Friday, March24, 2017 L-36.com


Marine Weather and Tides
West Chatham, 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 6:34AMSunset 6:59PM Friday March 24, 2017 2:03 AM EDT (06:03 UTC) Moonrise 4:38AMMoonset 3:16PM Illumination 12% Phase: Waning Crescent; Moon at 26 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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ANZ254 Coastal Waters From Provincetown Ma To Chatham Ma To Nantucket Ma Out 20 Nm- 117 Am Edt Fri Mar 24 2017
.small craft advisory in effect until 2 am edt early this morning...
.gale watch in effect from noon edt today through this evening...
Rest of tonight..NW winds 5 to 10 kt. Seas 3 to 5 ft.
Fri..SW winds 10 to 15 kt with gusts up to 25 kt...increasing to 15 to 20 kt with gusts up to 35 kt in the afternoon. Seas 3 to 5 ft. A chance of rain.
Fri night..SW winds 15 to 20 kt with gusts up to 35 kt. Seas 4 to 7 ft. A chance of rain.
Sat..W winds 10 to 15 kt...becoming N 5 to 10 kt in the afternoon. Gusts up to 25 kt. Seas 3 to 5 ft. A chance of rain.
Sat night..NE winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft. A chance of rain.
Sun..E winds 10 to 15 kt with gusts up to 25 kt. Seas 3 to 5 ft. A chance of rain.
Sun night..E winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft. A chance of rain.
Mon..SE winds 15 to 20 kt with gusts up to 25 kt. Seas 3 to 5 ft. Rain likely.
Mon night..E winds 15 to 20 kt with gusts up to 25 kt. Seas 3 to 5 ft. Rain likely.
Tue..NE winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 6 ft. A chance of rain.
Tue night..E winds 10 to 15 kt with gusts up to 20 kt. Seas 5 to 7 ft. 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 117 Am Edt Fri Mar 24 2017
Synopsis for massachusetts and rhode island coastal waters.. High pres will move E of the waters Fri. A cold front will pass across the waters from the N on Sat...stay S of the waters on Sunday...then return as a warm front Mon. Low pres will cross the srn waters Mon. Another low pres will cross the waters late Wed and move east of the waters Thu. 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 West Chatham, MA
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location: 41.73, -69.97     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 240225
afdbox
area forecast discussion
national weather service taunton ma
1025 pm edt Thu mar 23 2017

Synopsis
High pressure along the eastern seaboard will move offshore
later tonight bring windy and milder conditions Friday. A cold
front will push south across the region Saturday, then stall
south of new england early next week. Weak low pressure waves
forecast to push along this front, with the potential for
periods of rain and mixed precipitation. Another stronger front
may approach around the middle of next week.

Near term /until 6 am Friday morning/
1025 pm update...

a few high level clouds were starting to arrive in southern new
england. However it will be a while longer before we would need
to worry about precipitation 10 pm dew point depressions were
still on the order of 10 to 25 degrees. The mainly clear sky and
very dry air will lead to good radiational cooling for the next
few hours. This will set the stage for mixed precipitation later
tomorrow, so will need to monitor this evolution closely
overnight.

Mainly made tweaks to the forecast to reflect observed trends.

The latest guidance is still rather quick to bring up dew
points. Although the lamp guidance still appears to have better
timing.

730 pm update...

mainly clear skies, except for a few strips of thin cirrus seen
across new england and down the eastern seaboard on latest ir
satellite imagery at 23z. Leading edge of lower and mid level
clouds working into the eastern great lakes and along the
ny/canadian border, moving steadily se. Based on the satellite
trends, expect high clouds to approach western areas by around
midnight, then move steadily SE with mid deck clouds pushing in
around or after 07z-08z.

Noting light precip moving out of southern ontario into western
ny state on latest NE regional mosaic 88d radar, though
observations beneath the obs not reporting precip at 23z. Very
dry airmass across the region, with dewpts in the single digits
either side of zero, so will take quite a while to saturate the
airmass, as dewpts upstream mainly in the 5-10 degree range.

With the much lower dewpts and mainly clear skies for a few
more hours than previously forecast, will need to monitor temps
which could go into freefall with quick radiational cooling once
winds drop off.

Current forecast in pretty good shape, with dry conditions
expected through the night. Needed to update dewpts, which were
too high based on observations. Remainder of forecast brought
current.

Previous discussion...

we expect radiational cooling the first part of the night,
shutting down later tonight as the clouds thicken. Dew points
start in the single numbers below zero and climb into the teens
by late night. We favored going a couple of degrees below
guidance with a range from the high single numbers in the
interior to near 20 along the coastline. Most areas would be in
the teens.

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

high pressure offshore will provide a flow of milder air. Winds
above the surface will climb to 30-40 knots by midday. That will
provide a flow of moist air with precipitable water values
reaching near an inch by Friday evening. Weak overrunning
created by this southwest flow will create clouds and light
precipitation starting in the morning. Temperatures will be cold
enough at the start for snow, but quickly moderate to rain by
afternoon if not sooner. The transition period may feature some
sleet.

The best chance for this precipitation will be in northern and
western mass. But frozen amounts will be light, with any
snow/sleet accumulation less than an inch.

Have high confidence in the overall trend, but only moderate
confidence in the precipitation types.

The strong southwest low level jet will also provide the
momentum for gusty winds, especially during the afternoon when
mixing is greatest. It still appears the greatest risk for gusts
over 30 mph to be along the boston-providence corridor and
southeast from there.

Max temperatures should make a 5-10 degree rise from today, but
values in the mixed layer Friday are supportive of highs in the
low to mid 40s so still below march normals.

Friday night...

clouds and a southwest flow of milder air will keep
temperatures from falling too much, and most of that should be
in the evening. Temps may rise a little overnight. We maintained
a chance of showers in far northern mass, but low values for
pops.

Long term /Saturday through Thursday/
Highlights...

* seasonal temperatures on Saturday with periods of light rain
* unsettled weather at times Sunday-Tuesday with some rain,
sleet and/or freezing rain possible during the overnight
periods
* low pressure and a cold front push across around mid week,
then improving conditions around next Thursday
overview...

while the 12z operational model suite and ensembles continue to
signal an active weather pattern across the northeast u.S.

During most of this timeframe, noting some improving conditions
toward the end of the long term. Still noting a mainly amplified
but progressive steering pattern through most of the long term
period.

Noting a fast flow aloft to start this weekend while cutoff h5
low sits across the central mississippi valley. This will keep
weak low pres waves moving across the northeast while a front
wavers across southern new england. The cutoff low will lift ne
while it opens up to a short wave over the weekend into early
next week, while large high pressure builds southward out of
quebec across maine and N nh. Some question as to whether the
eastern extent of the stationary front over the region will
shift south for a time during the weekend. At this point, the
ridging may push a bit too far E to bring somewhat drier
conditions.

The cutoff low will bring another shot of lift and moisture
and, with some marginally cooler air trying to work in from the
passing ridge to the e, may see a wintry mix of snow, sleet
and/or freezing rain Sun night into early Mon morning. This
should pass quickly as yet another h5 short wave works E from
the central u.S early next week. Another surface low and
associated cold front should shift sometime in the tue-wed
timeframe, though wide model solution spread lends to lower
timing confidence.

May see improving conditions push in around late Wed or thu,
but again exact timing is still very much in question.

Details...

Saturday-Saturday night... Moderate confidence.

Will be a mild day on Saturday as h85 temps start off from +5c
to +8c. However, as high pressure builds SE out of quebec into n
nh and maine during the day. Will see periods of rain develop
during the day along an advancing cold front that will sink S of
the region. Temps will top off near seasonal normals, from the
mid-upper 40s across N mass, ranging to the mid 50s across s
coastal areas.

Saturday night-Sunday... Moderate confidence.

As temps fall steadily behind the front, readings will approach
the freezing mark across N central and W mass into far N ct.

Partial thickness pattern suggests that precip will change over
to sleet/freezing rain mainly across the higher terrain of n
central and W mass, with some snow also mixed in for a time
overnight. QPF will be light, generally 0.1 inches or less, but
any icing could be problematic. Will continue to monitor this
closely.

Temps will slowly rise, so any mixed precip should change back
to light rain. However, temps may not reach freezing until late
morning across some of the higher terrain of the worcester hills
and berkshires near the ma/nh border. Another shot of steadier
precip will push out of ny state during the afternoon. It will
be a cooler day with highs only in the mid-upper 30s well inland
to the lower 40s across the coastal plain.

Sunday night-Monday... Moderate confidence.

Will see yet another shot of QPF and lift move across the
region during this timeframe. Also noting increasing pwats in
the s-sw flow aloft, on order of 0.8 to 1 inch. QPF amounts
through 18z up to 0.5 to 0.6 inches are possible, with the best
shot between 06z-12z Mon but mainly S of where the colder temps
will be. However, this is still another more problematic
situation for possible winter weather headlines, especially for
portions of central and western mass into far N ct. Have
highlighted this in the hazardous weather outlook.

Temps will again slowly rise during Mon morning, but precip
will continue through the day. Expect readings to top off from
around 40 degrees across the higher terrain to the upper 40s
across S coastal areas as milder air starts to push toward the
region.

Monday night through Thursday... Low confidence.

Noting somewhat better general forecast agreement through most
of this timeframe, but timing and track of specific features
still in question.

Could see another round of mixed precip late Mon night mainly
around the route 2 area of the worcester hills and berkshires
with marginally cold temps with some residual cold air damming,
which should not last too long as temps rise through the 40s on
Tuesday. May see a brief break in the precip as well as a weak
ridge builds across.

Another h5 short wave/surface low will shift NE Tue night/wed.

Again, appears another round of rain will move in ahead of
associated cold front. Some model spread with the frontal
passage, with faster timing shown on the ecmwf, and somewhat
slower on the 12z gfs. Held on to chance pops through midday
wed, then should start to see improving conditions wed
afternoon/night.

As ridging develops at the surface and aloft across the great
lakes/western quebec by 12z Thursday, looks like a dry but cool
day.

Aviation /02z Friday through Tuesday/
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Friday night/...

tonight...VFR. High confidence.

Nw winds becoming light and variable or calm for a time tonight.

Winds then become light south to southwest late tonight. Area
of high clouds pushes into western areas by around 03z-04z,
steadily shifting se.

Friday and Friday night... Moderate confidence.

Vfr with some MVFR mainly north of the mass pike. Increasing
and lowering clouds during the morning. Areas of MVFR
cigs/vsbys in light snow or sleet, with best chance along or
north of boston and the mass pike. All frozen precip should
change to rain during late morning/early afternoon. Southwest
winds will gust 25-30 knots during the day, highest along the
coast and in higher terrain. Winds diminish Friday night.

Kbos taf... High confidence in taf.

Kbdl taf... High confidence in taf.

Outlook /Saturday through Tuesday/...

Saturday-Saturday night... Moderate confidence. Periods of light
rain through Saturday with areas of MVFR CIGS and local MVFR-
ifr vsbys. May see brief period of mix of sleet/freezing rain
overnight Sat night across higher terrain of central and W mass
into N ct. NE wind gusts to around 20 kt Sat night across cape
cod and the islands.

Sunday-Monday... Low to moderate confidence. Areas of MVFR
cigs/vsbys with local ifr conditions through most of the period.

May briefly improve for a time during the daylight hours. Areas
of rain, sleet and/or freezing rain possible late Sun night
into Mon morning, which may linger most of Mon across the higher
terrain. E-se winds may gust to around 20 kt along the
immediate E coast Monday.

Tuesday... Low confidence. Areas of MVFR cigs/vsbys with local
ifr at times. Should see mainly patchy light rain, though can
not rule out brief freezing rain early Tue morning and again
late Tue night with marginally cold temps.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Friday night/...

main change this evening was to post a gale watch for the
eastern outer coastal waters. Have moderate confidence in gusts
up to 35 kt across those waters. If confidence grows overnight,
this watch may be converted to a gale warning. Just wanted to
highlight the potential for mariners.

Tonight... High confidence.

Diminishing NW winds becoming light SW overnight. Seas near 5
feet on the outer waters east of massachusetts early, but
subsiding during the night. Seas elsewhere less than 5 feet. A
small craft advisory lingers on those eastern outer waters for
a few more hours until seas subside.

Friday... Moderate confidence.

High pressure moves well offshore, bringing southwest winds to
the waters. Potential for wind gusts 25-30 knots. This will
build seas with 5 foot heights on many of the waters by the
afternoon. Patchy light rain may bring brief visibility
restrictions. Small craft advisories are being issued for most
waters. An advisory for the eastern outer waters will be issued
once we move clear of the existing headline.

Friday night... Moderate confidence.

Southwest winds 25 to 30 knots may become west toward morning.

Seas of 5-7 feet will linger through the night on the outer
waters and all southwest-exposed waters such as ri sound. Small
craft advisory will lower on boston harbor and narragansett bay,
but linger on the remaining waters.

Outlook /Saturday through Tuesday/...

Saturday... High confidence. NW winds gusting to around 25 kt
sat morning, then diminish and veer to NE by Sat night. Gusts
may approach 25 kt on the southern outer waters Sat night. Seas
5-6 ft on the southern waters early then subside.

Sunday... Moderate confidence. E winds gusting to around 25 kt,
become SE Sun night. Small crafts may be needed. Seas build to
around 5 ft over the outer waters E and S of CAPE cod and the
southern outer waters.

Monday-Tuesday... Low to moderate confidence. E-ne winds gusting
to 25 kt. Seas building to 4-7 ft over the eastern open waters
mon night-tue.

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

Ma... None.

Ri... None.

Marine... Small craft advisory from 10 am Friday to 6 am edt Saturday
for anz232>235-237-255-256.

Small craft advisory from noon to 8 pm edt Friday for anz230.

Small craft advisory from 10 am Friday to 3 am edt Saturday
for anz231-251.

Small craft advisory from 10 am to 10 pm edt Friday for anz236.

Gale watch from Friday afternoon through Friday evening for
anz250-254.

Small craft advisory until 2 am edt Friday for anz254.

Synopsis... Wtb/evt
near term... Wtb/belk/evt
short term... Wtb
long term... Evt
aviation... Wtb/evt
marine... Wtb/belk/evt


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 20 mi30 min 36°F3 ft
44020 - NANTUCKET SOUND 23 mi74 min 38°F1 ft1033.7 hPa (+0.4)
NTKM3 - 8449130 - Nantucket Island, MA 31 mi46 min W 4.1 G 6 32°F 37°F1034.3 hPa
WAXM3 - Waquoit Bay Reserve, MA 31 mi79 min 30°F 11°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi46 min 34°F 37°F1034.3 hPa

Wind History for Nantucket Island, MA
(wind in knots)    EDIT      (on/off)   Help
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NW15
G24
NW14
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NW13
G26
NW16
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NW7
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G12
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NW9
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G26
NW14
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G22
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G34
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N20
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NW6
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G8
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G12
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G14
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G10
SW6
G11
SW6
G10
SW4
G11
W4
G8

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA2 mi72 minWNW 410.00 miFair30°F9°F41%1034.3 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi68 minWNW 310.00 miFair30°F6°F36%1033.6 hPa
Provincetown, Provincetown Municipal Airport, MA23 mi68 minWNW 810.00 miFair34°F16°F48%1034 hPa

Wind History from CQX (wind in knots)
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Last 24hrNW9
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NW9NW7Calm5W4CalmCalm4NW4Calm
1 day ago3CalmW34W7W8W10
G22
NW9
G21
NW12
G21
N9
G21
NW14
G26
NW9
G30
NW16
G27
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G28
NW19
G35
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G32
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G31
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G25
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2 days agoNW43NW4NW4NW3NW44CalmCalmSW55SW6SW6
G16
SW11
G16
S7SW7SW7SW7SW4SW5W5CalmCalmNW7

Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
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Pleasant Bay
Click for Map
Fri -- 04:38 AM EDT     Moonrise
Fri -- 06:18 AM EDT     0.47 feet Low Tide
Fri -- 06:36 AM EDT     Sunrise
Fri -- 11:33 AM EDT     3.17 feet High Tide
Fri -- 03:16 PM EDT     Moonset
Fri -- 06:51 PM EDT     0.17 feet Low Tide
Fri -- 06:56 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.72.321.71.30.80.50.611.82.63.13.12.82.31.91.40.90.30.20.51.11.92.7

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Fri -- 01:04 AM EDT     0.00 knots Slack
Fri -- 04:32 AM EDT     1.75 knots Max Flood
Fri -- 04:37 AM EDT     Moonrise
Fri -- 06:36 AM EDT     Sunrise
Fri -- 07:28 AM EDT     -0.00 knots Slack
Fri -- 10:12 AM EDT     -1.65 knots Max Ebb
Fri -- 01:19 PM EDT     0.00 knots Slack
Fri -- 03:16 PM EDT     Moonset
Fri -- 04:56 PM EDT     2.03 knots Max Flood
Fri -- 06:56 PM EDT     Sunset
Fri -- 08:00 PM EDT     -0.00 knots Slack
Fri -- 10:44 PM EDT     -1.68 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.8-0.10.81.41.71.71.30.5-0.5-1.3-1.6-1.5-1.1-0.30.61.41.921.81.10-1-1.6-1.7

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 (2,6,7,8)
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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.