It seems like NPS could have re-opened Tioga after the storms that dropped 1" at Mammoth on 11/20 and 11/21, but it's easier/much less work to just keep it closed. Mammoth reported 25" on 11/27 which definitely was enough to close Tioga for good. Note that they report snowfall for previous 24 hours sometime in the morning, probably around 6 AM.
Am I the only one who noticed that 2019 Spring/Summer opening date at https://www.nps.gov/yose/planyourvisit/seasonal.htm now says Jul 1 and "Tioga Road opened on June 21 with access to entry only from 10 am to 11 am and 3 pm to 4 pm daily. It opened without restriction on July 1."