The phrase "See you in a few hours" is correct and usable in written English. You could use this phrase when writing to someone that you will meet up with later that day. For example, you could write, "I'll meet you at the park at 4pm. See you in a few hours!".
As they pulled away, she called out, "See you in a few hours!" and blew a kiss.
See you in a few hours.
"I'll see you in a few hours, my fruitcake," said Santa.
See you again in a few hours.
See you guys in a few hours.
Thanks Mr. Pink for the private jet see you all in a few hours in LA @drinkmrpink @sheerazhasan.
We're looking forward to seeing you there in a few hours.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.