Thursday, May25, 2017 L-36.com


Marine Weather and Tides
Boston, MA

Version 3.4
What's New / NOTES
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
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.

Sunrise 5:11AMSunset 8:10PM Thursday May 25, 2017 2:18 PM EDT (18:18 UTC) Moonrise 5:25AMMoonset 7:58PM Illumination 0% Phase: New Moon; Moon at 0 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- 116 Pm Edt Thu May 25 2017
This afternoon..NE winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 3 ft. Areas of fog. Rain with areas of drizzle. Vsby 1 to 3 nm.
Tonight..NE winds 5 to 10 kt. Gusts up to 25 kt in the evening. Seas 2 to 3 ft. Areas of fog. Rain with areas of drizzle. Vsby 1 nm or less.
Fri..NW winds 5 to 10 kt. Seas 2 to 3 ft. Areas of fog. Rain likely. Vsby 1 nm or less.
Fri night..NW winds 5 to 10 kt. Seas 2 to 3 ft. A chance of rain.
Sat..N winds around 5 kt...becoming ne in the afternoon. Seas 1 foot or less.
Sat night..S winds around 5 kt. Seas 1 foot or less.
Sun..SE winds around 5 kt. Seas 1 foot or less.
Sun night..SE winds around 5 kt. Seas 1 foot or less. A chance of showers.
Mon..E winds around 5 kt. Seas 1 foot or less. A chance of showers.
Mon night..S winds around 5 kt. Seas 1 foot or less. 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 Edt Thu May 25 2017
Synopsis for massachusetts and rhode island coastal waters.. A potent low pressure system will move over the area today and into tomorrow. Heavy rainfall will limit visibility at times. Anticipate quiet weather for the weekend with another frontal system moving through late Sunday into 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 Boston, MA
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location: 42.36, -71.02     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 251738
afdbox
area forecast discussion
national weather service taunton ma
138 pm edt Thu may 25 2017

Synopsis
Low pressure and its attending warm front will bring a steady rain
and drizzle to the region today along with cool northeast winds. The
rain will be heavy at times tonight into Fri as the low tracks along
the southern new england coast to just east of CAPE ann Friday. Big
improvement to start of the holiday weekend as weak high pressure
delivers dry weather with mild days and cool nights both Sat and
sun. However by Sunday night and into Monday another coastal low may
bring the risk of showers, although a washout is not expected.

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

* highlights...

- widespread light to moderate rain continues
- should transition more to drizzle around 3 to 4 pm
- increasing onshore easterly winds, cooler air off waters
* latest discussion...

cool, dreary, wet day continues. Low spinning over the mid-atlantic,
approaching, beginning to wrap in on itself, strengthening as it
occludes, stacks. Gradient winds increasing off the waters, the
temperatures dropping to their respective wet-bulb. Lot more moisture
in the air and beginning to see lower visibility developing with
mist and areas of fog. Going to turn more dismal into the evening
period prior to the forecast moderate to heavy rain overnight.

Temperatures remaining steady in the 50s.

Not too much change in the forecast which is overall good from
the overnight crew. Subtle changes to account for trends.

* previous discussion...

a cool, wet day on tap. Mature low pressure beginning to undergo
occlusion as it becomes negatively tilted across the mid-atlantic,
lifting over the NE CONUS overnight. Into this evening, ahead of
the low, will continue to see isentropic ascent of the warm-moist
conveyor belt with sub-tropical connections beneath broad diffluence
aloft. Widespread rain across the region with embedded heavier rain
showers aided by convergent low-level forcing of higher theta-e air.

The deep column moisture present, as seen per morning 12z soundings
out of upton ny and chatham ma plus intrusion of warmer air that
contributes to higher freezing level heights with the southerly sub-
tropical connection sets up efficient warm-rain processes. But with
evolving dynamics and negative-tilting, would appear that the crux
of deeper moisture and strongest forcing stays S E of S new england,
the heaviest rain into this evening confined over the outer CAPE and
islands from now till roughly 3-4 pm. It is then that dryer air aloft
associated with conveyor belt motions wrapping into the low, dries
the column within the mid to upper levels. Still a measure of lift
and forcing upon the moist boundary layer, expect areas of fog and
drizzle to encompass the region as the surface warm front slowly
drags n, stalling roughly SW to NE along the immediate S coast of
new england where moisture will pool.

Previous forecast fairly spot on and there were very little changes
other than accounting for the latest trends. Agree with what has
been said prior: cooler with greater rain intensity as the column
saturates towards the respective wet-bulb, winds out of the N ne
with the surface warm front situated S slowly lifting n. A cool,
raw, damp day overall.

Still monitoring low level winds for the afternoon period as they
ramp up in response to the deepening low center with the negative-
tilt occlusion. Agree with the previous forecaster that a stout
inversion N of the warm front should limiting the mixing of such
winds to the surface. Again, can't rule out some rogue wind gusts
but nothing to the effective of widespread warranting a wind
advisory.

Short term 6 pm this evening through 6 pm Friday
Tonight into Friday...

anomolous low pressure system will continue its eastward
progression during the overnight hours. A potent pv-anomaly will
round the base of the trough and develop a surface low over the
middle atlantic region. This low will trek right over southern new
england bringing widespread rainfall. Some of it will be heavy at
times as the system becomes vertically stack resulting in deep
moisture through the entire column. Pwat values are also near an
inch to 1.5 inches with increasing LLJ aiding in moisture advection.

This will result in another chance for locations south and east of
the i-95 corridor of seeing an inch of rainfall. This much rain
combined with the king high tide may result in urban flooding as the
water will have trouble receding.

Guidance is also hinting as some elevated convection with a few
models having some surface CAPE late tonight into tomorrow morning.

Therefore continued with the mention of isolated thunder. This may
also enhance precipitation amounts.

Widespread heavy rainfall will begin to wind down by Friday morning
as the low begins to move offshore. However, pretty good comma head
signature with a deformation zone in the mid-levels could set up.

This will keep the dreary weather going through much of the day
before beginning to let up by nightfall.

Long term Friday night through Wednesday
* highlights...

* mainly dry weather W mild days and cool nights Saturday and Sunday
* risk of rain returns Sun night into Monday
* seasonably warm Tue & Wed but low risk of scattered showers
* details...

Friday night...

improving weather as closed mid level low over the gulf of maine
exits seaward and allows rising heights along with mid level
anticyclonic flow to move across new england. This will promote a
drying trend overnight. Temps will be seasonably cool with lows in
the upper 40s and low 50s.

Saturday...

wnw flow aloft with mid level mean ridge axis across the eastern
great lakes will provide dry weather and seasonable temps across
southern new england. Models do differ on cloud cover Sat with gfs
showing much more low level moisture. Given the wnw flow aloft
thinking at least partial sunshine will verify. This combined with
light winds will provide very pleasant conditions with highs 70-75
ct river valley and 60s elsewhere. Weak pressure gradient will
support cooling afternoon seabreezes for the coastline.

Sunday...

deep layer ridging lingers across the area promoting dry weather
much of the day. However model time sections and moisture profiles
indicate lots of clouds likely on Sunday. 00z deterministic and
ensemble guidance in good agreement that rain showers associated
with upstream system should arrive into southern new england either
late in the day or after sunset. So as of now the bulk of the
daylight hours of Sunday appear dry, especially across ri and
eastern ma. Given the expected cloud cover highs should be a few
degs cooler than Saturday. Fortunately sse winds should be fairly
light but will keep the immediate coastline cooler.

Monday...

weak coastal low may pass south of new england along with its precip
shield impacting the area. Doesn't look like a washout but enough
support to keep showers in the forecast. Somewhat cool with highs in
the 60s given cloud cover and light onshore winds.

Tuesday Wednesday...

not as cool as parent low pressure over the great lakes provides
warmer southwest flow into new england. With the milder temperatures
comes the risk of scattered showers as mid level flow becomes
increasingly cyclonic.

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 ... Moderate confidence.

18z update... No major changes to the forecast. Minor tweaks to
account for trends. Otherwise, on track.

Today...

into midday -ra ra transitioning to dz with increasingly lower
visibility with fg. Lowering CIGS S to N with time towards ifr.

N NE winds becoming more E ne, gusty at times potentially as
high as 30-35 kts though thinking isolated. Mainly 20-25 kts.

Tonight...

ifr-lifr CIGS and vsbys. Ra +ra potential mainly from 6-12z with
embedded tsra possible. E winds continue with mainly 20-25 kt
gusts.

Friday...

ifr MVFR CIGS with sct-bkn -shra, on and off through the day.

Conditions may improve toVFR across western terminals in the
late afternoon. Northwest winds for all terminals, becoming
gusty into the later half of the day.

Friday night...

shra dissipating while improvingVFR. NW winds blustery
initially, relaxing. CIGS becoming bkn to sct.

Kbos taf...

lower conditions moving in as low pressure approaches the
terminal today, passing across overnight. So overnight winds
are going to be a challenge, gusty at first but becoming light
while turning counter-clockwise NE to NW with low passage.

Closely watching the 6-12z Friday time- frame for +ra potential
and possible embedded tsra. Whether impacts to the am push.

Kbdl taf...

will hold winds more N funneling through the ct river valley,
turning NW with low pressure passage overnight. Fg dz into this
afternoon, more ra and possible +ra tsra overnight 6-12z time-
frame. Lowering ifr into midday, lifr into evening and holding
so, especially with CIGS through Friday morning.

Outlook Friday night through Monday ... Moderate confidence.

Friday night...

a mix of MVFR-vfr but a trend toward dry weather overnight as
surface winds become wnw.

Saturday and Sunday daytime...

vfr. Light winds Sat with seabreezes at the coast. Winds Sunday
more from s-se direction at fairly light speeds.

Sunday night-Monday...

cigs vsbys trending to MVFR ifr in showers. Winds from the
southeast, trending from the south Monday.

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.

1 pm update... No major changes.

Today...

approaching system from the west will help increase winds and
seas through the day. SCA continues where confidence is highest
for seas above 5 feet. Also went ahead an issued SCA for near
shore waters for the potential for gusts near 25 kts. Rain and
fog will limit vsbys through the day.

Tonight...

poor vsbys in rain and fog Thursday night. Easterly winds
around 25 knots eastern coastal waters with strongest winds
during the evening. These winds then lift north of the waters.

Seas building up to 10 feet across the CAPE ann waters, less
elsewhere. SCA continue. Cannot rule out an iso thunderstorm
over the waters tonight.

Friday...

potent low pressure system still over the region will keep seas
and winds up through the period. SCA will be needed.

Outlook Friday night through Monday ...

Friday night...

low pressure over gulf of maine moves seaward with wnw winds
developing across the ma ri waters resulting in a drying trend and
improving vsby.

Saturday and Sunday...

fairly light winds and tranquil seas as high pres crest over the
area. Dry weather and good vsby too.

Sunday night and Monday...

a series of weak lows may develop and pass south of new england,
near the 40n 70w benchmark.

Tides coastal flooding
Combination of a very high astronomical tide and onshore flow
will result in widespread minor coastal flooding tonight.

Persistent easterly flow yesterday and today will help aid in a
storm surge around .7 to 1.0 which will push many sites above
flood stage. The salisbury to CAPE ann stretch of coastline
continues to be the most at risk, since the low level ene jet
would have just moved north of this area just a couple of hours
before high tide with a moderately significant NE wave fetch in
place. However, the expected total water level looks to be high
enough to support areas of minor coastal flooding along the
coastline south of gloucester to plymouth as well as
provincetown. Thus, went ahead an issued a coastal advisory for
much of the ma east coast including CAPE cod and nantucket for
tonight's high tide. Waves will not be a major factor but looks
like enough low level wind gradient to produce 6 to 10 foot
waves in the near shore waters in ipswich bay, about CAPE ann,
and massachusetts bay. Some erosion is likely along the
salisbury and plum island shorelines where wave action will be
somewhat more significant.

Elsewhere along the ma and ri coasts, the combination of the high
astronomical tide and a tidal departure near a half foot may be
enough to cause pockets of minor coastal flooding as has become more
common during such king tide cycles. A statement may be needed for
the islands, and both the ma and ri south coasts, including
narragansett and buzzards bay shorelines, for the Thursday
evening night high tides. Right now confidence is to low.

Little to no storm surge is expected at the time of the late Friday
night or very early Saturday am high tide. This as well as
offshore flow may limit the potential. Will have to continue to
watch as we cannot rule out the potential for isolated pockets
of minor coastal flooding.

Box watches warnings advisories
Ct... None.

Ma... Coastal flood advisory from 10 pm this evening to 3 am edt
Friday for maz007-015-016-019-022-024.

Ri... None.

Marine... Small craft advisory until 4 pm edt this afternoon for
anz231>234.

Small craft advisory until 6 pm edt Friday for anz235-237-250-
251-254>256.

Synopsis... Nocera dunten
near term... Nocera dunten sipprell
short term... Dunten
long term... Nocera
aviation... Nocera dunten sipprell
marine... Nocera dunten
tides coastal flooding... WFO box staff


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 2 mi61 min 52°F 54°F1008.6 hPa
44013 - BOSTON 16 NM East of Boston, MA 20 mi89 min ENE 21 G 25 52°F 52°F4 ft1007.6 hPa (-2.8)
44029 - Buoy A0102 - Mass. Bay/Stellwagen 27 mi135 min ENE 19 G 23 53°F 52°F4 ft1008.8 hPa
FOXR1 - 8454000 - Providence, RI 43 mi61 min E 7 G 12 55°F 58°F1006.3 hPa
PVDR1 44 mi61 min NE 8 G 11 56°F 1006.6 hPa55°F
FRVM3 - 8447386 - Fall River, MA 46 mi61 min 57°F 58°F1007.2 hPa
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 46 mi61 min NE 9.9 G 15 57°F 1005.8 hPa
FRXM3 47 mi61 min 56°F 55°F
IOSN3 - Isle of Shoals, NH 47 mi79 min ENE 23 G 25 52°F 1010.1 hPa (-1.8)48°F
CPTR1 - 8452944 - Conimicut Light, RI 48 mi61 min NE 8.9 G 13 56°F 60°F1006.7 hPa
BGXN3 - Great Bay Reserve, NH 49 mi94 min ENE 8.9 56°F 1012 hPa50°F

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Boston, Logan International Airport, MA1 mi25 minNE 151.00 miLight Rain Fog/Mist52°F51°F97%1008.4 hPa
East Milton, MA11 mi23 minENE 13 G 23 mi51°F50°F96%1008.3 hPa
Norwood, Norwood Memorial Airport, MA14 mi26 minNE 101.25 miLight Rain Fog/Mist54°F52°F93%1007.6 hPa
Bedford, Hanscom Field, MA16 mi23 minNE 131.25 miLight Rain Fog/Mist53°F48°F86%1009.5 hPa
Beverly, Beverly Municipal Airport, MA16 mi26 minNE 13 G 211.00 miLight Rain Fog/Mist52°F51°F97%1008.4 hPa

Wind History from BOS (wind in knots)
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Last 24hrE6E7E9E7E8E7E5SE4NE3N3E3NE4CalmNE7E9E10NE11NE13NE13E14E19
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1 day agoE7E8E6E6E5CalmCalmS4S6S5S5S5S6S3SE3SE4E4E4NE6E5NE5NE5E6E4
2 days agoSE7SE10S11S9S8SE5SE4NE3N7N5N5N5NW5NW4N5N6W4NW7NW8NW9N7N7SE9E7

Tide / Current Tables for Charlestown, Charles River, Massachusetts
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Charlestown
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Thu -- 05:13 AM EDT     Sunrise
Thu -- 05:16 AM EDT     -1.59 feet Low Tide
Thu -- 05:24 AM EDT     Moonrise
Thu -- 11:27 AM EDT     10.89 feet High Tide
Thu -- 03:46 PM EDT     New Moon
Thu -- 05:32 PM EDT     -0.85 feet Low Tide
Thu -- 07:57 PM EDT     Moonset
Thu -- 08:08 PM EDT     Sunset
Thu -- 11:42 PM EDT     12.30 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
10.98.75.82.80-1.5-1.10.93.66.69.210.710.79.26.841.3-0.6-0.61.13.979.911.9

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Thu -- 02:08 AM EDT     -1.49 knots Max Ebb
Thu -- 05:13 AM EDT     Sunrise
Thu -- 05:16 AM EDT     0.00 knots Slack
Thu -- 05:24 AM EDT     Moonrise
Thu -- 07:50 AM EDT     1.47 knots Max Flood
Thu -- 11:02 AM EDT     -0.00 knots Slack
Thu -- 02:27 PM EDT     -1.39 knots Max Ebb
Thu -- 03:46 PM EDT     New Moon
Thu -- 05:34 PM EDT     0.00 knots Slack
Thu -- 07:56 PM EDT     Moonset
Thu -- 08:03 PM EDT     1.56 knots Max Flood
Thu -- 08:08 PM EDT     Sunset
Thu -- 11:25 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-1-1.3-1.5-1.4-1.2-0.30.81.41.51.40.90-0.7-1.1-1.4-1.4-1.2-0.60.51.41.61.51.20.4

Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
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GOES Local Image of Northeast    EDIT
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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.