Wednesday, August21, 2019 L-36.com


Marine Weather and Tides
West Chatham, MA

Version 3.4
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7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
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Sunrise 5:54AMSunset 7:34PM Wednesday August 21, 2019 4:56 PM EDT (20:56 UTC) Moonrise 10:42PMMoonset 11:32AM Illumination 63% Phase: Waning Gibbous; Moon at 21 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- 402 Pm Edt Wed Aug 21 2019
.small craft advisory in effect from 8 pm edt this evening through Thursday evening...
Tonight..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 3 to 5 ft. A slight chance of showers and tstms this evening, then a chance of showers and tstms after midnight. Some tstms may produce damaging winds, large hail, and heavy rainfall this evening.
Thu..SW winds 10 to 15 kt. Seas 3 to 5 ft. Patchy fog. Vsby 1 nm or less.
Thu night..W winds 5 to 10 kt. Seas 3 to 5 ft. A chance of showers.
Fri..NW winds 5 to 10 kt. Seas 2 to 4 ft. A chance of showers. Vsby 1 to 3 nm.
Fri night through Sat night..NE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Sun through Mon..E winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 6 ft. 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 402 Pm Edt Wed Aug 21 2019
Synopsis for massachusetts and rhode island coastal waters.. A south to southwest wind will persist tonight and Thu until a cold front sweeps across the waters sometime Thu night into early Fri morning. Dry weather and good vsby follows for Fri and Sat as high pres builds over quebec. A northwest wind persists Sun and Mon as the high shifts over the canadian maritimes. 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 211904
afdbox
area forecast discussion
national weather service boston norton ma
304 pm edt Wed aug 21 2019

Synopsis
Scattered strong thunderstorms will diminish this evening. Hot
and humid conditions persist Thursday then a period of showers
and isolated thunderstorms expected Thursday night as a cold
front stalls near the south coast. Wet weather may linger into
Friday along the south coast, otherwise improving conditions.

High pressure builds across the maritimes, with steady onshore
winds bringing cool temperatures this weekend into early next
week. There may also be a chance for a few showers Sunday
through Tuesday.

Near term until 10 pm this evening
Despite marginal mid level lapse rates, moderate instability
across sne with mlcapes 1500-2000 j kg. Scattered
showers t-storms will continue to develop through the afternoon
as mid level shortwave moves in from the west.

0-6km shear 30-35 kt so potential for storms to organize into
multi-cellular line segments per the hi-res cams. Damaging wind
is the primary threat with large hail also possible with the
strongest cores and any rotating storms. Modest 850 mb jet
develops later this afternoon early evening increasing low
level shear so a few supercells can't be ruled out and will
have to watch for potential rotating storms which could produce
an isolated tornado. While all sne is at risk for severe storms,
the greatest risk will be across northern ct into interior ma
where best updraft helicity is focused. Timing of strongest
storms will be through 9 pm.

In addition, pwats pushing 2 inches later this afternoon so
risk of heavy rainfall may result in areas of urban and poor
drainage flooding, especially in areas of thunderstorm training.

Short term 10 pm this evening through 6 pm Thursday
Expect convection to diminish later this evening as instability
decreases while focus shifts to the south coast overnight. Just
a few showers or an isolated t-storm possible late tonight near
the south coast. Patchy low clouds and fog expected to develop
along the coast. Warm and humid night with lows upper 60s to
lower 70s.

Thursday...

cold front moves into the interior this afternoon but remains
west of the coastal plain through early evening. Another hot
and humid day as 850 mb temps around 17-18c. Highs in the upper
80s to lower 90s with dewpoints into the lower 70s, although
becoming less humid in the interior in the afternoon as
dewpoints fall through the 60s behind the front. Heat index
values mid upper 90s in eastern ma ri so close to heat advisory
criteria.

Regarding convective potential, capes around 1000 j kg expected
which may be limited by some drier air aloft moving in during
thu. This may help suppress convective activity although can't
rule out a few showers or t-storms in the afternoon along the
boundary. Better chance for convection will be late Thu and
especially Thu night as deeper moisture returns from the west
along the frontal boundary.

Long term Thursday night through Wednesday
Highlights...

* showers and a few thunderstorms linger Thursday night as the cold
front slowly crosses
* showers linger on Friday with cooler temperatures
* expect mild temperatures and dry conditions Saturday
* cooler than normal temperatures expected Sunday through Tuesday
along with spotty light rain or showers at times
details...

Thursday night and Friday...

this period will be a transition between two air masses, as a cold
front slowly makes its way through bringing a renewed chance of
showers overnight into the first half of Friday. The main players
will be the approaching upper trough and surface cold front, which
guidance has begun to suggest will develop another surface low or
wave feature along that frontal boundary as it gets hung up in the
vicinity of the south coast late. This will bring renewed
showers chances overnight Thursday into the first half of
Friday, especially along and south of the ma pike in closest
proximity to the best surface convergence related to the cold
front and secondary low. Ample moisture lingering... Pwats are
slow to drop behind the front late Thursday, staying near 2"
along the south coast through 15z Friday. Good synoptic lift as
well under the rrq of a 115kt h300 jet together with the surface
low wave could produce an additional 0.25- 0.5" of rain with
locally higher amounts. Instability looks to be limited mainly
to several hundred j kg CAPE over ri and southeast ma, through
about midnight which is where we stand the best chance of seeing
some embedded thunderstorms in the evening early overnight
hours. The details will depend greatly on the strength and track
of this feature which could potentially take the heaviest rain
offshore or further north if it wavers n-s. Dewpoints will be
dropping from NW to se, which will keep low temps higher in
southeast ma ri, in the upper 60s, with upper 50s for NW mass.

Friday showers linger in the morning and potentially into early
afternoon as the wave moves off. Post frontal air mass is much drier
with dewpoints back squarely in the comfortable zone by late Friday,
in the 50s for most, save for potentially the extreme south coast.

Surface pressure increasing and skies clearing through the day. A
big airmass change in the works, with cooler (slightly below
average) temps in the 70s.

Previous discussion...

Saturday through Tuesday...

quite a bit of model solution spread amongst the members this
morning, with lends to lower confidence on the forecast during this
timeframe.

Rather confident with the slow but steady movement of the high
pressure across northern new england, setting up across maine into
eastern quebec and new brunswick late this weekend. This will set up
a NE and eventually easterly wind flow by the start of the work
week. Could see some gusts up to 20-25 mph across CAPE cod and the
islands, possibly into S coastal areas on Sunday. The big question
will be whether patchy light rain and or showers could develop from
time to time from Sunday to Tuesday. Where these showers and or rain
set up is in question, but have kept slight chance pops going for
now. At this point, looks like there might be a somewhat better
chance for more organized showers Monday into Tuesday, but not a lot
of confidence.

With the steady onshore flow, expect temps to run around 5 degrees
or so below seasonal normals, mainly from Sunday to Tuesday. Highs
on Sunday and Monday may not break 70 at some locations along e
coastal mass.

Aviation 19z Wednesday through Monday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ... Moderate confidence.

Through 00z...

mix ofVFR MVFR cogs. Scattered showers t-storms developing
through the afternoon will be accompanied by brief ifr and
heavy downpours gusty winds.

Tonight...

a few showers t-storms this evening shifting to south coast
later tonight. MVFR ifr stratus and patchy fog developing after
midnight, especially near the south coast and over portions of
the ct valley.

Thursday...

areas of MVFR ifr early, then improving toVFR by midday.

Isolated showers t-storms possible in the afternoon.

Kbos terminal... Moderate confidence in taf. A few t-storms
possible 4-8 pm. Brief downpours, gusty winds and ifr possible
in any strong storms. MostlyVFR tonight.

Kbdl terminal... Moderate confidence in taf. A few t-storms
likely through 8 pm. Brief downpours, gusty winds and ifr
possible in any strong storms. MostlyVFR tonight.

Outlook Thursday night through Monday ... Moderate confidence
Thursday night:VFR. Chance shra, slight chance tsra.

Friday:VFR. Slight chance shra.

Friday night through Saturday:VFR.

Saturday night: ifr. Breezy.

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

Sunday night: mainlyVFR, with local ifr possible. Breezy.

Monday: breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ... High confidence.

A period of marginal 20-25 kt wind gusts possible tonight over
southern waters along with building seas to around 5 ft so have
continued the sca. Winds diminish by early thu. A few
showers t-storms possible this evening shifting to south
coastal waters overnight. Vsbys may also be reduced at times in
fog late tonight and Thu morning.

Outlook Thursday night through Monday ... Moderate confidence.

Thursday night: winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, slight chance of
thunderstorms.

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

Chance of rain showers.

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

Saturday: winds less than 25 kt.

Saturday night: winds less than 25 kt. Seas locally approaching
5 ft. Visibility 1 nm or less.

Sunday: low risk for small craft advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Slight chance of
rain. Local visibility 1 nm or less.

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

Monday: low risk for small craft advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Slight chance of
rain.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 8 pm this evening to 8 pm edt
Thursday for anz254>256.

Small craft advisory from 11 pm this evening to 8 am edt
Thursday for anz235-237.

Synopsis... Kjc bw
near term... Kjc
short term... Kjc
long term... Evt bw
aviation... Kjc bw
marine... Kjc bw


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 20 mi56 min 71°F2 ft
44020 - NANTUCKET SOUND 23 mi36 min SW 16 G 19 75°F 75°F71°F
NTKM3 - 8449130 - Nantucket Island, MA 31 mi56 min SSW 6 G 13 77°F 77°F1013.8 hPa (-0.9)
WAXM3 - Waquoit Bay Reserve, MA 31 mi71 min SSE 5.1 80°F 1013 hPa73°F
44018 - SE Cape Cod 30NM East of Nantucket, MA 34 mi66 min S 12 G 12 71°F 2 ft1012.7 hPa (-1.7)67°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi56 min 77°F 74°F1013.6 hPa (-0.9)

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA2 mi64 minSSW 7 G 1910.00 miFair79°F72°F79%1014 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi60 minSSW 139.00 miA Few Clouds80°F71°F74%1013.1 hPa
Provincetown Municipal Airport, MA23 mi60 minSSW 1110.00 miFair78°F71°F79%1013.2 hPa

Link to 5 minute data for KCQX

Wind History from CQX (wind in knots)
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Last 24hr4SE4SE3CalmCalmS3S3CalmS3S3SW4S3S34CalmSW44S56S7--SW6SW8
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SW3W43CalmSW4SW3W3W3Calm3NW46643NE64E6SE5
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Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
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Pleasant Bay
Click for Map
Wed -- 12:53 AM EDT     0.41 feet Low Tide
Wed -- 05:54 AM EDT     Sunrise
Wed -- 06:16 AM EDT     3.20 feet High Tide
Wed -- 11:32 AM EDT     Moonset
Wed -- 01:11 PM EDT     0.41 feet Low Tide
Wed -- 06:39 PM EDT     3.24 feet High Tide
Wed -- 07:31 PM EDT     Sunset
Wed -- 10:42 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.60.40.71.322.83.23.12.51.91.410.70.40.511.82.53.13.22.82.21.61.2

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
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Wed -- 01:57 AM EDT     -0.00 knots Slack
Wed -- 04:34 AM EDT     -1.74 knots Max Ebb
Wed -- 05:54 AM EDT     Sunrise
Wed -- 07:40 AM EDT     0.00 knots Slack
Wed -- 10:55 AM EDT     1.93 knots Max Flood
Wed -- 11:31 AM EDT     Moonset
Wed -- 02:22 PM EDT     -0.00 knots Slack
Wed -- 04:59 PM EDT     -1.74 knots Max Ebb
Wed -- 07:30 PM EDT     Sunset
Wed -- 08:07 PM EDT     0.00 knots Slack
Wed -- 10:42 PM EDT     Moonrise
Wed -- 11:19 PM EDT     1.82 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.50.9-0.1-1-1.7-1.7-1.3-0.60.31.21.81.91.71.20.4-0.7-1.5-1.7-1.5-0.9-0.10.81.51.8

Weather Map and Satellite Images
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GOES Local Image of    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 (16,3,4,5)
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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.