Wednesday, January23, 2019 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 6:59AMSunset 4:46PM Wednesday January 23, 2019 1:37 PM EST (18:37 UTC) Moonrise 8:58PMMoonset 9:52AM Illumination 92% Phase: Waning Gibbous; Moon at 18 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 Wed Jan 23 2019
.storm watch in effect from Thursday morning through Thursday afternoon...
This afternoon..SW winds around 15 kt with gusts up to 25 kt. Seas 4 to 6 ft.
Tonight..S winds 15 to 20 kt with gusts up to 35 kt. Seas 5 to 8 ft.
Thu..S winds 25 to 30 kt, increasing to 30 to 35 kt in the afternoon. Gusts up to 50 kt. Seas 9 to 14 ft. Areas of fog. Rain. Vsby 1 nm or less.
Thu night..W winds 20 to 25 kt with gusts up to 40 kt, diminishing to 15 to 20 kt with gusts up to 25 kt after midnight. Seas 9 to 14 ft. Patchy fog. A chance of rain. Vsby 1 nm or less.
Fri..W winds 10 to 15 kt with gusts up to 20 kt, increasing to 15 to 20 kt with gusts up to 30 kt in the afternoon. Seas 8 to 10 ft.
Fri night..W winds 15 to 20 kt, diminishing to 10 to 15 kt after midnight. Gusts up to 30 kt. Seas 7 to 10 ft.
Sat..W winds 5 to 10 kt with gusts up to 20 kt. Seas 4 to 7 ft.
Sat night..S winds 5 to 10 kt with gusts up to 20 kt. Seas 3 to 5 ft.
Sun..SE winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 6 ft. A chance of rain and snow showers. Vsby 1 to 3 nm.
Sun night..SW winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 7 ft. A chance of showers. 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 Wed Jan 23 2019
Synopsis for massachusetts and rhode island coastal waters.. An area of low pres tracks across the great lakes today and is followed by a wave of low pres lifting over srn new england on Thu. Widespread rain and strong south gales will prevail across the waters on Thu. Winds may reach storm force Thu. Arctic high pres follows for Fri and Sat. Another weather system brings a chance of rain and snow showers 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 Nantucket, MA
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location: 41.27, -70.06     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 231600
afdbox
area forecast discussion
national weather service boston norton ma
1100 am est Wed jan 23 2019

Synopsis
Low pressure lifting across the great lakes into quebec will
result in considerably milder temperatures today. The risk for
showers will increase tonight and reach maximum strength on
Thursday. Heavy rainfall and possible flooding, strong coastal
winds and unseasonably mild temperatures are expected on
Thursday. Mainly dry and more seasonable temperatures follow on
Friday, then turning colder Saturday. Snow showers are possible
Sunday then another frontal system may impact the region
Tuesday.

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

low pressure was lifting northeast across the eastern great
lakes, while high pressure continued to shift off the mid
atlantic coast. The result was warm advection at the surface and
aloft, along with an abundance of clouds. While dry weather will
dominate through the afternoon, enough forcing will allow for
spotty light precipitation to impact our far northwest zones.

While any of this precipitation will be very light, soundings
support mainly light sleet light freezing rain. Given temps are
still below freezing, have opted to issue a winter weather
advisory through early this evening along the east slopes of the
berkshires and all of franklin county. Even if readings rise a
few degrees above freezing, there still could be some issues
since the ground is quite cold from the last few days.

Otherwise, expect much of the region to see high temps recover
into the upper 30s to the lower 40s.

Also, after collaboration with the nerfc did opt to expand the
flood watch across all but the islands for Thursday. A
widespread 1 to 2 inches of rain with locally higher amounts are
anticipated. In addition... Snow water equivalents across much
of the region averaging 1 to 2 inches. This coupled with a
frozen ground may lead to pockets of significant urban street
flooding along with some river stream flooding. Therefore... Felt
a watch was certainly worth it.

Short term 6 pm this evening through 6 pm Thursday
Tonight...

primary low pressure moves into canada. Precip water plume
increases overnight as it is drawn north, with values reaching
over 1 inch by Thursday morning. Upper jet shifts farther east,
and our area increasingly moves upper the right entrance region
of the jet, especially after midnight. Expect increasing
coverage of rain during the night.

Southerly flow will bring milder air into the region with higher
dew point values as well. Temperatures will slowly rise
overnight... Guidance suggests temperatures rising into the 50s.

Low level jet increases during the night, with speeds of 65 to
75 kt at 850 mb and 60 to 70 kt at 925 mb. Expect gust potential
overnight at 30 to 40 mph. Best chance for this wind will be
over ri and SE mass, and may extend into NE ct.

Thursday...

srn new england remains under the right entrance region, so
expect continued ascent combined with the well-above-normal
precip water values. Rain which increases overnight should fall
at its maximum rate during this time. Total amounts of 1-2
inches is favored, with small areas of 2-3" possible. K index
reaches 30+ over ri and SE mass during the afternoon, indicating
some instability that could generate isolated tstms during the
afternoon. This hold potential for urban and small stream
flooding, with focus over ct-ri and SE mass. We will issue a
flash flood watch for this area.

Another concern is the wind. The low level jet continues to
increase Thursday, with speeds of 95 kt at 850 mb and 70-80 kt
at 925 mb. Cold water temps may attempt to stabilize the
surface layer but warm advection pushing land temps into the 50s
may be enough to draw strong winds to the surface, especially ri
and SE mass. We will issue a high wind watch for this area, and
anticipate wind advisories will eventually be issued over a
broader area.

Tides coastal flooding:
astronomical tides were elevated yesterday, which is cause for
concern along the south coast, but strongest winds and surge
expected to occur after the Thu morning high tides which will
minimize risk.

Long term Thursday night through Tuesday
Highlights...

* mainly dry and turning colder Fri into sat
* snow showers possible Sunday
* another round of snow rain showers possible mid week
overview and model preferences...

as noted yesterday, long range ensemble guidance continues to
favor predominantly negative nao ao and epo setup. This pattern
favors a broad, longwave trof settling across the E third of the
conus through much of the long term, and both operational and
ensemble guidance support this. With this trof in place, lobes
of the arctic vortex will be shifting S and e, impacting new
england with modified arctic air, and robust upper lvl energy.

While there remains some uncertainty in the sfc reflections of
these features, given they are not currently well sampled, a
general blend of guidance will be used as a baseline, giving a
rough outline of the potential impacts.

Details...

thu night...

lingering precip as low pres moves toward labrador. Timing
dependent, as both cold and dry air will be filtering through
the column. Low risk for some sn, especially across W ma ct
during the evening before the drier air cuts erodes the
remaining moisture. Gradual clearing overnight, with mins
falling into the 20s by early am fri. With mins below freezing,
damp sfcs may have ice by am.

Fri...

secondary arctic front introduces the coldest of the modified
arctic air mass late fri. Highs slightly colder than normal as
the strongest cold advection does not arrive until late fri. The
cold FROPA is mainly dry per latest soundings, but a few shsn
cannot be ruled out thanks to some lower lvl instability and
moisture pooling along the bl.

Fir night into sat...

as previous forecaster noted, modified arctic airmass in place.

H85 temp anomalies run about -10c. Lows Sat morning and highs
sat below normal as a result.

Sat night into Sun night...

first lobe of the arctic vortex rotates through the great lakes
and ontario with a sfc low pres in tow. Warm advection results
across the NE CONUS along with a modest pwat plume. A period of
shsn possible, and will need to monitor the potential
development of an inverted trof linked to this low pres inland
which could provide a focus for locally heavier sn. Most keep
this to the n, but something to watch.

Mon...

modest ridging ahead of a second lobe of the vortex suggests a
brief dry period.

Mid next week...

secondary vortex rotates to the s, however the longwave trof
has will have also shifted somewhat e. Suggesting that the final
track of any sfc low pres is further E than the inside runner
from the weekend. Again, given the time period, low confidence
in any one solution, but something to watch.

Aviation 16z 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 ...

today... High confidence.

Vfr through about 21z. Then MVFR CIGS gradually filter eastward
from w-e through the evening. Bulk of the precipitation llws
holds off until during the overnight hours.

Tonight... Moderate to high confidence.

Conditions lower to ifr most areas during the night. Rain
develops as milder air moves into southern new england. High dew
points will also contribute to fog formation during the night.

Strong winds at 2000 feet will generate southwest wind gusts of
40 to 50 kt. The winds at 2000 feet will also generate low
level wind shear
Thursday... Ifr CIGS vsbys with areas of MVFR in rain and fog.

Strong wind gusts of 45 to 50 kt possible, as well as low level
wind shear. A cold front swings through later in the day,
and may generate isolated thunder to go along with the rain.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf
outlook Thursday night through Sunday ...

Thursday night through Friday:VFR. Windy with local gusts to
30 kt.

Friday night:VFR. Breezy.

Saturday:VFR.

Saturday night and Sunday: mainlyVFR, with areas ifr possible.

Breezy. Slight chance shsn.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ...

today... High confidence.

High pressure moves offshore, bringing a southwest flow of air
up across the waters. Winds should increase during the day,
although the stronger winds are just approaching our southern
waters late in the day.

Tonight... Moderate confidence.

Strong low level southwest winds above the surface will continue
to increase during the night. Winds in the jet will reach 60-70
kt and should support gale force gusts during the night. These
winds and the long fetch will build seas to 5-10 feet.

Developing rain will reduce vsbys to 1-3 miles at times. The
increasing low level moisture will also help generate areas of
fog, which will also reduce vsbys.

Thursday... Moderate confidence.

Strong low level jet... About 2000 feet up... Will continue much
of the day with winds reaching 95 kt at about 5000 feet and
70-80 kt at 2000 feet. This will support southwest gales and may
support low-end storm force gusts. We have bumped the gale
watch up to a storm watch on most waters. Boston harbor and
narragansett bay will remain at a gale watch.

The strong winds will build seas especially across the southern
waters where heights may reach 15-17 feet. Rain and isolated
tstms will reduce local visibility to 1 to 3 nm.

Outlook Thursday night through Sunday ...

Thursday night into Friday night: moderate risk for small craft
advisory winds with gusts up to 30 kt. Rough seas up to 15 ft.

Saturday and Saturday night: winds less than 25 kt. Local rough
seas.

Sunday: low risk for small craft advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Chance of rain showers, chance of
snow showers. Areas of visibility 1 to 3 nm.

Box watches warnings advisories
Ct... Flash flood watch from Thursday morning through Thursday
evening for ctz002>004.

Ma... High wind watch from Thursday morning through Thursday
afternoon for maz007-019>024.

Flash flood watch from Thursday morning through Thursday
evening for maz002>022-026.

Winter weather advisory until 8 pm est this evening for maz002-
003-008-009.

Ri... High wind watch from Thursday morning through Thursday
afternoon for riz007-008.

Flash flood watch from Thursday morning through Thursday
evening for riz001>007.

Marine... Storm watch from Thursday morning through Thursday afternoon
for anz231>235-237-250-251-254>256.

Gale watch from Thursday morning through Thursday afternoon
for anz230.

Gale watch from late tonight through Thursday afternoon for
anz236.

Synopsis... Wtb doody
near term... Frank
short term... Wtb
long term... Doody
aviation... Wtb doody
marine... Wtb doody


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
NTKM3 - 8449130 - Nantucket Island, MA 2 mi43 min SSW 7 G 12 42°F 31°F1025.6 hPa
44020 - NANTUCKET SOUND 19 mi37 min S 12 G 14 37°F 33°F1025.1 hPa (-3.7)34°F
WAXM3 - Waquoit Bay Reserve, MA 33 mi112 min SSE 5.1 42°F 1027 hPa34°F
BZBM3 - 8447930 - Woods Hole, MA 37 mi43 min 41°F 33°F1024.5 hPa
44090 42 mi37 min 36°F2 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 mi44 minS 1110.00 miOvercast40°F36°F86%1025.7 hPa

Wind History from ACK (wind in knots)
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Last 24hrNW14NW12NW8W7NW7NW7W8W6NW4NW6W6NW4CalmCalmE4SW8SW12SW11S11SW10S11S10S12S11
1 day agoNW16W18
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2 days agoS17S13S16SW16
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Tide / Current Tables for Nantucket, Nantucket Island, Nantucket Island, Massachusetts
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for Nantucket Harbor Entrance Channel, Massachusetts Current
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Nantucket Harbor Entrance Channel
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Wed -- 12:39 AM EST     -0.00 knots Slack
Wed -- 05:24 AM EST     -1.52 knots Max Ebb
Wed -- 06:59 AM EST     Sunrise
Wed -- 07:39 AM EST     0.00 knots Slack
Wed -- 08:51 AM EST     Moonset
Wed -- 09:36 AM EST     1.32 knots Max Flood
Wed -- 12:21 PM EST     -0.00 knots Slack
Wed -- 04:45 PM EST     Sunset
Wed -- 05:41 PM EST     -1.55 knots Max Ebb
Wed -- 07:57 PM EST     0.00 knots Slack
Wed -- 07:58 PM EST     Moonrise
Wed -- 10:05 PM EST     1.56 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.2-0.1-0.4-0.7-1.1-1.5-1.4-0.70.41.21.30.80.2-0.2-0.5-0.7-1.1-1.4-1.5-101.11.61.3

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 (13,3,4,5)
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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.