OP here... thanks for the votes of confidence. I am not only sick because he's gone, but my kids get home at 3 today and will burst into tears again if he's not found by then.
I've read the sites for indoor only cats who've escaped and don't know exactly what his behavior would have been. He is very friendly and more like a dog than a cat, always bolts out the door if given half a chance. That kind of cat is supposed to have a further distance possibility from the house, but also more likely to be "found" because he will approach people.
On the other hand, it was dark, cold, and wet when he got out and now it's been over 12 hours and he's cold,wet, scared and hungry. Maybe he's hunkered down tight and low. I've looked EVERYWHERE for blocks since 8 am this morning. I can't go in backyards but I've peered over fences and into every bush I can reach. Way more than 5 houses over too!
I posted on the server, the .net website, a neighbor sighted him probably 15 mins after he got out and broke my heart... he was pacing up and down the sidewalk looking for his door back home. We live in a townhouse on a narrow street.
I'm just sick and keep hoping someone will find him and call. I can't sit for more than 20 mins without going back out looking and calling for him.