Friday, May25, 2018 L-36.com


Marine Weather and Tides
West Chatham, MA

Version 3.4
What's New / NOTES
5/20/2018 -- NOAA is having problems with the data feed that I use to draw the graphs. They are aware of the issue and working to resolve it. Sometimes changing the location by about a mile will give a correct graph. 3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.

Sunrise 5:10AMSunset 8:05PM Friday May 25, 2018 2:43 PM EDT (18:43 UTC) Moonrise 4:03PMMoonset 3:21AM Illumination 83% Phase: Waxing Gibbous; Moon at 11 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
    EDIT      (on/off)   Help
ANZ254 Coastal Waters From Provincetown Ma To Chatham Ma To Nantucket Ma Out 20 Nm- 116 Pm Edt Fri May 25 2018
.small craft advisory in effect through Saturday evening...
This afternoon..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 4 to 6 ft.
Tonight..SW winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 6 ft.
Sat..SW winds 15 to 20 kt, diminishing to 10 to 15 kt in the afternoon. Seas 3 to 5 ft.
Sat night..SE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft. Areas of fog. Showers likely with a chance of tstms. Vsby 1 nm or less.
Sun..E winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 6 ft. Showers likely with a chance of tstms. Vsby 1 to 3 nm.
Sun night..E winds 10 to 15 kt with gusts up to 25 kt, becoming ne 5 to 10 kt after midnight. Seas 5 to 7 ft. A chance of showers.
Mon..NE winds 5 to 10 kt. Seas 4 to 6 ft.
Mon night..S winds 5 to 10 kt. Seas 3 to 5 ft. Patchy fog. Vsby 1 to 3 nm.
Tue..NW winds 5 to 10 kt. Seas 2 to 4 ft.
Tue night..N winds around 5 kt. Seas 2 to 3 ft. Patchy fog. Vsby 1 to 3 nm. 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 116 Pm Edt Fri May 25 2018
Synopsis for massachusetts and rhode island coastal waters.. High pressure will allow for breezy return S flow today into Saturday. This ahead of a back door cold front late Saturday behind which winds back out of the ne. Stall S of the waters Sunday into Monday, looking at wet weather chances to prevail before clearing out Tuesday with a brief period of high pressure settling back in before more unsettled weather late week. 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 West Chatham, MA
   Hourly   EDIT   Help
location: 41.73, -69.97     debug


Area Discussion for - Boston, MA
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 kbox 251754
afdbox
area forecast discussion
national weather service boston norton ma
154 pm edt Fri may 25 2018

Synopsis
High pressure centered south and east of new england will bring
a very warm dry day with gusty southwest winds. A cold front
drops south across the region late Saturday into Saturday
evening, bringing scattered showers and thunderstorms followed
by much cooler and unsettled weather Sunday with some
improvement by Monday. Mainly dry and warmer weather returns for
Tuesday through Thursday as high pressure moves in.

Near term until 6 pm this evening
150 pm update...

unseasonably warm conditions persist this afternoon. High
pressure is centered well SE of the area, placing us in a return
flow from the W sw. Sunny mostly sunny skies continue, temps
climbing into the upper 80s to low 90s for most locales, except
cooler near the south coast CAPE islands due to onshore wind
component. Will also have excellent mixing this afternoon,
allowing for wind gusts 25 to around 30 mph. Hot but not humid
away from the south coast with dew points in the 40s to low 50s.

Short term 6 pm this evening through 6 pm Saturday
Tonight...

diminishing winds and quiet, dry weather. S SW winds prevailing,
breezy along the S se-coast, ushering higher dewpoint air into
the region. This will limit temperatures to drop overnight to
their cross-over threshold (the dewpoint that which was observed
at time of MAX daytime heating). Lows around the lower 60s.

Saturday...

chance of late-day scattered shower and thunderstorm activity. Yet
signals of an unremarkable convective-supporting environment. Rising
heights through the column, pockets of dry air, somewhat mid-level
confluence, perhaps upper-level speed diffluence. Only thing going,
another n-stream vortlobe, canadian high pressure following, presses
a sagged cold front S W as a back-door across S new england, a much
cooler airmass in tow. Certain low-level lift on a mild, somewhat
humid boundary layer airmass, with upper 50s to low 60s dewpoints.

High-res guidance spitting out some scattered activity, convective
with weak mid-level instability, pockets of negative showalters,
total-totals above 50, and k-indices exceeding 35. While noting
precipitable waters upwards of 1.5 inches and indications of mid-
level subsidence, can't rule out scattered shower and thunderstorm
activity along the back-door cold front, yet feel what GOES up will
not sustain and come right back down given the absence of shear
weak hodograph profile. More likely in regions with surface to h7
lapse rates of 7-8 c km. Falling cores while noting inverted-v model
forecast soundings, in addition to lightning can't rule out gusty,
downdraft winds, especially given downdraft CAPE upwards of 2000
j kg. Airmass thunderstorms overall, perhaps more focused atop high
terrain with any upsloping anabatic flow.

Chance pops continue but future forecasts may want to include threats
of heavy rain and gusty winds into the forecast grids. Difficult to
nail down where across the interior, away from the NE coast at least,
but as to when, the back door cold front pushing into afternoon during
peak interior heating per model forecast consensus, a late-day show
seems likely continuing into evening.

Long term Saturday night through Thursday
Big picture...

a southern jet moves over mexico and the southern usa. This jet
forms a closed low over the gulf of mexico with upper high pressure
over northern mexico and the southwest atlantic. This southern
pattern remains static through the middle of next week and allows
tropical moisture to feed north into areas south of the ohio valley
and south of mason-dixon. The question for new england is whether
any northern stream disturbances during the coming week can reach
down and pull this moisture farther north into our area.

Zonal flow is aloft over canada and parts of the northern usa. One
shortwave trough moving through this flow crosses the northeast usa
Sunday and Monday. Closed low over the western usa this weekend
ejects into the northern stream by midweek and crosses new
england late in the week. Both of these systems have the
potential to pull the tropical moisture north as they moves
through our area, one on Sunday and the other late in the week.

Both will need to be monitored.

Model consensus shows 500 mb contours starting around 576 dm and
building to 582 dm during mid week. This is higher warmer than
normal during the long term. The surface layer flow favors a cool
period over the weekend but then trending warmer than normal again
Tuesday through Thursday.

Model mass fields are similar over new england through Wednesday
night, but diverge over the western usa Tuesday night. The
differences then spread to new england by late week. Our thermal
fields also show similarity through Tuesday but then start diverging
mid to late week. This generates moderate confidence in the Saturday
night-to-Monday forecast, then moderate to high confidence midweek,
diminishing a little on Thursday.

Concerns...

Saturday night-Sunday...

the cold front stalls south of our area overnight. High pressure
building over the maritimes brings increasing east winds trailing
the front and a cool moist marine flow to southern new england.

Model 1000 mb winds show 20-30 knot easterlies raking the
massachusetts east coast with strongest winds on CAPE ann and outer
cape cod. Ocean temps are in the mid 50s, except upper 40s and low
50s around the outer CAPE and nantucket. This would suggest Saturday
night min temps in the 50s and MAX temps Sunday mid to upper 50s
east and mid 60s west, farthest away from the ocean.

The upper shortwave approaching from the great lakes Sunday and its
supporting 70-knot upper jet may induce a wave along the stalled
front. This should keep a chance of showers with us Sunday, with
enough confidence to toss in likely pops.

Monday through Thursday...

shortwave trough moves east of us by Monday morning. Cross sections
for relative humidity show moisture below 700 mb lingering but
diminishing in magnitude. This suggests clouds will linger, although
some breaks are possible. Also can't rule out a slight chance of
showers, but the lack of appreciable lift puts a damper on that
possibility.

High pressure builds down from northern ontario Tuesday and
Wednesday, then moves offshore Thursday. This should be a period of
sunny weather. Mixing is projected to reach 825 mb Tuesday and
Wednesday, and 900 mb Thursday. Temperatures at those levels support
max sfc temps in the low to mid 80s, while dew points suggest min
temps in the 50s.

Aviation 18z Friday through Wednesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Saturday ... High confidence thru tonight.

Moderate confidence on timing of back door cold front and
associated impacts during later Saturday.

Today...

vfr all areas through the day. W SW winds gusting to 25-30 kts
through this afternoon.

Tonight...

sw winds diminish to around 10 kts, but remain brisk over S se
coast with gusts up to 20 kts. Llws potential along the CAPE and
islands. Low chance for development of ifr CIGS on ack.

Saturday...

back door cold front produces a wind shift from the W SW to N ne
during the afternoon evening, first near bed bos and then later
for points S sw. Sct shra tsra towards late-day, producing
tempo MVFR cig vsby impacts. Can't rule out brief, gusty winds
upwards of 30+ kts with any activity. Low chance for development
of ifr CIGS on CAPE islands.

Kbos terminal... High confidence in TAF thru tonight, moderate
confidence for timing of back door cold front on sat. Wsw winds
gusting to 25 kts thru this aft'n, can't rule out some gusts to
30 kts. Winds diminish this evening. Wsw winds around 10 kts to
start Saturday then wind shift to nne with back door cold front
during the afternoon.

Kbdl terminal... High confidence in taf. Wsw winds gusting to 25
kts thru this aft'n, can't rule out a few gusts to 30 kts. Back
door cold front holds off until later on Sat sat eve which would
produce a wind shift from wsw to nne..

Outlook Saturday night through Tuesday ... Moderate confidence.

Saturday night: mainlyVFR, with areas ifr possible. Breezy.

Chance shra, chance tsra.

Sunday: MVFR ifr conditions possible. Breezy. Chance shra,
slight chance tsra.

Sunday night: mainly ifr, with areasVFR possible. Breezy.

Slight chance shra, isolated tsra, patchy br.

Memorial day: mainlyVFR, with local ifr possible. Slight
chance shra.The
Monday night: mainlyVFR, with areas ifr possible. Patchy br.

Tuesday:VFR.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percthe ent.

Short term through Saturday ... High confidence.

This afternoon into tonight...

small craft advisories for all waters, especially S se, with
brisk wsw winds gusts around 25 kts, thus allowing waves to
build at or above 5 feet. Winds dampening overnight, advisories
allowed to drop off.

Saturday...

small craft advisories may be needed. Increasing chances of
late day showers and thunderstorms ahthe ead of a NE wind-shift
associated with a back door cold front. Gusty winds immediately
behind the front upwards of around 25 kts building seas upwards
of 5 feet. Greatest threat of SCA conditions over the E waters.

Outlook Saturday night through Tuesday ... Moderate confidence.

Saturday night: winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, chance of
thunderstorms.

Sunday: low risk for small craft advisory winds with gusts up
to 25 kt. Local rough seas. Chance of rain showers, chance of
thunderstorms.

Sunday night: winds less than 25 kt. Areas of rough seas.

Chance of rain showers, isolated thunderstorms.

Memorial day: winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers.

Monday night: winds less than 25 kt. Areas of seas approaching
5 ft. Local visibility 1 to 3 nm.

Tuesday: winds less than 25 kt. Seas locally approaching 5 ft.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... Air quality ALERT until 11 pm edt this evening for riz001>008.

Marine... Small craft advisory until 2 am edt Saturday for anz232>234-
250.

Small craft advisory until 8 pm edt this evening for anz230-
231-236-251.

Small craft advisory until 11 am edt Saturday for anz235-237.

Small craft advisory until 8 pm edt Saturday for anz254>256.

Synopsis... Wtb sipprell
near term... Wtb sipprell nmb
short term... Sipprell
long term... Wtb
aviation... Wtb sipprell nmb
marine... Wtb sipprell nmb


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 20 mi73 min 55°F1 ft
44020 - NANTUCKET SOUND 23 mi63 min SW 18 G 21 60°F 57°F1012 hPa55°F
WAXM3 - Waquoit Bay Reserve, MA 31 mi118 min 4.1 69°F 1013 hPa57°F
NTKM3 - 8449130 - Nantucket Island, MA 31 mi73 min WSW 8.9 G 22 63°F 60°F1013.2 hPa
44018 - SE Cape Cod 30NM East of Nantucket, MA 34 mi113 min SSW 14 G 14 60°F 2 ft1010.3 hPa (-2.4)53°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi73 min 61°F 58°F1012.5 hPa

Wind History for Nantucket Island, MA
(wind in knots)    EDIT      (on/off)   Help
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
-12
PM
-12
PM
11
AM
12
PM
1
PM
2
PM
Last
24hr
SE9
SE12
G17
SE8
G15
S9
G16
S6
G13
S8
G13
S7
SW5
G9
S7
G10
S9
G12
SW7
G14
SW9
G13
SW8
G12
SW7
G13
S8
G14
SW8
G12
SW8
G15
SW6
G16
SW10
G17
SW10
G20
SW12
G20
SW9
G17
1 day
ago
SW7
W6
G9
W6
G10
W6
G11
SW7
G10
SW5
G8
SW5
G10
SW5
G9
NW8
G21
N4
G7
N3
G6
N5
NE6
E7
E11
E7
G11
SE5
G10
E8
NE8
G13
NE10
NE9
G13
E10
G13
E11
E9
G12
2 days
ago
S9
S5
S5
G8
S4
G9
S5
G10
S5
G10
S5
G11
S4
G10
S4
NE2
E4
NE2
NE2
SE1
NW2
G5
W2
E3
SW6
W6
G11
W7
G12
W10
G15
W7
G14
NW6
G11
N4
G8

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA2 mi51 minSW 12 G 2210.00 miFair68°F57°F70%1012 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi47 minSW 18 G 2410.00 miFair and Breezy75°F55°F52%1011.1 hPa
Provincetown Municipal Airport, MA23 mi47 minSSW 14 G 2010.00 miFair74°F57°F57%1010.3 hPa

Wind History from CQX (wind in knots)
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
Last 24hrSE10
G16
SE10
G14
5
G15
S7S6S65SW9
G17
SW11
G18
SW13
G20
SW8
G21
SW9
G19
SW11
G19
SW9
G19
SW12
G21
SW8
G17
SW8
G17
SW10
G20
SW8
G15
SW10
G17
SW7
G19
SW11
G20
SW9
G19
SW12
G22
1 day agoSE7SW6SW6SW7SW6SW5SW53NW4NE9NE7NE9NE7E7E4SE5E7E7E8E10E9NE8E75
2 days agoSW5SW7SW6SW5SW3S3S5SW45SW4CalmCalmCalmCalmSW3SW3SW4346NW8665

Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Pleasant Bay
Click for Map
Fri -- 03:21 AM EDT     Moonset
Fri -- 05:11 AM EDT     Sunrise
Fri -- 05:51 AM EDT     0.03 feet Low Tide
Fri -- 11:10 AM EDT     3.13 feet High Tide
Fri -- 04:02 PM EDT     Moonrise
Fri -- 06:14 PM EDT     -0.03 feet Low Tide
Fri -- 08:02 PM EDT     Sunset
Fri -- 11:42 PM EDT     3.30 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
32.72.31.70.90.200.41.122.83.132.72.41.91.10.4-00.10.71.72.63.2

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
   EDIT      (on/off)   Help   One Week of Data
Pollock Rip Channel
Click for Map
Fri -- 12:35 AM EDT     0.00 knots Slack
Fri -- 03:21 AM EDT     Moonset
Fri -- 04:08 AM EDT     1.98 knots Max Flood
Fri -- 05:12 AM EDT     Sunrise
Fri -- 07:00 AM EDT     -0.00 knots Slack
Fri -- 09:57 AM EDT     -1.65 knots Max Ebb
Fri -- 12:56 PM EDT     0.00 knots Slack
Fri -- 04:02 PM EDT     Moonrise
Fri -- 04:33 PM EDT     2.13 knots Max Flood
Fri -- 07:29 PM EDT     -0.00 knots Slack
Fri -- 08:01 PM EDT     Sunset
Fri -- 10:30 PM EDT     -1.77 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.50.41.21.721.810-0.9-1.5-1.7-1.4-0.80.10.91.62.12.11.50.5-0.5-1.3-1.7-1.7

Weather Map and Satellite Images
       (on/off)   HelpWeather Map
wmap_A
GOES Local Image of Northeast    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.
target = "new">Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Boston, MA (14,3,4,5)
      (on/off)   Help

Ground Weather Radar Station Boston, MA
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.