1Tomorrow, the day after today; used as a noun or adverb. あした is the everyday reading, while あす and みょうにち are more formal or written-language readings.
あした学校に行きます。
I'll go to school tomorrow.
あすの会議は午後3時からです。
Tomorrow's meeting starts at 3 p.m.
みょうにちの天気予報を見てください。
Please check tomorrow's weather forecast.
明日までに宿題を出してください。
Please turn in your homework by tomorrow.
2The near future; used to indicate something that may happen very soon, as in 明日にも〜 ("as early as tomorrow").
その決定は明日にも発表される可能性がある。
The decision may be announced as early as tomorrow.
明日を見据えて計画を立てる。
Make plans with an eye toward the near future.
彼は明日にも来ると言っているが確かではない。
He says he might come as early as tomorrow, but it's not certain.