Post-season analysis from the National Hurricane Center finds that Hurricane Zeta strengthened to major hurricane status just before landfall.
After each hurricane season, the National Hurricane Center (NHC) does a detailed review and write-up of each storm that formed. Occasionally, data from this analysis will yield an upgrade or downgrade in strength for a storm.
The 2020 Atlantic hurricane season saw a record breaking 30 named storms, more than the 2005 season when Katrina formed. One of the records from 2005 that remained unchanged was the number of major (category 3+) hurricanes.