The Weather Forecasting Forum

Hi to all, I'm a young Italian boy and i link very much that software!

I'd want to know where it is possible to find GRIB files in the web and if i can download them with a script. And so: what models can i find wind grib???

thanks a lot!!!

Hello,
I feel at somewhat of a disadvantage here, your command of English is far better than my command of Italian. To answer your question you can find GRIB data at the NOMADS 5 site; http://nomad5.ncep.noaa.gov/ncep_data/
It is available either through ftp or http transfer. Hope this helps.

Cordially,
Carl Sidor

thanks a lot!

can you indicate me as i should download a file from http? an example script (i'm interested to the Y@D@ etc etc!)

Sorry, my skill with scripting is practically non-existant. When I get GRIB data, I do it manually, because I also use the same files for PCGRIDDS32. I think you might have a bit of a problem using a script to get the files, due to the fact that you must specify the run of the model that you wish first, (00,06,12,18 or 24Z) then the specific forecast hours that you wish to examine. For the GFS model, each run has individual forecast hours from 00 out to more than 160 hours. Each forecast hour will consist of about 160-180kb or so depending on which variables you have selected. I'm sure that there is a script that will do the job for you, but I think that you will have to update it each day. Also, the files that you select will be sent to the NOMADS server for you to download via http.
Won't this mean that your script will have to make two separate connections? Maybe someone has a better idea what you will need to do. Sorry I cannot be more helpful.

Carl Sidor

Carl Sidor wrote:Sorry, my skill with scripting is practically non-existant. When I get GRIB data, I do it manually, because I also use the same files for PCGRIDDS32. I think you might have a bit of a problem using a script to get the files, due to the fact that you must specify the run of the model that you wish first, (00,06,12,18 or 24Z) then the specific forecast hours that you wish to examine. For the GFS model, each run has individual forecast hours from 00 out to more than 160 hours. Each forecast hour will consist of about 160-180kb or so depending on which variables you have selected. I'm sure that there is a script that will do the job for you, but I think that you will have to update it each day. Also, the files that you select will be sent to the NOMADS server for you to download via http.
Won't this mean that your script will have to make two separate connections? Maybe someone has a better idea what you will need to do. Sorry I cannot be more helpful.

Carl Sidor

then i must IMPORT the grib file manually all the times?

i take an example:

http://nomad5.ncep.noaa.gov/pub/ens/arc ... s20060328/

there are some files in this folder.

which file can I download to have an interesting plotting?

I haven`t done any grib on DAWS for a long time, but I think you`ll run into problems with DAWS crashing. Most, if not all of the current grib files are probably too large for DAWS to ingest.

Unless I`m wrong?

Well, it depends. I find DAWS can handle anything under, say, 2.5MB. BUT, I've experiemented with GRIB and have not had much luck. It doesn't have much support in DAWS, and half the stuff doesn't work for me. The files are always smoothed so the data isn't too detailed (which isn't the end of the world), but half of the variables don't work for me, and scripting is a nightmare with GRIB. Although technically all you have to change is CUST... but I find it annoying that it gives you temperature in K.

Sirlight87:
You might try going to the ftp part of NOMADS5 and requesting the 00 run of the date (i.e. 2006328 00) then requesting the 00,12,24,36 and 48 forecast hour data. Request all levels and all variables. This should make all the forecast hour files about 160kb each or so. Request that they be sent to the NOMADS server, not the other option. This will give you the option of either ftping the individual files or getting them by http. Then download them to your favorite storage place, and you should be all set. Remember, though, that DAWS will work best if you only import one forecast hour at a time, and look at that. When you have seen everything that you wish, then import another forecast hour and look at that one. When I tried to import more than one hour, DAWS did not display it for me. Good Luck!
Cordially,
Carl Sidor

Just an addendum:
I was relying on memory for the above advice, and I found out my memory needs some help. I went to the NOMADS 5 site, and found that some additional information is necessary. The part of the site I would recommend is the ftp2u side. Select the GFS high resolution model, then the run of the model that you want. Then when you have chosen the forecast hours that you want to look at (i.e. pgribf 24) then go down the page to the GRIB filter. I based my estimate of file size on the fact that I define a subregion to make the download time shorter, as I use a slow dial-up connection. I would recomment that you do likewise, as GRIB files can be quite large and will contain data that you may not need. This will also prevent DAWS from crashing due to too much data. Then proceed as above.
Carl Sidor

FYI guys, Tim said polishing up the GRIB stuff in DAWS is one of the highest priorities on his list. So hopefully the problems will be cleared up soon.

Shannon Vasquez