GRIB .bz2 files help please

[LadyInBed]

I have been looking for alternate sources of GRIB .bz2 files
to download to a pc (not via e-mail or to phone)

Using zyGrib I have been downloading GRIBs via the zyGrib server.
With the parameters I have set, the file that loads - 20111213_204952_.grb.bz2 is 6.2Mb and shows the following info:

I found the site Euronav GRIB Weather files which led me to Global Marine Networks (GMN) from where I downloaded the NorthEurope GRIB - NorthEurope.wind.grb.bz2 which is 100Kb and shows the following info:

This is obviously the minimum info required.

I would like to get a GRIB that gives the isobar lines and wind gusts.
(I think if I get the isobar lines then the Pressure box will automaticly filled in)

There must be other sites that supply .bz2 files, can anyone give the links please.

 

[RobbieW]

Not sure if this helps your understanding - bz2 indicates that a specific compression algorithm has been used on the file. They could be unpacked with, for instance, 7Zip which would leave you with the base .grb file. zyGrib also reads files in the .grb format (just checked) so any site serving these should work.

My own experience is that the data options given through zyGrib are more extensive than those of any other site I've used to date. Certainly better than USGrib or Saildocs.

btw, I think if you move the cursor around over the chart what you'll get are the values for the point at which your cursor currently is. Thats what I get for wave heights anyway. I'm assuming that you have selected 'isobars' from the Data drop down menu when displaying a file ? zyGrib is a fairly complex tool that I found takes a bit of getting used to.

 

[LadyInBed]

zyGrib should also read files in the .grb format so any site serving these should work.

Thanks, I will have a look around for .grb files and try them.

I think if you move the cusor around over the chart what you'll get are the values for the point at which your cursor currently is. Thats what I get for wave heights anyway.

Yes, that is what you get with the zygrib download (as in top pic) but the other download from GMN is only providing the very basic data (as in bottom pic) hence the small 100Kb file size.

 

[LadyInBed]

I found some .grb files at oiswww eumetsat int and tried MPE_20111214_1100_M9_00.grb and MPE_20111214_1230_M7_57.grb but got the following error in zygrib

so maybe zygrib doesn't accept .grb files

 

[RobbieW]

More likely that the data in the file is not of a type that zyGrib was written to display, the page title suggests this is something rather specialised. I can load .grb from both USGrib and Saildoc into zyGrib. Try http://weather.mailasail.com/Franks-Weather/Grib-And-Objective-Forecast-Listing which has links to more sources than you can shake a stick at.

 

[LadyInBed]

More likely that the data in the file is not of a type that zyGrib was written to display

I think you are right about that.

I can load .grb from both USGrib and Saildoc into zyGrib.

Yes, I can get those ok but they are via e-mail

Try [Franks site] which has links to more sources than you can shake a stick at.

Yes, I have been there but as far as I can see, apart from the e-mail sites, the others are pay sites or sites there you use an application such as zygrib or UGrib to load the files.

I would really like links to raw grb or bz2 downloads.

 

[RobbieW]

I would really like links to raw grb or bz2 downloads.

Apologies for the egg sucking lessons earlier; but you've now piqued my curiosity. Why do you want to be able to download those files direct ? I had a look around the NOAA site but that mostly seems to talk about the configurability of the data request.

I'm curious because in 6 years or so of using GRIB files I've found that using one of the local tools to select the data I want today satisfies my sailing needs. Whether the local tool is zyGrib, USGrib or Airmail - Airmail provides an interface to Saildocs which formats your request, you can cut and paste from Airmail into another mail handler to actually send the email. The examples in your original post contrast a 6Mb file with a 100Kb file, if I have access to a broadband/HSDPA connection the first is fine but if all I have is SSB/Iridium even the second is too big. So the ability to select the data I want, before requesting and locally to my PC, is important.

 

[LadyInBed]

Why do you want to be able to download those files direct ?

My intention is to get a kindle g3 and use it's free net access to download the grib files, then transfer them to my laptop.
Now, I don't know much about the kindle but I am fairly sure that you can't run zygrib on it but I think it can download files, that is why I was looking for sources to get the bz2 (or grb) files.
If I can't find the files, and it is staring to look that way, e-mail via Saildoc is an alternative or if none of the above work then I will just have to be satisfied with looking at weather sites on-line.

 

[markdj]

In zygrib you can untick the information you download, reduce the resolution, reduce the number of days to forecast, reduce from 3hr to 6hr intervals and select a smaller forecast area.

This should get your download amount down to acceptable levels, otherwise use ssb.

 

[franksingleton]

I have been looking for alternate sources of GRIB .bz2 files..........
/QUOTE]

First, possibly teaching grannies to suck eggs, Saildocs, Ugrib, zyGrib all use the GFS. The only differences are in the data that they make available. zyGrib extracts data on gusts that the others do not. I have not looked at GMN lately; being essentially an advertising gimmick for their radio services, their service was too restricted to be worthy of note given other GRIB sources so I dropped it from my site. That may have changed.

GRIB data files are fairly well compressed and I have never been sure of how much gain there is by using ;bz2. Maybe it matters for large files.

If you want to receive GRIBs by email then the only two free services that I know are Saildocs either via Airmail or by simply sending an email request, or MailASail.

The advantage with Saildocs is in the repeat request facility. Once you have got the format right, it is the most efficient way of getting GRIBs. As well as the repeat facility, you can have variable time intervals. For example, last season I was using time integrals of 3 or 6 hours for the first 36 hours and 12 hours from then to 192 hours.

You can open .grb files using the zyGrib viewer – but I am sure that you know that. Maybe if you want to use Kindle you will have to forego gusts. I have been looking at GRIB apps on my iPad. But none gives gusts.

You do seem to have an inordinately large download. Do you really need all the data? Do you need isobars? By the very nature of NWP models, they will tell you nothing that you cannot see by looking at the wind vectors.

PS CAN you transfer a file o a PC? I would have expected Amazon to pre-empt this one. Otherwise we would all do the same and Amazon would finish up with a big bill for the costs and getting no book revenue.

 

[estarzinger]

Do you really need all the data?

While on the data topic - do you see much/any value in the CAPE? Does it correlate strongly with squall intensity/activity? I have never looked at it much (not sure but I don't remember it even being available on saildocs - it is not one of the viewfax/airmail check boxes).

 

[LadyInBed]

Maybe if you want to use Kindle you will have to forego gusts. I have been looking at GRIB apps on my iPad. But none gives gusts.

Yes, Gusts seem to be a parameter that is available when you download the data from within zygrib, as is Wave data, which is downloaded by ticking the boxes in the [FNMOC-WW3 waves] tab of the zygrib download request.

You do seem to have an inordinately large download. Do you really need all the data?

What made it large was that I had the resolution set to 0.5. If I drop it to 1.0 the file is just under a Meg and at 2.0 it is about 240Kb.

Do you need isobars?

They appear (as if my magic) when I reselect 'wind map' under 'Data' even if the source is Saildocs or GMN

PS CAN you transfer a file o a PC? I would have expected Amazon to pre-empt this one. Otherwise we would all do the same and Amazon would finish up with a big bill for the costs and getting no book revenue.

It would appear that you can!
As I understand it from a very helpful man in PC World, a cable is supplied that connects from the power socket to a USB port. It can be used for charging the kimble from the PC and the PC sees the kimble as an external HDU so you can create folders and up/download books, music, photos and PDF's, so on that basis you can transfer any data which would include gribs
PS the 'man in PC World' owned one. He was into car maintenance and had put workshop manuals onto the kimble as both pdf and jpg

 

[estarzinger]

What made it large was that I had the resolution set to 0.5. If I drop it to 1.0 the file is just under a Meg and at 2.0 it is about 240Kb.

Just be aware that when using Iridium (or pactor/HF radio), one usually trys to keep the grib to 20-30kb. So, even 240k sounds huge to those of us who use gribs at offshore (out of cell phone range)!

When at sea, I usually get just wind at 1 degree squares, for every 6 or 12hrs for 5 days (the accuracy is about nill after that), and (obviously depending on the request size) that usually is in the 20-30kb size.

 

[franksingleton]

Yes, Gusts seem to be a parameter that is available when you download the data from within zygrib, as is Wave data, which is downloaded by ticking the boxes in the [FNMOC-WW3 waves] tab of the zygrib download request.
What made it large was that I had the resolution set to 0.5. If I drop it to 1.0 the file is just under a Meg and at 2.0 it is about 240Kb.
They appear (as if my magic) when I reselect 'wind map' under 'Data' even if the source is Saildocs or GMN
It would appear that you can!
As I understand it from a very helpful man in PC World, a cable is supplied that connects from the power socket to a USB port. It can be used for charging the kimble from the PC and the PC sees the kimble as an external HDU so you can create folders and up/download books, music, photos and PDF's, so on that basis you can transfer any data which would include gribs
PS the 'man in PC World' owned one. He was into car maintenance and had put workshop manuals onto the kimble as both pdf and jpg

CAPE is an index of instability. If you choose an area where you know that there is vigorous convection eg the ITCZ, then you will see high values of CAPE. Red colours seem to be the most vigorous. Looking at zyGrib for the Eastern Med just now, there is a yellow area associated with a cold from moving from the Adriatic SE and decreasing with time. I would assume that there is a high chance of thunderstorms with enhanced lightning risks in the areas with the higher CAPE values.

Like you, I have never used CAPE but can see that it might be useful as a lightning avoidance or, at least, warning tool.

I certainly do not download pressure automatically from zyGrib. If I select “Wind” and nothing else, I only get wind. Selecting Data- Wind Map, I get wind vectors and coloured areas of wind strength, effectively isotachs.

With Saildoce a message such as
Send gfs:48N,53N,10W,3E|0.5,0.5|0,24,...,192|

will give me wind and pressure. If I put “wind” at the end it will give me just wind.

The message

Sub gfs:48N,53N,10W,3E|0.5,0.5|0,3,...,24,36...,192|wind days=0

Will give me wind only at 0.5 deg spacing, every 3 hours to T + 24, then every 12 hours thereafter. I will get a message every day until I send a cancel message.

To keep file size down, I am happy to use the 0.5 deg resolution but get just winds, perhaps gusts and, maybe, precipitation. Nothing else. Also, I keep the area fairly small.

You may be correct about interfacing Kindle and a PC. With my iPad, there is also a cable used for linking to the USB port on the computer. This lets the PC see the iPad as a disc drive. However, I can only “see” jpeg files on the iPad in a DCIM folder ie as if on my digital camera. I can see no other Folders on the iPad. I cannot create a folder on the iPad. I cannot copy and paste to the iPad. I can only transfer music and picture files using the iTunes syncing.

Of course, Kindle might be different. Your PCWorld man might (no doubt does) have skills denied to me.

 

[franksingleton]

I found http://www.euronav.co.uk/Weather/gribfiles.htm to be not very good. It omits zyGrib, Sailsocs, MailASail and all iPad/iPhone apps. Dependong on your needs, Weathertrack, Weather4D and iGrib are all worth while thinking about.

Weathertrack at about £7 is the most expensive but the most comprehensive with some "non-Grib" features as well. The most basic and cheapest is iGrib at £3. All are free to use.

Nor do they mention Passageweather as a "non-Grib" source.