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Old 07-12-2009, 19:34   #46
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Originally Posted by LeaseOnLife View Post
Viewfax portion of the latest beta airmail
Thank you for the information. Do you have any idea what the little "red stick" next to the "pan" box is or do? and also the "diamond" next to the red stick.
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Old 07-12-2009, 20:34   #47
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Do you find GRIB forecasts ?

Thanks for starting this thread.

I found GRIB and other 'global' forecasting models (e.g. WindGuru.com) badly under-estimate wind strength in my area. Cook Strait has strong terrain effects, so no great surprise? But how well do they work in [1] your coastal area, and [2] open ocean conditions?

What % of time do you find them within 10 kts of actual wind strength?

Agree with Hud3, JohnA, etc re: using local forecasts. GRIBs help me pick risks some days out, but 15 knot GRIB forecasts for the Cook Strait often compete with 35 kt MetService forecasts and 30 kt actual winds.

At very least, local effects seem to matter ...
We don't whistle for wind round here!
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Old 11-12-2009, 09:14   #48
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Hi Roger...

You should try ExpeditionLT in combination with PredictWind. They have created a special modelling method for GRIBS which are more accurate,but,there is a price...

Quote:
PredictWind combines sophisticated wind weather prediction technology with local topography maps to create the highest resolution marine forecast available for over 20,000 locations around the world.

In addition you can access a lower resolution marine forecast for any area around the world. The marine weather modelling technology is only available through the PredictWind website.

Developed by research scientists over 30 years, it has been adapted to provide hourly predictions to localised areas as small as one square kilometre.

PredictWind, used by the winner of the last two America’s Cups, is now accessible at no charge with a 1 Month Free Trial
Have a look:
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Old 26-12-2009, 08:07   #49
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The latest release of OpenCPN does not show the wind barbs or speed in this grib report from the Skagerrak,only bar. pressure and wave height.
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Old 26-12-2009, 12:31   #50
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Based on the grib listing in #49,here are the various outputs using ExpeditionLT. A click on a map position shows the info box.
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Old 26-12-2009, 19:50   #51
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Overlays (layers):
- wind, waves, rain, pressure, water temp, air temp

A spot meteogram nice. A 'following the course/time, multi spot' one I would simply LOVE!

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Old 27-12-2009, 05:15   #52
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Dave...

I don't know if it only occurs in Vista,but I feel the barographs are a bit too heavy, also the wind barbs. Could the lines be made somewhat thinner?
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Old 27-12-2009, 07:50   #53
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Sinbad7

Do you have access to a grib viewer that is able to display 500mb data? In Saildoc lingo this is a request similar to:
Quote:
send gfs:10N,45N,70W,40W|1,1|24,48,72,96,120,144|PRESS, WIND,WAVE,HGT
The 500mb data is the "HGT" at the end. I was just wondering if it is worthwhile to "pester" Dave with this one. I assume that it's only wind speed and direction, but hope for streamlines as well, and dream of "short waves" on top of that!!
Any screen dumps would be appreciated.

Thomas
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Old 27-12-2009, 08:16   #54
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High resolution grib predictions are available by subscription from Wind Forecast, Marine Weather, GRIB, Marine Forecast, Wind Prediction

The attached is based on the Central European grib for 1800 UTC today.
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Old 27-12-2009, 09:41   #55
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This is what I'm talking about:
"Mariner’s Guide to the 500 – Millibar Chart" is found here:
Mariners Weather Log Vol. 52, No. 3, December 2008

Thomas
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Old 27-12-2009, 09:54   #56
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Thomas..

Very interesting article indeed although somewhat complex...
Requires the preparation of the grib file using data from a more stable altitude.
I don't know whether PredictWind uses such a data source for their grib files.
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Old 27-12-2009, 11:01   #57
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Latest OpenCPN v 1226 working perfectly now in Vista.
Also proper display of windbarbs in the European gribs.
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Old 23-02-2010, 07:44   #58
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Hi all.

OPCN has come a long way since it's first GRIB presentation but it is still not possible to read 'Current' messages as in "ggeo-Oslofjord00.grb" from retro.met.no
(File is too large to upload here.)
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Old 23-02-2010, 08:17   #59
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GRIB Animations

Perhaps this is a "feature request" post, but in any case ...

I note that in zyGrib (for both Linux and Windows) and Ugrib (for Windows), it's possible to construct an animation based on successive 6 hour predictions. It's really quite an entertaining little weather movie, as well as very informative when doing research on weather windows. In my view this would be both "cute" and helpful in OpenCPN. Not urgent, but perhaps worth considering.
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Old 23-02-2010, 09:27   #60
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Hi,

1) If wave data is available in a grib file, will OpenCPN display it?

2) Will weather routing function be part of OpenCPN (alike it is done in MaxSea), and, if so, will it use the wave data (to avoid or take advantage of specific wave conditions)?

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