Wednesday, November22, 2017 L-36.com


Marine Weather and Tides
Siasconset, MA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 6:41AMSunset 4:21PM Wednesday November 22, 2017 7:41 AM EST (12:41 UTC) Moonrise 10:46AMMoonset 8:50PM Illumination 15% Phase: Waxing Crescent; Moon at 4 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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ANZ005 626 Am Est Wed Nov 22 2017
Synopsis for eastport me to stonington me out 25 nm.. Low pres will approach from the south today and track east of the waters this evening. A cold front will cross the waters this evening. High pres will build across the region Thu. A cold front will cross the waters Fri.

7 Day Forecast for Marine Location Near Siasconset, MA
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location: 38.84, -69.85     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 221148
afdbox
area forecast discussion
national weather service taunton ma
648 am est Wed nov 22 2017

Synopsis
A cold front approaches the region today, and with moisture
working up the eastern seaboard to bring a period of rain this
morning, especially SE new england. Quiet weather Thursday and
Friday. Another shot of wet weather and breezy conditions this
weekend. Drier and milder toward the middle of next week.

Near term until 6 pm this evening
Latest runs of the high resolution guidance, most notably the
hrrr, appear to have a very good handle on the location and
timing of the band of moderate to heavy rainfall working into
southern new england this morning. As such, relied heavily upon
the hrrr to try and refine the rainfall details through today.

No other major changes to the forecast for today. Adjusted the
next several hours to reflect observed trends.

Previous discussion...

split flow across the region early this morning as northern
stream cold front approaches from the great lakes. Southern
stream shortwave coastal low off the carolina coast will move
northward up the east coast. This system will remain well
offshore but its moisture plume will impact the region.

Currently, surface cold front is making its way into upstate
ny. Radar imagery shows some showers along this front, but
overall moisture is pretty meager. Southern new england remains
in the warm sector ahead of this approaching front thus temps
early this morning have reside above average. In fact, the
office is currently a balmy 51 degrees with nantucket at 56f.

Focusing south, latest goes-16 satellite shows moisture
beginning to stream northwards towards new england thanks to
bermuda high pressure. Current radar imagery shows widespread
showers across the carolina coast, with scattered showers
developing across long island and into southeast massachusetts.

These showers are associated with the upper level jet and mid-
level moisture at 700mb. At the surface, theta-e gradient has
set-up with a 1000-925mb frontogenesis which has help aided the
showers in southern new england. The profile has moisten up as
guidance suggested as rainfall is being reported from wst to
ewb.

Over the next few hours, moisture will continue to stream into
the region as surface cold front from the west approaches. This
will help pool the moisture into the area and push pwat values
to above 1.0 inch by the mid-morning hours. Showers will begin
to overspread the rest of the region after 7am. The combination
of the upper level jet and LLJ will help aid in strong lift for
the region. In fact, guidance continues to hint at strong omega
during the mid-morning hours especially along and points east of
i-95. This combined with the high pwats will lead to heavy
downpours across ri and eastern ma. Ncar ensembles continue to
show the potential for 40dbz during the 7am to noon time-frame.

Also cannot rule out a rumble or thunder as guidance continues
to hint as sb CAPE thanks to higher dewpoints.

Continued to trend QPF towards the ec but with the hi-res
guidance mix in as well. Appears that heavy precip axis will be
along of just east of the i-95 corridor. This is also supported
by the href, ncar ensembles and hrrr. Generally 0.5 to 1 inch
qpf will fall across a line east of ijd to bvy. Highest amounts
will occur just east of i- 95. Areas west of the worcester hills
will see rainfall amounts less than 0.25 inches.

As the front pushes through southern new england, precip will
exit the region by the mid-afternoon. Behind the front, dry but
cooler air will quickly usher into the region leading to temps
dropping through the afternoon hours and winds beginning to pick
up. Overall anticipate a rainy morning leading to heavy
downpours slowing the morning commute. Conditions will improve
by the afternoon hours leading to a great, but chilly start to
the holiday travel.

Short term 6 pm this evening through 6 pm Thursday
Tonight into thanksgiving day...

cold front will be offshore by this evening as strong CAA usher
into the region. Good mixing with this cold air aloft resulting
in gusty NW winds near 20-25 mph during the overnight hours.

Surface high pressure approaching from the west may be enough to
allow for the winds to slacken off resulting in radiational
cooling before daybreak. Highest confidence is across the
interior. Thus will keep temps cooler than mav met guidance.

Chilly start to the thanksgiving holiday as high pressure from
the west builds into the region. Weak shortwave aloft will
increase cloud cover during the afternoon. Moisture associated
with this wave looks meager enough to keep the forecast dry.

Westerly winds at the surface as temperatures in the upper 30s
to low 40s across the region. Overall, a chilly but dry turkey
day as temperatures will remain 5 to 10 degrees below normal.

Long term Thursday night through Tuesday
* highlights...

- quiet weather through Friday
- showers possible at times this weekend, could be breezy
Sunday
- turning mild Tuesday into Wednesday, could also be breezy
* overview...

22 00z guidance suite is rather good overall agreement into
Sunday. More detail differences become more prevalent early next
week. Continue to favor a consensus approach to smooth over the
less predictable details, particularly with timing and amplitude
of various shortwaves moving through the larger synoptic pattern.

In general, expecting a mid level longwave trough to linger
near our region Friday into Saturday. As previously note, this
is more of a split flow during this time. Majority of the
guidance merges this flow into a deeper mid level trough Sunday
into Monday. This mid level trough expected to finally move
over the maritimes toward the middle of next week.

Only concern for precipitation during this time will be this
weekend. Besides a series of front Saturday, will need to
monitor the progress of an offshore low pressure. At this time,
thinking this coastal low remains far enough east to not have a
major impact other than increasing the pressure gradient,
especially Sunday.

Aviation 12z 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 ... High confidence.

Today... Mixed MVFR ifr CIGS through the day with ra and vsbys
1-3sm at times in ra +ra, low risk tsra, especially E of kpvd-
kghg. Areas W may remain mixed MVFRVFR with mainly -ra. Ra
clears and rapid improvement toVFR occurs after 18z from w-e
as winds shift to the NW and become gusty.

Tonight into Thursday...VFR. Westerly flow around 10 kt.

Kbos terminal...

bulk of -ra ra progged 12-20z, mainly MVFR cigs, with +ra ifr
threats 14-18z. Feel tsra will remain SE of the terminal.

Clearing toVFR after 20z, with cold frontal passage expected
between 18-20z.

Kbdl terminal...

feel ra +ra threats will remain e. Looking at mostly -ra
developing around 12z persisting through 18z. MVFR CIGS with
lesser impact to vsby. Clearing out shortly after 18z.

Outlook Thursday night through Sunday ...

thanksgiving day:VFR.

Thursday night through Friday night:VFR. Breezy.

Saturday:VFR. Breezy. Slight chance shra.

Saturday night:VFR. Slight chance shra.

Sunday:VFR. Breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Thursday ...

today... High confidence.

Passing cold front during the day and passing coastal low well east
of the waters will lead to widespread rainfall today which could
limit vsbys. Seas will remain near 5 feet for the outer waters but
sca have been let go elsewhere.

Tonight into tomorrow... High confidence.

Strong CAA across the relatively warm waters will result in gusts nw
winds between 25-30 kts. Seas will also build in response. SCA have
been reissued to account for this trend. Low confidence on gales for
the eastern ocean waters. Conditions will improve on thanksgiving,
but seas will remain choppy into the afternoon.

Outlook Thursday night through Sunday ...

thanksgiving day: winds less than 25 kt. Local rough seas.

Thursday night: winds less than 25 kt. Seas up to 5 ft.

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

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

Sunday: moderate risk for small craft advisory winds with gusts
up to 30 kt. Seas up to 5 ft. Slight chance of rain showers.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory from 4 pm this afternoon to 4 am est
Thursday for anz230>234-251.

Small craft advisory from 4 pm this afternoon to 1 am est
Thursday for anz236.

Small craft advisory from 4 pm this afternoon to 2 pm est
Thursday for anz235-237.

Small craft advisory from 4 pm this afternoon to 8 pm est
Thursday for anz250.

Small craft advisory until 8 pm est Thursday for anz254>256.

Synopsis... Belk dunten
near term... Dunten
short term... Dunten
long term... Belk
aviation... Belk dunten
marine... Belk dunten


Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Nantucket, Nantucket Memorial Airport, MA168 mi49 minSSE 139.00 miOvercast54°F54°F100%1014.9 hPa

Wind History from ACK (wind in knots)
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Last 24hrSW18SW18
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1 day agoW19
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2 days agoS15SW22
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Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
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GOES Local Image of Northeast    EDIT
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Wind Forecast for Boston, MA (7,2,3,4)
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Ground Weather Radar Station Upton, NY
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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.