Advice on missing cat
I live in a pretty small apartment. I let my cats out once in a while, if it's daylight they never really leave line of sight from the apartment, while at night they'll disappear sometimes up to an hour or so and come back (at which point I have to lasso them so they don't run off again; it's like they just check in every few minutes). My two cats are from the same litter, and they are about 1 year 3 months old.
Last night I let them out around 11:30 pm, and while one was back around midnight, the other has not come back yet (currently 2:25 pm). I know cats just kind of disappear sometimes, but I'm getting worried because my cats have never been gone for more than an hour before and here she is going on a full day. It's topping about 100 degrees outside, and we're expecting thunderstorms later tonight.
I'm past the point where I was totally freaking out (around 6 or 7 am this morning, after having not gone to sleep at all waiting for her to show up), but I am getting more and more worried. I put some food and sweaty clothes out on my porch to try and attract her. Unfortunately, I just live in this small apartment so I don't really have something like a garage door I can just leave open, so now I'm afraid to leave my house for more than 30 minutes or an hour in case she comes back while I'm gone. If she's not back by tonight I'm going to start posting fliers around the neighborhood.
Frankly, knowing the personalities of the two cats, it doesn't surprise me at all which one came back and which one disappeared (she was always more adventurous), but I'm trying to avoid going into a panic attack. Is it normal for a cat to go from checking in every 20-30 minutes to just disappearing for a day or two at a time?
forgot to add, she is wearing a collar, but it does not have any tags on it.