Thursday, December13, 2018 L-36.com


Marine Weather and Tides
Nantucket, 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 6:58AMSunset 4:12PM Thursday December 13, 2018 2:54 PM EST (19:54 UTC) Moonrise 12:20PMMoonset 11:06PM Illumination 37% Phase: Waxing Crescent; Moon at 6 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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ANZ255 Coastal Waters Extending Out To 25 Nm South Of Marthas Vineyard And Nantucket- 116 Pm Est Thu Dec 13 2018
This afternoon..E winds 5 to 10 kt. Seas 2 to 3 ft.
Tonight..E winds 5 to 10 kt. Seas 2 to 3 ft.
Fri..SE winds 5 to 10 kt. Seas 2 to 4 ft.
Fri night..S winds 5 to 10 kt. Seas 3 to 4 ft. A chance of rain.
Sat..SW winds 5 to 10 kt, becoming ne with gusts up to 20 kt in the afternoon. Seas 2 to 4 ft. A chance of rain.
Sat night..NE winds 15 to 20 kt with gusts up to 30 kt. Seas 4 to 7 ft.
Sun..E winds 15 to 20 kt with gusts up to 30 kt. Seas 5 to 8 ft. A chance of rain.
Sun night..NE winds 15 to 20 kt with gusts up to 30 kt. Seas 6 to 9 ft. A chance of rain.
Mon..N winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 7 ft. A chance of rain.
Mon night..NW winds 20 to 25 kt with gusts up to 30 kt. Seas 4 to 7 ft. 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 116 Pm Est Thu Dec 13 2018
Synopsis for massachusetts and rhode island coastal waters.. 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. High pres builds back towards the waters from the W on Tue. 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 Nantucket, MA
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location: 41.27, -70.06     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 131805
afdbox
area forecast discussion
national weather service boston norton ma
105 pm est Thu dec 13 2018

Synopsis
Cold weather continues today with a period of light snow flurries
likely across interior S new england. Mild temperatures arrive Friday
and continue into early next week. Light to moderate rain possible
late Friday through Saturday evening, while an uncertain forecast
prevails thereafter with an offshore storm potential Sunday into
Sunday night concluding into Monday morning. Cold and dry thereafter
through Thursday with the possibility of a late-week storm system.

Near term until 6 pm this evening
1 pm update...

light snow focused across western new eng. As low levels
moisten, a few flurries possible in eastern new eng. Forecast
on track.

Previous discussion...

robust mid level low and shortwave across new york will be
moving through sne this afternoon. There is only weak lift
assocd with this feature as it is battling the subsidence with
the strong high pres which is slowly departing new eng. Best
moisture and isentropic lift will be focused to the sw. Low
level dry air in place but models indicate increasing low level
moisture with best moisture across western ct ma where some
light snow is expected through the afternoon. Any accum will be
limited to a coating to 0.5", especially in the higher
elevations in the berkshires and NW hartford county. A few
flurries are possible further E into central and eastern new
eng. Snow growth region is near saturation through most of the
afternoon so freezing drizzle threat is low. Snow growth region
dries out tonight but precip will likely be over by this time.

Highs will be in the low to mid 30s across eastern new eng, and
upper 20s to lower 30s across interior, coldest higher terrain.

Short term 6 pm this evening through 6 pm Friday
Once a mid level shortwave moves by our region, dry weather will
prevail across all of southern new england. Depending upon the
timing, there remains a low risk for a brief period of freezing
drizzle towards the end as the drier air invades the snow
growth region. Like the previous forecaster, do not have enough
confidence in this to include it in the forecast. Probability
favors a simple end to the snow showers flurries. Will need to
monitor this aspect of the forecast for this evening.

Friday still appears to be a transition day. High pressure off
the east coast of new england moves farther offshore. As it
does, winds will come from the south, starting our gradual
warmup. Expecting all of southern new england to be above
freezing by the time there is a risk for precipitation late in
the day across the western half of our region. High temperatures
should be near normal.

Long term Friday night through Wednesday
* highlights...

- light to moderate rain possible around Saturday
- skirting offshore storm system Sunday - Sunday night
- cold and dry Monday through Thursday
- another storm system possible late week
* overview...

not much change with respect to the overview discussion below which
was published yesterday.

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 out of the pacific 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...

Friday night through Saturday night...

consensus forecast trend Friday night through Saturday night of n-
stream dissociated energy from a downsheared, cut-off stacked low
sweeping through the NE CONUS with a surface reflection trailing
cold front. Lead isentropic ascent emanating from s-stream cut-off
low tied into the pacific sub-tropical jet undergoing lift beneath
stable heights, wedge of high pressure, confluent mid-upper level
flow. Can't rule out chance pops with light to moderate rain given
weak mid-level ascent and support per right-rear-quadrant of a h3
jet. Quite possible a tongue of high theta-e, high precipitable
water air wedges in right ahead of the cold front prior to sweeping
new england. Yet uncertainty given how quickly the cold front sweeps
through, dry air following. Marginal thermal fields, lack of any
arctic air. Onset high-terrain freezing rain per wet-bulb processes
possible, otherwise all liquid. Waffling h5 ridging coupled with
surface high pressure Saturday night, a low confidence forecast.

Sunday through Sunday night...

if secondary n-stream follow-up pv-streamer dips further S faster,
then seemingly sooner the s-stream cut-off low pivots and wraps back
beneath lower heights, negative-tilted, promoting rapid cyclogenesis
and storm maturation closer to the S new england shoreline. However,
notable forecast model spread continues with feature morphology, a
slower pace, the cut-off low nudged out to sea yielding perhaps a
skirt of or a complete miss in outcomes. Low confidence despite a
trend towards better consensus. Confident arctic air bottled well
n w, thermal fields will be marginal. If wintry precip-types, will
need a deeper low center manifesting its own cold air downward, h85-
7 low positioning crucial in such a case. Isentropic ageostrophic
n flow from departing high pressure wedge likely aiding as well. A
couple more forecast model runs and hopefully there will be a better
idea on specifics. Higher pops towards S E coastal new england along
with stronger winds closer to the forecast low center near the 40n
70w benchmark, cyclonic motions associated, an eye on comma-head
trowaling features. Quick moving given progressive flow downstream,
looking at outcomes around a 12-hour period. Chance pops. Ensemble
mean and accompanying probability preference.

Monday through Thursday...

initial arctic blast equatorward in wake of the deepening h5 trough
over E SE canada. Blustery NW winds making it feel colder. Coldest
air Wednesday morning with high pressure in control, radiational
cooling processes. Moderating temperature trend into Thursday with
southerly winds as high pressure shifts e. Preference towards the ec
ensemble mean.

Thursday night onward...

another storm possible late-week, but too early to say on specifics.

Only worthy of a mention based on run-to-run ec consistency with
accompanying ecens trends.

Aviation 18z Thursday through Tuesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday ...

through 00z...

areas of MVFR ifr in light snow across western ma and ct
valley, otherwiseVFR cigs.

Tonight... Moderate confidence.

MVFR CIGS across western ma and ct with a low risk for some very
light snow or fzdz. OtherwiseVFR with partial clearing SE new
eng.

Friday... Moderate confidence.

MVFR CIGS across much of the interior, especially western new
eng. MainlyVFR CIGS SE new eng.

Friday night... Moderate confidence.

Areas of MVFR ifr cigs. Chance of light rain.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf.

Outlook Saturday through Monday ...

Saturday: mainlyVFR, with local MVFR possible. Slight chance
ra.

Saturday night:VFR. Breezy.

Sunday: mainlyVFR, with areas MVFR possible. Breezy. Slight
chance ra, slight chance sn.

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

Chance ra, chance sn.

Monday: mainlyVFR, with areas ifr possible. Breezy. Slight
chance ra.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday ... High confidence.

Once seas subside later this morning across the eastern coastal
waters, expecting rather tranquil boating conditions to prevail
through Friday as a high pressure passes by.

Outlook Friday night through Monday ...

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

Friday night through Saturday: winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain.

Saturday night: moderate risk for small craft advisory winds
with gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain.

Sunday through Sunday night: moderate risk for small craft
advisory winds with gusts up to 30 kt. Rough seas up to 9 ft.

Chance of rain.

Monday: low risk for small craft advisory winds with gusts up
to 25 kt. Rough seas up to 8 ft. Slight chance of rain.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... None.

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


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
NTKM3 - 8449130 - Nantucket Island, MA 2 mi55 min ESE 1.9 G 8.9 35°F 37°F1033.1 hPa (+0.3)
44020 - NANTUCKET SOUND 19 mi45 min E 5.8 G 7.8 34°F 40°F1033.4 hPa22°F
WAXM3 - Waquoit Bay Reserve, MA 33 mi70 min 1.9 35°F 1033 hPa23°F
BZBM3 - 8447930 - Woods Hole, MA 37 mi55 min 35°F 40°F1032.9 hPa (+0.0)
44090 42 mi55 min 43°F1 ft

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA1 mi62 minVar 410.00 miPartly Cloudy35°F21°F57%1033 hPa

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N11N10N8N7N7N8NE11NE6CalmCalmNE5NE3NE5E8E8E8SE44
1 day agoSE5CalmNE3NE4N5N3NW3W6NE4E5NE3N6N4N7NW3NW14NW15
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2 days agoN12N12N9N10N7N5N3N5N5N5N5N4N4NW5NW4NW6N5N4N5NE6S43SE4S9

Tide / Current Tables for Nantucket, Nantucket Island, Massachusetts
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Nantucket
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Thu -- 04:19 AM EST     2.78 feet High Tide
Thu -- 06:57 AM EST     Sunrise
Thu -- 09:51 AM EST     0.77 feet Low Tide
Thu -- 11:20 AM EST     Moonrise
Thu -- 04:11 PM EST     Sunset
Thu -- 04:19 PM EST     3.23 feet High Tide
Thu -- 10:06 PM EST     Moonset
Thu -- 10:32 PM EST     0.30 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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11.522.52.82.72.41.91.40.90.811.522.52.93.23.12.72.11.50.80.40.3

Tide / Current Tables for Nantucket Harbor Entrance Channel, Massachusetts Current
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Nantucket Harbor Entrance Channel
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Thu -- 03:14 AM EST     -0.00 knots Slack
Thu -- 06:57 AM EST     Sunrise
Thu -- 08:22 AM EST     -1.35 knots Max Ebb
Thu -- 10:34 AM EST     0.00 knots Slack
Thu -- 11:20 AM EST     Moonrise
Thu -- 12:19 PM EST     1.00 knots Max Flood
Thu -- 02:48 PM EST     -0.00 knots Slack
Thu -- 04:11 PM EST     Sunset
Thu -- 08:42 PM EST     -1.27 knots Max Ebb
Thu -- 10:06 PM EST     Moonset
Thu -- 10:48 PM EST     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.20.90.40-0.1-0.2-0.5-0.9-1.3-1.2-0.50.410.90.4-0.1-0.3-0.3-0.4-0.8-1.2-1.2-0.70.2

Weather Map and Satellite Images
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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 (14,3,4,5)
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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.