How much do you weigh? Regardless, a 147 isn't going to be a great powder board, but the rocker helps it float a little.
I wouldn't buy a board for powder just for this trip unless you really think you'll use it at other times as well. Especially since you don't know if there will be massive amounts of powder when you're there.
Worst case scenario, if you board isn't cutting it, you could just rent a nice board for the days that you need something bigger. You can get a pretty good board for about $50 a day which is better than dropping $500ish on a board you may not need.
There are also places to demo boards so you could try that as well.
Im 5'5 and I weigh 175, Ive road in powder before but not massive ammounts of powder. I would like to pick up another board eventually so I have something for powder days but for this trip I think I might take your advice. I could also rent a board from my buddys shop and bring it with me just so I get something a little higher quality. Thanks for your input.