GRIB files

[castaway]

Just trying to use grib files for the first time.

www.grib.us

I login.
Select an area.
Click Request data
Click Download
A window opens asking me to
either 'open with' (browse)
or
Save

I have tried all the various options I have but think I am missing somthing somwhere!

Any help thankfully received.

Nick

 

[truscott]

Do you have the Grib viewer installed? Or are you simply trying to download via the website?

http://www.grib.us/Downloads.aspx

Some Chart Plotters will work with the GRIB Files (OpenCPN for example will show the text value of the data in the GRIB file) so you don't strictly need the viewer.

You can also get GRIB files sent to you as an email.

This site is a great place to start;

http://weather.mailasail.com/Franks-Weather/Grib-Files-Getting-And-Using

Saildocs can email you the GRIB files too. Instructions for using it are on the above link and also here; http://weather.mailasail.com/Franks-Weather/Saildocs-Free-Grib-Files

I use the grib viewer from GRIB.US to manage my downloads, and save the data in a directory that both the viewer and OpenCPN default to.

Hope this helps.

PT.

 

[RichardS]

Are you using Ugrib to view the file -it's free?

Zoom in on the general area you want, select the precise grib file area, click download grib file with box "Display Grib file" ticked, grib file is downloaded from grib.us and displayed automatically.

You can then play with animations etc.

Richard

 

[franksingleton]

Just trying to use grib files for the first time.

www.grib.us

I login.
Select an area.
Click Request data
Click Download
A window opens asking me to
either 'open with' (browse)
or
Save

I have tried all the various options I have but think I am missing somthing somwhere!

Any help thankfully received.

Nick

I give a lot of info on GRIbs at http://weather.mailasail.com/Franks-Weather/Grib-Files-Getting-And-Using

I and some others have had problems using UGrib. I find zyGrib to be more robust. See http://weather.mailasail.com/Franks-Weather/Zygrib-Ftp-Grib-Service

It is a little faster to download; it has better chart projections. It has a bigger choice of parameters.; it is the sane data as UGrib and most other free GRIB services ie the US Global Forecast System. This is as good as anything else for general patterns over the next 5 days.

I suggest that you use GRIBs alongside UK Met Office forecast charts.

 

[simonjk]

Sounds like you have not downloaded UGrib from Grib.us

Download the software onto your computer, install it, and run it. Then select the area you wish to download and have a play with the options (left hand side of the screen).

As Frank says, use the GRIB in conjunction with the UK Met Office charts, these are a good comparison and can give you and idea as to how high confidence levels are.

Oh, and it would be remiss of me to plug my bug, 'GRIB for Sailors' which is for sailor's like you who are using GRIB for the first time. You can download it, and even view samples of it at http://www.weatherweb.net/books.htm

Happy to help if you have more questions,
Simon

 

[castaway]

Many thanks to all for the replies.

All sorted now with the aid of prompts and links !

Regards

Nick

 

[vyv_cox]

I see you have done it now, but no-one has mentioned the problem I had when I first used it. I omitted to nominate a folder where the charts were to be saved, and as usual the prompts were in 'computerese' so I had no idea what the problem was. Fooled me for some time before I realised.

 

[franksingleton]

I see you have done it now, but no-one has mentioned the problem I had when I first used it. I omitted to nominate a folder where the charts were to be saved, and as usual the prompts were in 'computerese' so I had no idea what the problem was. Fooled me for some time before I realised.

Both UGrib and zyGrib require you to specify a folder to save the files. One advantage of Saildocs and MailASail is that both send emails which are automatically saved in your Inbox. Saildocs has a useful repeat request facility so that one message gives a daily email until you say STOP or have said how many days.

I do not know why but several people - including me - have had problems with UGrib from time to time. zyGrib just seems, to me at least, to be more robust.

 

[CharlesSwallow]

Great that you are now able to download grib files.

I use them as my primary weather info source in Greece and have always found them to be reliable. Use the "Animation" feature for very accurate, up to four or five days advanced predictions which I have found much better than Poseidon.

Chas

 

[simonjk]

Have to jump in here because I get twitchy when I see the term 'very accurate' attached to GRIB files 4 to 5 days ahead.

Firstly, remember GRIB is only the compression method used. Most GRIB files actually contain the GFS model data which is exactly the same data you see at website like Weatheronline, Wetterzentrale, Metcheck, Windguru, Windfinder and many, many more.

Secondly, no model is 'very accurate' beyond approximately 48-hours. The data produced should be used for guidance only. There is no harm planning on it, and when that's the only data you have it's sure better than nothing, but the key is to look at the model data at least once per day (more often is possible) to monitor the changes in the forecast from run to run.

Sorry to be pedantic.

Simon

 

[CharlesSwallow]

Have to jump in here because I get twitchy when I see the term 'very accurate' attached to GRIB files 4 to 5 days ahead.

Firstly, remember GRIB is only the compression method used. Most GRIB files actually contain the GFS model data which is exactly the same data you see at website like Weatheronline, Wetterzentrale, Metcheck, Windguru, Windfinder and many, many more.

Secondly, no model is 'very accurate' beyond approximately 48-hours. The data produced should be used for guidance only. There is no harm planning on it, and when that's the only data you have it's sure better than nothing, but the key is to look at the model data at least once per day (more often is possible) to monitor the changes in the forecast from run to run.

Sorry to be pedantic.

Simon

Not based upon a documented survey or dedicated study but my memory tells me that the animations I download from US Grib have often been, for my cruising area anyway, more accurate days ahead than (especially) Weatheronline Wetteronline. Maybe the term "very accurate" has a specific meaning in the meteorological world? However these downloads, although not infallable, give me a more reliable info source than anything else I can get aboard in the central/eastern Med.

Chas

 

[simonjk]

Chas,

Should have said that I was not criticising you for using the term 'very' ! As a bench forecaster I amn reluctant to use the term 'very' even when forecasting the next 24-hours

The files you download from GRIB are exactly the same as the files you would see on Weatheronline or any other website which uses GFS data and so accuracy levels will actually be exactly the same.

I guess what may be different is the visualisation of the data, and it may be that the way Ugrib displays the data is better suited to interpretation.

You are right that GRIB software which displays model output is good to use for guidance in the Med area (although of course SWIS forecasts are pretty good too )

Best wishes,
Simon

 

[bluedragon]

I use Windguru Pro, Simon's service and others, and know of course it's all the same few data sources with interpolation. Because of this I'd never bothered with GRIB file viewers until yesterday, when having a few hours free I thought I'd download USGRIB and ZyGRIB and have a play. Of course the data is identical as Simon says, but I did find the display and animations quite interesting for let's say 2-5 day planning purposes. Easier to see the big picture evolving than the tabular form on web-based services or even the maps they offer. It's a personal thing, but I might persevere with especially ZyGRIB for a while along with my usual sources.

 

[simonjk]

Hi bluedragon,

Try ugrib from www.grib.us, I find it the most user friendly and it's the main program I used when writing my Grib for Sailors book.

As Frank mentioned, there is loads of information on his web site too.

Simon

 

[bluedragon]

Thanks Simon, I did try that yesterday (got the name wrong). Not quite as fully-featured as ZyGRIB I thought, but a nice uncluttered presentation. In fact I will run them both for a few weeks and see which (if any) I keep going back to.

 

[simonjk]

You could try GribView 2.0 as well (http://www.theyr.com/grib/index.asp)

They will try to sell you higher res model data but you probably don't need this. GFS is adequate.

Simon

 

[iainhu]

Problems with grib.us viewer

A problem I suffered this summer with the grib.us viewer was that it refused to recognise me.

It's usual that when you connect from a new location it asks you to verify yourself via your Email address and so each mobile connection from around the Aegean seems to require you to do this. I've had no problems before but this year it simply told me I was unknown and to register.

I could log into the website itself, I could confirm my Email, I could even copy and paste it into the local grib.us viwer, but it steadfastly refused to allow me to download data via the viewer. I could through get it via the website although that was more painful needing me to define the apprx area each and every time. This did though prove that I am still registered. And the laptop used to access the files has worked fine from Greece before and always from the UK.

A message via the website to grib.us got no response :-(

Anyone else had a similar problem?

.../Iain

 

[bluedragon]

You could try GribView 2.0 as well (http://www.theyr.com/grib/index.asp)

They will try to sell you higher res model data but you probably don't need this. GFS is adequate.

Simon

I tried Theyr in the past (their web based service) but believe or not the reason I just couldn't get to grips with it was their choice of colour for wind speeds! Don't laugh, but I found going from dark blue to light blue to whitish yellow as wind speed increased so counter-intuitive it drove me nuts!! Probably just me, but there you...presentation is as important as the data.

 

[franksingleton]

A problem I suffered this summer with the grib.us viewer was that it refused to recognise me.
........./Iain

That is the problem that I and others have had with UGrib. As I said, zyGrib seems more stable.

I usually say that GRIBs give good guidance to about 5 days ahead. I hate the word "accuracy" because it is so difficult to define in a forecast. Meso scale forecasts will not better the GFS except where topography is the main driver. Bill Reilly says that SWS does better through the Gibraltar Strait than the GFS. That I can well imagine. However, when it comes to areas such as the W Med or the Bay of Biscay none of WindGuru, SWS etc will do appreciably better than the GFS. I will not go into the reasons here. There are pages on my site about forecast accuracy limitations.

My page http://weather.mailasail.com/Franks-Weather/Grib-Forecast-Examples shows some examples of GRIBs - all GFS. These are not selected other than I more or less picked them at random when doing talks. The only selection was that I tried to get examples where there were changes occurring.

 

[bluedragon]

Frank, I've been trying to understand for years why the mesoscale models on let's say WindguruPro are much closer to actual coastal winds than GFS, which on the day almost always seems to be about 1 force too low. Let's take the Devon & Cornwall coast where I am now (Dartmouth to Falmouth). Are the higher res. models taking account of topography as you say, or sea breeze, or what? The fact is that over many years (in West Wales as well) they always seem to give higher forecast values and these are closer to actual in many if not most cases.