Sunday, February17, 2019 L-36.com


Marine Weather and Tides
Nahant, 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 6:36AMSunset 5:19PM Sunday February 17, 2019 11:55 PM EST (04:55 UTC) Moonrise 3:58PMMoonset 6:11AM Illumination 98% Phase: Waxing Gibbous; Moon at 13 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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ANZ230 Boston Harbor- 1027 Pm Est Sun Feb 17 2019
Overnight..SE winds around 5 kt. Waves around 2 ft. A slight chance of snow, then snow with vsby 1 nm or less.
Mon..NE winds 5 to 10 kt, increasing to 10 to 15 kt with gusts up to 20 kt in the afternoon. Waves around 2 ft. Snow. Vsby 1 nm or less.
Mon night..NW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. A chance of snow in the evening.
Tue..NW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft.
Tue night..NW winds around 10 kt. Waves around 2 ft in the evening, then 1 foot or less.
Wed..W winds 5 to 10 kt. Waves 1 foot or less.
Wed night..SE winds 5 to 10 kt. Waves 1 foot or less. Snow. Sleet with freezing rain likely after midnight. Vsby 1 to 3 nm.
Thu..S winds 5 to 10 kt, becoming nw in the afternoon. Waves 1 foot or less, then around 2 ft in the afternoon. A chance of rain. Freezing rain and sleet likely in the morning.
Thu night..NW winds around 10 kt. Waves around 2 ft in the evening, then 1 foot or less.
Fri..NW winds 5 to 10 kt. Gusts up to 20 kt in the morning. Waves 1 foot or less.
Fri night..NW winds 5 to 10 kt. Waves 1 foot or less. 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 1027 Pm Est Sun Feb 17 2019
Synopsis for massachusetts and rhode island coastal waters.. A low pressure system will pass se of nantucket Mon. High pres builds in from the W on Tue and Wed. Low pres approaches the waters from the sw Wed night, then passes just S of the waters on 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 Nahant, MA
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location: 42.44, -70.94     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 180300
afdbox
area forecast discussion
national weather service boston norton ma
1000 pm est Sun feb 17 2019

Synopsis
Accumulating snow overspreads the region late this evening and
overnight from west to east and continues into Monday, in
association with a low pressure tracking south of new england.

Large high pressure will bring dry but cold conditions Monday
night into early Wednesday. Snow will push across the region
late Wednesday into Wednesday evening as low pressure approaches,
then will become a wintry mix overnight before changing to rain
Thursday morning. The low will head to the gulf of maine
Thursday night. Dry conditions should return Friday into early
Saturday.

Near term through Monday
10pm update...

already noting some 20-30dbz echos across portions of ct,
however as previous forecast shift noted, the dewpoint
depressions at the surface, which are still running 10-15f are
eroding much of the sn. Obs sites still +10sm and a few reports
on twitter support this suggesting more sn grains rather than
actual dendrites just yet.

However, with recent guidance updates, the latest wrf NAM and
other rapid update guidance is still on track, that this will be
overcome rather quickly. Plume of moisture increasing in the
dgz, combining with both destabilization in the mid layers and
low- mid lvl f-gen expanding e. Noting support for this as the
precip shield is becoming more organized and beginning to form
bands.

Given these factors, forecast updates will include a slightly
more robust wetbulb factor through early am, an adjustment of
qpf based on latest guidance which is handling this slow start,
and slight adjustment to the SE ma coastline through the day
thanks to evidence of potential coastal front enhancement.

Models are beginning to better resolve it.

Sn totals slightly higher mainly across plymouth and northern
bristol co, but only by an inch or less, otherwise, locations of
warnings advisories are good, so see no need to change these
with this update.

Short term Monday night through 6 pm Monday
Highlights...

* snow develops between 10 pm and 2 am from southwest to northeast
* heaviest snow occurs through 9 am near and ESP south of pike
* snow continues Mon afternoon with focus across central eastern ma
1) overview and impacts:
approaching shortwave will increase the forcing for ascent and allow
snow to overspread the region roughly between 10 pm and 2 am Monday
morning. The heaviest snow is expected near and especially south of
the ma turnpike overnight. This is where the best forcing resides
and the guidance indicates a few hours of omega exceeding 20 units
in the snow growth region. There also is a -epv signature present
along with 700 mb lapse rates on the order of 6-7 c km. This is
supportive for a window of 1 to perhaps 2 inch per hour snowfall
rates. While this is relatively a short window, it looks to impact
ri and SE ma during the morning commute (albeit less traffic than
usual given the holiday). Ptype should mainly be snow, but enough
mid level warmth may invade the immediate south coast and
particularly the CAPE islands for a change to sleet rain towards 12z
Monday.

The first phase of the storm should come to an end by mid morning
Monday. However, there is a second portion of this event we need to
discuss. An inverted trough feature along with moist low level
onshore flow will allow for periods of generally lighter snowfall to
linger into the afternoon. In fact, the area needed for ice
nucleation dries out across portions of western ma northern ct
for a time. This may result in some freezing drizzle too.

While lighter snowfall will be the rule with the second portion of
the storm, we will need to watch central and eastern ma for locally
heavier bands. Moist onshore flow may result in some enhancement of
the snow along the east slopes of the worcester hills and perhaps
even the berks. Along the eastern ma coast, the land sea interface
may result in ocean enhancement. A look at the model cross sections
reveals saturated soundings in the optimal snow growth region. So
there might be a few bands of moderate to perhaps even briefly heavy
snow later in the morning into the late afternoon in this region.

Outside of these bands of more significant snow across central and
eastern ma, roads may be manageable given lighter snowfall rates and
marginal temperatures. Light snow showers may linger into the the
early evening hours, but any accumulations after 7 or 8 pm should be
less than an inch.

2) headlines and snow accumulations:
based on the latest data feel a widespread 3 to 6 inches of snow is
in store for much of the region. Guidance also points to a swath of
potentially 4 to 7 inch amounts in the pvd-tan-pym-ewb corridor.

Will go ahead and upgrade this region to a marginal winter
storm warning. We also will have to watch the CAPE and south
coasts of ma and ri, but more marginal temperatures and the
potential for a period of sleet rain, did not feel confident
enough to go with a warning. The rest of our county warning area
will be under a winter weather advisory. There is a low risk
though that marginal warning criteria is realized along the east
slopes of the berks orh hills with better ratios and perhaps
even boston itself with the inverted trough. Again though, just
was not confident enough in this region.

The bottom line is a moderate snow event is in the cards for the
region. Biggest impact will the morning commute near and
especially south of the ma turnpike. Also, the afternoon commute
may be an issue from the worcester hills and onto the eastern
ma coast from the inverted trough.

Long term Monday night through Sunday
* dry and cold conditions Monday night into Wednesday morning
* a chance for snow Wednesday afternoon evening, likely
changing to a wintry mix overnight then to rain Thursday
before tapering off
* another round of dry weather follows Friday into early
Saturday
* potential for more mixed precipitation Sat afternoon into
Sunday
overview...

high amplitude mid level trough remains across the western u.S.

Early in this forecast period, with general w-sw steering flow
extending from the base of this trough across the mid
mississippi and ohio valleys into the northeast through most of
this week. Some height amplification possible around late Wed or
thu as subtropical ridge off the florida coast into the sw
atlc. This may occur close to the same time as the approach of
developing low pressure out of the mississippi valley toward new
england. May see a wintry mix of precip Wed night before
eventually changing to rain thu.

May see another dry spell late this week into next weekend.

Models beginning to signal deamplification of the western
trough Thu night or fri, but rather high uncertainty with the
timing and ultimate movement of leftover troughing late Sat or
next sun.

Details...

Monday night into Wednesday morning...

last of light snow from exiting low pres will linger mon
evening across E coastal areas. Should taper off across the
outer CAPE and nantucket by around 06z. Cold air works back
across the region on n-nw winds ahead of sprawling high pres
across the plains into the western great lakes. May see wind
gusts up to around 20-25 kt or so along the immediate E coast as
well as CAPE cod and the islands.

H85 temps will drop by Tue morning, and continue to fall to -11c
to -14c by Tue evening! So, expect overnight lows both Mon and
tue nights to bottom out at around 5 degrees or so below seasonal
normals. Readings will fall to the single digits across the
higher inland terrain and mainly the teens elsewhere, though may
be a bit milder (about 20 to 25) along the immediate S coast
and islands.

The gusty winds will diminish on Tuesday as the center of the
large high approaches from the w, so expect light NW or calm
winds by Tue night.

May start to see mid and high clouds approach late Tue night
into Wed morning ahead of next approaching system.

Wednesday afternoon through Thursday...

the next southern stream system will work NE out of the
mississippi valley to the great lakes. As with the last few
systems, may see a secondary low develop as it approaches the
region Wed night into Thu morning. With some model solution
spread with each model's handling of the secondary low track,
still rather uncertain how quickly the precip will move in then,
as milder air works in aloft, when the precip mixes with
pl fzra overnight Wed night, then eventually all rain during thu
before tapering off as the low exits Thu afternoon. Current
forecast suggests that highs on Thu could reach the upper 30s to
mid 40s.

May see some gusty e-se winds around Thu morning along east
coastal areas, especially CAPE cod and the islands, which may
combine with the high astronomical tides to possibly produce
some minor coastal flooding around midday thu. Check for
details under the tides section below.

Friday through Sunday...

coastal low and associated mid level trough from Thu moves east
of new england. Expect a dry NW flow aloft and seasonable temps
fri into Sat as high pres moves across.

The next system in the fast mid level steering flow may
approach late Saturday through most of Sunday. Potential for
more mixed precipitation Saturday night into early Sunday, but
rather high uncertainty with wide model solution spread.

Aviation 03z Monday through Friday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Monday ... High confidence.

Tonight and Monday... MainlyVFR early this evening.

Snow overspreads the region from southwest to northeast between
03z and 07z. This will result ifr to lifr conditions developing
overnight and persisting through Monday afternoon. Heaviest
snow occurs near and especially south of the ma turnpike through
about 13z or 14z Monday, where lifr conditions will be most
prevalent.

Generally lighter snows linger later Monday morning into the
afternoon and there may even be pockets of freezing drizzle in
western ma northern ct. Despite the overall diminishing snow
intensity, localized bands of moderate to even briefly heavier
snow will remain possible across central and eastern ma into mon
afternoon. Ptype should be all snow except for the immediate
south coast and especially the CAPE islands, where a change to
sleet rain may occur for a time Monday morning. Total snow
accumulations of 3 to 6 inches are anticipated for much of the
region.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf.

Outlook Monday night through Friday ...

Monday night: mainlyVFR, with local MVFR possible. Breezy.

Tuesday through Tuesday night:VFR. Breezy.

Wednesday: mainlyVFR, with local ifr possible. Chance sn.

Wednesday night: mainly ifr, with areas MVFR possible. Breezy.

Sn likely, fzra likely, pl likely.

Thursday: mainly MVFR, with areasVFR possible. Breezy. Chance
ra, chance fzra.

Thursday night through Friday:VFR. Breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Monday ... High confidence.

Tonight and Monday... High confidence.

Generally light winds and flat seas this evening. Small craft
seas up to 5 feet and northeast wind gusts up to 25 knots
develop across the southern waters near daybreak Monday and
continue into the afternoon. A few gusts approaching 25 knots
are possible Monday across some of the southern sounds and bays,
but felt it was to marginal for headlines at this point.

Periods of rain, sleet, and snow overnight into Monday will
reduce vsbys at time for mariners.

Outlook Monday night through Friday ...

Monday night: low risk for small craft advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of snow, chance of
freezing spray.

Tuesday: winds less than 25 kt. Local rough seas.

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

Wednesday: winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of snow. Local visibility 1 to 3 nm.

Wednesday night: winds less than 25 kt. Seas locally
approaching 5 ft. Snow likely, rain likely, sleet likely,
freezing rain likely. Visibility 1 to 3 nm.

Thursday: low risk for small craft advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Rain likely, freezing rain likely.

Thursday night: winds less than 25 kt. Local rough seas.

Friday: winds less than 25 kt. Areas of seas approaching 5 ft.

Tides coastal flooding
Highest astronomical tides of 2019 are expected Wed and thu,
with forecasted tide heights up to 12 foot or greater in boston
harbor around midday both days. Current forecast suggests
offshore winds on Wed (nw), but there could be a period of
onshore winds (e-se) which will depend upon how low pressure
tracks across the region Thu morning with the incoming tide.

It won't take much to produce minor coastal flooding along the
eastern massachusetts coastline. At this point, it looks like
the greatest threat for minor coastal flooding may occur with
the Thursday midday tide, but Wednesday's tide should also be
monitored.

Box watches warnings advisories
Ct... Winter weather advisory until 4 pm est Monday for ctz002>004.

Ma... Winter weather advisory until 4 pm est Monday for maz022>024.

Winter storm warning until 4 pm est Monday for maz017>021.

Winter weather advisory until 4 pm est Monday for maz002>008-
010-013>016-026.

Winter weather advisory until 4 pm est Monday for maz009-011-
012.

Ri... Winter weather advisory until 4 pm est Monday for riz006>008.

Winter storm warning until 4 pm est Monday for riz001>005.

Marine... Small craft advisory from 1 am to 5 am est Tuesday for anz232.

Small craft advisory from midnight Monday night to 5 am est
Tuesday for anz233-234.

Small craft advisory from 10 pm Monday to 6 am est Tuesday for
anz231-251.

Small craft advisory from 11 pm Monday to 6 am est Tuesday for
anz235-237.

Small craft advisory from 3 pm Monday to 6 am est Tuesday for
anz250.

Small craft advisory from 6 am Monday to 6 am est Tuesday for
anz254>256.

Synopsis... Frank evt
near term... Doody
short term... Frank
long term... Evt
aviation... Frank evt
marine... Frank evt
tides coastal flooding...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 8 mi56 min 31°F 1017 hPa (-1.1)
44013 - BOSTON 16 NM East of Boston, MA 17 mi66 min S 7.8 G 9.7 33°F 39°F2 ft1017.1 hPa (-0.8)21°F
44029 - Buoy A0102 - Mass. Bay/Stellwagen 21 mi112 min S 12 G 14 32°F 39°F2 ft1016.1 hPa
IOSN3 - Isle of Shoals, NH 40 mi56 min S 8.9 G 9.9 32°F 1016.7 hPa (-1.0)18°F
BGXN3 - Great Bay Reserve, NH 43 mi71 min Calm 26°F 1018 hPa21°F
44018 - SE Cape Cod 30NM East of Nantucket, MA 45 mi66 min S 7.8 G 9.7 31°F 2 ft1017.3 hPa (-1.2)19°F
44098 - Jeffrey's Ledge, NH (160) 48 mi48 min 40°F2 ft

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Boston, Logan International Airport, MA6 mi62 minS 610.00 miOvercast32°F19°F59%1017.1 hPa
Beverly, Beverly Municipal Airport, MA10 mi63 minSSE 410.00 miOvercast32°F21°F64%1016.5 hPa
East Milton, MA18 mi2 hrsS 8 mi27°F18°F69%1017.7 hPa
Laurence G Hanscom Field Airport, MA19 mi60 minESE 410.00 miOvercast31°F17°F56%1018 hPa
Norwood, Norwood Memorial Airport, MA21 mi63 minN 010.00 miOvercast32°F19°F59%1016.9 hPa
Lawrence Municipal Airport, MA22 mi62 minE 310.00 miOvercast29°F18°F63%1017.1 hPa

Wind History from BOS (wind in knots)
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Last 24hrNW12NW13NW9NW16
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NW12NW8NW10N6NW9NW10--3NE4E7SE6E5E8E9E9SE6SE9S9S7S6
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2 days agoE4S5S5S6SE7SE13SE10SE9SE10SE8S5S6S10SE7S11S12S13S12S19
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Tide / Current Tables for Nahant, Massachusetts
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Nahant
Click for Map
Sun -- 02:30 AM EST     0.28 feet Low Tide
Sun -- 05:10 AM EST     Moonset
Sun -- 06:37 AM EST     Sunrise
Sun -- 08:45 AM EST     10.36 feet High Tide
Sun -- 02:58 PM EST     Moonrise
Sun -- 03:13 PM EST     -0.91 feet Low Tide
Sun -- 05:18 PM EST     Sunset
Sun -- 09:27 PM EST     9.18 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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3.81.80.50.51.83.96.28.41010.39.47.55.12.60.3-0.9-0.41.23.35.77.8997.8

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Sun -- 02:38 AM EST     0.00 knots Slack
Sun -- 05:05 AM EST     1.30 knots Max Flood
Sun -- 05:10 AM EST     Moonset
Sun -- 06:37 AM EST     Sunrise
Sun -- 08:26 AM EST     -0.00 knots Slack
Sun -- 12:22 PM EST     -1.35 knots Max Ebb
Sun -- 02:58 PM EST     Moonrise
Sun -- 03:12 PM EST     0.00 knots Slack
Sun -- 05:18 PM EST     Sunset
Sun -- 06:12 PM EST     1.33 knots Max Flood
Sun -- 09:03 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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-1.1-1-0.60.41.11.31.310.3-0.4-0.9-1.2-1.3-1.3-1.1-0.20.81.31.31.30.80-0.6-1

Weather Map and Satellite Images
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Wind Forecast for Boston, MA (23,6,7,8)
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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.