Friday, December6, 2019
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Marine Weather and Tides
Groton, MA

Version 3.4
NOTICE
10/9/2019 Updated the Marine Zones.
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 7:00AMSunset 4:15PM Friday December 6, 2019 12:09 AM EST (05:09 UTC) Moonrise 2:37PMMoonset 2:04AM Illumination 68% Phase: Waxing Gibbous; Moon at 9 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- 1019 Pm Est Thu Dec 5 2019
.small craft advisory in effect until 2 am est Friday...
Overnight..W winds 15 to 20 kt with gusts up to 25 kt. Waves around 2 ft.
Fri..W winds 10 to 15 kt with gusts up to 20 kt, becoming sw 5 to 10 kt in the afternoon. Waves around 2 ft. Snow. Vsby 1 to 3 nm.
Fri night..NW winds 5 to 10 kt, increasing to 10 to 15 kt after midnight. Gusts up to 20 kt. Waves around 2 ft. A chance of snow.
Sat..NW winds around 10 kt. Gusts up to 20 kt in the morning. Waves around 2 ft.
Sat night..NW winds 5 to 10 kt. Waves 1 foot or less.
Sun..SW winds 5 to 10 kt. Waves around 2 ft.
Sun night..S winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. A chance of showers.
Mon through Tue..SW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. Showers likely.
Tue night..W winds 10 to 15 kt with gusts up to 25 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 1019 Pm Est Thu Dec 5 2019
Synopsis for massachusetts and rhode island coastal waters.. Stiff nw winds will blow overnight behind an exiting cold front. A fast moving low pres system will approach from the west on Fri, sweeping across the waters Fri night. Large high pres then builds in from the west Sat into Sat night. The high pres system moves off the coast Sun as a slow moving cold front approaches from the west Mon into 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 060304 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 1004 PM EST Thu Dec 5 2019

SYNOPSIS. Tonight, any snow showers in Western MA and far northwest CT will gradually diminish. Under clear skies, light winds and a deep snowpack (some parts of interior MA and CT still have snow depth over a foot), expect temperatures to drop into the teens in the interior and 20s elsewhere. Tomorrow, clouds will increase ahead of a fast-moving clipper system that will push through with periods of light snow in the afternoon and early evening. Best chance of seeing light accumulations would be along and north of the MA turnpike. The East Slopes of the Berkshires could see upwards of 2 inches. Colder, drier air moves in Friday night and Saturday as high pressure brings dry weather for the weekend. The high moves offshore Sunday, starting a return flow of milder air for the first half of the week. Parts of the area could even reach 60 degrees by Tuesday. However, this would be accompanied by a widespread rain event from Sunday night through Tuesday. A cold front moves through Tuesday night, followed by a return to cooler temperatures for Wednesday.

NEAR TERM /THROUGH FRIDAY/.

10 PM update .

Tonight .

Radar returns have diminished and the last of the light showers are coming to an end this evening. The forecast is mostly on track, with only small changes to bring temperatures in line with observations.

Previous Discussion .

Light snow was briefly reported in Pittsfield and radar has picked up on some reflectivity in northwest CT but in general, snow has not made it to the ground east of the Berkshires. Nonetheless, have introduced a slight chance for snow showers west and along the CT River valley. Otherwise, clouds will gradually clear out this evening. Helped by a fresh snowpack, radiational cooling will drop lows into the upper teens and low 20s for Western and Central MA. Mid 20s are expected for other locations with the exception of Cape and the Islands, which should bottom out in the upper 20s and low 30s.

SHORT TERM /FRIDAY NIGHT/. Friday . ***A CLIPPER SYSTEM IS EXPECTED TO BRING COATING TO AN INCH OF SNOW ESPECIALLY ALONG & NORTH OF THE MA TURNPIKE LATE FRI AFTERNOON INTO EARLY EVENING. LOCALLY 2-3 INCHES POSSIBLE IN THE EAST SLOPES OF THE BERKSHIRES.***

Clouds overspread the entire area from west to east by mid morning. A progressive clipper system is expected to bring a period of light snow late afternoon into the early evening hours. There appear to be two areas of good 700-850mb jet dynamics, one near the Berkshires and the other along south coast. However, 925mb temperatures look to be above freezing south of the MA turnpike so not expecting accumulations except coating on grassy surfaces there. North of the turnpike, however, temperatures might be cold enough to support up to an inch of snow. Towards the Berkshires, where there is a combination of good dynamics and sub-freezing temperatures, up to 2 to 3 inches of snow are possible in the higher elevations. Confidence for 3 inches of snow is currently low, however, so have opted to issue a Special Weather Statement instead of a Winter Weather Advisory. Snow will quickly come to an end west to east by around 10pm so mid-level dry air moves in and shuts off the precipitation. In summary, most locations will likely see under an inch of snow but given that the snow would likely overlap with parts of evening commute, motorists should be aware of slippery travel.

After the snow exits, skies would gradually clear overnight. The extent of radiational cooling will depend on how quickly the winds decouple. There might be a short window before sunrise where temperatures can fall quickly. So right now, looking at mid to upper teens for much of interior MA and low to mid 20s elsewhere except for low 30s on the Cape.

LONG TERM /SATURDAY THROUGH THURSDAY/. Highlights .

Dry through the weekend with unseasonably cold temperatures on Saturday and Sunday AM. Temperatures rebounding on Sunday.

Rain spreading in early next week with temperatures trending upward. Potential for strong winds on Monday and Tuesday.

Cooler temperatures return on Wednesday.

Daily Concerns .

Saturday and Sunday .

Cyclonic flow on Saturday with a trough lifting northeast of the region. Good agreement between deterministic models with cold northwesterly flow aloft. Mid level ridge building into the eastern Great Lakes. The surface response will be high pressure building just to the west of New England. Am a bit skeptical on the current sky forecast given the upper level pattern. Typically with cyclonic flow, cold air advection and day time heating there is more in the way of diurnal cu, but opted to leaned on the consensus amongst guidance which keeps it sunny. Something to keep in mind for future updates to the forecast. High temperatures range from the upper 20s across the higher elevations in western and central MA to the mid 30s along the coast. Moderate to high confidence in the forecast.

High pressure builds in over New England Saturday evening into early Sunday. This will bring clear skies and light winds. Expect strong radiational cooling due to this setup. Bumped down temperatures toward the 10th percentile of guidance which brings low temperatures into the single digits above zero across the MA/CT/NH border. Low temperatures elsewhere will generally be in the teens, but it will be slightly warmer along the coast with lows in the low to mid 20s. High confidence in the forecast.

High pressure shifts to the east as the day progresses on Sunday. Winds aloft will shift to a southwesterly direction and advect warm air into the region. Skies will be partly to mostly sunny with highs rebounding into the mid 30s along the MA/NH/VT border and the low 40s across the coast and SE MA. High confidence in the forecast.

Sunday evening through Wednesday .

Pattern change beginning late on Sunday through the middle of next week. Shifting from a zonal pattern to a more amplified pattern. A positively tilted trough will dig from the Pacific Northwest Sunday evening into the Central Plains by Monday evening. There are still some differences between the GFS and ECMWF/GEM. The ECMWF/GEM feature a northern and southern stream trough where the weaker southern trough lags over the Southwestern US and the northern becomes nearly neutrally tilted over the Central US. The GFS quickly absorbs the southern stream trough. This does not have major implications on how things evolve other than the GFS developing a deeper low than than ECMWF/GEM over the central Great Lakes late on Monday into Tuesday. The overall progression of the system is in good agreement through Tuesday. The low lifts from the central Great Lakes into eastern Ontario and Quebec. This keeps New England in storm warm air advection and anticipate that precipitation will remain all rain. There could be some snow mixing in across western MA as colder air filters in as things wind down late on Tuesday into early Wednesday. Still concerned about winds and wind gusts on Monday and Tuesday with a 40 to 60 kt 925 hpa low level jet developing. Held off from bumping winds up due to some disagreement between the ECMWF and GFS where the jet sets up, but may need to do so in future updates. Not out of the question that there are a few rumbles of thunder Monday into Tuesday.

Temperatures will be warm on Monday and Tuesday due to the strong warm air advection. High temperatures will generally be in the 50s. Think there is a possibility for some 60 degree readings if strong winds develop and we tap into the mixed layer. Cooler temperatures return on Wednesday as the system lifts into Quebec. Flow will become northwesterly advecting cold air into the region. Highs on Wednesday drop into the low 30s across the Berkshires and the low 40s along the coast and SE MA. Low to medium confidence in the forecast.

AVIATION /03Z FRIDAY THROUGH TUESDAY/. 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.

00Z update .

Tonight . VFR conditions with cigs around 40-80kft. Gusty winds gradually diminishing overnight. Westerly gusts of 20-25 knots possible before the boundary layer decouples.

Friday . VFR initially, but cigs will lower to MVFR along with brief periods of light to moderate snow 18z-00z. Expecting mainly rain across the Cape and Islands and a period of a rain/snow mix at PVD. Potential for brief periods of IFR across northern MA, including BOS, with any heavier snow bands moving through. Precipitation ends from west to east Friday evening.

KBOS Terminal . High confidence in TAF. Moderate confidence after 18Z.

KBDL Terminal . High confidence in TAF.

Outlook /Saturday through Tuesday/ .

Saturday through Sunday: VFR. Breezy.

Sunday Night: MVFR/IFR conditions possible. Breezy. Chance SHRA.

Monday: Mainly MVFR, with areas IFR possible. Windy with local gusts up to 30 kt. SHRA likely.

Monday Night: Mainly MVFR, with areas IFR possible. Breezy. SHRA likely.

Tuesday: Mainly MVFR, with areas IFR possible. Windy with local gusts up to 30 kt. SHRA likely.

MARINE. Short Term /through Friday Night/ . High confidence.

Today . Increasing NW winds 25-35 kt as the day progresses. Mainly dry along with good vsby.

Tonight . NW winds 25-35 kt along with mainly dry weather and good vsby. Winds beginning to slacken late.

Friday . clipper low zips across CT/RI and southeast MA during the day and accompanied by a period of light winds until about 00z. Vsby will lower to 1 mile or less in snow.

Outlook /Saturday through Tuesday/ .

Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft.

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

Sunday: Winds less than 25 kt.

Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of seas approaching 5 ft. Chance of rain showers.

Monday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 11 ft. Rain showers likely.

Monday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 12 ft. Rain showers likely.

Tuesday: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 13 ft. Rain showers likely.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . None. RI . None. MARINE . Small Craft Advisory until 7 AM EST Friday for ANZ232>235-237. Small Craft Advisory until 2 AM EST Friday for ANZ230-236. Small Craft Advisory until 9 AM EST Friday for ANZ231-251. Gale Warning until 5 AM EST Friday for ANZ250-254>256.

SYNOPSIS . BL/Chai NEAR TERM . Frank/Chai SHORT TERM . Frank/Chai LONG TERM . BL AVIATION . BL MARINE . Frank/BL/Chai


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 35 mi51 min 33°F 42°F1012.8 hPa
BGXN3 - Great Bay Reserve, NH 53 mi84 min W 13 31°F 1011 hPa20°F
44013 - BOSTON 16 NM East of Boston, MA 55 mi79 min WNW 25 G 31 36°F 48°F3 ft1011.5 hPa (+3.2)21°F

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fitchburg, Fitchburg Municipal Airport, MA8 mi77 minNW 810.00 miA Few Clouds28°F12°F53%1014.4 hPa
Nashua - Boire Field Airport, NH14 mi73 minWNW 910.00 miFair29°F15°F56%1014.6 hPa
Laurence G Hanscom Field Airport, MA20 mi78 minWNW 1510.00 miFair30°F12°F47%1014.9 hPa
Jaffrey Airport-Silver Ranch, NH24 mi77 minNW 9 G 1910.00 miFair25°F12°F58%1014 hPa

Link to 5 minute data for KFIT

Wind History from FIT (wind in knots)
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1 day agoNW6N8NW6NW5W11NW3CalmCalmCalmCalmCalmW8W7SW5SW4SW3CalmCalm3NW353NW4NW5
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Tide / Current Tables for Charlestown Bridge, Charles River, Massachusetts
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Charlestown Bridge
Click for Map
Fri -- 12:21 AM EST     1.37 feet Low Tide
Fri -- 01:01 AM EST     Moonset
Fri -- 06:43 AM EST     8.92 feet High Tide
Fri -- 06:58 AM EST     Sunrise
Fri -- 12:50 PM EST     1.71 feet Low Tide
Fri -- 01:34 PM EST     Moonrise
Fri -- 04:11 PM EST     Sunset
Fri -- 07:02 PM EST     8.72 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.41.62.53.85.67.48.78.98.275.43.62.11.72.33.44.96.78.28.78.37.25.73.9

Tide / Current Tables for Charles River Dam, Charles River, Massachusetts
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Charles River Dam
Click for Map
Fri -- 12:23 AM EST     1.37 feet Low Tide
Fri -- 01:01 AM EST     Moonset
Fri -- 06:46 AM EST     8.92 feet High Tide
Fri -- 06:58 AM EST     Sunrise
Fri -- 12:52 PM EST     1.71 feet Low Tide
Fri -- 01:34 PM EST     Moonrise
Fri -- 04:11 PM EST     Sunset
Fri -- 07:05 PM EST     8.72 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.51.62.43.85.57.48.68.98.37.15.53.62.21.72.33.34.86.68.18.78.47.35.73.9

Weather Map
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GEOS Local Image of    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.
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Wind Forecast for Boston, MA (0,6,7,8)
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Ground Weather Radar Station Boston, MA
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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.