Saturday, September21, 2019 L-36.com


Marine Weather and Tides
Groton, MA

Version 3.4
NOTICE
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen

Sunrise 6:31AMSunset 6:48PM Saturday September 21, 2019 11:03 AM EDT (15:03 UTC) Moonrise 11:13PMMoonset 1:43PM Illumination 50% Phase: Third Quarter Moon; Moon at 22 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- 1059 Am Edt Sat Sep 21 2019
This afternoon..SE winds around 5 kt, increasing to 5 to 10 kt. Waves 1 foot or less.
Tonight..S winds 5 to 10 kt. Waves 1 foot or less.
Sun..SW winds 5 to 10 kt. Waves 1 foot or less.
Sun night..SW winds around 10 kt. Waves 1 foot or less.
Mon..SW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft.
Mon night..SW winds 10 to 15 kt, becoming W 5 to 10 kt after midnight. Waves around 2 ft in the evening, then 1 foot or less. Showers likely.
Tue..W winds 5 to 10 kt. Waves 1 foot or less. A chance of showers in the morning.
Tue night..NW winds 5 to 10 kt. Waves 1 foot or less.
Wed..NW winds 5 to 10 kt, becoming ne in the afternoon. Waves 1 foot or less.
Wed night..SE winds around 5 kt, becoming sw after midnight. 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 1059 Am Edt Sat Sep 21 2019
Synopsis for massachusetts and rhode island coastal waters.. High pres builds slowly S of the waters through Sun. Meanwhile lingering E swell from distant hurricane humberto will impact the waters today. A cold front approaches the waters Mon night, sweeping across the waters early Tue. 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 211418
afdbox
area forecast discussion
national weather service boston norton ma
1018 am edt Sat sep 21 2019

Synopsis
High pressure remains in control into Monday with summer-like
temperatures and dry weather. A cold front will bring a period
of showers late Monday and Monday night followed by cooler, but
seasonably warm, weather through the rest of next week.

Near term until 7 pm this evening
10 am update (no major changes)...

dry cyclonic flow aloft with mid level ridge axis over ny state
is providing 1024 mb surface high over ny pa and will advect
eastward into new england. This will translate to abundant
sunshine today and summer-like temps. SPC mesoanalysis has +18c
at 925 mb over the region this morning. This will support highs
this afternoon in the low 80s away from the coastline, where
seabreezes will limit highs to the 70s. No matter how you slice
it a gorgeous day late sep day with summer-like temps. Although
humidity levels will remain manageable with dew pts remaining
in the 50s. The take away - enjoy!
only weather concern will be leftover swells from once hurricane
humberto. Current buoys reporting east swells around 5 feet
every 11 seconds. This will be sufficient to yield modest surf
and strong rips especially east facing ocean beaches on
nantucket and CAPE cod. Thus rip current statement remains in
effect. Elsewhere less wave energy should result in smaller
surf and lower prob of strong rips.

Short term 7 pm this evening through 6 pm Sunday
Dry weather tonight into Sunday. The warming trend continues
with a high pressure off to our southeast producing an
increasing southwest wind. Above normal temperatures through
this period.

Long term Sunday night through Friday
* highlights...

- rain anticipated late Monday into Monday night
- thereafter mild days, cool nights, dry the remainder of the week
- temperatures running above average throughout
* overview...

amplifying pattern. Impressive N pacific jet signaled by a +wpo +epo
that cascades energy and mild air over the CONUS initially. Kicking
downsheared energy across the 4-corners region, a closing mid-level
low latched onto continental moisture, there's a chance for rainfall
around Monday night discussed in more detail below. However by late
september a pattern-amplification emerges. One-two punch, NW pacific
tapah becoming post-tropical, ingested into the bering straight low,
subsequent latent heat release amplifies the longwave trof that re-
captures earlier cut-off N pacific energy. Heightened ak ridge that
ultimately downshears a deep trof across the W CONUS into the end of
september, pna becomes largely negative as does the epo wpo. With a
continued active N atlantic tropics emphasized by the phase 1 mjo,
an impressive heat pump and anomalously higher heights emerge over
the E conus. No surprise to see above average temperature trends and
below average precipitation per cpc. However along the ne-periphery
of the heat-bubble no-trouble, there are opportunities for cooler
air and rainfall chances along se-sweeping cold front boundaries. So
not entirely convinced we'll see the brunt of the heat expected for
the SE CONUS N into the mid-atlantic. Perhaps just on the cusp yet
however for late september is still above average when highs are
normally around 70 and lows normally around 50. A pattern of mild
days and cool nights, some shots of wet-weather in-between. Break
down the details below.

* discussion...

Monday into Monday night...

widespread showers and appreciable rainfall remains possible. Lean
towards wetter solutions given consensus forecast mid-level closed-
low solution acting on a narrow-ribbon of continental moisture. Much
of the same, precipitable waters up around 1.75-inches, warm-cloud
layer up around 12 kft preceding the sweeping cold front. A moist-
adiabatic, conditionally-unstable profile, albeit brief and right
along the front, expected lift, low-level convergent forcing, and
synoptic ascent beneath cyclonic flow and diffluence aloft makes a
case of decent upward motions that should promote collision as well
as coalescence such that decent rains should develop. Positive to a
neutral tilt trof with modest W SW shear preceding, instability is
in question given marginal, moist-adiabatic lapse rates. Rumbles of
thunder not ruled out, nor heavier downpours. Chance to likely pops.

There's increasing signal of the possibility of significant rainfall
with amounts around 0.50 inches.

Rest of the week...

rain chances around Thursday night appear suppressed by the weight
of increasing heights across the E conus. However with the prior
mentioned amplified pattern tightening over the W and central conus
that new england finds itself beneath NW flow aloft, the opportunity
for some slightly cooler air and rainfall chances along SE sweeping
cold fronts over the weekend into early next week. However overall
temperatures still look to run above average.

Aviation 14z Saturday through Wednesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday ... High confidence.

14z update (no major changes)...

vfr. Generally light W winds today across the interior. Sea-
breezes developing by midday along the coasts, impacting coastal
terminals. Isolated ifr in low clouds and fog for portions of
the ct river valley around kore in the morning hours.

Kbos terminal... High confidence in taf.

Kbdl terminal... High confidence in taf.

Outlook Sunday night through Wednesday ...

Sunday night:VFR. Breezy.

Monday:VFR. Breezy. Chance shra.

Monday night:VFR. Breezy. Shra likely, slight chance tsra.

Tuesday:VFR. Slight chance shra.

Tuesday night through Wednesday:VFR.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Sunday ... High confidence.

10 am update (no major changes)...

adjusted the timing of small craft advisories for today. Based
on latest buoy reports, swell is diminishing slower than
previously thought. Rough seas continuing up to 8 feet across
portions of the outer coastal waters.

Swell from hurricane humberto will continue to diminish through
the day. Relatively light winds will mean smaller wind waves.

Local seabreezes near the coast today. Relatively tranquil winds
and seas expected tonight into Sunday, with light S to sw
winds.

Outlook Sunday night through Wednesday ... Moderate confidence.

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

Monday: moderate risk for small craft advisory winds with gusts
up to 25 kt. Areas of rough seas. Chance of rain showers.

Monday night: low risk for small craft advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain showers likely,
slight chance of thunderstorms.

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

Chance of rain showers.

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

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

Box watches warnings advisories
Ct... None.

Ma... High rip current risk until 6 pm edt this evening for maz022-
024.

Ri... None.

Marine... Small craft advisory until 2 pm edt this afternoon for anz250-
251-254-255.

Small craft advisory until 11 am edt this morning for anz256.

Synopsis... Belk sipprell
near term... Belk nocera sipprell
short term... Belk
long term... Sipprell
aviation... Belk nocera sipprell
marine... Belk nocera sipprell


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 35 mi51 min 76°F 1022.8 hPa
BGXN3 - Great Bay Reserve, NH 53 mi78 min WSW 1.9 70°F 1023 hPa60°F
44013 - BOSTON 16 NM East of Boston, MA 55 mi73 min W 5.8 G 7.8 64°F 64°F4 ft1021.7 hPa (+1.3)58°F

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fitchburg, Fitchburg Municipal Airport, MA8 mi71 minN 010.00 miFair74°F55°F52%1023.3 hPa
Nashua - Boire Field Airport, NH14 mi67 minN 010.00 miFair72°F57°F59%1023.7 hPa
Laurence G Hanscom Field Airport, MA20 mi72 minN 410.00 miFair75°F55°F50%1023.8 hPa
Jaffrey Airport-Silver Ranch, NH24 mi71 minVar 310.00 miFair71°F54°F55%1024.6 hPa

Link to 5 minute data for KFIT

Wind History from FIT (wind in knots)
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Last 24hrNW10N7NW5CalmCalmW7NW6CalmCalmCalmCalmCalmNW4NW5N6NW4CalmCalmCalmCalmCalmCalmCalm3
1 day agoE4--CalmCalmCalmSE5SE4CalmCalmN3N3NW4NW3CalmNW3CalmCalmCalmCalmCalmNW6NW10W10NW7
2 days agoN10N10
G15
NE8E11NE9NE5NE4SE5CalmNW4NW3N3N3N3N4N5N3N5N5N3N4CalmCalmE5

Tide / Current Tables for Riverside, Merrimack River, Massachusetts
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for Amelia Earhart Dam, Mystic River, Boston Harbor, Massachusetts
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map
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wmap_A
GEOS Local Image of Northeast    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Boston, MA (11,2,3,4)
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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.