How you can trade,
1.Wait and watch for the BOC press conference and sell the breakdown of corrective up trend.
2. Wait and watch for the TCP on lower time frame before the BOC and sell the breakout of that during the BOC rate decision.
In both cases you have to watch for the breakout.
1. Breakout of the 4hr corrective up trend.
2. breakout of the lower time frame trend continuation pattern. like 15 minute.
In case price clearly break up the channel line it will change the then we will analyse it again before any short.
Use reasonable stop loss.