Thursday, October21, 2021
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Marine Weather and Tides
West Chatham, MA

Version 3.4
NOTICE
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
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 6:59AMSunset 5:51PM Thursday October 21, 2021 5:52 PM EDT (21:52 UTC) Moonrise 6:31PMMoonset 7:48AM Illumination 99% 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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ANZ254 Coastal Waters From Provincetown Ma To Chatham Ma To Nantucket Ma Out 20 Nm- 427 Pm Edt Thu Oct 21 2021
.small craft advisory in effect through Friday evening...
Tonight..S winds 15 to 20 kt with gusts up to 25 kt. Seas 3 to 5 ft.
Fri..SW winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 6 ft.
Fri night..SW winds 10 to 15 kt with gusts up to 20 kt, becoming W 5 to 10 kt after midnight. Seas 3 to 5 ft.
Sat..NW winds 5 to 10 kt. Seas 2 to 4 ft. A chance of showers.
Sat night..NW winds 10 to 15 kt. Seas 2 to 4 ft. A chance of showers.
Sun and Sun night..NW winds 10 to 15 kt with gusts up to 20 kt. Seas 3 to 5 ft.
Mon..N winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Mon night and Tue..NE winds 10 to 15 kt. Gusts up to 20 kt. Seas 4 to 6 ft.
Tue night..NE winds around 15 kt with gusts up to 20 kt. Seas 7 to 10 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 427 Pm Edt Thu Oct 21 2021
Synopsis for massachusetts and rhode island coastal waters.. Low pres continues to move up through the great lakes tonight into Friday. A mainly dry cold front moves through the waters Friday. A low passes southeast of the southern waters on Saturday before high pressure returns late in the weekend. An elongated frontal system moves across the waters Monday and Tuesday, with high pres building back in for Wednesday. 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 West Chatham, MA
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location: 41.73, -69.97     debug


Area Discussion for - Boston, MA
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FXUS61 KBOX 212016 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 416 PM EDT Thu Oct 21 2021

SYNOPSIS. High pressure moves off the east coast and a low moves into the Saint Lawrence River Valley. Ahead of the trailing cold front warm air advection has brought unseasonably warm temperatures and breezy conditions to the region. A broken line of showers moves across southern New England overnight into early Friday morning. Mostly dry but much cooler this weekend. Unsettled weather may return for much next week, but confidence in this portion of the forecast period is low. It will be cooler than normal much of the week.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/.

Tonight .

* Scattered showers possible across the northern half of the area overnight tonight. Most locations will stay dry, however. * Gusty conditions overnight for the south coast into Cape Cod and the Islands.

As a low pressure system tracks from the Great Lakes into southern Quebec, a cold front will approach Southern New England from the west. Guidance indicates a pre-frontal trough crossing our area overnight tonight. However, it is very limited in moisture so not expecting much in the way of rainfall. Most areas will stay dry except for a few scattered showers across the northern half of the area. Modeled PoPs after the 12z Hi-Res Ensemble Forecast (HREF) that comprise of five hi-res guidance over two time steps. We will see an increase in cloud cover, however, which will help keep overnight lows relatively mild by late October standards. Nonetheless, there should be quite a temperature spread across the region, with lows in the upper 40s and low 50s across interior MA/CT to upper 50s and low 60s across southeastern MA. Finally, a 30-35 kt 850mb jet noses in overnight, which may lead to gusty conditions continuing overnight with 25-30 mph gusts possible especially across the MA/RI south coast into Cape Cod and the Islands.

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

Friday .

Aforementioned cold front crosses the area during the day, starting a cooling trend after a stretch of anomalously mild temperatures with highs running 10 to 15 degrees above climatological normal. Southwest winds turn west and then northwest during the afternoon, with dew points falling into the upper 40s and lower 50s. Highs should still reach the upper 60s and low 70s across the Connecticut River valley as well as much of Eastern MA and RI under a mix of sun and clouds.

The cold front becomes quasi-stationary and drifts slowly off shore as a surface low rides along the boundary bringing the chance for a few showers Friday afternoon, especially for Nantucket.

Friday Night .

Mostly dry and seasonably cold overnight Friday with 925mb temperatures falling to +4 to +7C across interior MA and CT. Overnight lows should fall into the low and mid 40s away from Cape Cod and the Islands. With broad surface high stretching from the Appalachians into Quebec, there should be mostly clear skies away from the immediate coast. But with enough of a surface pressure gradient, winds should not fully decouple so temperatures will not tank although a few upper 30 readings are possible in the usual cold spots. After all, it is late October!

LONG TERM /SATURDAY THROUGH THURSDAY/. Big Picture .

Closed low over sits over Northern Ontario Saturday and early Sunday before racing along the Canadian border late Sunday. Shortwave races out of the Central Rockies Sunday to the Mid Atlantic coast Tuesday, but significant differences in the models with the Canadian model most different. Upper ridge then builds over the Eastern USA for midweek.

Upper contours remain within climatological average through the period. However, the low-level flow turns from the east and northeast Monday through Wednesday, which would support cooler than average temperatures.

Forecast confidence is high for the weekend, then drops to low for early next week.

Details .

Saturday-Sunday . Closed upper low will maintain a cyclonic flow over Srn New England this weekend. Shortwaves move through the flow each day, with associated jets generating weak lift. This may be enough to generate a few sprinkles/light showers, but mostly dry weather. Cross sections show moisture around 850 mb, and a mixed layer to between 850 and 900-mb. Expect mixed clouds and sun. Temps in the mixed layer support will be equiv to -1C to +1C at 850-mb, so expect max temps in the upper 50s and low 60s each day. Fair skies and light wind and dews of 35 to 45 . expect nighttime min temps in the upper 30s and 40s.

Monday through Thursday . Variable model solutions on the weather next week. There is a general agreement on high pressure over Quebec, with a low-level east flow over Srn New England. Low pressure from the Midwest is projected to move to the Mid Atlantic coast, but the GFS races it offshore and out to sea while the ECMWF and Canadian/GGEM keep it close to the coast and move it slowly out to sea through the week. High pressure may suppress the QPF to our west and south, but some guidance moves it in. Thus the low confidence. The forecast will mostly show slight chance pops of showers, except low-end chance pops on Thursday. Low-level temps in the easterly flow support 850-mb equiv temps around -2C . supporting max temps in the 50s and lower 60s, warmest Thursday.

AVIATION /20Z THURSDAY THROUGH TUESDAY/. Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.

20Z update .

Rest of today . High confidence. VFR. Gusty SW winds 20-25 kt at times especially towards the Cape and islands.

Tonight . High confidence. Mostly VFR with 6-10k ceilings. Scattered showers possible especially across northern half of the area but most locations stay dry. Couldn't rule out brief localized low VFR to MVFR where showers develop. Gusty SW winds around 25 kt towards the south coast into the Cape and islands. S winds with 10-15 kt gusts possible for interior terminals.

Friday . High confidence. VFR. Mostly dry. Winds turn out of the west then northwest with a cold front, decreasing through the day. Exception is towards the Cape terminals where 15-20 kt SW gusts linger. In addition, there may be a few showers in the afternoon hours along with low VFR to MVFR ceilings.

Friday night . High confidence. VFR. Low VFR to MVFR ceilings could linger near ACK early in the evening before transitioning to VFR. NW winds 5-10 kt.

KBOS Terminal . High confidence in TAF.

KBDL Terminal . High confidence in TAF.

Outlook /Saturday through Tuesday/ .

Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.

Saturday Night: Mainly VFR, with local IFR possible.

Sunday: VFR.

Sunday Night: Mainly VFR, with local MVFR possible.

Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA.

Monday Night through Tuesday: Mainly MVFR, with areas VFR possible. Breezy. Slight chance SHRA.

MARINE. Forecaster Confidence Levels.

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

* Small Craft Advisories posted for most of the waters.

Gusty southwest winds develop this evening ahead of an approaching cold front. In addition, 5 ft plus seas develop across the southern and eastern outer waters overnight tonight, then falling below Small Craft criteria by late tomorrow. A few showers are possible across Nantucket Sound and adjacent waters Friday afternoon. Southwest winds turn west and then northwest overnight Friday.

Outlook /Saturday through Tuesday/ .

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.

Saturday Night: Winds less than 25 kt.

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

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

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

Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Local rough seas. Slight chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES. CT . None. MA . None. RI . None. MARINE . Small Craft Advisory until 11 AM EDT Friday for ANZ232>235-237. Small Craft Advisory from 8 PM this evening to 8 AM EDT Friday for ANZ236. Small Craft Advisory until 2 PM EDT Friday for ANZ250. Small Craft Advisory until 8 PM EDT Friday for ANZ254>256.

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


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CHTM3 3 mi53 min SSW 6G12 65°F 62°F1014.3 hPa (-0.0)
44090 20 mi57 min 62°F1 ft
44020 - NANTUCKET SOUND 23 mi33 min SW 16G19 66°F 64°F1014.2 hPa
NTKM3 - 8449130 - Nantucket Island, MA 31 mi53 min SW 8G11 66°F 62°F1014.9 hPa (-0.6)
WAXM3 - Waquoit Bay Reserve, MA 31 mi68 min S 2.9 79°F 1014 hPa73°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi53 min 66°F 64°F1014.2 hPa (-0.8)

Wind History for Nantucket Island, MA
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA2 mi61 minSW 710.00 miFair65°F60°F84%1014.7 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi57 minSW 1110.00 miFair67°F59°F76%1013.9 hPa
Provincetown Municipal Airport, MA23 mi57 minSSW 1110.00 miFair66°F58°F75%1013.5 hPa

Link to 5 minute data for KCQX

Wind History from CQX (wind in knots)
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Last 24hr30SE4S5--S4SW3SW300SW3SW33SW3SW3SW3SW6SW6SW9SW10
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1 day ago3W5W7W83033445W6W9
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2 days ago03NW4NW7NW7NW8
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Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
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Pleasant Bay
Click for Map
Thu -- 02:41 AM EDT     3.21 feet High Tide
Thu -- 06:59 AM EDT     Sunrise
Thu -- 07:48 AM EDT     Moonset
Thu -- 09:33 AM EDT     0.09 feet Low Tide
Thu -- 02:54 PM EDT     3.39 feet High Tide
Thu -- 05:48 PM EDT     Sunset
Thu -- 06:31 PM EDT     Moonrise
Thu -- 09:59 PM EDT     -0.08 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Thu -- 01:23 AM EDT     -1.75 knots Max Ebb
Thu -- 04:24 AM EDT     0.00 knots Slack
Thu -- 06:59 AM EDT     Sunrise
Thu -- 07:48 AM EDT     Moonset
Thu -- 07:52 AM EDT     2.06 knots Max Flood
Thu -- 10:47 AM EDT     -0.00 knots Slack
Thu -- 01:38 PM EDT     -1.76 knots Max Ebb
Thu -- 04:41 PM EDT     0.00 knots Slack
Thu -- 05:49 PM EDT     Sunset
Thu -- 06:31 PM EDT     Moonrise
Thu -- 08:11 PM EDT     2.09 knots Max Flood
Thu -- 11:11 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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