Ugh, nerd sniped again. So I downloaded zygrib and xygrib, but they gagged on the NBM grib files. LuckGrib was able to ingest and show them in a pretty slick UI, but only showed me visibility, not ceiling. NOAA's Weather and Climate Toolkit, along with grib_filter, was able to ingest the ceiling and visibility data. degrib can also ingest it and convert it to kml. So, it can be done...