I have an '88 with a manual transmission, but it does the same thing. I don't know that it ever climbs that high, but I can keep it down by letting idle a little high (1100 rpms) at lights. I am at some point going to put an axillary fan on it to try to help and I have seen a water pump that is suppose to flow at a higher rate at low RPM's.
Don't know if that helps too much, but I do see the same general thing happen to mine. After a while, you learn what your Jeep needs to stay happy and you don't even think about it