GBPUSD is forming a short term cycle bottom at 1.6515 level on 4-hour chart. Now the rise from 1.6515 is possibly be resumption of uptrend from 1.5708, a break above 1.6840 key resistance will confirm the cycle bottom and signal another rally towards 1.7042 (Aug 5 high). Support level is at 1.6515, below this level will suggesting that the uptrend from 1.5708 has completed at 1.6841 level already, then the following downtrend could take price back to 1.6300-1.6350 area.
