Tuesday, March28, 2017 L-36.com


Marine Weather and Tides
East Dennis, 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 6:27AMSunset 7:04PM Tuesday March 28, 2017 12:01 PM EDT (16:01 UTC) Moonrise 7:01AMMoonset 7:50PM Illumination 1% Phase: Waxing Crescent; Moon at 1 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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ANZ231 Cape Cod Bay- 1018 Am Edt Tue Mar 28 2017
This afternoon..NE winds around 5 kt. Seas 1 foot or less. A slight chance of showers...then a chance of showers with isolated tstms. Vsby 1 to 3 nm.
Tonight..NE winds around 5 kt. Seas 1 foot or less. Patchy fog. Showers. Vsby 1 nm or less.
Wed..N winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft. A chance of showers. Vsby 1 to 3 nm.
Wed night..N winds 15 to 20 kt with gusts up to 30 kt. Seas 3 to 5 ft.
Thu..N winds 15 to 20 kt...diminishing to 10 to 15 kt in the afternoon. Gusts up to 30 kt. Seas 2 to 4 ft.
Thu night..N winds 5 to 10 kt. Seas 2 to 3 ft.
Fri..NE winds 5 to 10 kt. Seas around 2 ft. A chance of rain.
Fri night..SE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Rain likely. Vsby 1 to 3 nm.
Sat..E winds 15 to 20 kt with gusts up to 30 kt. Seas 2 to 3 ft. Rain likely.
Sat night..NE winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. A chance of rain. Winds and seas higher in and near tstms. 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 1018 Am Edt Tue Mar 28 2017
Synopsis for massachusetts and rhode island coastal waters.. A warm front will remain south of the coastal today as another low tracks across southern new england tonight. Strong high pressure over quebec builds S into new england Wednesday into Thursday. More unsettled weather is in the forecast for late Friday into Saturday 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 East Dennis, MA
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location: 41.75, -70.16     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 281350
afdbox
area forecast discussion
national weather service taunton ma
950 am edt Tue mar 28 2017

Synopsis
Wet weather continues through tonight. Some improvement expected
on Wednesday. High pressure brings dry and cool weather Wednesday
night and Thursday. Low pressure from the ohio valley passes south
of new england over the weekend. This brings a mix of precipitation
Friday and Saturday, followed by dry weather Sunday and Monday.

Near term /until 6 pm this evening/
10 am update...

soupy conditions persist today ahead of later day showers / widespread
rain and an isolated risk of thunderstorms.

First, the soupy conditions. The back-bent stalled frontal boundary
across our region N of which NE flow prevails in an overall moist
airmass. Agree with the previous forecaster, it may struggle to lift
n. The thick deck of clouds significantly limiting warming across
the region. Dewpoints dropped overnight with the N flow, albeit light,
allowing for locally dense fog to develop into morning.

Special weather statement for the hazardous weather till 11 am. Should
see conditions improve with daytime heating, though the higher terrain
will likely stay immersed in the low cloud decks with visibility of
1 to 2 miles much of today into the evening hours before clearing
out behind a cold front overnight.

Secondly, late day wet-weather and the isolated risk of thunderstorms.

An area of low pressure presently across the mid- atlantic will push
e today parent with a weak open-wave mid level impulse. Associated
lift and ascent, especially frontogenetically along attendant frontal
boundaries of a decent moist-instability axis, and weak cyclogenesis,
will yield widespread rain with embedded thunderstorms. Some things
worth noting:
1.) anomalous precipitable waters up to +2 standard deviations and
above the 90th percentile with respect to climatology sweeping n,
overrunning the mostly stalled frontal boundary. Consensus forecast
of values up around 1.1 inches per S fetch of the moist-instability
axis N over S new england, albeit weak per evaluation of h925-85 flow.

2.) with the moist-instability axis some convective threats are met
with respect to k-indices, negative showalters, and total-totals.

However, consensus and ensemble mean guidance has a majority of the
mucape values along the s-coast and points s. The region of stronger
instability and deeper moisture is more centered off the mid-atlantic,
especially over the warmer gulf stream. Some concern that perhaps
both instability and better moisture are robbed n.

3.) however, decent upslope ahead of mid-level troughing and positive
differential vorticity in a right entrance region of an upper level
jet streak. Forecast consensus signaling strong omega throughout
the column of the aforementioned warm-moist airmass, especially within
the mid-levels. Within the conditionally unstable profile, this adds
weighting to the isolated thunder chances. Just a slip of instability
to the n, can't rule out that rumble of thunder.

4.) finally, there still is some uncertainty as noted above. The
evolution of the low along with the parent low to mid level
convergence zone. Some of the latest guidance really putting out
some hefty precipitation amounts. Watching closely the activity
out of jersey and the delmarva. It'll be interesting if we see a
decent deep-layer forcing setup over the S coast, however we
could see a wobble N or S in this region and in addition there
could be some complications S if convective activity emerges
that robs the environment n. Just some things we have to keep in
mind.

So having my coffee, watching radar, thinking we could see a good
dousing of rain for the afternoon into evening period. Going with
high categorical pops with the expectation of new england seeing
on average 0.50 to 0.75 inches of rain, some locations seeing
locally higher amounts. Again, difficult to say exactly where with
absolute specificity, however the consensus of forecast guidance
is focused s/e where there's the possibility of instability /
thunder and that's where we'll keep a broad focus. Would help
with the drought conditions at the very least.

Keep it cool given the thick clouds and light N winds. Believe it'll
be a struggle for the stalled frontal boundary to lift n. Highs in
the mid to upper 40s, maybe an isolated 50 degree reading. Warmest
conditions s/w, cooler n/e. As noted by the previous forecaster,
still a good cold air advection signature further n/e.

Short term /6 pm this evening through 6 pm Wednesday/
Tonight...

frontal wave once again shifts E of the region during the
overnight hours. This will once again allow a mix of cold
advection and drier air to entrain from w-e especially from
about 03z to 09z. Rainfall gradually dissipates, but it may take
some time for the lowest lvl moisture to fully erode.

Therefore, some fog and low clouds may linger beyond the precip
ending times. May need to monitor for a few spots of patchy
dense fog as a result. Otherwise, another mild/damp night for
the most part, but cooling will occur within a few hours of
sunrise such that min temps could drop back into the mid 30s.

Wednesday...

finally a break from the prolonged damp conditions. Drier air
will entrain through the entire column through the day allowing
skies to clear and sunshine to poke through. Although some cold
advection clouds may increase through the peak afternoon
heating. H85 temps, although cooling are still near 0c by early
afternoon. Therefore, highs could easily still reach the upper
40s and low 50s especially where enough sunshine is observed.

Breezy with nnw flow increasing through the day, gusts could
reach 25-30 mph at times.

Long term /Wednesday night through Monday/
Big picture...

a rather flat longwave pattern with individual shortwaves moving
east through that flow. One shortwave moves off through the
maritimes Wednesday night. Another ejects out of the southwest usa
and crosses new england Friday-Saturday.

Models continue to change run-to-run, leaving low confidence in the
details.

Details...

Wednesday night-Thursday...

surface low pressure passes south of nova scotia as high pressure
builds in from canada. Strong pressure gradient between the systems
will maintain north breezes along the eastern ma coastline with
lighter winds farther inland. The resulting cold advection should be
sufficient to maintain mixing from at least 950 mb where winds will
be 30-35 knots. This will mean gusty winds in at least eastern
massachusetts early in the night, diminishing overnight as the
pressure gradient diminishes.

High pressure builds over new england Thursday, bringing fair skies
and mixing to between 850 and 900 mb. Temps at these levels support
max sfc temps in the 40s.

Friday-Saturday...

questions continue with end-of-week system. General model agreement
on surface low moving up the ohio valley and then jumping to the mid
atlantic coast Friday night, passing south of new england Saturday
or Saturday night. Projected low level winds show 25-30 knot
southeast jet from nj through eastern pa and central ny at 12z
Friday. Light south flow into western ct and western ma. Meanwhile
model QPF shows measurable pcpn almost all the way to boston.

We passed on a straight importing of the model values in favor
of limiting morning pops and QPF to areas worcester and
west... Then spreading east to the rest of our area during the
afternoon/evening. Timing and track of the surface low and
resulting northeast winds supports likely pops across all of
southern new england. Precipitable water values reach .75 to
1.00 inches over our area.

Temperatures and resulting precip type are also a lingering
question. High pressure departing through the maritimes provides a
small cold air damming signal, both in the pressure pattern and a 25
knot low level ageostropic flow. Surface winds off the gulf of maine
should keep coastal areas above freezing, and daytime temps may
nudge above freezing each day. But interior locations may at least
have a rain/snow mix and may see a period of sleet or freezing rain
especially Friday night and Saturday morning.

Sunday-Monday...

high pressure builds in with dry weather. Building heights and
warming temps aloft suggest Monday will be several degrees milder
than Sunday.

Aviation /13z Tuesday through Saturday/
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Wednesday/...

14z update...

through 18z today... High confidence.

Mainly ifr/lifr with CIGS below 800ft. Vsbys slowly improving if
they haven't already. Light n/e flow.

Late today into tonight... High confidence.

Mix of ifr/lifr. Ra moving in around 19z ct and 22z ma. Ra
tapers off from W to E 03z-09z. Low risk tsra. Ifr/lifr in
lingers afterwords.

Wednesday... High confidence.

Improving conditions through sunrise withVFR everywhere by
15z. Nnw winds. Gusts to 20-25 kt at times.

Kbos taf... High confidence. Ifr and lifr through much of the
period.

Kbdl taf... High confidence. Ifr and lifr through much of the
period.

Outlook /Wednesday night through Saturday/...

Wednesday night-Thursday...

vfr as high pressure builds over the region. Strong gusty north
winds along the eastern ma coast including bos early at night
with gusts 30-35 knots. Winds diminishing overnight and on Thursday.

Friday-Saturday...

MVFR lowering to ifr in the afternoon, then ifr/lifr cigs/vsbys
Friday night and Saturday. Rain expected but with a period of sleet
and freezing rain possible inland Friday night-Saturday. East-
southeast winds Friday become northeast by Saturday.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Wednesday/...

10 am update... No major changes to the forecast.

Today and tonight... High confidence.

Mainly quiet boating weather as winds and seas remain below
small craft advisory thresholds. These winds will shift, mainly
e today, then veer around to the NW by early tomorrow morning.

Fog/drizzle along with showers may lead to low visibilities at
times. Low risk for a modest thunderstorm on the waters late
today through the early overnight hours, especially on the
southern waters.

Wednesday... High confidence.

Nw flow increases with gusts 25-30 kt at times through the day
and seas on the E waters increasing to 5-7ft by late wed
afternoon. Small craft advisories will be needed.

Outlook /Wednesday night through Saturday/...

Wednesday night... Low-moderate confidence.

Low confidence for low-end north gales along the eastern waters.

Otherwise moderate confidence for north winds gusting 25-30 knots,
diminishing overnight. Seas 5 to 8 feet, mainly on the eastern and
southeast outer waters. A small craft advisory will be needed.

Thursday... High confidence.

Diminishing north wind with speeds near 25 knots during the morning.

Seas 5 to 8 feet on the eastern outer waters diminishing through the
day. Lingering small craft advisory will be needed in these areas.

Friday-Saturday... Moderate-high confidence.

Midwest weather system moves to the mid atlantic coast Friday and
passes south of new england Saturday. Increasing southeast winds
during Friday but speeds remain below 25 knots until Friday night.

Winds turn from the northeast Saturday and from north Saturday night
with speeds 25-30 knots. Seas build Friday night and Saturday with
heights 5 to 7 feet. Small craft advisory will be needed.

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

Ma... None.

Ri... None.

Marine... None.

Synopsis... Wtb/doody
near term... Wtb/doody/sipprell
short term... Doody
long term... Wtb
aviation... Wtb/doody/sipprell
marine... Wtb/doody/sipprell


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 11 mi57 min 37°F1 ft
44020 - NANTUCKET SOUND 22 mi71 min 39°F1 ft1016.7 hPa (-0.3)
WAXM3 - Waquoit Bay Reserve, MA 23 mi76 min 41°F 41°F
BZBM3 - 8447930 - Woods Hole, MA 31 mi43 min 40°F 38°F1015.9 hPa
NTKM3 - 8449130 - Nantucket Island, MA 32 mi43 min ENE 7 G 8 40°F 40°F1016.5 hPa
44013 - BOSTON 16 NM East of Boston, MA 49 mi71 min ENE 3.9 G 3.9 39°F 40°F4 ft1016.8 hPa (-0.5)

Wind History for Nantucket Island, MA
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Last
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SE11
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NE5
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hyannis, Barnstable Municipal-Boardman Airport, MA8 mi65 minNNE 610.00 miOvercast41°F39°F96%1016.2 hPa
Chatham, Chatham Municipal Airport, MA10 mi69 minENE 610.00 miOvercast41°F39°F93%1017.3 hPa
Provincetown, Provincetown Municipal Airport, MA18 mi65 minE 710.00 miOvercast42°F37°F85%1017.1 hPa
Otis Air National Guard Base, MA20 mi66 minno data10.00 miOvercast39°F39°F100%1016.9 hPa

Wind History from HYA (wind in knots)
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Last 24hrE8
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S9S5SW4N5N7N8N12N11
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1 day agoE10E8E9SE9
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E8E7E6E5E6E6E746E6E4E5E5E8E7E9
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2 days agoNE8NE11NE10N11N9N7N8N8
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N6N3N3N4CalmN5N4NE5N3CalmN3NE4NE6E9NE12
G17
E11

Tide / Current Tables for Sesuit Harbor, East Dennis, Cape Cod Bay, Massachusetts
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Sesuit Harbor
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Tue -- 06:01 AM EDT     -0.84 feet Low Tide
Tue -- 06:29 AM EDT     Sunrise
Tue -- 07:01 AM EDT     Moonrise
Tue -- 12:15 PM EDT     11.37 feet High Tide
Tue -- 06:24 PM EDT     -0.90 feet Low Tide
Tue -- 07:02 PM EDT     Sunset
Tue -- 07:49 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1110.18.15.42.60.2-0.80.12.357.810.111.3119.26.63.71-0.7-0.61.346.89.5

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Tue -- 12:47 AM EDT     -2.09 knots Max Ebb
Tue -- 03:55 AM EDT     0.00 knots Slack
Tue -- 06:29 AM EDT     Sunrise
Tue -- 07:00 AM EDT     Moonrise
Tue -- 07:09 AM EDT     2.26 knots Max Flood
Tue -- 10:23 AM EDT     -0.01 knots Slack
Tue -- 01:05 PM EDT     -2.18 knots Max Ebb
Tue -- 04:13 PM EDT     0.00 knots Slack
Tue -- 07:01 PM EDT     Sunset
Tue -- 07:29 PM EDT     2.38 knots Max Flood
Tue -- 07:48 PM EDT     Moonset
Tue -- 10:47 PM EDT     -0.01 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-1.9-2.1-1.7-10.11.21.92.32.11.50.5-0.8-1.8-2.2-1.9-1.3-0.30.91.82.32.31.91-0.3

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 (12,3,4,5)
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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.