They tend to remain essentially in the same area for extended periods of time , usually moving in waves .
A stationary front is a non-moving ( or stalled ) boundary between two air masses , neither of which is strong enough to replace the other .
neither tend to remain essentially in the same area for extended periods of time , usually moving in waves .
A stationary front is a non-moving ( or stalled ) boundary between two air masses , neither of which is strong enough to replace the other .