Thursday, March21, 2019 L-36.com


Marine Weather and Tides
West Chatham, MA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 6:41AMSunset 6:55PM Thursday March 21, 2019 8:02 AM EDT (12:02 UTC) Moonrise 7:46PMMoonset 7:22AM Illumination 100% Phase: Full Moon; Moon at 15 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- 716 Am Edt Thu Mar 21 2019
.small craft advisory in effect from 6 pm edt this evening through Friday afternoon...
.gale watch in effect from Friday evening through Saturday evening...
Today..SE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Tonight..E winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Gusts up to 25 kt. Seas 4 to 7 ft. Rain. Vsby 1 nm or less.
Fri..SE winds 15 to 20 kt, becoming sw in the afternoon. Gusts up to 25 kt. Seas 6 to 9 ft. Patchy fog. A chance of rain. Vsby 1 to 3 nm.
Fri night..SW winds 15 to 20 kt, becoming W 20 to 25 kt after midnight. Gusts up to 45 kt. Seas 7 to 10 ft, except 10 to 14 ft S and E of nantucket. Scattered showers.
Sat..W winds 25 to 30 kt with gusts up to 45 kt. Seas 7 to 10 ft, except 10 to 15 ft S and E of nantucket. Scattered showers.
Sat night..NW winds 20 to 25 kt with gusts up to 40 kt, diminishing to 15 to 20 kt with gusts up to 30 kt after midnight. Seas 6 to 9 ft.
Sun..W winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 7 ft.
Sun night..W winds 10 to 15 kt with gusts up to 20 kt. Seas 3 to 5 ft.
Mon..SW winds 5 to 10 kt with gusts up to 20 kt. Seas 3 to 5 ft. A chance of rain.
Mon night..NW winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 7 ft. A chance of rain. 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 Thu Mar 21 2019
Synopsis for massachusetts and rhode island coastal waters.. High pres lingers across the waters today. A gale center develops off the mid atlc coast tonight then heads ne to long island by daybreak Fri, then across ri and eastern ma Fri afternoon and into coastal maine Fri evening. The gale will intensify into a storm Fri night along the maine coast. This powerful storm lingers near the maine coast Sat before finally exiting ne Sat night. High pres builds across the mid atlc waters Sun. 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
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location: 41.73, -69.97     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 211122
afdbox
area forecast discussion
national weather service boston norton ma
722 am edt Thu mar 21 2019

Synopsis
High pressure south of nova scotia provides mainly dry and
seasonable conditions today. A coastal storm impacts the region
tonight into early Friday morning with periods of rain, heavy at
times, and gusty winds. Steady rain tapers off to
showers drizzle Friday. Steady rain tapers off to
showers drizzle Friday. Snow showers linger Friday night, with
windy conditions expected late Friday night into Saturday.

Milder Sunday and Monday, a return to colder than normal
conditions is expected Tuesday in mid next week.

Near term until 6 pm this evening
715 am update ...

noting some highly disorganized and light echos across nj S ny,
coincident with the very end of the best overrunning from
approaching warm front. This is linked to the low pres which
will develop to the S during the day, and as it does so it is
likely to continually usurp much of the moisture. Given this,
outside of a light shra this morning across W ma ct, still
anticipate mainly dry conditions throughout the day, which
remains in agreement with the current mesoscale guidance updates
this morning. Otherwise, filtered sunshine this morning will
give way to more dense ovc throughout the day.

Previous forecast discussion ...

focus today will be trough amplification over the mid atlc region.

This results in downstream short wave ridging to develop over
southern new england. For this reason much of the 00z guidance has
trended toward a dry forecast for most of ma ri and ct today. In
fact will likely see sunshine through mid high clouds across ri and
eastern ma much of the day. Given partial sunshine highs should
reach the upper 40s to lower 50s, cooler along the coast given se
winds off the chilly ocean waters.

Farther west into ct and western-central ma less sunshine given more
cloud cover along with a chance of rain developing after 5 pm. Will
likely see returns on radar but abundant low level dry air should
preclude much or all precip from reaching the ground before 21z 5
pm.

Short term 6 pm this evening through 6 pm Friday
4 am update ...

tonight ...

negative tilt closed low over the mid atlc states and corresponding
coastal low tracks northeast up the coastline into ri eastern ma by
12z fri. This system captures plume of subtropical moisture
currently off the nc coast with pwats AOA 1.0 inches (+1 standard
deviation (sd) from climo) streaming into southern new england
overnight. Strong onshore wind anomalies of +2 sd at 925 mb and 850
mb will be acting on this moisture plume to yield a period of heavy
rainfall roughly from 04z to 10z. If this timing holds heavy rain
likely exits northeast before the morning commute commences. System
is progressive so window of heavy rainfall is limited to 3 to 6
hours and this will cap rainfall totals to 0.35 to 0.75 inches.

Isolated amounts of 1+ inches are possible given elevated
instability yielding potential convection. However any 1+ inch
amounts should be very isolated with confined to northeast ma.

Ptype... Model soundings suggest there could be enough evaporative
cooling for some snow and or sleet mixed in with the rain early this
evening across northern ct into western-central ma. However this
will be short lived so bulk of event will be all rain.

Friday ...

vertically stacked occluded low moves slowly northward from LI at
12z then up the i-95 corridor of ri into eastern ma, while still
intensifying from about 990 mb low to 983 mb along the maine coast
by 8 pm. During this time mid level dry slot moves across the region
in the morning resulting in a transition to drizzle and lower top
showers as the morning progresses. A second round of showers in the
afternoon as comma-head rotates thru the region. Maybe a period of
dense fog in the morning especially across ri and eastern ma as low
tracks overhead. Improving during the afternoon as the low exits
into maine and winds shift to the NW with colder drier air
overspreading the region. So a period of mild weather across ri and
eastern ma where warm sector invades yielding early highs of 45-50.

However only in the upper 30s to lower 40s across the interior.

Long term Friday night through Wednesday
Highlights...

* snow showers and wind Friday night into Saturday.

* milder Sunday into early Monday.

* rain snow shower mix on Monday
* cold air returns late Monday into mid next week.

Overview and model preferences...

two lobes of the arctic vortex to monitor as amplified mid lvl
ridge across the continental divide gradually dissipates in
favor of a more zonal pattern across the conus. Meanwhile,
downstream remains generally zonal, reflective of the positive
nao ao setup. In any case, a period of generally colder than
normal conditions are expected into the middle portions of next
week, except where rising heights on Sun between these two
arctic lobes. The first, linked to occluding low pres in the bay
of fundy will have strong wrap-around component Fri night
featuring a change to sn and strong winds. The second, a
stronger lobe, settles across N quebec and labrador, with
longwave trof settling across the ne. Will need to watch this
as vort-maxes rotate around the trof, but given the zonal flow
offshore, suppression and fast movement of any baroclinic waves
is favored at this time. However, given the typical uncertainty
handling these waves, will need to watch the mid week period.

Otherwise, a general consensus blend of guidance will be used to
baseline this update.

Details...

fri night into sat...

as low pres occludes toward the bay of fundy, noting strong
comma head lift wrapping into S new england. With it, modest
theta-e within the cold conveyor suggests that decent precip may
linger into the overnight hours. CAA and bl suppression
suggests that this precip falls as sn. Enhancement by mid lvl
lapse rates above h7 near 7.0c km. Therefore, a few bursts of
heavy sn cannot be ruled out. This is especially true in the
berkshires as well as central ma ct hills where an upslope
component can be realized. Spotty amounts may exceed an inch or
two where all of these factors coincide.

Otherwise, high pres upstream is building toward +1030mb with
strong pres rises. CAA will allow lower lvl mixing to exceed h85
where LLJ is about 40-50kt. Therefore, will flirt with wind
advisory criteria, which will last into the day on sat. Aside
from the inherent wind impacts, early Sat wind chills are likely
to fall into the single digits and remain in the teens and 20s
throughout the day.

Sun...

brief reprieve as mid lvl height rise in advance of the
secondary, stronger arctic lobe. This should briefly allow temps
to reach near or above seasonal normals thanks to the high,
late march Sun angle. Mainly dry as high pres slides to the s.

Mon into tue...

reinforcing arctic wave, the lower lvl feature coincident with
arctic lobe settling just to the s, moves through likely late
mon based on current mean between ensembles and operational
guidance. Weak frontal wave connected to subtropical moisture
may allow for some shra shsn. Although ana-frontal lift looks
favored based on the frontal wave development. The main impact,
will be the introduction of another cold period, with h85 temp
anomalies nearing 3 std deviations below normal, or 20c lower
than usual. For what it’s worth, the progged h85 temps are
near record low values per the SPC sounding climatology. Expect
a period of below normal temps, where its possible highs will
struggle to break out of the 30s.

Mid late week...

as mentioned above, with cutoff settling near labrador,
longwave trof dipping toward the mid-atlantic, and progressive
flow offshore. Expect stalled frontal boundary to remain s, such
that any coastal wave developing along it remains suppressed to
the s. However, given this is toward the end of the long term
period, confidence in solutions remains somewhat low. Although
widely variable spatially, ensemble members from both the ecens
and GEFS favor this, so this update will reflect this thinking.

Aviation 11z Thursday through Monday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday ... High confidence.

Today ...

vfr, winds veering to the SE through the day, reaching 10-20 kt
this afternoon along with dry weather. Any light precip holds
off until mainly after 00z or later and confined to western
ma ct.

Tonight ...

llws likely across ri and eastern ma peaking 06z-09z as strong
low level SE jet 50-60 kt moves across the region.VFR at 00z
quickly lowers to MVFR and then ifr after 06z as rain
overspreads the region 03z-06z. Rain heavy at times along with isolated
-tsra possible.

Friday ...

at 12z heavy rain over northeast ma exits northward with lighter
showers drizzle remainder of the day. Ifr lifr in the morning
lifts to MVFR during the afternoon. Winds becoming NW and
increasing up to 40 kt by late afternoon early evening.

Kbos terminal... High confidence in taf. Dry weather thru the
daylight hours then rain overspreading terminal 03z-06z Friday.

Llws 06z-09z Fri with ws020 14050kt
kbdl terminal... High confidence in taf.

Outlook Friday night through Monday ...

Friday night: mainly MVFR, with local ifr possible. Strong
winds with areas of gusts up to 40 kt. Scattered shra,
scattered shsn.

Saturday: mainlyVFR, with local MVFR possible. Strong winds
with local gusts up to 40 kt.

Saturday night:VFR. Windy with gusts up to 30 kt.

Sunday into Monday: mainlyVFR.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday ... High confidence.

Today ...

ridge of high pressure from south of nova scotia into southern new
england will provide light to modest SE winds, dry weather and good
vsby.

Tonight ...

strengthening low pressure moves from the md coast to li. East winds
increase to 20 to 30 kt along with periods of heavy rain and fog
yielding poor vsby.

Friday ...

strengthening low pres moves from LI at 12z into ri and eastern ma
during the afternoon, then into coastal me by evening. Showers,
drizzle and areas of dense fog lower vsby but improves from south to
north as winds shift to the west and increase up to 40 kt.

Outlook Friday night through Monday ...

Friday night into Saturday: gale force winds with gusts up to
40 kt. Rough seas up to 14 ft.

Saturday night: low risk for gale force winds with gusts up to
35 kt. Areas of rough seas.

Sunday: low risk for small craft advisory winds with gusts up
to 25 kt. Local rough seas.

Sunday night into Monday: winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain.

Tides coastal flooding
Strongest winds and surge still appear to arrive during low tide,
around 09z Friday. However with low pressure overhead at high tide
(18z fri) and pressure rises not arriving until after high tide,
there could be enough leftover surge and wave action for minor
coastal flooding. Greatest risk is across northeast ma coastline
including CAPE ann. Astro tide in boston 17z Fri is 11.7 ft. Surge
values could range from 0.5 to 1.0 ft with ensemble storm surge from
stevens institute the highest. Nonetheless worse case appears to be
minor coastal flooding.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Gale watch from Friday evening through Saturday evening for
anz231>235-237-250-251-254>256.

Small craft advisory from 9 pm this evening to 6 pm edt Friday
for anz232>234.

Gale watch from late Friday night through Saturday evening for
anz230-236.

Small craft advisory from midnight tonight to 6 pm edt Friday
for anz231-251.

Small craft advisory from 6 pm this evening to 6 pm edt Friday
for anz235-237-254-255.

Small craft advisory from 8 pm this evening to 6 pm edt Friday
for anz250.

Small craft advisory from 1 pm this afternoon to 6 pm edt
Friday for anz256.

Synopsis... Nocera doody
near term... Nocera doody
short term... Nocera
long term... Doody
aviation... Wtb nocera doody
marine... Nocera doody
tides coastal flooding...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 20 mi33 min 37°F1 ft
44020 - NANTUCKET SOUND 23 mi23 min SE 7.8 G 12 39°F 38°F1025.1 hPa32°F
NTKM3 - 8449130 - Nantucket Island, MA 31 mi33 min SE 6 G 11 40°F 42°F1025 hPa
WAXM3 - Waquoit Bay Reserve, MA 31 mi78 min ESE 2.9 38°F 1025 hPa31°F
44018 - SE Cape Cod 30NM East of Nantucket, MA 34 mi73 min SE 9.7 G 12 37°F 1025.5 hPa (+0.0)29°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi33 min 40°F 39°F1024 hPa

Wind History for Nantucket Island, MA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chatham, Chatham Municipal Airport, MA2 mi71 minSE 410.00 miFair37°F30°F76%1026.1 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi67 minVar 410.00 miFair39°F28°F67%1024.7 hPa
Provincetown Municipal Airport, MA23 mi67 minS 510.00 miFair36°F28°F76%1025.5 hPa

Wind History from CQX (wind in knots)
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Last 24hr4CalmS5S8S7SW8SW7SW6
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1 day ago5NW75--NW7NW5445E5CalmSE5E3CalmCalmW3W3W3NW4NW4NW4NW3CalmCalm
2 days ago5W7--NW44SW765SW4SW8CalmNW3CalmCalmW3NW3CalmCalmCalmW3W3W3W34

Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
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Pleasant Bay
Click for Map
Thu -- 02:25 AM EDT     3.70 feet High Tide
Thu -- 06:42 AM EDT     Sunrise
Thu -- 07:21 AM EDT     Moonset
Thu -- 09:14 AM EDT     -0.53 feet Low Tide
Thu -- 02:48 PM EDT     3.90 feet High Tide
Thu -- 06:53 PM EDT     Sunset
Thu -- 07:46 PM EDT     Moonrise
Thu -- 09:42 PM EDT     -0.62 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.933.63.63.12.51.70.8-0-0.5-0.30.41.62.83.73.93.52.92.11.20.3-0.4-0.6-0.1

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Thu -- 12:52 AM EDT     -2.01 knots Max Ebb
Thu -- 03:59 AM EDT     0.00 knots Slack
Thu -- 06:42 AM EDT     Sunrise
Thu -- 07:21 AM EDT     2.24 knots Max Flood
Thu -- 07:21 AM EDT     Moonset
Thu -- 10:22 AM EDT     -0.00 knots Slack
Thu -- 01:11 PM EDT     -2.14 knots Max Ebb
Thu -- 04:19 PM EDT     0.00 knots Slack
Thu -- 06:53 PM EDT     Sunset
Thu -- 07:46 PM EDT     Moonrise
Thu -- 07:46 PM EDT     2.44 knots Max Flood
Thu -- 10:53 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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-1.8-2-1.7-101.11.82.22.11.60.5-0.8-1.7-2.1-2-1.4-0.40.81.72.32.42.11.1-0.1

Weather Map and Satellite Images
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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.
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Wind Forecast for Boston, MA (8,2,3,4)
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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.