You can just click on the map on pivotal weather and get the soundings as the maps come out. Same with the College of Dupage models, but for some reason I was having trouble with the NAM soundings. Tropical Tidbits has it too, but not for the NAM (no idea why)
http://www.pivotalweather.com/model.php?m=nam&p=refcmp_ptype&rh=2017120506&fh=78&r=conus&dpdt=