def _outFile_from_url(url, save_dir):
    """
    Define the filename for a grib2 file from its URL.

    Parameters
    ----------
    url : str
        A URL string for a grib2 file we want to download.
    save_dir : dir
        The directory path to save the file.
    """
    if 'pando' in url:
        outFile = '_'.join(url.split('/')[-2:])
    else:
        outFile = url.split('/')[-3][5:] + '_' + url.split('/')[-1]

    outFile = save_dir / outFile

    if not outFile.parent.is_dir():
        outFile.parent.mkdir(parents=True, exist_ok=True)
        print(f'👨🏻‍🏭 Created directory: [{outFile.parent}]')

    return outFile