Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-05-2012, 19:05   #1
Senior Cruiser
 
s/v Beth's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Location: Coos Bay, Oregon
Boat: Valiant 40 (1975)
Posts: 4,066
Interpreting Buoy Data and trip planning.

As you can imagine, I have suddenly gained a great interest in buoy data. They speak of dominate wave period and average period of the waves. Which one should I use for my planning?
Also, one should ideally have some wind out there, so should I leave port at the end of a high- with winds calm and waves down but starting up again, or at the beginning of a high pressure area, with the assurance that there will always be some wind off the Washington coast?
__________________

__________________
s/v Beth is offline   Reply With Quote
Old 03-05-2012, 19:27   #2
Senior Cruiser
 
jackdale's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 5,048
Images: 1
Re: Interpreting Buoy Data and trip planning.

Buoy data is historical.

I would also suggest using the NOAA weatherfax for forecasts.

Northeast Pacific WX Briefing Package

For buoys use the wave height and wave period and wave direction. Low long period waves on the stern are much easier on the system than short high waves on the bow.
__________________

__________________
ISPA Yachtmaster Ocean Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203,204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
jackdale is offline   Reply With Quote
Old 03-05-2012, 20:52   #3
Senior Cruiser
 
s/v Beth's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Location: Coos Bay, Oregon
Boat: Valiant 40 (1975)
Posts: 4,066
Re: Interpreting Buoy Data and trip planning.

Jack, the link you gave me is great. How accurate is NOAA beyond 24 hours? Having just been spanked, I am a little gun shy.
__________________
s/v Beth is offline   Reply With Quote
Old 03-05-2012, 21:36   #4
Senior Cruiser
 
jackdale's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 5,048
Images: 1
Re: Interpreting Buoy Data and trip planning.

I have used them offshore; they are like any forecast, as you go further out they become less reliable. I like the NOAA forecasts for HI to PNW. They give a sense of where you want to be in 4 days. The 500mb analysis is great to show how systems could track.

I also use Ugrib (GRIB.US > Home) for 7 day forecasts when I go around Vancouver Island.

It is essential to monitor current conditions; the buoys are great for that.
__________________
ISPA Yachtmaster Ocean Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203,204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
jackdale is offline   Reply With Quote
Old 12-05-2012, 16:34   #5
Registered User

Join Date: Dec 2011
Posts: 25
Howdy!
I use another NOAA product that does very well for isobar/wind predictions, try-

www.nws.noaa.gov

click on FORECAST - AVIATION
select FORECAST - WINDS-TEMPS
select the IMAGE for a graphic view

This has worked for me on a regular basis.

73
__________________
ljsailing is offline   Reply With Quote
Old 12-05-2012, 17:32   #6
Registered User

Join Date: Mar 2012
Location: Solomons, MD
Boat: Aquarius Pilot Cutter 24
Posts: 57
Images: 4
Re: Interpreting Buoy Data and trip planning.

Quote:
Originally Posted by s/v Beth View Post
They speak of dominate wave period and average period of the waves.
I'm no expert here, but I did have some radio spectrum analysis classes decades ago. So total WAG here:

If there was just one sinusoid wave, then the dominant and average would be the same. When you get a mix of different period waves, then that is no longer so. If the dominant wave is very much stronger than any others, then the average should be close to the dominant. In this case, you might expect to see "regular" (uniform? predictable? smooth?) wave action.

In the case where the average is very different from dominant, then there must be many different period waves out there. So you might expect to be sailing through a "dishwasher like" situation.

cas
__________________
cas206 is offline   Reply With Quote
Old 12-05-2012, 17:52   #7
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Re: Interpreting Buoy Data and trip planning.

Quote:
Originally Posted by jackdale View Post
Buoy data is historical.

I would also suggest using the NOAA weatherfax for forecasts.

Northeast Pacific WX Briefing Package

For buoys use the wave height and wave period and wave direction. Low long period waves on the stern are much easier on the system than short high waves on the bow.

That is awesome.

There is so much on NOAA but it is so hard to find.

Thanks.
__________________
Who knows what is next.
Therapy is offline   Reply With Quote
Old 12-05-2012, 19:36   #8
Senior Cruiser
 
s/v Beth's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Location: Coos Bay, Oregon
Boat: Valiant 40 (1975)
Posts: 4,066
Re: Interpreting Buoy Data and trip planning.

Thanks for all the info. I have now bookmarked the NOAH briefing and found it to be very accurate in describing the weather 2-3 days in advance. The dominate vs average wave explanation makes sense. Will try it out.
__________________
s/v Beth is offline   Reply With Quote
Old 12-05-2012, 20:00   #9
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Interpreting Buoy Data and trip planning.

Quote:
Originally Posted by jackdale View Post
(...) The 500mb analysis is great to show how systems could track.(...)
This is already contained in forward sea level products.

At least this is what I heard from NOAA staff.

b.
__________________
barnakiel is offline   Reply With Quote
Old 12-05-2012, 21:10   #10
Senior Cruiser
 
jackdale's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 5,048
Images: 1
Re: Interpreting Buoy Data and trip planning.

Quote:
Originally Posted by barnakiel View Post
This is already contained in forward sea level products.

At least this is what I heard from NOAA staff.

b.
That is true. There are some other redundancies in the weatherfax as well.
__________________
ISPA Yachtmaster Ocean Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203,204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
jackdale is offline   Reply With Quote
Old 13-05-2012, 07:17   #11
Senior Cruiser
 
s/v Beth's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Location: Coos Bay, Oregon
Boat: Valiant 40 (1975)
Posts: 4,066
Re: Interpreting Buoy Data and trip planning.

jack, can you get the twice daily briefings over a HF radio receiver and graphed out on your laptop? How easy is that to do?
__________________
s/v Beth is offline   Reply With Quote
Old 13-05-2012, 10:02   #12
Senior Cruiser
 
jackdale's Avatar

Cruisers Forum Supporter

Join Date: Mar 2008
Location: Calgary, AB, Canada
Posts: 5,048
Images: 1
Re: Interpreting Buoy Data and trip planning.

Quote:
Originally Posted by s/v Beth View Post
jack, can you get the twice daily briefings over a HF radio receiver and graphed out on your laptop? How easy is that to do?
On the HI deliveries we have get our weather information emailed to us by the boat owners after they edit the file and compress it. We have been using Expedition, but that is fairly expensive software that assumes that boat is in race trim. I would recommend Ugrib (GRIB.US > Home) which is free. You might play with that a little through its internet connection.

In 2000 we used a SSB through a modem to a laptop and a printer. We used the NOAA station at Point Reyes.

You can get grib files sent to you via email through saildocs.

Requesting grib files from Saildocs (2010-07-08)
__________________
ISPA Yachtmaster Ocean Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203,204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)
jackdale is offline   Reply With Quote
Old 13-05-2012, 14:07   #13
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Interpreting Buoy Data and trip planning.

You can also request a radiofax img via email.

b.
__________________

__________________
barnakiel is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:16.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.