The rally from 1.7729 may be wave i of 3 (or C). Similar to the EURUSD, the GBPUSD is vulnerable to weakness into the 1.7938-1.8068 zone (Fibonacci zone) before strength continues.
As mentioned yesterday, the targets going forward for bulls are at 1.8430 and 1.8878. These are Fibonacci extensions of the 1.7443-1.8133 rally.