Thursday, December12, 2019
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Marine Weather and Tides
Cambridge, 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 7:02AMSunset 4:13PM Thursday December 12, 2019 11:43 PM EST (04:43 UTC) Moonrise 5:47PMMoonset 8:19AM Illumination 98% Phase: Waning Gibbous; Moon at 16 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- 943 Pm Est Thu Dec 12 2019
Overnight..S winds around 5 kt, increasing to 5 to 10 kt. Waves 1 foot or less.
Fri..S winds 5 to 10 kt, becoming se 10 to 15 kt in the afternoon. Gusts up to 20 kt. Waves 2 to 3 ft. A chance of showers.
Fri night..SE winds 5 to 10 kt, becoming E 10 to 15 kt with gusts up to 20 kt after midnight. Waves 2 to 3 ft. Rain. Vsby 1 to 3 nm.
Sat..SE winds 10 to 15 kt with gusts up to 20 kt, becoming S 5 to 10 kt in the afternoon. Waves 2 to 3 ft. Rain. Vsby 1 to 3 nm.
Sat night..SW winds 10 to 15 kt with gusts up to 25 kt. Waves around 2 ft, except 3 to 5 ft at the outer harbor entrance. Rain likely.
Sun and Sun night..W winds 15 to 20 kt with gusts up to 30 kt. Waves around 2 ft, except 3 to 5 ft at the outer harbor entrance.
Mon..W winds 10 to 15 kt with gusts up to 25 kt. Waves around 2 ft.
Mon night..W winds 5 to 10 kt. Waves 1 foot or less. A chance of snow. Vsby 1 to 3 nm.
Tue..NE winds 5 to 10 kt. Waves around 2 ft. A chance of rain and snow. Vsby 1 to 3 nm.
Tue night..NW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. 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 943 Pm Est Thu Dec 12 2019
Synopsis for massachusetts and rhode island coastal waters.. High pres centered over the waters late this evening, will shift offshore overnight and Fri. Low pres from the gulf states will head northeast Fri night, passing over the waters Sat, then over northern new england Sat night. Westerly gales blow across the waters Sun and Sun night. High pres builds briefly over the waters on Mon, then is followed by a storm system approaching from the southwest on 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 Cambridge, MA
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location: 42.36, -71.11     debug


Area Discussion for - Boston, MA
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FXUS61 KBOX 130211 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 911 PM EST Thu Dec 12 2019

SYNOPSIS. High pressure gradually shifting off to the northeast late tonight. There is a risk for scattered light precipitation across western Massachusetts and northern Connecticut, which may begin as a very light wintry. Temperatures will gradually increase Friday night as winds become onshore. Low pressure will bring mainly rain Friday night and Saturday which will fall heavily at times with areas of dense fog due to melting snow. Dry and blustery conditions move in on Sunday, then colder air arrives Monday. Another system brings snow to start Monday night, then a wintry mix that will change to rain across the coastal plain, but remaining mixed rain and/or snow well inland into Tuesday. Dry and cold conditions return during Wednesday.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/.

910 PM Update .

Large high pressure will gradually slide east of the region tonight, but it will still be close enough to keep us dry/cold. Overnight low temps will generally be in the 15 to 25 degree range with the coldest readings in the typical outlying locations. Many locations are just a few degrees away from their low temps already. In fact, temps should level off or even rise a few degrees after midnight as clouds begin to thicken and lower especially across western MA/CT.

SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/.

* Risk for very light icing across parts of the interior Friday with the greatest threat across the CT River Valley

Friday .

High pressure continues building off to the east while a shortwave lifts in from the southwest. Expect moisture advection from the south with the best forcing still setting up across interior MA and CT. There are some timing differences between high resolution guidance and the synoptic scale guidance where the NMM brings in light precipitation quickly tomorrow morning whereas the GFS/GEM and ECMWF are much slower bringing precipitation in. Think that the slower solution may be on to something due to the drier air currently in place and the current synoptic setup, but will need to refine things in future updates. There will be warming aloft with 0 to +5 degree Celsius air advecting in. The overrunning warm air will bring rain to much of the region, but think that colder air will be locked in across the valleys across western MA and CT. Think the 12Z NAM depicts this best. These locations have the best opportunity for a wintry mix possibly as freezing rain or drizzle during the morning and into the afternoon. As previously stated if any icing occurs amounts will be light, but it does not take much for hazardous travel. High temperatures will be in the 40s across the coastal plain. Expect light precipitation to spread into the coastal areas late.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/. Highlights .

* Low pressure brings the potential for heavy rain & localized flooding late Friday into Saturday. Interior areas may see periods of dense fog and icing during precipitation onset due to shallow cold air and warm rain falling on cold surfaces but any icing issues will be very transient. Flooding risks may be increased by snowmelt.

* Leftover rain/snow showers linger into Sunday. Strong northwest winds, especially in coastal areas with gusts up to 40 kts. Gale headlines might be needed for Sunday over the waters.

* Drying out and seasonably cold on Monday before the next system arrives on Tuesday, giving us another round of snow before mixing with or changing to rain. Confidence is growing with an impactful storm but precipitation types remain uncertain.

* Unseasonably cold but dry on Wednesday and Thursday. Details .

Friday night through Saturday .

***Heavy Rain and Flood Potential on Saturday***

By Friday night, the 500mb long wave trough starts digging out of the midwest into the southeast states. This will set up a strong southwest mid level wind flow allowing the deep layer moisture to work into the northeast late Friday into early Saturday morning, with PWATs up to 2-3 standard deviations above normal and pockets of 3-4 standard deviations along the Eastern MA coast. Looking at the guidances from WPC and using model blend, it looks like we can expect between 0.75 to 1.5 inch of QPF for Western MA/CT and 1 to 2 inches of QPF in Eastern MA/RI, with highest amounts near the coast. In general, shower coverage increases into the evening but widespread heavy rain is expected after midnight when the atmosphere becomes fully saturated at all levels. Shallow cold air might hang around in the interior high elevations or CT River valley long enough for a brief period of light freezing rain late Friday night. But this will be very transient with the surge of warm air overnight. While this is a relatively progressive system, heavy rainfall rates at times on Saturday morning and afternoon could lead to localized flooding. With the low level jet kicking in late Friday night, overnight temperatures on Friday will exhibit a non-diurnal trend. There would also be a significant uptick in dew points, with 40s in Western MA/CT and 50s elsewhere. The high dew points combined with a southerly wind will be very efficient in melting the existing snowpack. High temperatures on Saturday look to be in the mid to upper 40s across the interior and mid to upper 50s near the coast.

An issue of concern for Saturday is the potential for localized flooding. NOHRSC is forecasting up to 2 inches of snowmelt in the East Slopes of the Berkshires and along the CT River valley in MA by late Saturday night. So the combination of snowmelt runoff and heavy rain may result in localized urban and poor drainage flooding. We will continue to monitor river levels for any rises.

The other concern is areas of dense fog, especially in the normally prone valley locations with warm rain falling on cold surfaces or snow. With light winds, have to watch the risk of fog late Friday night into early Saturday morning.

Sunday .

** Strong winds on Sunday **

Low pressure will shift northeast into Maine and the Maritimes by Sunday morning, though there may be scattered showers on Sunday morning. A cold front pushes through late Saturday night into early Sunday. There could be some snow showers in the East Slopes of the Berkshires and the Northern Worcester Hills Sunday morning into early afternoon but any accumulations would be very light. The main concern on Sunday, however, is the wind. In wake of the departing low, northwest winds increase, possibly gusting up to 25 kts in the interior higher elevations and up to 40 kts over the waters. This is supported by Bufkit soundings show a momentum transfer of 35 kts at the bottom of the boundary layer and 52 kts at the top of the boundary layer in Boston early Sunday afternoon. As a result, we will likely need gale headlines for Sunday.

Next Monday through Tuesday .

** Potential for snow mixing with/changing to rain on Tuesday but low confidence this far out**

Another cold front will sweep across the region by Monday morning, bringing gusty northwest winds and colder air across the region. Expect highs on Monday to be in the 30s and 40s. Another low pressure system looks to impact the area by early Tuesday. With the cold air in place, it should start off as snow before changing to mixed precipitation or rain away from the interior. The 12z ECMWF shows the low pressure tracking over the 70W/40N benchmark so it is not out of the question this could remain mostly snow and bring impactful snowfall to the I-95 corridor. But since we are still 5 days away, confidence is low given the spread in model guidance and all solutions remain on the table. The precipitation comes to an end late Tuesday along with a cold front passage.

Next Wednesday through Thursday .

Other than some possible ocean-effect snow showers on the Cape, Wednesday looks dry but with below average high temperatures in the 20s in the interior and 30s near the coast. Thursday looks to be even colder with sub-freezing highs possible for all locations. A clipper system may skirt northwest MA late Thursday but confidence is extremely low a week out.

AVIATION /02Z FRIDAY THROUGH TUESDAY/. Forecaster Confidence Levels .

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

00Z update .

Short Term /through Friday/ .

Tonight . High confidence. VFR conditions with light winds.

Friday . Moderate to high confidence. MVFR to IFR conditions spreading in across interior MA & CT with scattered light precipitation expected to develop. It may be cold enough for some light snow and/or freezing drizzle. Greatest risk for freezing drizzle would be across the BAF and BDL terminals. Meanwhile, across eastern MA and RI VFR to marginal MVFR conditions expected with light rain overspreading.

KBOS Terminal . Moderate confidence in TAF

KBDL Terminal . Moderate confidence in TAF.

Outlook /Friday Night through Tuesday/ .

Friday Night: Mainly IFR, with local MVFR possible. Breezy. RA, FZRA likely.

Saturday: Mainly IFR, with areas MVFR possible. Breezy. RA likely.

Saturday Night: Mainly MVFR, with local IFR possible. Windy with gusts up to 35 kt. Chance RA.

Sunday: Mainly VFR, with local MVFR possible. Strong winds with local gusts up to 40 kt.

Sunday Night: VFR. Strong winds with local gusts up to 40 kt.

Monday: VFR. Windy with local gusts up to 30 kt. Slight chance SN.

Monday Night: MVFR/IFR conditions possible. Chance SN, FZRA likely.

Tuesday: Mainly IFR, with areas MVFR possible. Breezy. Chance FZRA, chance PL, slight chance RA, slight chance SN.

MARINE. Short Term /through Friday/ .

Today . High confidence. NW winds continue to diminish as high pressure builds in from the west. Wind gusts will continue decreasing as the high relaxes the pressure gradient.

Tonight and Friday . High confidence. High pressure will be in control of our waters tonight keeping winds/seas below small craft thresholds. High pressure moves east of the waters Fri, allowing southerly winds to increase with gusts of 20 to 25 knots developing during the afternoon. We also may see some marginal 5 foot seas develop across our outer waters.

Outlook /Friday Night through Tuesday/ .

Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Rain. Local visibility 1 to 3 nm.

Saturday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 11 ft. Rain likely. Areas of visibility 1 to 3 nm.

Saturday Night: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 12 ft. Chance of rain.

Sunday through Sunday Night: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 13 ft.

Monday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain.

Monday Night: Winds less than 25 kt. Seas up to 5 ft. Rain likely, chance of snow. Areas of visibility 1 to 3 nm.

Tuesday: Winds less than 25 kt. Areas of rough seas. Chance of rain, freezing rain likely.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . None. RI . None. MARINE . Small Craft Advisory from 3 AM Saturday to 1 AM EST Sunday for ANZ231-232-251. Small Craft Advisory from 9 PM Saturday to 1 AM EST Sunday for ANZ233-234. Small Craft Advisory from noon Friday to 1 AM EST Sunday for ANZ235-237-250-254-256. Small Craft Advisory from 6 PM Friday to 1 AM EST Sunday for ANZ255.

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


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 3 mi73 min 28°F 41°F1038.7 hPa
44013 - BOSTON 16 NM East of Boston, MA 24 mi113 min S 5.8 G 7.8 32°F 46°F1 ft1038.8 hPa (-1.2)19°F
44029 - Buoy A0102 - Mass. Bay/Stellwagen 31 mi99 min SSW 5.8 G 7.8 33°F 46°F1 ft1037.4 hPa
FOXR1 - 8454000 - Providence, RI 41 mi73 min SSW 2.9 G 2.9 28°F 41°F1039.6 hPa
PVDR1 42 mi73 min SE 4.1 G 5.1 30°F 1039.8 hPa22°F
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 45 mi73 min ESE 5.1 G 6 29°F 1039.7 hPa
FRVM3 - 8447386 - Fall River, MA 45 mi73 min 28°F 43°F1039.8 hPa
CPTR1 - 8452944 - Conimicut Light, RI 46 mi73 min SE 8.9 G 12 31°F 41°F
FRXM3 46 mi73 min 27°F 20°F
IOSN3 - Isle of Shoals, NH 49 mi43 min SW 8.9 G 11 31°F 1038.8 hPa (-0.5)16°F

Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Boston, Logan International Airport, MA4 mi49 minS 710.00 miMostly Cloudy28°F17°F63%1039.6 hPa
East Milton, MA10 mi52 minS 9 mi22°F16°F78%1039.7 hPa
Norwood, Norwood Memorial Airport, MA12 mi50 minN 010.00 miFair22°F15°F75%1039.4 hPa
Laurence G Hanscom Field Airport, MA12 mi52 minN 010.00 miFair20°F16°F85%1040.7 hPa
Beverly, Beverly Municipal Airport, MA18 mi50 minN 010.00 miFair23°F18°F81%1039 hPa

Link to 5 minute data for KBOS

Wind History from BOS (wind in knots)
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Tide / Current Tables for Charlestown Bridge, Charles River, Massachusetts
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Charlestown Bridge
Click for Map
Thu -- 12:14 AM EST     Full Moon
Thu -- 04:49 AM EST     0.64 feet Low Tide
Thu -- 07:03 AM EST     Sunrise
Thu -- 07:19 AM EST     Moonset
Thu -- 10:59 AM EST     10.76 feet High Tide
Thu -- 04:11 PM EST     Sunset
Thu -- 04:46 PM EST     Moonrise
Thu -- 05:24 PM EST     -0.53 feet Low Tide
Thu -- 11:35 PM EST     9.47 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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8.67.152.91.20.71.73.768.310.110.810.18.363.41-0.4-0.21.33.45.77.89.2

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Thu -- 12:14 AM EST     Full Moon
Thu -- 01:42 AM EST     -1.09 knots Max Ebb
Thu -- 04:48 AM EST     0.00 knots Slack
Thu -- 07:03 AM EST     Sunrise
Thu -- 07:03 AM EST     1.31 knots Max Flood
Thu -- 07:18 AM EST     Moonset
Thu -- 10:32 AM EST     -0.00 knots Slack
Thu -- 02:00 PM EST     -1.26 knots Max Ebb
Thu -- 04:11 PM EST     Sunset
Thu -- 04:46 PM EST     Moonrise
Thu -- 05:19 PM EST     0.00 knots Slack
Thu -- 07:31 PM EST     1.25 knots Max Flood
Thu -- 10:59 PM EST     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.8-1-1.1-1-0.70.211.31.210.4-0.3-0.9-1.2-1.3-1.2-1-0.30.71.21.21.10.7-0

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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Boston, MA (23,6,7,8)
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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.