Thursday, April27, 2017 L-36.com


Marine Weather and Tides
Groton, MA

Version 3.4
What's New / NOTES
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 5:44AMSunset 7:44PM Thursday April 27, 2017 2:50 PM EDT (18:50 UTC) Moonrise 6:54AMMoonset 9:13PM Illumination 3% Phase: Waxing Crescent; Moon at 2 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- 144 Pm Edt Thu Apr 27 2017
This afternoon..E winds around 5 kt. Waves 1 foot or less. Areas of fog. Vsby 1 nm or less.
Tonight..S winds around 5 kt. Waves 1 foot or less. Areas of fog. Vsby 1 nm or less.
Fri..SW winds 5 to 10 kt. Waves 1 foot or less. Areas of fog. Scattered showers. Vsby 1 nm or less.
Fri night..SW winds 5 to 10 kt. Waves 1 foot or less.
Sat..SW winds 5 to 10 kt with gusts up to 25 kt. Waves around 2 ft.
Sat night..NW winds 5 to 10 kt. Waves 1 foot or less.
Sun..NE winds 5 to 10 kt. Waves 1 foot or less.
Sun night..SE winds around 5 kt. Waves 1 foot or less. A chance of showers.
Mon..SE winds 5 to 10 kt. Waves 1 foot or less. A chance of showers.
Mon night..S winds 5 to 10 kt. Waves around 2 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 144 Pm Edt Thu Apr 27 2017
Synopsis for massachusetts and rhode island coastal waters.. Low pressure system south of the region will weaken as it moves towards the north atlantic. Weak high pressure today followed by a weak front early Friday. This front will stall over the waters into Sat. High pressure system will set-up over the eastern waters on Sunday followed by a passing warm front on Monday. 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 Groton, MA
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location: 42.6, -71.63     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 271741
afdbox
area forecast discussion
national weather service taunton ma
141 pm edt Thu apr 27 2017

Synopsis
Fog and drizzle will linger across the east coast today and into
tonight. A fast-moving disturbance may bring a few more rain
showers and perhaps an isolated thunderstorm very late Thursday
night into mid morning Friday, with a drying trend Friday
afternoon. Mainly dry and warm weather for Saturday afternoon. A
cold front crosses the region Saturday night, bringing much
cooler weather for Sunday, especially along the coast. Another
cold front will likely bring a period of showers sometime Monday
into early Tuesday.

Near term /until 6 pm this evening/
10 am update...

minor adjustments this morning. Noting a few breaks in W ma/ct
thanks to infusion of drier air into the column under a more w
component to the flow. This should lead to enough breaks to
realize some of the upper lvl warm air where h85 temps continue
to hover above 10c. Meanwhile E areas remain under influence of
trapped moisture much of the day. Therefore, could be a lot of
parity in temps across the region especially this afternoon.

Latest guidance (even mesoscale guidance) is likely a bit too
warm for E coast. Tried to adjust based on current trends to
better reflect expected temperature outcomes.

Previous discussion...

fog burns off in the morning with daytime heating and as more
westerly flow develops in the atmosphere. The upper level low moves
farther east of the region as the surface low dissipates. Still have
light easterly flow, so fog and drizzle may persist a bit longer
across the immediate east coast but should push offshore by the
late morning/early afternoon.

More of a return w-sw flow develops in the region thereafter helping
increase temperatures. Models agree on a substantially warmer day
today, getting well into the 60s for a majority of the region with a
few sites reaching 70s. This is cooler than some of the guidance
as low stratus will limit heating today. However, if clouds
break up more than current thinking then many spots could reach
70 and current forecast will be to low. Still anticipate cooler
conditions along the eastern coastline. Overall expect a dry
weather day as a shortwave ridge will move across the area on
Thursday.

Short term /6 pm this evening through Friday night/
Tonight and Friday...

the next low pressure system and associated upper level trough will
be approaching late tonight into Friday morning. The low pressure
will be well west of the area and passing across the upper great
lakes and into western and central ontario. Meanwhile, the surface
cold front will be approaching southern new england and running into
the upper level ridge, which will be causing it to weaken. There
will initially be enough vertical lift overnight into early Friday
along with some elevated instability to give the region some showers
and thunderstorms. Outside of the rain with the flow ahead of the
cold front turning more southerly, the region will see a return of
at least patchy fog tonight into early Friday with more onshore flow
and inherent moisture advection.

The front should be through by the afternoon, allowing for clearing
and the return of sunshine. Despite being behind the front,
anticipate a mild day on Friday afternoon with highs in the low to
upper 70s with cooler conditions along the south coast.

Model guidance is hinting at some surface cape,good shear and steep
lapse rates Friday afternoon. However, subsidence behind the morning
shortwave and very dry mid levels of the atmosphere should result
prevent convection from developing Friday afternoon. Something to
keep an eye.

Long term /Saturday through Wednesday/
Highlights...

* warm on Sat away from the south coast, with a low risk for a few
afternoon/early evening thunderstorms
* turning much cooler Sat night and sun, especially on the coast
* period of showers likely sometime Mon into early tue
details...

Friday night...

mid level dry air moves off to our east late at night. An
approaching front to our west should be enough to start moisture
pooling once more, late. Dry weather should prevail. Given the
higher starting point from earlier Friday, expecting min
temperatures to be near the normal high temperatures.

Saturday...

with a slow-moving front to our west should mean one more day of
well above normal temperatures. As this front gets closer to
southern new england, and temperatures get higher, there will
be an increasing risk for showers and a few thunderstorms. The
critical factor for any thunderstorms will be how quickly the
mid level dry air exits. Mid level lapse rates are marginal, and
should be most favorable to our south. Will need to monitor this
over the next day or so, but still thinking thunderstorms remain a
rather low risk.

Saturday night and Sunday...

a strong high pressure system will build into eastern canada.

This will send a cold front south of the region Saturday night,
resulting in much lower temperatures Sunday, but still near
normal. May see a spot shower or two Saturday night/Sunday, but
the vast majority of the time should remain dry.

Monday into Tuesday morning...

a low pressure still expected to move across the great lakes
Monday, then into eastern canada Tuesday. Timing of the warm
front is still in question, and will likely waver over the next
few days. Leaning toward the slower end of the solution
envelope, with a strong high pressure over labrador. Tricky
temperatures Monday. If this warm front gets hung up to our
south, the current forecast is likely a little too high.

Tuesday afternoon into Wednesday...

low confidence given the time range, but most guidance suggests
mainly dry and pleasant weather as a weak ridge of high pressure
builds in from the west.

Aviation /17z Thursday through Monday/
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Friday night/...

through 00z... Moderate confidence.

A few breaks ofVFR this afternoon will give way to widespread
MVFR CIGS by 20z. The CIGS gradually lower again this evening to
ifr by around 00z. Winds outside of lingering sea breezes shift
mainly s-sw.

Overnight... Moderate confidence.

Ifr/lifr conditions in another mix of low CIGS and fog. Fog
likely not as widespread as last night, and should mainly be
focus around the S coast of ma/ri and possibly snaking up the
ct valley late. In any fog lifr vsbys possible at times. Some
showers and isolated tsra possible mainly between 09z and 14z
from w-e. This will help improve conditions to mainly ifr.

Tomorrow and tomorrow night... High confidence in trends, but
lower confidence in exact timing in taf.

Ifr/MVFR CIGS and fog, along with showers and isolated
thunderstorms end between 12z and 16z in the morning, with
fairly rapid improvement toVFR in clearing. Winds turn w, with
gusts to 15 kt at times.VFR continues into the overnight thanks
to W winds, although there is a low risk for showers, but mainly
after daybreak sat.

Kbos taf... Moderate confidence in taf. Ifr conditions expected
overnight, but lower confidence in the lifr risk.

Kbdl taf... Moderate confidence in taf. Timing may be off. There
is also a low risk for lifr fog late this evening and early
tomorrow morning.

Outlook /Saturday through Monday/...

Saturday and Sunday... High confidence in mainlyVFR conditions.

Monday... Moderate confidence. MVFR/ifr conditions possible in
lower clouds and some showers, especially late.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term /through Friday night/... High confidence.

Small craft advisories are in effect for the southern and ocean
waters. Seas will remain above 5 feet due to lingering swell from
low pressure system south and east of the region. Vsbys restrictions
across the waters will continue today and into tonight in dense fog.

Approaching cold front will be weak as it crosses the waters on
Friday. However it will help improve vsbys on Friday. Still will see
lingering 5 footers across the outer waters so SCA has been
extended.

Outlook /Saturday through Monday/... Moderate confidence.

Winds expected to remain less than 25 kt through most of this
period. Rough seas should slowly diminish across the outer
coastal waters Saturday night into Sunday. There may be a few
nearshore gusts to 25 kt Sunday. Will need to monitor Sunday for
a possible small craft advisory as a cold front passes by.

Tides/coastal flooding
* isolated minor coastal flooding impacts during astronomically
high tide tonight along the east coasts
we are in a spring tide cycle with high tides that are
astronomically high. This combined with an anticipated storm
surge of around 0.5 to 1 foot may set the stage for isolated
pockets of minor coastal flooding along the east coasts around
the time of high tide very late tonight.

The astronomical high tides remain very elevated through the
end of the week.

Due to the breadth of the fetch, we may encounter enough wave action
with lengthening periods on top of an elevated tide to cause pockets
of erosion tonight along the martha's vineyard south coast,
nantucket south and east coasts, and the outer CAPE ocean side
from truro to chatham.

Boston high tides (flood stage at boston 12.5 feet)...

12.15 feet / Friday 12:15 am
providence high tides (flood stage at providence 7 feet)...

6.25 feet / Thursday 9:50 pm

Box watches/warnings/advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory until 2 pm edt Friday for anz235-237.

Small craft advisory until 8 pm edt Friday for anz250-254>256.

Synopsis... Belk/dunten
near term... Doody/dunten
short term... Dunten
long term... Belk
aviation... Belk/dunten
marine... Belk/dunten
tides/coastal flooding...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 35 mi51 min 54°F 47°F1013.4 hPa (-0.0)
BGXN3 - Great Bay Reserve, NH 53 mi66 min ESE 1.9 59°F 1014 hPa56°F
44013 - BOSTON 16 NM East of Boston, MA 55 mi61 min ENE 1.9 G 3.9 50°F 50°F4 ft1012.8 hPa (+0.0)

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fitchburg, Fitchburg Municipal Airport, MA8 mi59 minN 010.00 miOvercast66°F57°F73%1013.2 hPa
Nashua - Boire Field Airport, NH14 mi55 minN 010.00 miOvercast63°F57°F81%1014.3 hPa
Bedford, Hanscom Field, MA20 mi55 minWNW 410.00 miOvercast63°F55°F76%1014.1 hPa
Jaffrey Airport-Silver Ranch, NH24 mi59 minS 310.00 miOvercast64°F57°F81%1013.5 hPa

Wind History from FIT (wind in knots)
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Last 24hrN7N6NE7N65CalmN3N4NW3CalmCalmCalmE3CalmCalmCalmNW3N3NE3CalmCalmCalmCalmCalm
1 day agoNE9NE7NE7NE5N6NE6N63N5N65N4N64N64N5N7N5N7N8NE4N6N7
2 days agoCalm--E7S9SE9SE10SE6SE4CalmCalmCalmCalmNE3NE4N4NE54NE54NE6E8NE9
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Tide / Current Tables for Riverside, Merrimack River, Massachusetts
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Riverside
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Thu -- 01:49 AM EDT     7.10 feet High Tide
Thu -- 05:43 AM EDT     Sunrise
Thu -- 06:51 AM EDT     Moonrise
Thu -- 09:42 AM EDT     -0.57 feet Low Tide
Thu -- 02:22 PM EDT     6.65 feet High Tide
Thu -- 07:40 PM EDT     Sunset
Thu -- 09:10 PM EDT     Moonset
Thu -- 09:58 PM EDT     -0.33 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
4.66.67.16.75.94.631.50.3-0.4-0.50.735.36.56.564.93.62.10.8-0-0.30.5

Tide / Current Tables for Amelia Earhart Dam, Mystic River, Boston Harbor, Massachusetts
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Amelia Earhart Dam
Click for Map
Thu -- 12:08 AM EDT     12.02 feet High Tide
Thu -- 05:44 AM EDT     Sunrise
Thu -- 06:29 AM EDT     -1.76 feet Low Tide
Thu -- 06:51 AM EDT     Moonrise
Thu -- 12:41 PM EDT     11.35 feet High Tide
Thu -- 06:47 PM EDT     -1.04 feet Low Tide
Thu -- 07:39 PM EDT     Sunset
Thu -- 09:10 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1211.49.56.63.40.4-1.5-1.50.43.16.29.11111.3107.74.81.9-0.4-10.43.16.29.2

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (14,3,4,5)
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Ground Weather Radar Station Boston, MA
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weather_mapweather_map weather_map

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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.