Monday, October23, 2017 L-36.com


Marine Weather and Tides
Groton, 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 7:09AMSunset 5:52PM Monday October 23, 2017 9:59 PM EDT (01:59 UTC) Moonrise 10:37AMMoonset 8:34PM Illumination 15% Phase: Waxing Crescent; Moon at 4 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- 716 Pm Edt Mon Oct 23 2017
.gale warning in effect from Tuesday evening through Wednesday morning...
Tonight..SE winds 5 to 10 kt. Gusts up to 20 kt after midnight. Waves around 2 ft. Patchy fog. Vsby 1 nm or less this evening.
Tue..SE winds 10 to 15 kt, becoming S 15 to 20 kt in the afternoon. Gusts up to 25 kt. Waves around 2 ft. A chance of rain and tstms.
Tue night..S winds 15 to 20 kt. Gusts up to 30 kt, increasing to 40 kt after midnight. Waves around 2 ft. Rain with tstms likely.
Wed..S winds 10 to 15 kt with gusts up to 30 kt, becoming sw 5 to 10 kt with gusts up to 20 kt in the afternoon. Waves around 2 ft. Patchy fog. Rain with a chance of tstms. Vsby 1 nm or less.
Wed night..SW winds around 5 kt. Waves 1 foot or less. Patchy fog. Rain.
Thu..W winds 5 to 10 kt. Waves 1 foot or less. A chance of showers.
Thu night..W winds 5 to 10 kt. Waves 1 foot or less.
Fri..SW winds around 5 kt. Waves 1 foot or less.
Fri night..S winds around 5 kt. Waves 1 foot or less.
Sat..SE winds around 5 kt. Waves 1 foot or less.
Sat night..E winds around 5 kt. Waves 1 foot or less. Patchy fog. 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 716 Pm Edt Mon Oct 23 2017
Synopsis for massachusetts and rhode island coastal waters.. Strong high pres will move farther E of new england tonight. A strong cold front approaches from the W late Tue, then lingers around the region until Wed night. Strong winds possible Tue into Wed, especially across the srn coastal waters. The front moves to the east of the waters Thu. A ridge of high pressure will build over the waters for Fri and Sat. 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 232324
afdbox
area forecast discussion
national weather service taunton ma
724 pm edt Mon oct 23 2017

Synopsis
A few showers may develop well ahead of a slowly approaching
cold front tonight into early Tuesday morning. As the front gets
closer, expect rounds of heavy rain late Tuesday into Wednesday
along with a period of strong to damaging wind gusts possible.

A few lingering showers are possible Thursday, but the trend
towards drier, less humid and more seasonable temperatures are
expected Thursday into Friday. Above normal temperatures may
return by this weekend.

Near term until 6 am Tuesday morning
7pm update...

primary changes with this update will be to hold E flow along e
coasta bit later than previously forecast, allowing some of the
low clouds and fog to linger in the bos metro. Otherwise,
gradually building of low clouds overnight everywhere. Delayed
shra timing a bit given overall lack of forcing, but with
increasing moisture a few could squeeze out during the am hours.

Overnight mins were raised a bit given slow increase in dwpts
and possibly a slight non-dirunal temp increase overnight.

Otherwise, forecast on track.

Previous discussion follows...

a stubborn area of very low clouds and dense fog has lingered
from the mid coast of maine SW to CAPE ann down to S of boston
as seen on goes-16 prelim, non-operational satellite loop.

Noting light e-se winds from about kowd-kbed-klwm east to the
coast as well as into the seacoast of maine, while the remainder
of the region has generally S winds at 20z. This is likely due
to the leftover remains of a backdoor cold front that pushed
into E mass Sunday. As the S pressure gradient increases with
the slow approach of a cold front, expect winds to finally shift
and allow the low clouds and fog to push offshore. Still some
question when this will happen, but feel it should for a time
this evening.

With some onshore wind component in place tonight, will still
see more low clouds and patchy fog, some locally dense, to push
back along E coastal mass. Also, with dewpoints in the upper 50s
to lower 60s, will see patchy fog develop away from the coast
as well as temps approach to dewpoints, mainly after midnight.

Scattered showers will develop early tonight across western
mass this evening, which should become more numerous after
midnight. As an h5 short wave wraps around cutoff low pressure
over the western great lakes, will see the vorticity line push
slowly E overnight, pushing the front eastward toward western
new england toward daybreak. Not a lot of instability with the
leading edge, so expect only showers at this point. QPF amounts
generally 0.1 inches or less across central and eastern areas,
possibly up to 0.2 inches across the E slopes of the berkshires
as plume of higher pwat air approaches.

The mild S winds will keep temps well above seasonal normals
overnight. Temps will bottom out in the mid 50s to lower 60s.

Could see record tying or setting high minimum temps for 10 24
at our four long term climate sites. Details will be in the
climate section.

Short term 6 am Tuesday morning through 6 pm Tuesday
Expect showers to move slowly across the region during the day
Tuesday. Very sultry airmass in place with increasing S winds.

Pwat values up to 1.6 to 1.7 inches will slide up the coast
ahead of the front. Will also see some heavier downpours develop
with this airmass mainly across western areas during the
afternoon. Heaviest rainfall looks to hold off until Tue night.

Good instability also develops across central and western areas
during Tue afternoon. Tq values increase to the upper teens,
with k indices reaching the lower-mid 30s across central and
western areas. Have mentioned some thunderstorms in the forecast
as well. Also, with strong low and mid level jet associated
with the approach surface front and mid level short wave, expect
s winds gusting up to 30-40 mph, highest along the S coast.

High temps will reach to upper 60s to mid 70s.

Long term Tuesday night through Monday
Highlights...

* period of strong to damaging wind gusts possible Tue into wed
* heavy rain will result in an urban street flooding threat tue-
wed along with a risk of isolated flash flooding
* less humid & more seasonable weather finally return Thu fri
overview and model preferences...

blocking across the W atlantic continually sharpens up toward
labrador through the long term. This allows for a near constant
trof reloading pattern over the conus, the first of which will
be associated with the heavy rain strong winds Tue into wed, but
after taking on negative tilt and lifting nne late week, a
secondary longwave trof develops in the lee of the continental
divide thanks to reinforcement of arctic influence. Will
continue with a baseline of ensembles given the highly amplified
pattern, which will take into account most solutions in the
envelope.

Details...

tue night and wed...

met overview...

a cold front becomes gradually parallel to the low-mid lvl flow
as strong upper lvl trof digs and takes on a negative tilt late
tue night into wed. The progression of the front across S new
england is very slow as a result, and is likely to take until
wed evening to fully shift offshore. The parent trof has a draw
of subtropical air with pwats reaching very close to 2.00 inches
(3 std deviations above normal). As dwpts respond to this
moisture in the low lvls, soundings become conditionally
unstable, resulting in 300-500j kg of CAPE available. Finally, a
strong llj, which peaks at about 60 kt at h92 and near 70 kt at
h85 shifts n-s through the area late night into early wed. This
will lead to a very unsettled, prolonged period of wet wx,
potentially exceeding 24 hrs.

Wind severe threat...

llj peaks late Tue night into early wed, with h92 speed values
around 60 kt even on the typically more conservative ECMWF eps
members. Combination of precip drag and some bl mixing thanks to
conditionally unstable lapse rates will likely lead to some of
this momentum reaching the ground. Widespread 35-45 mph wind
gusts are likely, even into interior new england. However, 50-60
mph are also possible, especially across SE ma ri where the
core of the LLJ peaks. With some instability, thunderstorms,
and or even a fine line of convection will more efficiently mix
these winds down, potentially leading to localized higher impact
damage. While this is possible anywhere in new england, highest
winds will still be featured across the se. Wind advisories
will be hoisted, and given fully leaved trees, will highlight
all of S new england for this risk, but still monitor for
localized higher impacts in thunderstorms fine convective line.

This coincides with the SWODY2 upgrade to a slight risk, given
localized gusts could produce more damage in convection. Peak
will be overnight into Wed morning. One final note, cannot rule
out a brief spinup given the high shear (helicity 300+) and low
lcls within the moist airmass. This is a very low localized
risk.

Heavy rain...

high pwats and the influence of convective potential could
yield pockets of heavy rain with rainfall rates exceeding 1in hr
at times. The combination of the slow movement of the front,
and strong S LLJ suggests a risk for training heavier cells,
which could lead to prolonged periods of high-rate rainfall. A
slight E component to the low lvl flow could lead to enhanced
upslope in E slopes of the berkshires and litchfield hills. Even
though dry, with ff guidance nearly 3-4 inches hr, the long
timeframe could exceed 3 or 6 hr ff guidance. Flashier streams
will see a risk for flooding. Therefore, will be hoisting a ff
watch with this update mainly for W portions of the forecast
area, where the enhancement is most apparent. Further e,
training heavy rain is still an issue, but the risk would be
more in the form of urban poor drainage flash flooding,
exacerbated if stripped leaves clog drains. We may need to
expand the ff watch for this risk in later updates. Overall
widespread 1.5-2.5 inches are expected with localized 3-4 inches
certainly possible.

Thu...

dry air moves in through the column aloft first, trapping some
lower lvl moisture into the day on thu. The combination of this,
some cold advection and strong cyclonic curvature aloft suggest
a risk for lingering clouds and shra through much of the day,
but not nearly as widespread as the previous 24-48 hours. H92
temps drop to about +6c on average, so expecting seasonable
temperatures with highs mainly in the upper 50s and low 60s
while weak flow overnight and gradual clearing should allow mins
to drop into the 40s.

Fri and sat...

dry period as weak mid lvl ridging forms between the exiting
cutoff trof to the NE and deepening longwave trof shifting e
into the prairies. H92 temps hover around +9c to +10c each day,
suggesting highs will be seasonably warm, mainly in the mid
60s, although overnight lows will be seasonable thanks to some
radiational cooling especially Fri night. Dwpts in the low-mid
40s during the afternoon suggest these will be near the
overnight lows.

Sun into mon...

with a very amplified pattern timing mesoscale features are not
resolved well this far out, but given a similar setup with a
gradually tilting trof with some subtropical moisture associated
with it, will have to watch for another round of low pres with
widespread rainfall. Will favor the slower timing of ensembles
given the meridional nature of the pattern. At the very least,
another unsettled wet period is possible early next week.

Aviation 00z Tuesday through Saturday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday ... .

Tonight... Moderate confidence.

MainlyVFR outside of bos which will remain ifr as long as winds
remain E to start the night. Once winds shift around to the S it
will improve at bos, but CIGS will gradually lower everywhere
else. MVFR CIGS possible after 04z, widespread by 08z except
cape islands. Some shra, mainly W ma ct overnight with reduced
vsbys. Winds increase out of the s, with gusts 20-25 kt mainly
after 06z.

Tuesday... High confidence in trends. Moderate confidence in
timing.

Expect mainly MVFR-ifr conditions in low CIGS and areas
of fog. Expect areas of -shra shra to push slowly into the
region during the day. Rain heavy at times late in the day
across W areas. Occasional tsra at times Tue afternoon. S-se
winds gusting up to 25-30 kt, possibly to 40 kt in any
thunderstorms. Highest gusts along S coast, CAPE cod and the
islands. Areas of llws likely, mainly after 15z.

Kbos terminal... Moderate confidence in taf.

Mainly ifr-lifr CIGS and ifr vsbys lingering through at least
04z, possibly later. E winds up to 10 kt should shift to se-s
overnight. Remaining ifr during at least early portion of the
morning push.

Kbdl terminal... Moderate confidence in taf.

Vfr through 00z, then CIGS lowering to MVFR. May see MVFR-ifr
vsbys in scattered showers by around 10z or so. S winds gusting
up to 20-25 kt by around midday Tuesday.

Outlook Tuesday night through Saturday ...

Tuesday night: mainly ifr, with local MVFR possible. Strong
winds with gusts to 40 kt. Ra, chance tsra, patchy br.

Wednesday: mainlyVFR late, with local ifr possible. Windy with
gusts to 35 kt. Ra, patchy br.

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

Chance shra, chance ra, patchy br.

Thursday:VFR. Breezy. Chance shra.

Thursday night through Friday:VFR.

Friday night:VFR. Patchy br.

Saturday:VFR.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Tuesday ...

have converted gale watches to warnings with this package for
all waters.

Expect increasing s-se winds tonight, gusting up to 20-25 kt
after midnight. Seas build up to 5-6 ft. Winds and seas highest
on the southern waters. Reduced visibility in areas of fog.

Scattered showers across the southern waters late tonight.

On Tuesday, S winds continue to increase, with gusts up to
30-35 kt. Seas continue to build, up to 6-9 ft. Visibility
restrictions develop in areas of locally heavy rain and patchy
fog. Scattered thunderstorms possible. Gale force wind gusts
likely Tue afternoon across most of the waters.

Outlook Tuesday night through Saturday ...

Tuesday night: gale force winds with gusts up to 45 kt. Rough
seas up to 11 ft. Rain, chance of thunderstorms, patchy fog.

Local visibility 1 to 3 nm.

Wednesday: gale force winds with gusts up to 40 kt early. Rough
seas up to 12 ft. Rain, chance of thunderstorms, patchy fog.

Local visibility 1 nm or less.

Wednesday night: winds less than 25 kt. Rough seas up to 11 ft.

Rain showers likely, rain, patchy fog.

Thursday: winds less than 25 kt. Areas of rough seas. Chance of
rain showers.

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

Friday: winds less than 25 kt. Seas up to 5 ft.

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

Saturday: winds less than 25 kt. Seas locally approaching 5 ft.

Box watches warnings advisories
Ct... Wind advisory from noon Tuesday to 11 am edt Wednesday for
ctz002>004.

Flash flood watch from Tuesday evening through Wednesday
morning for ctz002.

Ma... Wind advisory from noon Tuesday to 11 am edt Wednesday for
maz002>024-026.

Flash flood watch from Tuesday evening through Wednesday
morning for maz002-003-008>011.

Ri... Wind advisory from noon Tuesday to 11 am edt Wednesday for
riz001>008.

Marine... Gale warning from noon Tuesday to 11 am edt Wednesday for
anz231>234.

Gale warning from 8 pm Tuesday to 9 am edt Wednesday for
anz230-251.

Gale warning from 2 pm Tuesday to 8 am edt Wednesday for
anz236.

Gale warning from 11 am Tuesday to 8 am edt Wednesday for
anz235-237.

Gale warning from noon Tuesday to 2 pm edt Wednesday for
anz250-254.

Gale warning from 11 am Tuesday to 11 am edt Wednesday for
anz255-256.

Synopsis... Doody evt
near term... Doody evt
short term... Evt
long term... Doody
aviation... Doody evt
marine... Doody evt


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 35 mi41 min 63°F 1021 hPa
BGXN3 - Great Bay Reserve, NH 53 mi74 min Calm 56°F 1023 hPa56°F
44013 - BOSTON 16 NM East of Boston, MA 55 mi69 min SE 7.8 G 7.8 61°F 59°F1 ft1022.1 hPa (-1.1)

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fitchburg, Fitchburg Municipal Airport, MA8 mi67 minN 010.00 miA Few Clouds59°F57°F96%1022 hPa
Nashua - Boire Field Airport, NH14 mi63 minSE 510.00 miMostly Cloudy60°F59°F96%1023.1 hPa
Bedford, Hanscom Field, MA20 mi2.1 hrsESE 45.00 miFog/Mist59°F55°F87%1023 hPa
Jaffrey Airport-Silver Ranch, NH24 mi67 minSSE 610.00 miFair62°F60°F93%1022.6 hPa

Wind History from FIT (wind in knots)
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Last 24hrCalmSE3CalmCalmCalm3SE3SE3CalmS3S3CalmSE4SE6SE6SE11S4SE7S5S6CalmCalmCalmCalm
1 day agoCalmNW5CalmCalmCalmCalmCalmNW3CalmCalmCalmCalmCalmE4E3E433E3E8E4NE3N3Calm
2 days agoCalmCalmNW3CalmCalmNW5NW4NW4CalmCalm6NW4W45W7W7SW6NW10W8SW5CalmCalm33

Tide / Current Tables for Riverside, Merrimack River, Massachusetts
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Riverside
Click for Map
Mon -- 03:53 AM EDT     5.65 feet High Tide
Mon -- 07:07 AM EDT     Sunrise
Mon -- 10:34 AM EDT     Moonrise
Mon -- 11:24 AM EDT     0.34 feet Low Tide
Mon -- 03:59 PM EDT     5.98 feet High Tide
Mon -- 05:48 PM EDT     Sunset
Mon -- 08:32 PM EDT     Moonset
Mon -- 11:54 PM EDT     0.12 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.41.83.75.25.75.44.73.82.61.50.80.40.61.83.85.465.85.24.231.80.90.3

Tide / Current Tables for Amelia Earhart Dam, Mystic River, Boston Harbor, Massachusetts
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Amelia Earhart Dam
Click for Map
Mon -- 02:06 AM EDT     9.63 feet High Tide
Mon -- 07:07 AM EDT     Sunrise
Mon -- 08:06 AM EDT     0.88 feet Low Tide
Mon -- 10:33 AM EDT     Moonrise
Mon -- 02:14 PM EDT     10.22 feet High Tide
Mon -- 05:49 PM EDT     Sunset
Mon -- 08:33 PM EDT     Moonset
Mon -- 08:35 PM EDT     0.27 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
78.99.69.27.85.93.71.80.91.53.15.17.39.210.29.98.56.54.32.10.50.41.53.3

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

GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (21,6,7,8)
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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.