Wednesday, April21, 2021
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Marine Weather and Tides
Ocean Bluff-Brant Rock, MA

Version 3.4
NOTICE
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.

Sunrise 5:50AMSunset 7:32PM Wednesday April 21, 2021 8:02 AM EDT (12:02 UTC) Moonrise 12:58PMMoonset 3:15AM Illumination 71% 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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ANZ251 Massachusetts Bay And Ipswich Bay- 716 Am Edt Wed Apr 21 2021
.gale warning in effect from late tonight through late Thursday night...
Today..S winds 10 to 15 kt, increasing to 15 to 20 kt this afternoon. Gusts up to 25 kt. Seas 2 to 4 ft. A chance of showers with isolated tstms this afternoon.
Tonight..SW winds 15 to 20 kt with gusts up to 25 kt, becoming W 25 to 30 kt with gusts up to 35 kt after midnight. Seas 2 to 4 ft. Showers with a chance of tstms. Some tstms may produce gusty winds.
Thu..W winds 25 to 30 kt, diminishing to 20 to 25 kt in the afternoon. Gusts up to 40 kt. Seas 3 to 5 ft.
Thu night..W winds 20 to 25 kt. Gusts up to 40 kt, decreasing to 30 kt after midnight. Seas 3 to 4 ft.
Fri and Fri night..W winds 20 to 25 kt with gusts up to 30 kt. Seas 2 to 4 ft.
Sat..SW winds 10 to 15 kt. Seas around 2 ft.
Sat night..S winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft. A chance of rain.
Sun..E winds 15 to 20 kt with gusts up to 30 kt. Seas 3 to 5 ft. Rain likely.
Sun night..NW winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 6 ft. A chance of rain. Winds and seas 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 Am Edt Wed Apr 21 2021
Synopsis for massachusetts and rhode island coastal waters.. A strong cold front will then cross the waters early this evening bringing showers and isolated Thunderstorms. Gale force wnw to W wind gusts are expected behind the front tonight through Thursday. A ridge of high pressure will then pass south of the waters Friday and Saturday. A coastal storm moves in on Sunday bringing rain and gusty winds. For additional information on possible hazardous weather for the week ahead, please visit www.weather.gov/boston/ehwo


7 Day Forecast for Marine Location Near Ocean Bluff-Brant Rock, MA
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location: 42.15, -70.62     debug


Area Discussion for - Boston, MA
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FXUS61 KBOX 211123 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 723 AM EDT Wed Apr 21 2021

SYNOPSIS. A strong cold front will bring a period of showers and scattered thunderstorms this afternoon and early evening. Some storms will be capable of producing locally damaging wind gusts. Windy and much cooler weather follows behind the front late tonight into Thursday, then a warming trend Friday and Saturday. A coastal storm will likely bring rain and coastal wind Sunday followed by blustery and drier conditions Monday. Mild and dry weather expected into midweek as high pressure builds into the region.

NEAR TERM /UNTIL 6 PM THIS EVENING/. 720 AM update .

A few showers ahead of the front expected to move into portions of interior SNE this morning, otherwise a mainly dry morning with increasing south winds assocd with pre-frontal low level jet. This will advect higher dewpoints northward into SNE and combined with heating and fairly steep mid level lapse rates will contribute to CAPES up to 500 J/kg. This is marginal instability, but certainly enough given strong forcing along the front and favorable deep layer shear to support a broken line of stronger storms moving into western SNE after 18z. A few severe storms are possible with damaging wind the primary threat. But can't rule out a brief spin-up in western MA and CT valley near the low track where low level helicity may be enhanced. Soundings show favorable 0-3km CAPE and low LCLs which are a concern but low level jet and best helicity may end up ahead of the line of convection. We will closely monitor.

Previous discussion .

Highlights

* Slight risk for severe thunderstorms across western MA and much of CT. Expecting a line of storms to move in from the west bringing a risk of damaging wind gusts during the afternoon into the early evening. Line anticipated to weaken as it traverses eastward.

Shortwave trough located over the central/eastern Great Lakes early today. The trough will lift northeastward across the eastern Great Lakes into northern New England by the evening. Southern New England will remain within the warm sector for much of the day until a cold front moves through. The surface low associated with the front will lift from PA this morning northeastward through western MA/CT into northern New England.

Main concern for southern New England today is the risk of strong to severe thunderstorms. The risk is maximized across western MA/CT as highlighted by the SPC Day 1 Slight risk, but still not completely out of the question across areas further east. Expecting the low/front to provide the lift necessary for thunderstorm initiation. Ahead of the low will see southerly flow advect in upper 40 to low 50 degree dew points. Bulk shear values in the 0-6 km layer will be on the order of 40-60+ kts ahead of and along the forcing. Orientation of the shear to the forcing is mostly parallel, so anticipating convective mode to be linear. Instability values are on the order of a few hundred J/kg of MLCAPE with little MLCIN. The limited instability should be compensated for by the strong forcing for thunderstorm development today. Low level lapse rates are on the order of 6-8 degrees Celsius per km with mid level lapse rates falling in the 6-7.5 degree range.

Given this setup and forecast soundings am thinking the main risk will be damaging wind gusts. Cannot completely rule out some hail, but there just isn't a lot of CAPE within the hail growth zone. Lastly, SPC indicates there is a low risk of a tornado, but am not sold on this given the 0-1 km SRH generally remains out ahead of the forcing and does not overlap. If the forcing and SRH can overlap a bit then the risk is there especially with the low LCL heights and 0- 3 km CAPE over 100 J/kg in place across western MA and CT. CAMs show a line developing near/just west of the Capital District in NY and progressing eastward. Have kept the gusty wind mention in the forecast to highlight this as there is a 40-50 kt 925 hPa southerly jet moving across the area today. Have heavily leaned toward this guidance in the forecast for PoPs, QPF, wind speeds and gusts today. Does appear that based on the timing of the front moving in that the instability will be waning, which should limit how far east the severe risk extends and that the convective line weakens as it progresses eastward.

Should see some fairly good boundary layer mixing out ahead of the system moving in, which given the strong low level jet will bring another day of gusty winds. Have gone with the 75th percentile of guidance for high temperatures today given some uncertainty on how quickly mid to high clouds move in. The result is highs in the 60s for much of the region with some 70 degree readings in eastern MA. Could see a few scattered showers this morning, but the highest risk for any precipitation will be this afternoon into the evening.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/. Highlights

* Any lingering showers/storms come to an end as the cold front exits this evening. Gusty WNW to NW winds expected in wake of the front with much colder temperatures.

* Dry, but strong W to WNW winds across southern New England on Thursday. Not out of the question a few spots may need a Wind Advisory.

Expecting a closed off circulation to develop at 500 hPa as it lifts into northern New England from the eastern Great Lakes/Ontario/Quebec. This feature will lift northeastward toward New Brunswick on Thursday, but southern New England will remain under cyclonic flow. At the surface will remain pinched between the exiting system and high pressure building over the Southeastern US.

Tonight .

Cold front moves through and will bring an end to any showers/storms during the evening. Still have leaned on the CAM guidance as there if fairly good agreement. Expecting strong cold air advection in wake of the front with 925 hPa air of -3 to -5 degree Celsius air moving in with winds of 30-40 kts. It will not be too difficult to mix this down, so have gone with the 95th percentile of guidance for wind gusts. Should see speeds of 25-35 kts with the higher gusts after midnight. Much colder with low temperatures bottoming out in the 20s across the higher terrain the low to mid 30s elsewhere.

Thursday .

Strong W/WNW winds across southern New England. The pressure gradient remains quite tight with the exiting system and high pressure well to the southwest. Given the setup went with the 95th percentile of guidance as BUFKIT soundings show a well mixed boundary layer. Gusts are in the 35-40 kt range for much of southern New England, so anticipate a few spots will need a Wind Advisory in future updates. Have held off for now as most locations are borderline advisory criteria at this point in time.

Given the strong mixing with WNW flow. Increased high temperatures to the 75th percentile of guidance to account for some downsloping. However, with the cold airmass in place most locations will struggle to get into the mid 40s. Do have some upper 40 degree readings across the CT River Valley and eastern MA. On top of this have also lower dew points/RH values and this may lead to fire weather concerns for portions of the CWA. See the Fire Weather section below for more details on this.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/. Highlights

* Gradual warming trend Friday into Saturday * Rain likely Sunday along with gusty winds near the coast * Blustery and mainly dry weather Monday

Thursday night into Saturday .

Blustery and cold conditions Thu night as strong pres gradient remains in place. Lows mostly in the mid 30s but close to 30 over higher terrain with wind chills dropping into the 20s.

Still blustery on Fri with deep and well mixed boundary layer up to 800 mb supporting 25-35 mph west wind gusts but with moderating temps under abundant sunshine. Highs will recover well into the 50s to near 60 in the coastal plain and interior valleys. Then further moderation on Saturday with less wind as high pres builds to the south. 925 mb temps around 10C will support highs well into the 60s to near 70 degrees, but cooler along the south coast. Sunshine will give way to increasing afternoon clouds on Sat ahead of next system.

Saturday night into Sunday night .

Good agreement among deterministic and ensemble guidance of a coastal low impacting the region late Sat night into Sun evening. As expected at this time range, there is spread in the guidance with the low track but enough clustering near or south of SNE to suggest a period of heavy rain is possible. Details on timing and location of heaviest rain still have to be worked out. There is no antecedent cold air ahead of this system or during the event so ptype will be all rain. Gusty winds will also be a concern along the coast as SE low level jet ahead of the storm lifts across the region.

The risk for coastal flooding will depend on timing of the low level jet and highest storm surge with respect to the high tide. The 2 tide cycles of note are the Sunday morning and Sunday evening high tide. The Sun evening high tide is the higher of the 2 tide cycles. Latest guidance suggests the surge and seas may not be built up enough for much impact during the Sun morning high tide, while winds may have shifted to NW before the Sun evening high tide. However, timing of the wind and surge is uncertain at this time range and will be important to the coastal flooding risk.

Monday and Tuesday .

Trend will be for improving conditions Mon with blustery NW winds. However, there is uncertainty with how quickly the closed low exits New Eng which will impact temps and shower threat for Mon. A slower solution would keep threat of showers around on Mon, especially in the east, along with cooler temps Mon and Tue. If closed low exits further to the east, warmer temps to the west will spill into interior SNE on Tue.

AVIATION /11Z WEDNESDAY THROUGH SUNDAY/. Forecaster Confidence Levels.

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

Today . High confidence in trends. Moderate in timing.

VFR to start with gusty southerly winds developing by mid morning. Will gradually see MVFR and borderline IFR as showers and thunderstorms move through generally in the afternoon to early evening hours. As any storms move through could see conditions fall locally to LIFR. Have only mentioned thunder in the BAF/BDL TAF at this point in time as instability will be waning and should see the line weaken as it progresses eastward. As the cold front moves through will see winds shift to the SW/W. Gusts on the order of 25-30 kts throughout the day.

Tonight . High confidence.

Any showers come to an end during the evening and should see any lingering MVFR conditions improving to VFR. Winds shift to the WNW/NW and will be strong at 10-15 kts. Gusts of 25-30 kts during the evening increasing to 30-35 kts late.

Thursday . High confidence.

VFR with strong WNW/NW winds. Speeds of 15-25 kts and gusts of 30-40 kts. Could see some cloud bases of 4-6 kft during the afternoon.

KBOS TAF . High confidence in TAF.

KBDL TAF . High confidence in TAF. Moderate confidence on the exact timing of thunderstorms moving through this afternoon and how strong gusts will get as storms move through.

Outlook /Thursday Night through Sunday/ .

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

Friday: VFR. Windy with gusts up to 35 kt.

Friday Night through Saturday: VFR. Breezy.

Saturday Night: Mainly VFR, with areas MVFR possible. Breezy. Chance RA.

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

MARINE. Have extended the Gale Warning into Thursday night as Gale Force gusts persist.

Today . High confidence in much of the forecast, but uncertain on the thunderstorm risk as the line should weaken as it moves toward the waters.

Southerly winds increasing to 15-20 kts by this afternoon with gusts of 20-30 kts. Not out of the question there are a few thunderstorms late in the day as a cold front approaches.

Tonight . High confidence

Strong cold front crosses the waters during the evening. Expect any showers/storms to end during the evening. Winds shifting to the W/WNW once the front passes. W/WNW wind speeds increasing to around 30 kts after midnight with gale force gusts of 35-40 kts. Seas increasing to 6-10 ft.

Thursday . High confidence

Strong westerly winds persist across the waters throughout the day with speeds between 25-30 kts. Should see gale force gusts around 40 kts. Seas between 6-10 ft.

Outlook /Thursday Night through Sunday/ .

Thursday Night: Strong winds with gusts up to 40 kt. Rough seas up to 11 ft.

Friday: Strong winds with gusts up to 35 kt. Areas of rough seas.

Friday Night: Winds less than 25 kt. Local rough seas.

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

Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Chance of rain.

Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Rain likely.

FIRE WEATHER. Strong W winds are anticipated on Thursday in wake of the system exiting the region. The strong mixing will bring dry conditions for much of the CWA with minimum relative humidities between 25-40 percent. Should see gusts around 40-45 mph at times this in combination with the relative humidities may bring elevated fire weather concerns. This will be impacted by the precipitation that falls across southern New England today. Have reached out to the fire weather partners to determine if there will be need for an SPS. Right now based on the forecast am more concerned across eastern portions of the CWA, but will need to address this in later updates.

The pressure gradient remains tight with dry weather on Friday. Minimum relative humidities range between 25-40 percent once again with gusts around 30 mph at times. This will likely be another day where there could be potential elevated fire weather concerns. Stay tuned for later updates.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . None. RI . None. MARINE . Gale Warning from 4 AM Thursday to 2 AM EDT Friday for ANZ231>235-237-250-251. Gale Warning from 6 AM Thursday to 2 AM EDT Friday for ANZ230- 236. Gale Warning from 2 AM Thursday to 2 AM EDT Friday for ANZ254>256.

SYNOPSIS . KJC/BL NEAR TERM . KJC/BL SHORT TERM . BL LONG TERM . KJC AVIATION . KJC/BL MARINE . KJC/BL FIRE WEATHER .


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44013 - BOSTON 16 NM East of Boston, MA 14 mi22 min SSE 7.8 G 9.7 47°F 47°F1009.8 hPa45°F
44029 - Buoy A0102 - Mass. Bay/Stellwagen 26 mi118 min S 9.7 G 12 48°F 2 ft1009.4 hPa
44090 26 mi36 min 46°F
BHBM3 - 8443970 - Boston, MA 27 mi44 min 53°F 1009.1 hPa
WAXM3 - Waquoit Bay Reserve, MA 40 mi77 min SSE 2.9 56°F 1011 hPa53°F
FRVM3 - 8447386 - Fall River, MA 42 mi44 min 53°F 51°F1010.8 hPa
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 43 mi44 min S 8 G 11 53°F 1010.5 hPa
BZBM3 - 8447930 - Woods Hole, MA 43 mi44 min 54°F 49°F1011 hPa
FRXM3 43 mi44 min 53°F 51°F
CHTM3 48 mi44 min SSW 5.1 G 8.9 54°F 50°F1011.5 hPa
FOXR1 - 8454000 - Providence, RI 48 mi44 min S 6 G 11 53°F 51°F1010.3 hPa
PVDR1 48 mi44 min SSE 9.9 G 12 53°F 1010.3 hPa51°F
44020 - NANTUCKET SOUND 49 mi22 min 16 G 19 48°F
CPTR1 - 8452944 - Conimicut Light, RI 49 mi44 min 50°F 53°F1009.8 hPa

Wind History for Borden Flats Light at Fall River, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Marshfield Airport, MA5 mi67 minSSW 910.00 miFair54°F50°F88%1010.5 hPa
Plymouth, Plymouth Municipal Airport, MA18 mi70 minS 410.00 miFair49°F46°F90%1010.7 hPa
Provincetown Municipal Airport, MA24 mi66 minS 1010.00 miFair50°F47°F89%1011.4 hPa

Link to 5 minute data for KGHG

Wind History from GHG (wind in knots)
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1 day agoCalm4NE7NE7NE7E7SE8SE9SE9SE9S4SW6SW4SW6SW5W5SW4W4CalmW33W533
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Tide / Current Tables for Damons Point, North River, Massachusetts
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Damons Point
Click for Map
Wed -- 01:04 AM EDT     1.92 feet Low Tide
Wed -- 03:15 AM EDT     Moonset
Wed -- 05:52 AM EDT     Sunrise
Wed -- 07:00 AM EDT     8.13 feet High Tide
Wed -- 12:58 PM EDT     Moonrise
Wed -- 01:45 PM EDT     1.02 feet Low Tide
Wed -- 07:31 PM EDT     Sunset
Wed -- 07:46 PM EDT     7.51 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.41.92.43.75.16.57.68.17.76.75.23.82.41.31.11.83.24.66.17.27.575.94.6

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Wed -- 12:42 AM EDT     0.00 knots Slack
Wed -- 02:45 AM EDT     1.02 knots Max Flood
Wed -- 03:16 AM EDT     Moonset
Wed -- 05:53 AM EDT     Sunrise
Wed -- 06:19 AM EDT     -0.00 knots Slack
Wed -- 09:52 AM EDT     -0.97 knots Max Ebb
Wed -- 12:59 PM EDT     Moonrise
Wed -- 01:16 PM EDT     0.00 knots Slack
Wed -- 03:24 PM EDT     1.02 knots Max Flood
Wed -- 07:00 PM EDT     -0.00 knots Slack
Wed -- 07:32 PM EDT     Sunset
Wed -- 10:46 PM EDT     -0.88 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.50.20.910.90.70.2-0.4-0.7-0.9-1-0.9-0.8-0.20.6110.90.6-0-0.5-0.7-0.9-0.9

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