Wednesday, July17, 2019 L-36.com


Marine Weather and Tides
West Chatham, MA

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Sunrise 5:19AMSunset 8:14PM Wednesday July 17, 2019 1:00 PM EDT (17:00 UTC) Moonrise 8:58PMMoonset 5:49AM 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- 1223 Pm Edt Wed Jul 17 2019
Today..SW winds 10 to 15 kt with gusts up to 25 kt. Seas 2 to 4 ft. A slight chance of showers with isolated tstms this morning.
Tonight..SW winds 10 to 15 kt with gusts up to 20 kt, diminishing to 5 to 10 kt after midnight. Seas 2 to 4 ft. Patchy fog. Showers likely with a chance of tstms. Some tstms may produce gusty winds, heavy rainfall, and frequent lightning. Vsby 1 nm or less.
Thu..SE winds 5 to 10 kt. Seas 2 to 4 ft. Showers with a chance of tstms. Some tstms may produce heavy rainfall. Vsby 1 nm or less.
Thu night..SE winds 5 to 10 kt, becoming N after midnight. Seas 2 to 4 ft. Patchy fog. Showers likely with a chance of tstms. Some tstms may produce heavy rainfall. Vsby 1 to 3 nm.
Fri..N winds around 5 kt, becoming sw in the afternoon. Seas 2 to 4 ft. Patchy fog. Vsby 1 to 3 nm.
Fri night..SW winds 5 to 10 kt. Seas 2 to 4 ft.
Sat..SW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Sat night..W winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Sun..W winds 5 to 10 kt. Seas 2 to 4 ft.
Sun night..SW winds 5 to 10 kt. Seas 2 to 4 ft. 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 1223 Pm Edt Wed Jul 17 2019
Synopsis for massachusetts and rhode island coastal waters.. High pres will shift E of the waters this afternoon. The remnants of barry spread across the waters late today through midday Thu. High pres builds across northern new england on Thu producing e-ne winds across the waters. The high will move E across nova scotia Thu night. South to southwest winds will bring a build up of heat and humidity Fri and Sat. A cold front approaches on Sunday, bringing a chance for showers and Thunderstorms. 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 171406
afdbox
area forecast discussion
national weather service boston norton ma
1006 am edt Wed jul 17 2019

Synopsis
A cold front will approach the region later today, with the
threat of scattered showers and thunderstorms, along with the
potential of heavy rainfall. As the front pushes across tonight,
the remnants of barry with bring more showers with locally
heavy rainfall, along with scattered thunderstorms which will
continue through most of Thursday. Hot and humid conditions
settle in for Friday through Sunday with heat related headlines
likely. A cold front sweeps through the region Monday with
scattered showers and thunderstorm. High pressure then builds
over new england Tuesday bringing seasonable temperatures and
much lower humidity.

Near term until 6 pm this evening
1005 am update...

* a few strong-severe t-storms possible this afternoon into this
evening along with a heavy rain localized flood threat
an abundance of clouds were in place at mid morning across
southern new england along with a few spot showers. There was also a
small cluster of brief heavy showers and thunderstorms near the
southern ri coast.

This isolated activity at mid morning have developed in the
warm air advection pattern. However, the main show is expected
this afternoon into this evening as scattered showers and
thunderstorms develop ahead of an approaching cold front. While
clouds have limited heating this morning, we were starting to
see some breaks develop across the interior. This should allow
high temperatures to reach the upper 80s in many locales with a
few lower 90s also possible. Dewpoints of 70+ should generate
1500 to 2500 j kg of CAPE this afternoon. The big limiting
factor will be poor mid level lapse rates which will likely keep
this from being a widespread severe weather event. However,
with shear increasing to between 30 and 35 knots with 70+
dewpoints a few strong to severe thunderstorms are certainly
possible with localized damaging wind gusts the main concern. In
fact, an isolated wet microburst is also possible in this
environment. In addition... Pwats of 2+ inches will result
torrential rainfall with any thunderstorms and bring the threat
for localized flooding.

So in a nutshell... While a widespread severe weather event is
unlikely a few strong to severe thunderstorms are certainly
possible. The high pwat atmosphere will be ripe for localized 1
to 2 inch per hour rainfall amounts and bring the risk for
localized flooding.

Lastly... The high dewpoint airmass will result in heat indices
reaching the middle 90s this afternoon. In fact, its not out of
the question that a few spots see heat indices into the upper
90s to near 100.

Short term 6 pm this evening through 6 pm Thursday
* a few strong to severe thunderstorms possible this evening
* heavy rainfall with localized urban & poor drainage flooding
possible this evening through Thursday
tonight and Thursday...

the front will slowly shift S into the region tonight as the
mid level steering flow becomes nearly zonal. Will see winds
shift to e-ne across N mass mainly around midnight or so. Will
continue to see the threat of thunderstorms that may produce
gusty to possibly damaging winds through around 02z, then should
subside somewhat.

However, the threat for heavy rainfall that may produce local
urban poor drainage flooding will continue, focusing on N ct ri
and SE mass where the best moisture convergence and feed will be
situated. Most short range high res models bring the bullseye
of heavy rainfall across this portion of the region. Along with
this, the nearly zonal flow will bring the remnants of barry
across central and southern areas overnight through midday
Thursday, enhancing the rainfall even more.

Current forecast QPF amounts could be from 1.5 to 2.5 inches
from this afternoon through Thursday, mainly from the mass pike
southward.

With e-ne winds behind the slowly moving cold front, low level
moisture will feed off the ocean, allowing the precip to linger
through the majority of Thursday from S of boston across se
mass into ri and NE ct, but should see some diminishing precip
further N and W during the afternoon.

Highs on Thursday will mainly be in the 70s.

Long term Thursday night through Tuesday
Big picture...

zonal flow across the northern half of the usa while subtropical
high pressure controls the southern half. Remnants of barry in the
zonal flow will move east of southern new england by Friday. Early
next week the subtropical high builds north over the western usa,
while a trough digs over the northeast usa.

Normal 500-mb heights for mid july are 580 to 582 dm. Forecast
heights build to 591 dm over the weekend, then trend to normal or a
little lower early next week as the upper trough digs in. From this,
we expect above-normal temperatures Friday-Saturday-Sunday, then
expect warmer than normal temperatures through the weekend, then a
trend to near normal temperatures early next week.

General agreement among the model mass and thermal fields through
the weekend. The fields early next week show a similar general
pattern with small differences. Overall forecast confidence is
moderate-high, but confidence in timing of the cold fronts Sunday-
Monday is low-moderate.

Concerns...

Thursday night and Friday...

remnants of barry pass south of southern new england Thursday night.

Winds are initially from the east and northeast, then turn from the
north after the remnants move past. The east flow is a wet pattern
is a wet pattern, especially in eastern ma and potentially in
central ma and ri. Expect continued showers and scattered
thunderstorms the first half of the night, diminishing to no
precipitation in western ma and northern ct after midnight. Pw
values remain at 2 inches or more across ri and eastern ma the first
half of the night, then diminish overnight. This means continued
potential for downpours in this area through midnight, then
diminishing showers after midnight.

Cross sections show lingering low-level moisture for clouds over all
of the region Friday morning. So expect clouds to start Friday, and
possibly some drizzle or widely scattered showers in coastal ma
Friday morning. But expect drying at cloud-level and warming temps
aloft suppressing further shower development... 700 mb temps climb
above 10c... And so we should see clearing during the day. With dew
points in the 60s, expect min temps Thursday night in the 60s.

Increasing Sun Friday will allow mixing to 850 mb, tapping
temperatures of 18-20c which would support MAX sfc temps of upper
80s to mid 90s. We bumped guidance values up 3-5f to line up this
these values. The temperatures and humidity will generate heat
index values in the 90s.

Friday night through Sunday...

high pressure builds surface and aloft, cresting over southern new
england Saturday and then pulling south on Sunday. Temps at 700 mb
crest about 13c Saturday, which should suppress anything that tries
to form a shower. Pw values fluctuate, but stay close to 2 inches
through the weekend. So the airmass will have a good supply of
moisture in it and surface dew points 70f to 75f. With dew points at
that level, expect overnight min temps Friday night and Saturday
night will be in the 70s to near 80, warm and muggy both nights.

Mixing to 850 mb will tap temperatures of 21-23c, supporting MAX sfc
temps of 95-100f. Heat index values will be above 100f most places
and above 105f in some inland areas.

Sunday starts quite warm aloft, but with the relaxing ridge we
should see temps aloft lowering with time. Temps at 700 mb start the
day above 10c, but lower just below by late in the day. This heat
dome should suppress convection for at least the first half of the
day. The question is whether the heat aloft diminishes enough to
allow showers tstms later in the day. Best chance for this would be
across the northern half of massachusetts. We have chance pops in
this northern area during the afternoon evening. Temps at 850 mb are
forecast at 20-22c, which translates to another day well into the
90s at the surface. This brings the heat index to 95-100, similar to
Friday.

Monday-Tuesday...

cold front sweeps south from canada Monday, with potential for
showers tstms. Pw values linger between 1.5 and 2 inches until the
front moves through, showing potential for downpours. High
pressure then moves in behind the front Tuesday, bringing rain-
free and less humid air.

Aviation 14z Wednesday through Sunday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ... Moderate confidence.

Today...

vfr conditions will dominate outside of scattered showers and
thunderstorms mainly this afternoon and evening. However, some
ifr conditions in low clouds may impact the southeast new
england coast at times, especially this morning as high dewpoint
air continues to stream into the region.

Isolated showers mainly across southeast new england at mid
morning with a small cluster of embedded thunderstorms across
near the southwest ri coast. Broader area of showers thunder
over western ny and western pa will approach our area during the
afternoon and into the evening. Additional sct shra isold tsra
will develop from n-s during the day, some that may produce +ra
and possibly gusty winds. Ifr- lifr conditions with any +ra.

Lower confidence on exact timing of impacts. W-sw winds 5-10 kt,
gusting up to 20 kt at times along the S coast. Sct-bkn cigs
becoming ovc late.

Tonight...

sct-lkly shra chc tsra through most of the night. Continued +ra
threat with ifr-lifr conditions. W-sw winds 10 kt or less,
shifting to e-ne from CAPE ann around 04z S to near outer cape
cod toward daybreak. CIGS lowering to ifr-lifr with local ifr
vsbys in patchy fog along the S coast, CAPE cod and the islands
and possibly into the ct valley around or after midnight. Ovc
conditions overall.

Thursday...

cat shra across NE ct ri S coastal mass Thu morning, with lkly
shra mainly near S of the mass pike along with sct tsra.

Conditions slowly improve, but sct shra isold tsra may linger
inland, with better shot for shra tsra across E mass ri with
onshore flow lingering. E-ne winds around 10 kt with some gusts
up to 20 kt along E coastal terminals.

Kbos terminal...

high TAF confidence this morning, then moderate confidence this
afternoon and tonight. May see a few tsra this afternoon and
evening, along with possible +ra and gusty winds.

Kbdl terminal...

high TAF confidence this morning, then moderate confidence
this afternoon and tonight. Main concern will be for a few vcts
this afternoon into tonight with possible +ra and gusty winds.

Outlook Thursday night through Sunday ... High confidence.

Thursday night: mainlyVFR, with local ifr possible. Slight
chance shra.

Friday through Saturday night:VFR.

Sunday:VFR. Slight chance shra.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ... High confidence.

Today...

high pressure pushes further offshore this morning. Meanwhile, a
cold front approaches from the st lawrence valley. This will
result in SW winds of 10 to 15 knots with gusts up to 20 knots
across the southern waters. However, both wind gusts and seas
should remain below small craft advisory thresholds. Potential
for a few strong thunderstorms with localized strong winds later
today into this evening, especially across the near shore
waters.

Tonight...

a cold front will push S during the night, with SW winds
shifting to e-ne across the eastern waters to outer CAPE cod,
but will remain SW across the southern waters. Showers and
isolated thunderstorms continue, which will be locally heavy at
times. Areas of fog develop, mainly across the southern near
shore waters to E of CAPE cod.

Thursday...

winds gradually shift to e-se across the southern waters during
the day, with e-ne winds 10-15 kt across the eastern waters.

Gusts up to 20 kt Thu morning on the eastern waters. Threat for
showers with locally heavy rainfall, along with a few
thunderstorms continues mainly from about boston harbor
southward, though will start to diminish during the afternoon.

Outlook Thursday night through Sunday ... High confidence.

Thursday night: winds less than 25 kt. Slight chance of rain
showers, slight chance of thunderstorms.

Friday: winds less than 25 kt.

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

Saturday through Saturday night: winds less than 25 kt. Areas
of seas approaching 5 ft.

Sunday: winds less than 25 kt.

Climate
Record highs for Wednesday july 17 are as follows:
bos: 98f in 1977 & 1999
bdl: 97f in 1999
pvd: 97f in 1977 & 1999
orh: 93f in 1900
record highest min temps for Saturday july 20:
bos: 75 in 2016
bdl: 73 in 1975
pvd: 77 in 1983
orh: 72 in 2013
record highs for Saturday july 20:
bos: 99 in 1991
bdl: 100 in 1991
pvd: 101 in 1991
orh: 92 in 1901
record highest min temps for Sunday july 21:
bos: 81 in 1991
bdl: 74 in 1977
pvd: 77 in 1980
orh: 73 in 1991

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... None.

Synopsis... Wtb evt
near term... Frank
short term... Evt
long term... Wtb
aviation... Frank evt wtb
marine... Wtb evt
climate... Staff


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44090 20 mi31 min 71°F1 ft
44020 - NANTUCKET SOUND 23 mi41 min 16 G 19 74°F1014.5 hPa
NTKM3 - 8449130 - Nantucket Island, MA 31 mi61 min WSW 8 G 17 74°F 75°F1015.7 hPa (-0.0)
WAXM3 - Waquoit Bay Reserve, MA 31 mi76 min WNW 2.9 79°F 1015 hPa75°F
44018 - SE Cape Cod 30NM East of Nantucket, MA 34 mi71 min SSW 14 G 16 72°F 1 ft1013 hPa (-0.7)71°F
BZBM3 - 8447930 - Woods Hole, MA 40 mi67 min 74°F 74°F1014.3 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 mi69 minSW 8 G 1910.00 miOvercast77°F73°F88%1015.2 hPa
Hyannis, Barnstable Municipal-Boardman Airport, MA17 mi65 minSW 16 G 2210.00 miOvercast81°F73°F79%1014.1 hPa
Provincetown Municipal Airport, MA23 mi65 minSSW 17 G 2210.00 miA Few Clouds79°F73°F82%1013.6 hPa

Wind History from CQX (wind in knots)
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1 day ago5354SW4SW3CalmCalmSW4SW3SW3CalmCalmNW3NW3NW3NW3NW3NW3CalmS4S6S86
2 days agoSW4SW53S53CalmCalmCalmCalmCalm334Calm3NW3334NW4NW656NW8

Tide / Current Tables for Pleasant Bay, Quonset Pont, Massachusetts
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Pleasant Bay
Click for Map
Wed -- 02:25 AM EDT     3.44 feet High Tide
Wed -- 05:19 AM EDT     Sunrise
Wed -- 05:49 AM EDT     Moonset
Wed -- 09:41 AM EDT     -0.17 feet Low Tide
Wed -- 03:01 PM EDT     2.94 feet High Tide
Wed -- 08:11 PM EDT     Sunset
Wed -- 08:57 PM EDT     Moonrise
Wed -- 09:48 PM EDT     0.25 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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22.93.43.43.12.62.11.40.6-0-0.10.31.122.72.92.82.52.21.710.40.30.6

Tide / Current Tables for Pollock Rip Channel, Massachusetts Current
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Pollock Rip Channel
Click for Map
Wed -- 01:13 AM EDT     -1.77 knots Max Ebb
Wed -- 04:16 AM EDT     0.00 knots Slack
Wed -- 05:20 AM EDT     Sunrise
Wed -- 05:50 AM EDT     Moonset
Wed -- 07:54 AM EDT     2.25 knots Max Flood
Wed -- 10:56 AM EDT     -0.00 knots Slack
Wed -- 01:47 PM EDT     -1.64 knots Max Ebb
Wed -- 04:47 PM EDT     0.00 knots Slack
Wed -- 08:11 PM EDT     Sunset
Wed -- 08:11 PM EDT     1.85 knots Max Flood
Wed -- 08:56 PM EDT     Moonrise
Wed -- 10:59 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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-1.5-1.8-1.7-1.1-0.30.71.52.12.21.91-0.1-1-1.5-1.6-1.4-0.70.211.61.81.71-0

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 (13,3,4,5)
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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.