possible. Seas building up to 10 ft over the outer waters.

Sunday into Monday...

blustery NW flow initially becoming light into Monday while turning
e beneath high pressure. Should see wave action diminish throughout
the period.

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

Ma... Winter storm watch from Friday morning through Saturday
afternoon for maz002>006-008-010-026.

Ri... None.

Marine... Small craft advisory until 2 pm edt Thursday for anz231>234-
251-255-256.

Small craft advisory until 8 am edt Thursday for anz230.

Small craft advisory until 8 am edt Thursday for anz235>237.

Small craft advisory until 8 pm edt Thursday for anz250-254.

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


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WAXM3 - Waquoit Bay Reserve, MA 3 mi108 min 42°F 25°F
BZBM3 - 8447930 - Woods Hole, MA 12 mi45 min 40°F 38°F1019.9 hPa
44020 - NANTUCKET SOUND 18 mi103 min 40°F3 ft1018.8 hPa (+2.4)
44090 19 mi59 min 37°F4 ft
NTKM3 - 8449130 - Nantucket Island, MA 29 mi45 min NNW 9.9 G 13 41°F 41°F1019.4 hPa
BUZM3 - Buzzards Bay, MA 33 mi93 min NNW 25 G 27 42°F 1020.6 hPa (+3.6)
FRVM3 - 8447386 - Fall River, MA 38 mi45 min 41°F 39°F1021.2 hPa
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 39 mi45 min NNW 11 G 16 42°F 1021.2 hPa
FRXM3 39 mi45 min 42°F 24°F
NWPR1 - 8452660 - Newport, RI 46 mi45 min NNW 15 G 18 42°F 40°F1020.9 hPa
PTCR1 - 8452951 - Potter Cove, Prudence Island, RI 47 mi45 min N 8 G 19 1021.9 hPa
NAXR1 - Narragansett Bay Reserve, RI 47 mi108 min N 9.9 42°F 1021 hPa26°F
CPTR1 - 8452944 - Conimicut Light, RI 48 mi45 min NNW 20 G 25 41°F 41°F1020.8 hPa

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Otis Air National Guard Base, MA6 mi38 minno data10.00 miA Few Clouds37°F23°F56%1020.3 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA11 mi37 minNNW 12 G 1910.00 miPartly Cloudy40°F28°F63%1019 hPa
Vineyard Haven, Marthas Vineyard Airport, MA15 mi40 minNNW 1310.00 miFair40°F24°F53%1019.9 hPa

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

Tide / Current Tables for Poponesset Island, Poponesset Bay, Nantucket Sound, Massachusetts
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Poponesset Island
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Wed -- 02:38 AM EDT     2.70 feet High Tide
Wed -- 06:29 AM EDT     Sunrise
Wed -- 07:38 AM EDT     Moonrise
Wed -- 08:41 AM EDT     -0.34 feet Low Tide
Wed -- 03:04 PM EDT     2.70 feet High Tide
Wed -- 07:04 PM EDT     Sunset
Wed -- 09:02 PM EDT     Moonset
Wed -- 09:03 PM EDT     -0.29 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.62.22.62.72.41.810.3-0.2-0.300.61.322.52.72.521.30.6-0-0.3-0.10.5

Tide / Current Tables for Cape Cod Canal, Massachusetts Current
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Cape Cod Canal
Click for Map
Wed -- 01:56 AM EDT     -4.90 knots Max Ebb
Wed -- 04:57 AM EDT     0.15 knots Slack
Wed -- 06:30 AM EDT     Sunrise
Wed -- 07:39 AM EDT     Moonrise
Wed -- 07:58 AM EDT     4.75 knots Max Flood
Wed -- 11:18 AM EDT     -0.15 knots Slack
Wed -- 02:17 PM EDT     -5.02 knots Max Ebb
Wed -- 05:21 PM EDT     0.22 knots Slack
Wed -- 07:05 PM EDT     Sunset
Wed -- 08:21 PM EDT     4.80 knots Max Flood
Wed -- 09:03 PM EDT     Moonset
Wed -- 11:42 PM EDT     -0.17 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-3.4-4.6-4.9-4.5-3.30.73.44.44.74.43.61.8-2.9-4.4-5-4.8-3.9-2.12.84.24.84.742.8

Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
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GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (22,6,7,8)
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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.