Definitely adult skis. at 140-145 you're definitely too heavy for any sort of junior ski, at least if you want any kind of decent performance (which you will if you're racing).
Depending how serious your racing is, you probably want to ask your coach for a recommendation (he/she may be able to help you try some demos too). Unless you're a pretty strong racer (in which case again I would go with your coach's advice rather than what you find here), you may not want the top of the line retail race ski, but it depends on your abilities. For Atomic, something like the GS/SL:9 or the LT/ST:12 would probably be better than the GS/SL:12.
You might also want to check out Rossignol, they make some really high performance skis that seem to work really well for younger and lighter racers.