Only with reading ナウ
Describes something fashionable or current. Often used in a slightly retro or playful way, reminiscent of 1980s–90s slang.
from English
その服、ちょっとナウいね。
That outfit is a bit trendy, isn't it.
currently at ...; now doing ...; in the middle of ...
Internet slang suffix attached to a place or activity to indicate one's current status, especially in social media updates. Usually written in hiragana.
In Shibuya right now.
ナウな情報をチェックしよう。
Let's check out the latest info.
Studying now.
This is trendy fashion.
Working right now.
古い means old-fashioned or outdated, the opposite of ナウ's sense of being current and trendy.
ナウキャスト is a specialized meteorological term for short-term weather forecasting, not related to ナウ's meaning of 'trendy' or 'currently doing'.
nowcast; very short-term forecast
From English 'now'. The trendy sense emerged in Japanese slang around the 1980s; the internet slang suffix developed later from the same English word.