Sunday, April18, 2021
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Marine Weather and Tides
Dennis Port, 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 5:53AMSunset 7:26PM Sunday April 18, 2021 5:29 PM EDT (21:29 UTC) Moonrise 9:54AMMoonset 12:54AM Illumination 44% Phase: First Quarter Moon; Moon at 7 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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ANZ232 Nantucket Sound- 416 Pm Edt Sun Apr 18 2021
Tonight..SW winds 10 to 15 kt, becoming W 5 to 10 kt after midnight. Seas around 2 ft.
Mon..W winds 5 to 10 kt, becoming sw 10 to 15 kt with gusts up to 20 kt in the afternoon. Seas around 2 ft.
Mon night..SW winds 10 to 15 kt. Gusts up to 20 kt in the evening. Seas around 2 ft.
Tue..SW winds around 10 kt, increasing to around 15 kt with gusts up to 20 kt in the afternoon. Seas around 2 ft.
Tue night..SW winds 10 to 15 kt. Gusts up to 20 kt in the evening. Seas around 2 ft.
Wed..S winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft. A chance of showers.
Wed night..S winds 15 to 20 kt, becoming W after midnight. Gusts up to 30 kt. Seas 3 to 4 ft. Showers likely.
Thu through Fri night..W winds 20 to 25 kt with gusts up to 30 kt. Seas 2 to 4 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 416 Pm Edt Sun Apr 18 2021
Synopsis for massachusetts and rhode island coastal waters.. Westerly winds below 10 knots persist this evening as exiting low pressure continues to make its way over the atlantic waters. Weak high pressure and drier conditions build into southern new england early next week before another low-pressure system brings the potential for rain and gusty winds by mid-week. 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 Dennis Port, MA
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location: 41.65, -70.12     debug


Area Discussion for - Boston, MA
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FXUS61 KBOX 181922 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 322 PM EDT Sun Apr 18 2021

SYNOPSIS. After a few showers affect the interior late this afternoon into early tonight, clearing skies and generally quiet weather is expected for the overnight. An upper level disturbance will help produce a period of scattered showers and isolated thunderstorms Monday afternoon, with temperatures warming to above average levels. Tuesday will be fair and quite mild. A cold front on Wednesday will bring showers and possibly a thunderstorm. High pressure then brings dry weather Thursday through Saturday. Another cold front approaches with showers on Sunday.

NEAR TERM /UNTIL 6 AM MONDAY MORNING/. 315 PM Update:

Overall a pretty nice afternoon across Southern New England with scattered to broken cumulus clouds and current temps in the 50s to near 60 in spots. However, regional radar mosaic continues to reveal scattered instability showers along a low-level convergence axis across the Adirondacks into southern VT this afternoon. This activity will continue to shift southeastward into interior MA with more isolated showers possible into the CT portion of the CT Valley. It remains less clear how far south and east this activity advances before the loss of daytime heating after sundown and the shower activity fights increasing PBL stabilization. Think the best chance to see showers extends from Orange to Fitchburg on southward to a Windsor Locks to a Pawtucket line. Can't discount a shower making its way further east into Metrowest and possibly into the Boston area but have left out of the forecast for now.

Otherwise, after any early showers fizzle out expecting a generally quiet evening under weak high pressure. Winds look to become decoupled tonight, which could open the door for patchy fog but it may be hit or miss if any develops at all. Areas that do receive any rain later this afternoon also stands a somewhat better shot at seeing patchy fog but not expecting widespread fog at this point. Lows upper 30s to lower-mid 40s.

SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/. 315 PM Update:

Monday into Monday Night:

Some early morning mid to high clouds that could lead to some nice sunrise scenes early Monday morning, but these are expected to lift northeast. With clearing skies, expect a period of strong heating to develop into the mid-morning to early afternoon.

We will then await the approach of a shortwave disturbance aloft, which will traverse into the Poconos/Catskills area by early afternoon. Facilitated by a SW-NE oriented convergence axis, expecting scattered showers to develop across eastern/southeast NY with isolated thunderstorms expected to blossom as well. Notably steep mid-level lapse rates are progged across most of Southern New England ahead of this activity, with values around 7-7.5 C/km per the 12z NAM. That said, wind fields aren't really that impressive, and a strongly-heated but well mixed PBL (inverted-V profile) with dewpoints only in the mid 30s lead to MUCAPEs around 200-400 J/kg. In terms of timing: most of the CAMs and the HREF bring this activity ENE into the Berkshires/CT Valley around 2-4 PM, and into central MA and northern RI/eastern CT around 3-5 PM. Given the potential for stablizing sea-breeze influence across eastern MA, it's a question how far east any thunder threat may extend. The limited instability may keep storm coverage to isolated or widely scattered as well. However given the mid-level lapse rates, a little bit of progged CAPE in the hail-growth zone and the low freezing levels around 4000', graupel or small sub- severe hail (pea to dime size) could be possible in stronger cells. Even stronger showers could produce graupel given the colder profiles aloft. Some locally strong, cool downdrafts are possible as well in storms given the well-mixed PBL. Not expecting any storms becoming severe given low instability and weak wind shear, and calling these strong storms could be a bit of stretch too, but folks outdoors should be prepared to seek shelter if storms threaten. Outside of storms, SW winds may gust to 20-25 mph. Highs mainly in the 60s, with upper 60s common in the interior away from the Berkshires, cooler mid 50s near the immediate southern and eastern coasts.

Showers and embedded storms are expected to diminish after sundown, with skies trending mostly clear. Radiational cooling in clear skies and light winds should bring lows into the lower to mid 40s.

LONG TERM /TUESDAY THROUGH SUNDAY/. Big Picture .

A series of shortwaves moves through during the next week. The shortwaves, mostly driven by the northern stream, will pass on Tuesday, Wednesday night, and Saturday night-Sunday. Best chance of showers will be Wednesday night and Sunday.

Height contours and the deeper thermal field will be normal or a little above Tuesday-Wednesday and again Friday-Saturday. Below normal on Thursday and Sunday.

Mass fields are in general agreement through Thursday, then diverge Friday through the weekend. Forecast confidence is moderate-high through Thursday, then trends low over the weekend due to timing uncertainty.

Details .

Tuesday . Upper shortwave moves from the Great Lakes northeast along the Canadian border. The supporting upper jet also follows the border with best lift moving over Northern New England. For Srn New England, moisture in the vertical is limited and concentrated around 850-mb. Precip water is around 0.6 inches, which is average for Apr 20. Subsidence dominates. Expect a weak surface cold front with a brief wind shift and some clouds, but no showers. Mixed layer reaches to at least 850-mb, with temps aloft 4-6C, supporting sfc max temps of mid 60s to low 70s.

The cold front, or what's left of it, stalls over/near Srn New England. Light winds in place over the region. The next disturbance moves up from the Ohio Valley, bringing increasing clouds. Clouds and light wind suggest min temps in the 40s.

Wednesday . Next shortwave moves east from the Great Lakes with a supporting upper jet moving a wave of low pressure northeast from the Ohio Valley. Both the GFS/ECWMF show a track through Western/Northern New England. This track suggests most precip initially stays to our west in the morning. As the wave of low pressure passes to our north, it will swing a cold front through Western MA/CT during the afternoon and Eastern MA toward evening.

This scenario would place Srn New England in the warm sector of the system. Increasing south winds with gust potential 25 to 30 mph. Showers in the west in the morning, then expect showers to sweep east during the afternoon. Total-totals are forecast to reach the low 50s ahead of the front, so potential exists for some thunder as well PWs increase to between 0.75 and 1.0 inches. maybe not a gullywasher but 0.1 to 0.4 inches in general and reaching 0.5 inches in a few spots. Warm sector temperatures will be working off of 4-6C aloft, supporting max temps in the 60s . a few warm spots could reach 70 if there is enough sun.

Winds shift out of the west-northwest behind the cold front during the late afternoon and night. This brings colder air in. With any clouds and wind the temps should go no lower than the 30s. With breaks and diminished wind the temps could reach 25-30.

Thursday through Sunday .

High pressure builds across the region. There will be some sky cover, but generally dry for Thursday through Saturday.

The next shortwave approaches from the west for Saturday night and Sunday. This will bring another period of showers.

AVIATION /19Z SUNDAY THROUGH FRIDAY/. Forecaster Confidence Levels.

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

18z TAF Update:

Rest of the Afternoon (thru 00z Mon): High confidence.

SCT-BKN VFR ceilings to prevail. Isolated to widely scattered showers currently over northern NY look to then traverse southeast from rough PSF-ORE-BED line south/west to BDL-SFZ line around 21-00z. Included VCSH for BAF, BDL and ORH; should stay south of BOS but may need to consider in later amendments. Winds WNW/NW around 7-12 kt, gusts to near 20 kt.

Tonight: High confidence.

Any showers which developed should fizzle early (shortly after sundown). VFR with a few mid-level clouds at times. Patchy fog could be possible but coverage looks quite limited at best. Light W winds.

Monday: High confidence thru noon, then trends moderate to high for the afternoon.

VFR through the morning. Potential for scattered showers, isolated thunderstorms moving in from eastern NY into the CT Valley and into central MA/northern RI in the 17-23z timeframe. While strong storms aren't expected, a couple could produce brief gusts as well as graupel or pea-sized hail. Some question how far east any shower/storm coverage makes it, with storms weakening into showers as they approach the BED- OWD- BOS corridor. While VFR should predominate, possible MVFR-visby in/near showers or storms. SW winds 7-12 kt, with gusts 17-22 kt.

Monday Night: High confidence.

Isolated showers mainly central/eastern MA should fizzle with sundown to VFR conditions. Light winds.

KBOS TAF . High confidence in TAF. Possible isolated showers ~21-00z, but should be dry.

KBDL TAF . High confidence in TAF. Isolated showers nearby ~20-22z.

Outlook /Tuesday through Friday/ .

Tuesday: VFR. Breezy.

Tuesday Night: VFR.

Wednesday: Mainly VFR, with areas MVFR possible. Breezy. SHRA likely, isolated TSRA.

Wednesday Night: Mainly VFR, with areas MVFR possible. Breezy. Chance SHRA.

Thursday: Mainly VFR, with local MVFR possible. Windy with gusts up to 30 kt.

Thursday Night: VFR. Windy with local gusts up to 30 kt.

Friday: VFR. Breezy.

MARINE. 315 PM Update:

Wind and wave conditions to remain below small craft advisory thresholds into Monday night.

For tonight: Initial WNW/W gusts around 10-20 kt (higher southern waters) decrease to around 5-10 kt. Seas around 2-4 ft. Possible showers early northeast waters but should be dry by mid-evening.

For Monday: S to SE winds increase to around 10 kt, gusts to around 15-20 kt with seas in the 2-3 ft range. Showers, perhaps with a rumble of thunder moving across the eastern waters late in the afternoon, but weakening trends likely.

For Monday Night: S to SW winds around 10 kt, with seas 2-3 ft.

Outlook /Tuesday through Friday/ .

Tuesday and Tuesday Night: Winds less than 25 kt.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms.

Wednesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain showers, slight chance of thunderstorms.

Thursday: Strong winds with gusts up to 30 kt. Areas of rough seas.

Thursday Night: Strong winds with gusts up to 30 kt. Seas up to 5 ft.

Friday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . None. RI . None. MARINE . None.

SYNOPSIS . WTB/Loconto NEAR TERM . Loconto SHORT TERM . Loconto LONG TERM . WTB AVIATION . WTB/Loconto MARINE . WTB/Loconto


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CHTM3 9 mi59 min SSW 6 G 9.9 52°F 49°F1007.7 hPa
44020 - NANTUCKET SOUND 14 mi39 min 12 G 14 48°F1 ft
44090 17 mi63 min 46°F1 ft
WAXM3 - Waquoit Bay Reserve, MA 22 mi104 min S 2.9 53°F 1008 hPa44°F
NTKM3 - 8449130 - Nantucket Island, MA 25 mi59 min WSW 6 G 14 51°F 49°F1008.5 hPa
BZBM3 - 8447930 - Woods Hole, MA 30 mi59 min 50°F 47°F1007.9 hPa

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA8 mi37 minSW 910.00 miPartly Cloudy53°F42°F66%1008.4 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA9 mi33 minSW 1010.00 miMostly Cloudy55°F38°F53%1007.4 hPa
Otis Air National Guard Base, MA21 mi1.7 hrsSW 1110.00 miMostly Cloudy52°F37°F58%1007.8 hPa

Link to 5 minute data for KCQX

Wind History from CQX (wind in knots)
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Last 24hr6NW4CalmCalmCalmW3W3W3W33CalmCalmNW3CalmCalm54W76NW754S9
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1 day agoSW9
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Tide / Current Tables for Dennis Port, Nantucket Sound, Massachusetts
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Dennis Port
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Sun -- 12:54 AM EDT     Moonset
Sun -- 05:01 AM EDT     3.37 feet High Tide
Sun -- 05:55 AM EDT     Sunrise
Sun -- 09:53 AM EDT     Moonrise
Sun -- 11:04 AM EDT     0.38 feet Low Tide
Sun -- 05:44 PM EDT     2.96 feet High Tide
Sun -- 07:24 PM EDT     Sunset
Sun -- 11:15 PM EDT     0.76 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.11.72.32.83.23.43.22.61.91.20.70.40.611.522.52.932.72.11.61.10.8

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Sun -- 12:53 AM EDT     Moonset
Sun -- 02:28 AM EDT     -0.00 knots Slack
Sun -- 05:06 AM EDT     -1.54 knots Max Ebb
Sun -- 05:55 AM EDT     Sunrise
Sun -- 08:13 AM EDT     0.00 knots Slack
Sun -- 09:53 AM EDT     Moonrise
Sun -- 11:39 AM EDT     1.80 knots Max Flood
Sun -- 03:09 PM EDT     -0.00 knots Slack
Sun -- 05:41 PM EDT     -1.43 knots Max Ebb
Sun -- 07:24 PM EDT     Sunset
Sun -- 08:51 PM EDT     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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1.51.10.4-0.5-1.2-1.5-1.4-0.9-0.20.61.31.71.81.510.1-0.8-1.3-1.4-1.1-0.60.10.81.3

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