I would guess a lot of schools have already decided to cancel tomorrow and are putting it out on their website and telling the kids, they just have not told the local news yet or the local news has not updated the info.I was just talking to my wife about why they hadn't yet. There's no chance it's now snowing buckets in central Iowa during the time buses would be transporting to school, and likely worse when they'd be leaving. Just let people get their ducks in a row with some advance notice.
Schools are trying to be proactive and getting out in the front, because they know about the pain it is for many to get childcare. I know the school I retired from has already posted it on their website, I am sure many will be doing so in the next few hours.