I was going to have to think about this until seeing that Harvest Moon 64 did indeed come out in 1999. Best game in the series, was such a blast to play, best characters in any Harvest Moon game I've played, it expanded on what made the original great and added so much more, it's a shame that was left off the main tournament, though it probably wouldn't have made it far against more popular games.
On a side note, Natsume needs to announce a Harvest Moon game for Wii U...