I claim "near-future" to be one word and not too late. I would also change "will be" to "is" to make it even less unplanned.
There is a near-future event at the town hall.
You can even try "soon-to-be" even though it isn't really used that way. Maybe invent "soon-to-be-recent"?
There is a soonish event at the town hall.
"Soon" is a good word for the near-future, but it would require slight rewrite.
"Soonish" is a casual word that should work well as adjective even if it may be seen as as an adverb only.
When you say future is too vague, maybe the actual date can serve your purpose.
There is a Saturday event at the town hall.
I would also recommend "planned" if a date was too specific.
If the event isn't really planned, maybe "pending / impending" is your go.
Plenty of possibilities, depending of what the actual use and style is. I would second the vote for "upcoming" as rather similar to "recent" . It works as a header for a list of events as well as for heads-up in a news-letter or on a poster.
Remember the upcoming/recent event at the town hall!