The question is:

I use LuckGrib on the Mac. I download both GFS and WW3 files each day, and want to quickly compare the GFS files to each other, and the WW3 files to each other. I would like to switch between the two GFS files, but the WW3 file is there - is it possible to temporarily remove the WW3 files?

This is indeed possible, and quite easy once you have done it a few times.

Try this:

• type: Cmd-F (this is the File->Filter File List… menu item)
• type: tab (this shifts the text input focus to the new search field)
• type: gfs

If you do this, the GRIB file list will only contain those files which match the given search field, “gfs”. Doing this will mean the WW3 files drop out. Now you can step between the files using the up/down arrow keys and jump directly between GFS files.

If you were to instead type “ww3”, the GFS files would drop out and you can step directly between WW3 files.

This search capability is quite powerful when used along with the file comment ability.

For example, consider the situation where you download two GFS files each day, one a small highly detailed look at your local situation and one a large area less detailed look at the whole surrounding area. In this case, you could add a file comment to the GRIB Requests to identify each file you download. To one request add the file comment: large, and to the other request, add the file comment: small.

Given the above situation, when you want to quickly compare the large files to each other, so you can see how the forecast has been changing over time, you can do so with the following steps:

• type: Cmd-F
• type: tab
• type: large

After doing that, you will only see the GRIB files related to the large GRIB request.

Using GRIB file comments, you can easily categorize files and also quickly filter the GRIB list to show only files in that category. A few examples of categories are: a particular trip; a weather event; a vessel name; an area you are interested in; or the type of GRIB file download.