Wednesday, December12, 2018 L-36.com


Marine Weather and Tides
Harwich Port, MA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 6:57AMSunset 4:12PM Wednesday December 12, 2018 6:58 AM EST (11:58 UTC) Moonrise 11:49AMMoonset 10:07PM Illumination 24% Phase: Waxing Crescent; Moon at 5 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- 345 Am Est Wed Dec 12 2018
.small craft advisory in effect from 7 am est this morning through this afternoon...
Today..NW winds 10 to 15 kt with gusts up to 30 kt. Seas around 3 ft. A chance of snow showers.
Tonight..N winds 10 to 15 kt with gusts up to 20 kt, becoming ne 5 to 10 kt after midnight. Seas around 3 ft. A chance of snow showers in the evening.
Thu..E winds 5 to 10 kt. Gusts up to 20 kt in the morning. Seas 2 to 3 ft.
Thu night..SE winds 5 to 10 kt. Seas around 2 ft.
Fri..SE winds 5 to 10 kt. Seas around 2 ft.
Fri night..S winds 5 to 10 kt. Gusts up to 20 kt after midnight. Seas around 2 ft. Rain.
Sat..S winds 10 to 15 kt, becoming W in the afternoon. Gusts up to 20 kt. Seas around 3 ft. Rain.
Sat night..N winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Gusts up to 25 kt. Seas 4 to 5 ft. Rain likely, mainly in the evening.
Sun..NE winds 10 to 15 kt with gusts up to 25 kt. Seas 5 to 6 ft. A chance of rain.
Sun night..NE winds 10 to 15 kt with gusts up to 20 kt. Seas around 5 ft. A chance of rain in the evening. 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 345 Am Est Wed Dec 12 2018
Synopsis for massachusetts and rhode island coastal waters.. Weak low pres will pass E across the waters this morning. High pres builds S from quebec today into Thu. Expect ocean effect snow bands to develop under n/nw winds across the ern ma waters today into tonight. This high pres will shift E of the waters on Fri. A storm system will approach the waters from the sw Fri night and Sat, lifting slowly across the waters Sat night and Sun. 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 Harwich Port, MA
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location: 41.57, -70.05     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 121151
afdbox
area forecast discussion
national weather service boston norton ma
651 am est Wed dec 12 2018

Synopsis
Mainly dry and cold weather prevails into Thursday, except for some
scattered ocean effect snow showers Wednesday, mainly across the
outer-cape. Mild temperatures arrive Friday and continue into early
next week. Light to moderate rain on tap for Friday night into
Saturday, while an uncertain forecast prevails thereafter with an
offshore storm potential Sunday into Monday followed by dry weather
for the remainder of the week.

Near term until 6 pm this evening
7 am update...

lot of mid-level energy riding overhead parent with a continental-
polar moist airmass pooling beneath an inversion up around h8
which will lower through the day with increasing sinking motions
as high pressure moves in. Only concerns are ocean-effect snow
showers lingering over the CAPE and islands along with gusty N nw
winds. Both diminishing towards evening. Details in the previous
discussion below.

Previous discussion...

latest streamline analysis placed the best surface convergence
zone across the upper CAPE and the vineyard early this morning.

Expecting this convergence area to move farther east during the
day, especially once a vigorous mid level shortwave moves off-
shore early this morning. Not seeing great reduction in visibility
so far this morning. Thus only light accumulation is expected.

The details will be crucial this morning, as even a 10 degree
shift in the dominant wind direction will alter the location of
the greatest snowfall. There is some mid level frontogenesis as
well, but thinking the ocean-effect snow process will be the
dominant factor today due to drier mid level air arriving this
afternoon. The greatest instability still appears to remain
over the coastal waters. The area of at risk for some snow will
be from coastal plymouth county, east across the CAPE and
islands.

Across the rest of S new england, clearing should be rather quick
this morning, expect perhaps towards the berkshires. Despite plenty
of sunshine, temperatures will still be below normal.

Short term 6 pm this evening through 6 pm Thursday
Strong high pressure moves from quebec across northern new england
tonight, then reaching a point south of nova scotia late Thursday.

Dry weather for most of southern new england tonight and Thursday.

With the high pressure not directly overhead, looking at abundant
mid level clouds arriving late tonight into Thursday as another
shortwave approaches from the west.

These clouds may not arrive in time to place an curbs on radiational
cooling tonight. Low temperatures in the teens and single digits
above zero will be common. Even near the coast, low temperatures
of 20-25 degrees are expected. The colder start and limited sunshine
Thursday will mean another day of well below normal high temperatures,
likely even lower than today.

Long term Thursday night through Tuesday
* highlights...

- seasonable and dry Thursday night into Friday
- light to moderate rain Friday night into Saturday
- hold a dry forecast Saturday night into Sunday
- uncertain forecast around Monday, dry through the week
* overview...

broadly speaking, evaluating temperature along potential vorticity
surfaces (2 pvu), seemingly subtle eastward propagation of a rossby
wave train. Favorable h5 trof development into the NE pacific (+epo
trends) resulting in SW advance W central canada +h85 temperature
anomalies from h2 h85 W perturbations from +enso EL nino source
regions coincident with a E propagating mjo from phase 3 to 4. Down-
sheared equatorward pv-streamers shifting into the conus, lee of the
rockies, storms manifesting further E along a sub-tropical pacific
jet. Captured, cut-off, propagating along a favorable storm-track as
colder air pv-streamers are continually downsheared E of the h5
ridging parent to aforementioned +h85 temperature anomalies over w
canada, the NE CONUS pattern has been quiet as of late beneath cold
northerlies.

But into mid-december, those cold northerlies becoming lax, there's
the opportunity for the favorable storm track to lift n, as is the
potential for secondary pv-streamers to wrap S and capture any such
storm development. Worth noting with respect to the weekend into
early next week forecast. Whether this pattern maintains is somewhat
uncertain per N pacific trends (wpo or epo) as well echoes occurring
up through the stratosphere with dominant N american ridging as the
sw heat-pump continues downstream across canada, the parent strato-
vortex shoved to the other side of the hemisphere. CPC 8 to 14 day
and 3 to 4 week outlooks concerning above-average temperatures seem
to coincide with such trends.

Details in the discussion below highlighting forecast thinking along
with forecast model preference.

* discussion...

Thursday night through Friday...

dry and seasonable. Deamplifying mid-level vortex exiting, consensus
model forecast guidance has heights rising with S winds in tow. The
influence of high pressure, winds light, partial clearing, there is
the potential for radiational cooling into Friday morning. However
some indication of a non-diurnal temperature trend with light winds
becoming s, increasing into Friday pushing highs into the 40s prior
to active weather into the weekend.

Friday night into Saturday night...

light to moderate rain. Likely pops especially towards the s-coast.

Cut-off low lee of the rockies along the sub-tropical pacific jet
loses its connection with the n-stream which races faster e. Broad
and diffuse connection through jet coupling echoed down to a surface
frontal boundary, mid to upper level isentropic upslope towards new
england, yet majority of surface to low level focus confined to a
secondary offshore mid-atlantic t-occlusion low with anomalous s
winds and precipitable waters. Isallobaric response, undercutting
drier northerlies as ridging pushes into E canada, leaning a storm
track shunted S drying us out into Saturday night. Preference to the
more run-to-run consistent ec. Brief period of freezing rain possible
along the high terrain with onset.

Sunday through Monday night...

low confidence forecast. Forecast model solutions struggling with a
secondary PV streamer wrapping into a now warm-core mid-upper level
low pushing E off the mid-atlantic. Timing crucial as to potential
interaction phasing, unclear is the proximity and morphology of
potential storm development to S new england. Noteworthy ensemble
member spread lending to uncertainty. Confident progressive flow
downstream lending to storm maturation further e, but will have to
watch for cyclonic, comma-head development reaching back over new
england. Again, preference towards ec model guidance. As noted by
the prior forecaster, within a mild regime, any wintry outcomes
would require a deeper storm center and cold manifestation with a
near-benchmark (40n 70w) track.

Tuesday onward...

arctic air bottled up well N per aforementioned trends within the
overview, a SW CONUS anti-cyclonic wave break emerging promoting
downstream NE CONUS h5 trof preference, with any storm development
possible by the end of the week, location dependent as well as to
whether it can manifest its own cold or colder air S determinant
towards any potential wintry weather outcomes.

Aviation 12z Wednesday through Sunday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ... High confidence.

Vfr throughout. Only concern is areas of MVFR-ifr with shsn
across the CAPE and islands into this evening. N NW winds today
becoming gusty, already so at a few locations, with gusts up
around 25 kts. Winds turning light overnight, shifting E into
Thursday.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf.

Outlook Thursday night through Sunday ...

Thursday through Thursday night:VFR.

Friday: mainlyVFR, with local MVFR possible. Fzra likely,
chance ra.

Friday night: mainlyVFR, with local ifr possible. Ra, fzra
likely.

Saturday: mainlyVFR, with areas MVFR possible. Breezy. Ra.

Saturday night:VFR. Breezy. Chance ra, chance sn.

Sunday:VFR. Breezy. Slight chance ra, slight chance sn.

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.

Northerly flow increases across the waters this morning. Rough
seas expected to develop across the outer coastal waters as a
result. A small craft advisory has been issued for many of our
open waters. In addition to the winds, ocean-effect snow showers
may reduce visibility at times to less than 3 nm late into this
evening across the eastern coastal waters. Winds diminish
tonight, but seas will take longer to subside, especially across
the eastern outer coastal waters.

Outlook Thursday night through Sunday ...

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

Thursday night: winds less than 25 kt.

Friday: winds less than 25 kt. Chance of rain.

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

Saturday: low risk for small craft advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Rain.

Saturday night: moderate risk for small craft advisory winds
with gusts up to 30 kt. Areas of rough seas. Chance of rain.

Sunday: low risk for small craft advisory winds with gusts up
to 25 kt. Rough seas up to 9 ft. Chance of rain.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory until 4 pm est this afternoon for
anz231>234-251.

Small craft advisory until noon est Thursday for anz250-254-
255.

Small craft advisory until 6 pm est this evening for anz256.

Synopsis... Belk sipprell
near term... Belk sipprell
short term... Belk
long term... Sipprell
aviation... Belk sipprell
marine... Belk sipprell


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44020 - NANTUCKET SOUND 13 mi39 min NW 18 G 21 32°F 40°F1013.1 hPa21°F
NTKM3 - 8449130 - Nantucket Island, MA 20 mi41 min NNW 8.9 G 18 33°F 38°F1012.7 hPa
44090 24 mi59 min 43°F4 ft
WAXM3 - Waquoit Bay Reserve, MA 25 mi74 min 6 31°F 1013 hPa20°F
BZBM3 - 8447930 - Woods Hole, MA 33 mi41 min 31°F 40°F1013.3 hPa
44018 - SE Cape Cod 30NM East of Nantucket, MA 44 mi69 min NNW 23 G 27 33°F 4 ft1011.7 hPa (+1.1)19°F

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA10 mi67 minNNW 9 G 1410.00 miOvercast33°F24°F70%1012.5 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA14 mi63 minNW 12 G 2110.00 miOvercast33°F23°F66%1012 hPa
Nantucket, Nantucket Memorial Airport, MA21 mi66 minNNW 148.00 miLight Snow33°F26°F75%1012 hPa

Wind History from CQX (wind in knots)
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Last 24hrNW3CalmCalmCalmS4S64SW5SW3CalmCalmNW3CalmNW3CalmCalmCalmNW3CalmCalmCalmCalm5NW9
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1 day ago5N336NE7
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N75NE6NE55N5CalmCalmNW3NW3CalmCalmCalmCalmCalmCalmNW3NW4NW4
2 days agoW33W5W755SW666SW4SW8
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Tide / Current Tables for Monomoy Point, Cape Cod, Massachusetts
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Monomoy Point
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Wed -- 03:02 AM EST     3.46 feet High Tide
Wed -- 06:57 AM EST     Sunrise
Wed -- 08:49 AM EST     0.59 feet Low Tide
Wed -- 10:48 AM EST     Moonrise
Wed -- 03:08 PM EST     3.76 feet High Tide
Wed -- 04:10 PM EST     Sunset
Wed -- 09:07 PM EST     Moonset
Wed -- 09:23 PM EST     0.24 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.92.63.23.53.32.82.11.40.80.60.91.52.22.93.53.83.632.31.50.70.30.30.8

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
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Wed -- 12:42 AM EST     -0.00 knots Slack
Wed -- 03:20 AM EST     -1.60 knots Max Ebb
Wed -- 06:30 AM EST     0.00 knots Slack
Wed -- 06:57 AM EST     Sunrise
Wed -- 09:48 AM EST     1.67 knots Max Flood
Wed -- 10:48 AM EST     Moonrise
Wed -- 12:50 PM EST     -0.00 knots Slack
Wed -- 03:29 PM EST     -1.65 knots Max Ebb
Wed -- 04:10 PM EST     Sunset
Wed -- 06:38 PM EST     0.00 knots Slack
Wed -- 09:07 PM EST     Moonset
Wed -- 10:11 PM EST     1.99 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.8-0.3-1.2-1.6-1.5-1.1-0.40.41.21.61.71.40.8-0.2-1.1-1.6-1.6-1.2-0.60.31.21.821.9

Weather Map and Satellite Images
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GOES Local Image of Northeast    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 (6,6,7,8)
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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.