In this situation, are you obliged to stop the vehicle and yield priority to the driver of the car travelling on the transverse road?

In this situation, the traffic signals are in operation and take precedence over road signs, including the visible STOP sign. The amber signal requires you to stop before the traffic signal, but it does not impose an obligation to give way to vehicles from the intersecting road, which at this moment also do not have a signal permitting them to enter the junction.