Friday, August18, 2017 L-36.com


Marine Weather and Tides
Winthrop Town, MA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
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 5:54AMSunset 7:41PM Friday August 18, 2017 2:07 PM EDT (18:07 UTC) Moonrise 2:18AMMoonset 5:22PM Illumination 13% Phase: Waning Crescent; Moon at 26 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 Fri Aug 18 2017
This afternoon..S winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. Showers likely with a chance of tstms. Some tstms may produce heavy rainfall.
Tonight..S winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. Patchy fog. Showers likely with a chance of tstms. Some tstms may produce heavy rainfall. Vsby 1 to 3 nm.
Sat..S winds 5 to 10 kt. Waves 1 foot or less. Patchy fog. A chance of showers. Vsby 1 to 3 nm.
Sat night..W winds around 5 kt. Waves 1 foot or less.
Sun..W winds around 5 kt. Waves 1 foot or less.
Sun night..W winds around 5 kt. Waves 1 foot or less.
Mon..W winds around 5 kt. Waves 1 foot or less.
Mon night..SW winds around 5 kt. Waves 1 foot or less.
Tue..SW winds around 5 kt. Waves 1 foot or less.
Tue night..SW winds 5 to 10 kt. Waves 1 foot or less. A chance of showers. Winds and waves higher in and near tstms. 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 Fri Aug 18 2017
Synopsis for massachusetts and rhode island coastal waters.. A warm front will lift north of the waters today. A cold front will then cross new england later tonight and Saturday, passing across the waters early Saturday night. This will bring showers and Thunderstorms along with areas of fog. High pressure will return with dry weather on Saturday night through Tuesday. A cold front will approach the waters midweek. 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 Winthrop Town, MA
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location: 42.37, -70.98     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 181712
afdbox
area forecast discussion
national weather service taunton ma
112 pm edt Fri aug 18 2017

Synopsis
Out ahead of a deep low pressure center lifting into S canada,
rain, possibly heavy at times, along with the threat of localized
flooding, is expected for today and tonight. A low risk of strong
to severe thunderstorms mainly over S W portions of ma and ct. A
cold front moves through new england Saturday with a few leftover
showers and thunderstorms, then moves off to the east Saturday
night. High pressure returns with fair seasonable weather Sunday
through Tuesday. Another cold front sweeps through new england
Wednesday, followed by more dry weather Thursday.

Near term until 6 pm this evening
* highlights (1p update)...

- simply put, widespread rain with embedded heavier showers
and thunderstorms.

- higher confidence with respect to localized flooding impacts
given forecast ascent upon the tropical environment. With
heaviest storms earlier today, rainfall rates of around 1 to
2 inches have been observed, storm total rainfall amounts up
to 3 inches.

- lower confidence with respect to strong to severe storms.

Greater focus over S W portions of ma and ct. Potential of
gusty winds. Lower risk of a brief tornado given the
environment.

- no headlines will be issued with this update.

* overview (1p update)...

scattered showers and thunderstorms evolving within a tropical
environment drawn N by a closed low pressure system over the n
great lakes region. The attendant surface warm front lifting ne
across N E areas of new england as discerned by SPC h925-85 meso-
analysis bucks up against the mid-upper level ridge S w. Warm-
moist tropical surging N with surface dewpoints in the 70s, over-
running and convergence, especially along the nose of h925-85
winds, heavy rain has been observed and should continue. Further
s w, greater instability lending to the threat of shower and
thunderstorm development, some strong to severe with heavy rain,
out ahead of a surface cold front and mid-level dry punch poised
to sweep through the region overnight into Saturday.

* discussion (1p update)...

straight-forward, continued forecast of widespread rain with embedded
heavier downpours and thunderstorms. Two things of concern: 1.)
localized flooding, and 2.) strong to severe storms.

Through afternoon, warm front presently over the immediate E waters
stretched N into me per SPC h925-85 dewpoint mesoanalysis is the
continued focus for heavy rain given convergent focus of h925-85
winds advecting tropical moisture n. Better chances of embedded
thunder S W within greater instability. This area continues to
progress slowly N e, hung up against the S W mid-upper level ridge
and anticyclonic flow. Expecting the focus of heavy rain to continue
right up till the cold front sweeps through the area Saturday.

Towards evening and overnight, monitoring upstream trends. Per goes-16,
clearing emerging across SE pa into the DELMARVA peninsula and per
spc mesoanalysis it is this area which has highest surface dewpoints
and greatest instability within a region of modest shear. Expectation
is that within this area strong to severe storms will develop and
they may rob the environment N up across albany into S W portions
of ma and ct. Moving N E with the mean wind, will have to watch the
evolution and morphology closely. As the boundary layer decouples
with warm-moist air continuing to surge aloft, expect storm activity
and enhanced h925-85 low- level convergence to meet and potentially
surge over S E new england during the overnight hours. It is this
timeframe where we may see the greatest threat of localized flooding
if activity does not emerge immediately S W ahead of the pre-frontal
trough presently observed via radar SW to NE across pa, upstate ny,
into new england.

Agree with spc. We're still within a strongly sheared environment
within a measure of helicity as signaled via SPC mesoanalysis and
ncar ensembles. Marginal instability that could be compensated
by the shear, can't rule out strong to severe weather across S w
areas of ma and ct. However, greater confidence of outcomes is
further S W of our region around SW pa, nj, DELMARVA with the
more potent focus of thermal-instability axes. Better low-level
lapse rates which are mediocre over S new england.

In greater agreement with wpc. Anomalous moist environment up to
3 standard deviations above normal. Tropical. This morning has
been an indication of how with any ascent rainfall rates of 1 to
2 inches per hour are possible. Precipitable waters well over 2
inches with k indices close to 40. The difficult part is nailing
it down, however with the latest guidance, the concern is over
s E areas of new england during the overnight period as convection
emerges around the delmarva, fueled by SW warm-moist flow, enhanced
by boundary layer decoupling, pushing NE with the mean wind and
maintained until the dry punch and cold front begin to sweep into
the region towards Saturday morning.

No flash flood flood watch at this time. Difficult to nail down
as it is possible heavy rain may stay offshore going into this
evening. However, can't rule out urban poor-drainage issues
even ahead of the pre-frontal trough approaching from the w.

Short term 6 pm this evening through 6 am Saturday
Tonight...

thermal axis will peak over the region tonight as upper level trough
begins to approach. LLJ will be on the increase early this evening.

This combined with the warm, moist airmass and approaching upper
level trough expect the first half of the night to be busy with
ongoing precipitation. Conditions will slowly improve from west to
east through the early morning hours, however the approaching cold
front appears to stall either over or west of the region. Thus
expect a very mild night as dewpoints will remain high, in the 70s.

Could see a round of fog overnight as temp dewpoint spread will be
low. In fact, cannot rule out the dense fog potential. Overall,
anticipate ongoing precip and fog through the night with conditions
slowly improving from west to east by the morning hours.

Long term Saturday through Thursday
Big picture...

subtropical high remains in control across the southern usa while a
general zonal flow continues across canada and the northern usa. The
flow becomes less zonal next midweek as alaska closed upper low digs
south over the gulf, subtropical upper ridge builds north over the
western usa, and upper low over hudsons bay digs south into the
northeast usa.

One shortwave moves across new england Saturday night, with brief
cooling aloft that destabilizes the airmass Sunday. A second
shortwave crosses new england Wednesday as the hudsons bay low
approaches and moves a supporting jet MAX across the region.

Contour heights are normal to a little higher than normal through
early next week. As the quebec closed low deepens, heights over new
england dip below normal midweek.

Model mass and thermal fields from the 00z suite are in general
agreement through Wednesday, building forecast confidence through
that time. Less agreement in the fields Thursday.

Details...

Saturday... Moderate confidence.

Models hold the the cold front over southern new england while
moisture fields race east and drier air moves in during the late
morning and afternoon. Pw fields show 1.5 inch values across much
of the region in the morning, but moving east of CAPE cod by
evening. CAPE fields show 1000-1500 j kg over easter ct ri eastern
mass midday. Winds aloft are marginally significant, especially at
500 mb with speeds of 40-45 knots. Stability parameters are mixed,
with totals in the mid to upper 40s in the early night, and li
values subzero over ri and eastern mass.

Expect the main area of showers heavy downpours to move east of
massachusetts during the morning. Drier air moves in at low levels,
with lingering moisture around 850 mb. This suggests at least some
clouds during the day, but with potential for sunny breaks. This
heating should push temps into the 80s, with enough instability to
generate scattered showers thunder along and ahead of the cold
front.

Saturday night...

cold front moves offshore, and surface winds become northwest. Skies
will either clear or partially clear. Dew points will linger in the
60s, with min temps close to that level.

Sunday...

upper shortwave and the coldest of the cold mid-level temps will be
over new england. The more significant cold temps as well as cloud-
level moisture will be over nh-vt. Cross-sections show southern new
england will have a moist layer based at 850 mb, but with drier air
above and below that layer. Expect diurnal clouds, probably a bit
more than guidance is suggesting, but otherwise a fair day with less
noticeable humidity. Temps aloft 12-14c support MAX sfc temps in
the upper 70s to mid 80s.

Surface high pressure builds in with light variable wind Sunday
night. With dew points in the upper 50s and around 60, expect min
temps around this same range. Guidance temps were nudged a couple of
degrees colder.

Monday-Tuesday...

high pressure builds over the region Monday and shifts offshore
south and east by Tuesday. Cross sections show dry air in place at
most levels through Tuesday evening, so expect dry weather both
days. Increasing mid and high clouds Tuesday ahead of the next
weather system. Temps aloft 14-15c Monday and 15-17c Tuesday,
supporting low-mid 80s Monday and 85 to 90 on Tuesday.

Tuesday night-Wednesday-Thursday...

closed low digs over quebec and the northeast usa with shortwave
driving a cold front into through new england. Expect
showers scattered tstms with the front Tuesday night Wednesday.

The airmass dries out Thursday, but lingering patches of
moisture in the mixed layer should generate some diurnal sky
cover.

Aviation 18z Friday through Wednesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through tonight ...

today and tonight... Moderate confidence.

Trending MVFR to ifr spreading N E if not already. Can't rule
out partial improvement over S W new england late at times.

Overall, expect -ra ra this morning, becoming ra +ra tsra later
today and continuing overnight, SW to ne, as conditions lower
ifr over most locations. With ra +ra, expect tempo MVFR-ifr vsby
impacts, locally dense ifr fog over the S coast overnight.

Strong S winds around 10-15 kts with gusts up to 25 kts, strongest
over S SE new england. Potential llws overnight with 40-45 kt sw
jet across S SE new england. All conditions improving as winds
turn W into early morning Saturday.

Kbos terminal... Moderate confidence.

Vfr with a gradual transition through the morning to MVFR ifr
along with a band of -ra and occasional +ra ra. Low risk for
occasional tsra through the day.

Kbdl terminal... Moderate confidence.

Hovering around MVFR. Some improvement is possible into the
later-half of the day prior to possible ra +ra tsra encroaching
from the S w. Low confidence concerning potential, as well as
timing and impacts.

Outlook Saturday through Tuesday ...

Saturday... Moderate confidence.

MVFR ifr CIGS and vsbys in showers and fog Saturday morning, then
lingering showers thunderstorms in eastern mass and ri in the pm.

Trend all places will be toVFR. A cold front over the region will
move offshore to the east by Saturday evening with winds shifting
from the west.

Areas of ifr CIGS vsbys in fog and low clouds later Saturday night.

Sunday through Tuesday... Moderate-high confidence.

Vfr. Areas of ifr in early morning fog low clouds, then improving
toVFR by each mid morning and continuing the remainder of each day.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through tonight ... Moderate confidence.

S winds will be on the increase, gusting up to 25 kts across
the S SE waters. Small craft advisory remain as winds will
result in heightened seas up around 5 feet.

Heavy rain with embedded thunderstorms sweeping W to E across
the waters today and tonight. Will likely be some visibility
restrictions.

Outlook Saturday through Tuesday ...

Saturday... Moderate confidence.

Lingering potential for scattered showers tstms through the day,
diminishing west to east late Saturday. Diminishing wind through the
day. Some gusts 20-25 knots in the morning. Seas near 5 feet on the
outer waters and on ri sound, but trending lower through the day.

Sunday through Tuesday... Moderate-high confidence.

High pressure builds over the waters. Winds remain 20 knots or less,
and seas 4 feet or less.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 5 pm this afternoon to 9 am edt
Saturday for anz231>234.

Small craft advisory from 5 pm this afternoon to 2 am edt
Saturday for anz236.

Small craft advisory until 11 am edt Saturday for anz235-237.

Small craft advisory from 8 pm this evening to 2 pm edt
Saturday for anz250-254.

Small craft advisory until 8 pm edt Saturday for anz255-256.

Synopsis... Wtb dunten
near term... Dunten sipprell
short term... Dunten
long term... Wtb
aviation... Wtb dunten sipprell
marine... Wtb dunten sipprell


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 4 mi49 min 79°F 1010.4 hPa
44013 - BOSTON 16 NM East of Boston, MA 18 mi77 min SE 14 G 16 69°F 68°F2 ft1012.3 hPa (-1.1)
44029 - Buoy A0102 - Mass. Bay/Stellwagen 24 mi123 min SSE 18 G 19 69°F 67°F2 ft1012.2 hPa
FOXR1 - 8454000 - Providence, RI 45 mi49 min SW 13 G 19 78°F 71°F1011.3 hPa
IOSN3 - Isle of Shoals, NH 45 mi67 min SE 18 G 18 67°F 1011.9 hPa (-1.5)66°F
PVDR1 46 mi49 min S 13 G 18 75°F 1012.2 hPa72°F
FRVM3 - 8447386 - Fall River, MA 47 mi49 min 76°F 73°F1013.7 hPa
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 47 mi49 min SSW 18 G 24 76°F 1011.8 hPa
BGXN3 - Great Bay Reserve, NH 48 mi82 min E 1.9 67°F 1013 hPa66°F
FRXM3 48 mi49 min 76°F 70°F
CPTR1 - 8452944 - Conimicut Light, RI 49 mi55 min S 21 G 25 73°F 72°F1012.3 hPa

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Boston, Logan International Airport, MA3 mi2.2 hrsS 1110.00 miOvercast76°F69°F79%1012.5 hPa
East Milton, MA13 mi71 minSSW 19 G 28 miBreezy79°F68°F69%1013 hPa
Beverly, Beverly Municipal Airport, MA15 mi74 minSSE 78.00 miOvercast73°F70°F90%1011.4 hPa
Norwood, Norwood Memorial Airport, MA16 mi74 minS 17 G 2210.00 miMostly Cloudy81°F71°F72%1011.7 hPa
Bedford, Hanscom Field, MA18 mi71 minS 910.00 miMostly Cloudy80°F66°F64%1012.2 hPa

Wind History from BOS (wind in knots)
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Last 24hrW10
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W9SW9W96W8S8S8S7SW8SW4S6S6S6SE3S7S5SE7S8SE7S10S11--S17
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NW13N8N6N5N9NW7N9N8NW8NW7NW6NW4W5W6NW7--CalmS5SW7W7
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SW7S11S13S13S13SW10SW10SW8SW7SW6SW8SW7SW7S6SW7W6NW6NW10NW10N11
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Tide / Current Tables for Belle Isle Inlet entrance, Boston Harbor, Massachusetts
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Belle Isle Inlet entrance
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Fri -- 02:18 AM EDT     Moonrise
Fri -- 02:42 AM EDT     -0.30 feet Low Tide
Fri -- 05:54 AM EDT     Sunrise
Fri -- 08:58 AM EDT     9.57 feet High Tide
Fri -- 02:58 PM EDT     0.30 feet Low Tide
Fri -- 05:21 PM EDT     Moonset
Fri -- 07:40 PM EDT     Sunset
Fri -- 09:17 PM EDT     11.12 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
4.41.90.1-0.20.82.74.97.299.68.97.45.33.11.10.31.135.37.81011.110.89.3

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Fri -- 02:18 AM EDT     Moonrise
Fri -- 02:19 AM EDT     0.00 knots Slack
Fri -- 05:10 AM EDT     1.15 knots Max Flood
Fri -- 05:54 AM EDT     Sunrise
Fri -- 08:06 AM EDT     -0.00 knots Slack
Fri -- 12:24 PM EDT     -1.07 knots Max Ebb
Fri -- 02:40 PM EDT     0.00 knots Slack
Fri -- 05:07 PM EDT     1.20 knots Max Flood
Fri -- 05:21 PM EDT     Moonset
Fri -- 07:39 PM EDT     Sunset
Fri -- 08:29 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-1.2-1-0.30.61.11.21.10.70.1-0.5-0.8-1-1.1-1-0.60.311.21.210.3-0.3-0.8-1.1

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
Geos

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.